The present invention relates to a combustible gas reforming method and a combustible gas reforming apparatus for reforming a combustible gas produced by a gasification apparatus which gasifies combustible materials such as coal, biomass, municipal wastes, industrial wastes, RDF (refuse-derived fuel) and waste plastics, and a gasification apparatus.

A gasification and slagging combustion furnace which has been developed as a technology for incinerating wastes or the like converts wastes into a combustible gas in a gasification apparatus and immediately combusts the combustible gas, thereby achieving high-temperature combustion. The high-temperature combustion is advantageous in that ash is reduced in volume and made harmless by being melted, and the combustion efficiency is improved (unburned combustibles in the incineration ash are reduced and the amount of exhaust gas is reduced due to low-temperature air ratio operation). However, the high-temperature combustion is problematic from the standpoint of energy utilization in that there is a limit to efficiency because all the energy is converted into heat as with a conventional incinerating furnace, and energy which is conservable cannot be produced.

In view of the above drawbacks, there has recently been developed a technology for utilizing a gas generated by a gasification apparatus (hereinafter referred to as "generated gas") as a "gas" to the utmost, rather than combusting the gas. The produced gas (hereinafter referred to as "product gas") is used as a fuel for a gas turbine, a gas engine, and an electric generating apparatus such as a fuel cell, or as a material for synthesizing a liquid fuel.

A cogeneration system which combines the generation of electricity by utilizing a product gas and the generation of electricity by heat recovery improves the energy utilization efficiency, and is being developed not only in the field of wastes, but also in the field of thermal power generation as a highly efficient coal fired power generation technology. The technology of utilizing a product gas as a material for synthesizing a liquid fuel will contribute to energy security in the future because conservable energy can be produced from energy resources which have heretofore been thrown away.

The technology for extracting a generated gas as a product gas was present in the past. However, since a gas produced by gasifying combustible materials in a low temperature range was used as it was at that time, the handling of a tar (macromolecular hydrocarbon: deposited at 400°C or lower and causing fouling trouble) and a char (which is combusted when being in contact with oxygen at high temperatures because it contains fixed carbon) posed problems, which have been responsible for preventing the technology from finding practical use.

According to the present gas utilization technology, in order to avoid the above tar problem, a high-temperature gasification apparatus (operable at a temperature of 1000°C or higher) is provided at a subsequent stage of a low-temperature gasification apparatus (operable at a temperature of 500°C to 900°C), and a generated gas produced by the low-temperature gasification apparatus is reformed with an oxidizing agent (oxygen, steam) in the high-temperature gasification apparatus. Since this process is a two-stage (low temperature + high temperature) gasification process, part of the generated gas produced by the low-temperature gasification apparatus in the first stage is combusted. While the above tar problem can be solved by the process, the energy utilization efficiency is lowered because part of the generated gas is converted into thermal energy.

Use of a catalyst has been considered to solve the above tar problem. The purpose of using a catalyst is to suppress an energy loss that is caused at high temperatures by promoting a decomposition reaction with the catalyst in such a temperature range in which the tar would normally be less liable to be decomposed.

FIG. 1 of the accompanying drawings is a diagram showing a construction of a gas reforming apparatus for carrying out a conventional combustible gas reforming method which uses a catalyst. In FIG. 1, reference numeral 301 represents a gasification apparatus which gasifies a raw material A such as coal, biomass, municipal wastes, industrial wastes, RDF, waste plastics, etc. A generated gas G_A produced by the gasification apparatus 301 is reformed (tar decomposition) into a product gas G_B by a gas reforming apparatus 302 which uses a catalyst C_A. The catalyst C_A which has contributed to the reformation of the generated gas G_A is turned into a degraded catalyst C_A', which is delivered to a catalyst regenerating apparatus 303. In the catalyst regenerating apparatus 303, the degraded catalyst C_A' is heated or regenerated by catalyst regenerating heat T_E caused by external energy or combustion of part of the generated gas. The heated or regenerated catalyst C_A is transferred again to the gas reforming apparatus 302.

As described above, the catalyst regenerating heat T_E is required for the catalyst regenerating apparatus 303 to heat or regenerate the catalyst. Heretofore, the catalyst regenerating heat T_E has been produced by combustion of part of the generated gas G_A or external energy such as fossil fuel, electricity, etc. Even if the gas reforming can be performed at a low temperature by using a catalyst to reduce thermal energy loss, energy of high quality is utilized likewise for heating or regenerating the catalyst, and hence the advantages of low-temperature reaction cannot be sufficiently utilized. Therefore, even though the gas reforming process is highly efficient, since the overall amount of consumed energy is increased, the running cost is increased, resulting in a reduction in the evaluation according to LCA. As the process becomes higher in efficiency, the evaluation according to LCA or exergy (the quality of energy), rather than a simple thermal efficiency, becomes important.

In the case where the gas reforming is performed using the catalyst, the supply of heat in the temperature range of 1000°C or less is sufficient differently from the reforming by the high-temperature gasification apparatus, and hence external energy having high quality as energy or combustion of the generated gas is not always necessary. Thus, it is necessary to construct a catalyst reforming process on the basis of the fact that heat required for heating or regenerating the catalyst can be supplied through a heat transfer surface or a medium.

The present invention has been made in view of the above problems. It is therefore an object of the present invention to provide a combustible gas reforming method and a combustible gas reforming apparatus which improve energy utilization efficiency for catalyst regeneration in reforming a gas with a catalyst and facilitate handling of the catalyst in a process for gasifying combustible materials including coal, biomass, municipal wastes, industrial wastes, RDF, waste plastics, etc. with a gasification apparatus and reforming the generated gas into a product gas. That is, it is an object of the present invention to provide a gasification furnace which can suppress generation of tar to a minimum to stably produce a generated gas having an excellent property, and can produce a generated gas capable of being utilized for the recovery of power at high efficiency, power generation, various liquid fuel synthesis processes, and various chemical material synthesis processes.

Another object of the present invention is to provide a combustible gas reforming method and a combustible gas reforming apparatus which improve the energy utilization efficiency in catalyst regeneration and gas reforming, and facilitate handling of the catalyst.

In order to achieve the above objects, according to the invention defined in claim 1, there is provided a combustible gas reforming method comprising: gasifying combustibles in a gasification apparatus; reforming a generated gas produced by gasification in a gas reforming apparatus using a catalyst to produce a product gas; and regenerating the catalyst degraded in the gas reforming apparatus in a catalyst regenerating apparatus; wherein waste heat of the combustible gas reforming process is used as a heat source for regenerating the catalyst in the catalyst regenerating apparatus and/or a heat source for heating.

According to the invention defined in claim 2, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; wherein the catalyst regenerating apparatus uses waste heat of the combustible gas reforming process as a heat source for regenerating the catalyst.

As described above, the waste heat of the combustible gas reforming process is utilized as the heat source required for catalyst regenerating heat in the catalyst regenerating apparatus and gas reforming reaction in the gas reforming apparatus, or the catalyst regenerating apparatus which uses the waste heat of the combustible gas reforming process is used. Therefore, a heat source having a low value such as the sensible heat of exhaust gas that is generated in a gasification process of a raw material can be used as the heat source for regenerating the catalyst or the heat source for gas reforming. Thus, since any external energy or the heat of combustion of the generated gas may be reduced or eliminated, the yield of the generated gas can be increased. As a result, the overall efficiency can be increased. The overall amount of consumed energy is thus reduced, the running cost is low, and an LCA evaluation is high.

According to the invention defined in claim 3, there is provided a combustible gas reforming method comprising: gasifying combustibles in a gasification apparatus; reforming a generated gas produced by gasification in a gas reforming apparatus using a catalyst to produce a product gas; and regenerating the catalyst degraded in the gas reforming apparatus in a catalyst regenerating apparatus; wherein char (unburned carbon) produced by gasifying the combustibles in the gasification apparatus is combusted in a char combustion apparatus, and the heat of combustion of the char is used as a heat source for regenerating the catalyst in the catalyst regenerating apparatus and/or a heat source for heating.

According to the invention defined in claim 4, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; wherein a char combustion apparatus is provided for combusting char (unburned carbon) produced by gasifying the combustibles in the gasification apparatus, and the catalyst regenerating apparatus uses the heat of combustion of the char generated in the char combustion apparatus for heating and regenerating the catalyst.

As described above, the char produced by gasifying the combustibles in the gasification apparatus is combusted in the char combustion apparatus, and the heat of combustion of the char is used as the heat source required for the catalyst regenerating heat or the gas reforming reaction in the gas reforming apparatus. Because any external energy or the heat of combustion of the generated gas may be reduced or eliminated, the yield of the generated gas can be increased. As a result, the overall efficiency can be increased. Specifically, the catalyst can be regenerated without combusting part of the product gas or without using external energy. Since the heat of combustion of the char, which is higher in temperature than the waste heat of the combustible gas reforming process, is used, the efficiency of heating and regenerating the catalyst is increased. Therefore, the overall amount of consumed energy is reduced, the running cost is low, and an LCA evaluation is high.

According to the invention defined in claim 5, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; wherein the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed, the gasification chamber being constructed to gasify the combustibles to produce a generated gas and the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles; and wherein the generated gas produced in the gasification chamber is delivered to the gas reforming apparatus and reformed in the gas reforming apparatus, and a combustion exhaust gas from the combustion chamber is delivered to the catalyst regenerating apparatus to heat and regenerate the catalyst with the heat of the combustion exhaust gas.

As described above, the gasification chamber and the combustion chamber each having a fluidized bed are integrated into a furnace. In addition to the effect of the invention of claim 4, the gasification apparatus has a function to gasify a raw material and a function to combust char. Since char generated in the same apparatus is combusted, any trouble caused by the delivery of the char is avoided. Since the raw material is gasified in the fluidized bed and the char is combusted in the fluidized bed, the diffusion of heat is excellent, and stable operation can be performed.

According to the invention defined in claim 6, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; wherein the gasification apparatus comprises a gasification apparatus having a fluidized bed which uses catalyst particles as at least part of a bed material, and a char combustion apparatus is provided for combusting char (unburned carbon) produced by gasifying the combustibles in the gasification apparatus; and wherein at the same time that the combustibles are gasified to produce a generated gas in the gasification apparatus, the generated gas is reformed by the catalyst particles, and the catalyst particles degraded by reforming the generated gas are delivered to the char combustion apparatus, and heated and regenerated in the char combustion apparatus, and the regenerated catalyst particles are returned to the gasification apparatus.

As described above, the gasification apparatus comprises a gasification apparatus having a fluidized bed which uses catalyst particles as at least part of a bed material, and at the same time that the combustibles are gasified to produce the generated gas in the gasification apparatus, the generated gas is reformed (tar decomposition) by bringing the generated gas and the catalyst particles as a bed material into contact with each other. Therefore, the generated gas is reformed efficiently, and catalyst particles that function as a desulfurizing agent and a dechlorinating agent can be used, and the generated gas can be desulfurized and dechlorinated. In addition to the effect of claims 3 and 4, gasification of the raw material and reforming of the gas, and combustion of the char and regeneration of the catalyst can be performed in one apparatus. Consequently, a catalyst regenerating apparatus can be eliminated, and the initial cost of the apparatus can be reduced.

According to the invention defined in claim 7, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; wherein the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed which uses catalyst particles as at least part of a bed material, the gasification chamber being constructed to gasify the combustibles to produce a generated gas and the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles; and wherein at the same time that the combustibles are gasified to produce a generated gas in the gasification chamber, the generated gas is reformed by the catalyst particles, and the catalyst particles degraded by reforming the generated gas are delivered to the combustion chamber, and heated and regenerated in the combustion chamber, and the regenerated catalyst particles are returned to the gasification chamber.

As described above, the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed which uses catalyst particles as at least part of a bed material, and at the same time that the combustibles are gasified into the generated gas in the gasification chamber, the generated gas is reformed by the catalyst particles, and the degraded catalyst particles are delivered to the combustion chamber, and heated and regenerated in the combustion chamber. Consequently, in addition to the effect of the invention of claim 6, the problem of handling of particles including char from the gasification chamber to the combustion chamber can be solved, and the heat efficiency is improved.

According to the invention defined in claim 8, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; and a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; wherein the gas reforming apparatus comprises a dust collecting and catalytic reaction apparatus having a dust collecting function to remove dust contained in the generated gas and a gas reforming function to reform the generated gas with the catalyst.

As described above, inasmuch as the dust collecting and catalytic reaction apparatus having a dust collecting function and a gas reforming function performs dust collecting of the generated gas from the gasification apparatus before the generated gas is reformed (tar decomposition) by the catalyst, the catalyst is prevented from being degraded and from being mixed with a dust. Further, separation of the catalyst is eliminated. In addition, the catalytic reaction apparatus may be of such a type as a reactor having a fixed bed which may possibly be clogged and may not be used in the presence of dust. Furthermore, the arrangement is suitable for preventing the catalyst, which decomposes tar at a low temperature, from being degraded or contaminated.

According to the invention defined in claim 9, there is provided a combustible gas reforming apparatus according to claim 8, wherein a char combustion apparatus and a catalyst regenerating apparatus are provided; and wherein the catalyst degraded by reforming the generated gas in the dust collecting and catalytic reaction apparatus is delivered to the catalyst regenerating apparatus, char (unburned carbon) produced when the combustibles are gasified to produce the generated gas by the gasification apparatus is delivered to the char combustion apparatus and combusted in the char combustion apparatus, and a combustion exhaust gas from the char combustion apparatus is delivered to the catalyst regenerating apparatus to heat and regenerate the catalyst.

As described above, since the catalyst degraded by reforming the generated gas is heated and regenerated by the catalyst regenerating apparatus with the heat of the combustion exhaust gas from the char combustion apparatus, in addition to the effect of the invention of claim 8, the catalyst can efficiently be regenerated and heated by the high-temperature heat of combustion of the char without using external energy or combusting part of the generated gas. It is thus possible to increase the yield of the generated gas. The overall amount of consumed energy is reduced, the running cost is low, and an LCA evaluation is high.

According to the invention defined in claim 10, there is provided a combustible gas reforming apparatus according to claim 8, wherein the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed, the gasification chamber being constructed to gasify the combustibles to produce a generated gas and the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles; and wherein a catalyst regenerating apparatus is further provided, the catalyst degraded by reforming the generated gas in the dust collecting and catalytic reaction apparatus is delivered to the catalyst regenerating apparatus, and a combustion exhaust gas from the combustion chamber is delivered to the catalyst regenerating apparatus to heat and regenerate the catalyst.

As described above, since the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed, and the catalyst degraded by reforming the generated gas is heated and regenerated by the catalyst regenerating apparatus with the combustion exhaust gas from the combustion chamber, in addition to the effect of the invention of claim 9, the problem of handling of particles including char from the gasification chamber to the combustion chamber can be solved, a heat loss due to a heat radiation is reduced, and the heat efficiency is improved.

According to the invention defined in claim 11, there is provided a combustible gas reforming apparatus according to claim 8, wherein the gasification apparatus comprises a gasification chamber, a combustion chamber, and a dust collecting and catalyst reaction chamber each having a fluidized bed, the gasification chamber being constructed to gasify the combustibles to produce a generated gas, the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles, and the dust collecting and catalyst reaction chamber being constructed to reform the generated gas from the gasification chamber; and wherein a catalyst regenerating apparatus is further provided, the catalyst degraded by reforming the generated gas in the dust collecting and catalyst reaction chamber is delivered to the catalyst regenerating apparatus, a combustion exhaust gas from the combustion chamber is delivered to the catalyst regenerating apparatus to heat and regenerate the catalyst, and the heated and regenerated catalyst is returned to the dust collecting and catalyst reaction chamber.

As described above, since the gasification apparatus comprises a gasification chamber, a combustion chamber, and a dust collecting and catalyst reaction chamber each having a fluidized bed, in addition to the effect of the invention of claim 10, the problem of handling of particles including char from the dust collecting and catalyst reaction chamber to the combustion chamber can be solved, and the heat efficiency is improved. Because the dust collecting and catalyst reaction chamber is integrally combined with the gasification apparatus, the initial cost of the apparatus is lowered.

According to the invention defined in claim 12, there is provided a combustible gas reforming apparatus according to claim 8, wherein the gasification apparatus comprises a fluidized-bed furnace having a gasification chamber, a combustion chamber, and a dust collecting and catalyst reaction chamber, the gasification chamber being constructed to gasify the combustibles to produce a generated gas, the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles, and the dust collecting and catalyst reaction chamber being constructed to reform the generated gas from the gasification chamber; and wherein the catalyst degraded by reforming the generated gas in the dust collecting and catalyst reaction chamber is delivered to the combustion chamber, heated and regenerated in the combustion chamber, and then the regenerated catalyst is returned to the dust collecting and catalyst reaction chamber.

As described above, since the catalyst degraded by reforming the generated gas in the dust collecting and catalyst reaction chamber is delivered to the combustion chamber, heated and regenerated in the combustion chamber, and then the regenerated catalyst is returned to the dust collecting and catalyst reaction chamber, in addition to the effect of the invention of claim 11, a catalyst regenerating apparatus can be eliminated. Therefore, the heat efficiency is improved and the initial cost of the apparatus is lowered.

According to the invention defined in claim 13, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; a catalytic reaction apparatus comprising the gas reforming apparatus and the catalyst regenerating apparatus, and a char combustion apparatus for combusting char (unburned carbon) produced by gasifying the combustibles in the gasification apparatus are provided; wherein the catalytic reaction apparatus is constructed to integrate a gas reforming chamber for reforming the generated gas using catalyst particles and a catalyst regeneration chamber for regenerating the catalyst, the catalyst regeneration chamber being constructed to heat and regenerate the catalyst degraded by reforming the generated gas in the gas reforming chamber, and return the regenerated catalyst to the gas reforming chamber; and wherein the generated gas from the gasification apparatus is delivered to the gas reforming chamber and reformed to produce a product gas, and a combustion exhaust gas from the char combustion apparatus is delivered to the catalyst regenerating apparatus to heat and regenerate the catalyst with the heat of the combustion exhaust gas.

As described above, since the gas reforming apparatus and the catalyst regenerating apparatus comprise a catalytic reaction apparatus which comprises an integral combination of a gas reforming chamber for reforming the generated gas with catalyst particles and a catalyst regeneration chamber for regenerating the catalyst, the generated gas can efficiently be reformed by fluidization of catalyst particles, and catalyst particles degraded by reforming the generated gas can efficiently be heated and regenerated. A heat loss due to a heat radiation is reduced, and the heat efficiency is improved. In addition, the initial cost of the apparatus is lowered. Therefore, the overall amount of consumed energy is reduced, the running cost is low, and an LCA evaluation is high.

According to the invention defined in claim 14, there is provided a combustible gas reforming apparatus according to claim 13, wherein the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed, the gasification chamber being constructed to gasify the combustibles to produce a generated gas and the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles; and wherein the generated gas produced in the gasification chamber is delivered to the gas reforming chamber and reformed in the gas reforming chamber, and a combustion exhaust gas from the combustion chamber is delivered to the catalyst regeneration chamber to heat and regenerate the catalyst with the heat of the combustion exhaust gas.

As described above, because the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed, in addition to the effect of the invention of claim 13, the problem of handling of particles including char from the gasification chamber to the combustion chamber can be solved, and the heat efficiency is improved.

According to the invention defined in claim 15, there is provided a combustible gas reforming apparatus comprising: a gasification apparatus for gasifying combustibles; a gas reforming apparatus for reforming a generated gas produced in the gasification apparatus using a catalyst to produce a product gas; and a catalyst regenerating apparatus for regenerating the catalyst degraded in the gas reforming apparatus; wherein the gasification apparatus comprises a gasification chamber and a combustion chamber each having a fluidized bed, the gasification chamber being constructed to gasify the combustibles to produce a generated gas and the combustion chamber being constructed to combust char (unburned carbon) produced by gasifying the combustibles; wherein the gas reforming apparatus and the catalyst regenerating apparatus have a gas reforming chamber and a catalyst regeneration chamber each having a fluidized bed which uses catalyst particles as at least part of a bed material, the catalyst regeneration chamber being constructed to heat and regenerate the catalyst degraded by gas reforming in the gas reforming chamber, and return the regenerated catalyst to the gas reforming chamber; wherein the gasification chamber, the combustion chamber, the gas reforming chamber, and the catalyst regeneration chamber are integrated into a single furnace, the generated gas from the gasification apparatus is delivered to the gas reforming chamber and reformed to produce a product gas in the gas reforming chamber, and a combustion exhaust gas from the combustion chamber is delivered to the catalyst regeneration chamber to heat and regenerate the catalyst with the heat of the combustion exhaust gas.

As described above, because the gasification chamber, the combustion chamber, the gas reforming chamber, and the catalyst regeneration chamber are combined into a single furnace, in addition to the effect of the invention of claim 14, the heat efficiency is further improved. Further, the initial cost of the apparatus is further lowered.

According to the invention defined in claim 16, there is provided a combustible gas reforming method according to claim 1 or 3, wherein the catalyst regenerating apparatus is supplied with a gas containing one or more of oxygen, steam, and hydrogen as a regenerating gas, and heat of reaction produced when the catalyst is regenerated is used together with process waste heat to heat and regenerate the catalyst particles.

According to the invention defined in claim 17, there is provided a combustible gas reforming apparatus according to any one of claims 2, 4, and 5 through 15, wherein the catalyst regenerating apparatus is supplied with a gas containing one or more of oxygen, steam, and hydrogen as a regenerating gas, and heat of reaction produced when the catalyst is regenerated is used together with process waste heat to heat and regenerate the catalyst particles.

According to the inventions defined in claims 16 and 17, a gas containing one or more of oxygen, steam, and hydrogen is supplied as a regenerating gas for regenerating the catalyst, and heat of reaction generated when the catalyst is regenerated and process waste heat are used to heat and regenerate catalyst particles. Since a shortage of the process waste heat can be supplemented with the heat of reaction, the yield of the generated gas can further be improved.

According to the invention defined in claim 18, there is provided a combustible gas reforming apparatus according to any one of claims 2, 4, and 5 through 17, wherein the gasification apparatus is charged with an absorbent for absorbing chlorine compounds or sulfur compounds when the raw material is gasified.

As described above, since the gasification apparatus is charged with an absorbent for absorbing chlorine compounds or sulfur compounds, the chlorine compounds and the sulfur compounds can be reduced, and harm to the catalyst is reduced. Since the service life of the catalyst is increased, the running cost of the apparatus is lowered.

• FIG. 1 is a view showing a system construction of an apparatus for carrying out a conventional combustible gasification method which uses a catalyst;
• FIG. 2 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 3 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 4 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 5 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 6 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 7 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 8 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 9 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 10 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 11 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 12 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 13 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 14 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 15 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 16 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 17 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 18 is a view showing an example of a construction of a dust collecting and catalytic reaction apparatus for use in an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 19 is a view showing an example of a construction of a dust collecting and catalytic reaction apparatus for use in an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 20 is a view showing an example of a construction of a dust collecting and catalytic reaction apparatus for use in an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 21 is a view showing an example of a construction of a dust collecting and catalytic reaction apparatus for use in an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 22 is a view showing an example of a construction of a dust collecting and catalytic reaction apparatus for use in an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 23 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 24 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 25 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 26 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 27 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 28 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 29 is a view showing a construction of a furnace section of the apparatus shown in FIG. 28;
• FIG. 30 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 31 is a view showing a construction of a furnace section of the apparatus shown in FIG. 30;
• FIG. 32 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 33 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 34 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention;
• FIG. 35 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 36 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 37 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 38 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 39 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 40 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 41 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 42 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 43 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 44 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 45 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 46 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 47 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 48 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 49 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 50 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 51 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 52 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 53 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 54 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 55 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 56 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 57 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 58 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 59 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 60 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 61 is a view showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIGS. 62A and 62B are views showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIGS. 63A through 63C are views showing an example of a construction of a catalyst regenerating and gas reforming apparatus according to the present invention;
• FIG. 64 is a view showing an example of a construction of a gasification apparatus according to the present invention;
• FIG. 65 is a view showing an example of a construction of a gasification apparatus according to the present invention;
• FIG. 66 is a view showing an example of a construction of a gasification apparatus according to the present invention;
• FIG. 67 is a view showing an example of a construction of a gasification apparatus according to the present invention;
• FIG. 68 is a view showing an example of a construction of a cracking apparatus for use in a gasification apparatus according to the present invention;
• FIG. 69 is a view showing an example of a construction of a gasification apparatus according to the present invention; and
• FIG. 70 is a view showing an example of a construction of a gasification apparatus according to the present invention.

Embodiments of the present invention will be described below. Reactions (tar decomposition) in a combustible gas reforming apparatus include the following reactions by representing tar component with C_nH_m:

• 1○ Cracking: CnHmOk + catalyst → CpHq + H₂ + C (deposited carbon) + CO
• 2○ Steam reforming: CnHmOk + H₂O + catalyst → CO + H₂
• 3○ Carbon dioxide reforming: CnHmOk + CO₂ + catalyst → CO + H₂

In the cracking (pyrolysis reaction), pyrolysis occurs on the catalyst, decomposing the tar into low molecular hydrocarbon and carbon monoxide. At the same time, carbon is deposited on the surface of the catalyst. The deposited carbon is one of the causes of deterioration of the catalyst (If the carbon covers the catalyst, then the catalyst is inactivated. The carbon deposited on the catalyst needs to be combusted away in a high-temperature oxidizing atmosphere with a regenerating apparatus). The above reaction is referred to as "cracking". Industrially, this reaction is equivalent to a reaction for lightening macromolecular hydrocarbons such as normal-pressure residual oil, similar to a tar, in a petroleum refining process. Catalysts for promoting the cracking, such as silica alumina, zeolite, or activated clay are known and in general use.

In the steam reforming and the carbon dioxide reforming, the tar reacts with steam (H₂O) and carbon dioxide (CO₂), and is reformed into CO and H₂. The reactions between hydrocarbon and H₂O and CO₂ in the presence of a catalyst are equivalent to a process of manufacturing hydrogen from a natural gas and, in recent years, a process of manufacturing a synthesis gas from macromolecular hydrocarbons such as naphtha, kerosene, etc. Catalysts for promoting the reforming, such as an Ni-based catalyst, etc. are known and in general use.

The above reactions of the cracking, the steam reforming, and the carbon dioxide reforming can be promoted at a low temperature by using catalysts. These catalysts contribute to any of the above reactions of the cracking, the steam reforming, and the carbon dioxide reforming. For the cracking reaction, however, typical metals (Al, Si, Ca, Mg) and their oxides, or their mixtures should preferably be used as catalysts. Specifically, these catalysts include zeolite (hydrated aluminosilicate), silica alumina (SiO₂-Al₂O₃), activated alumina (Al₂O₃), activated clay (SiO₂-Al₂O₃), dolomite (CaO, MgO), limestone (CaCO₃), calcium oxide (CaO), etc. Among these materials, the materials which have pores that have diameters of about 10 to 150 angstroms and allow the tar to be diffused in catalyst particles are preferred, and the materials having an excellent ability to adsorb macromolecular hydrocarbons are preferred.

In order to promote the reactions of the steam reforming and the carbon dioxide reforming, it is preferable to use catalysts (e.g., Ni/Al₂O₃, Ni/CaO·Al₂O₃, Ru/MgO·Al₂O₃) which comprise at least one of metals (Rh, Ru, Ni, Pd, Pt, Co, Mo, Ir, Re, Fe, Na, K) or oxides of these metals diffused in and carried on the surface of the above catalysts used as a carrier.

Of the above catalysts, some are highly active with respect to the reaction of the cracking and some are highly active with respect to the reactions of the steam reforming and the carbon dioxide reforming. By selecting those catalysts suitably, it is possible not only to decompose the tar, but also to change the composition of the reformed gas to adjust the composition of the product gas after gas reforming. If a catalyst that is highly active with respect to the reaction of the cracking is used, then a gas containing a large amount of hydrocarbon such as methane (CH₄) or ethylene (C₂H₂) can be produced. In the reactions of the steam reforming and the carbon dioxide reforming, a mixed gas of H₂ and CO is produced. In the reaction of the steam reforming, an H₂-rich gas is produced. In the reaction of the carbon dioxide reforming, a CO-rich gas is produced. Therefore, by changing the partial pressures of the reforming gas, it is possible to change the ratio of H₂/CO in the product gas.

FIG. 2 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. In FIG. 2, reference numeral 11 represents a gasification apparatus. A raw material A such as coal, biomass, municipal wastes, industrial wastes, RDF, waste plastics, etc. is charged into the gasification apparatus 11, and the raw material A is gasified into a generated gas G_A. In a gas reforming apparatus 12 which uses a catalyst (catalyst particles) C_A, a tar in the generated gas G_A is decomposed to reform the generated gas G_A, producing a product gas G_B. The catalyst C_A which has contributed to the reformation of the generated gas G_A in the gas reforming apparatus 12 is turned into a degraded catalyst C_A', which is delivered to a catalyst regenerating apparatus 13. In the catalyst regenerating apparatus 13, the degraded catalyst C_A' is regenerated by process waste heat T_P generated in the gasification process. The regenerated catalyst C_A is transferred again to the gas reforming apparatus 12. A temperature optimum for reforming the gas with the catalyst C_A is in the range of 800°C to 1100°C (preferably 900°C).

Since the process waste heat T_P is used to regenerate the degraded catalyst C_A' in the catalyst regenerating apparatus 13, the consumption of external energy is suppressed, and the effective heat utilization rate is improved. A reduction in the running cost due to a reduction in the consumption of external energy is achieved, and the evaluation according to LCA is improved.

The above advantages are obtained when the process waste heat T_P is used to regenerate the catalyst in the catalyst regenerating apparatus 13. The heat required to regenerate the catalyst C_A is often large in quantity and high at temperature. Most of the heat generated in the process is used to recover steam and preheat the gas to be charged, and hence excess waste heat is low-temperature (low-temperature-level) waste heat which is difficult to be used. If part of the high-temperature heat is used to regenerate the catalyst, then the amount of heat required to recover steam and preheat the gas to be charged becomes insufficient, resulting in a need for an auxiliary fuel. Therefore, the consumption of external energy may be increased. A temperature optimum for regenerating the catalyst C_A is in the range from 950°C to 1100°C (preferably from 950°C to 1000°C).

For example, the catalyst is generally regenerated at a temperature considerably higher than the reaction temperature for acting as the catalyst. In order to make the gas reformed by the catalyst C_A higher than the catalyst reaction temperature, part of the product gas G_B has to be combusted or an auxiliary fuel has to be used. If part of the product gas G_B is combusted, then the advantages of the catalyst utilization method that a low-temperature gas reforming can be performed, in comparison with a gas reforming involving a high-temperature process, are lost.

FIG. 3 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. Those parts shown in FIG. 3 which are identical or correspond to those shown in FIG. 2 are denoted by identical reference characters. Those parts shown in other figures which are identical or correspond to those shown in FIG. 2 are also denoted by identical reference characters. The apparatus shown in FIG. 3 is constructed to solve the problems which are caused by using the process waste heat T_P as the catalyst regenerating heat. The apparatus includes a char combustion apparatus 14 for combusting a char (unburned carbon) C_X which is produced when the raw material A is gasified in the gasification apparatus 11 of the apparatus shown in FIG. 2. The char combustion apparatus 14 supplies the heat of a combustion exhaust gas G_C which is generated by combustion of the char, as the catalyst regenerating heat, to the catalyst regenerating apparatus 13.

When the catalyst C_A in the gas reforming apparatus 12 reforms the generated gas G_A (tar decomposition) from the gasification apparatus 11, the catalytic function is degraded due to the deposition of carbonous material, etc. The catalyst regenerating apparatus 13 heats and regenerates the catalyst C_A' having degraded catalytic function by the combustion exhaust gas G_C supplied from the char combustion apparatus 14, and charges the regenerated catalyst C_A again into the gas reforming apparatus 12.

When the raw material A such as coal or ligneous biomass containing a large amount of fixed carbon is gasified in the gasification apparatus 11, a char C_X containing a large amount of fixed carbon is generated. Since the char C_X has its combustion rate extremely lower than volatile gas, the char C_X is accumulated in the gasification apparatus 11. The char C_X accumulated in the gasification apparatus 11 often poses operational problems. For example, if the gasification apparatus 11 comprises a fluidized-bed furnace, then the char C_X is accumulated on the surface of the fluidized bed because the specific gravity of the char C_X is lower than the specific gravity of the bed material. Even when the bed material is withdrawn from the bottom of the furnace for discharging incombustibles, the char C_X is not withdrawn, but only the bed material is withdrawn and a char bed is formed in the furnace, thus tending to shut off the gasification apparatus 11.

Since the char combustion rate and the gas combustion rate are related to each other by char combustion rate ≦ the gas combustion rate, the gas combustion normally consumes oxygen earlier than the char combustion. Therefore, even if oxygen is supplied to increase the combustion of the char C_X in order to suppress the accumulation of char C_X, the combustible gas is combusted (the energy of the combustible gas is converted into heat more than necessary). Since the temperature in the furnace is increased by such a degree corresponding to the supplied oxygen, the char combustion efficiency is improved due to the increased temperature, but the increased temperature does not have a large effect on the char combustion rate (but larger effect on increase of gas reactivity).

By providing the char combustion apparatus 14 separately from the gasification apparatus 11 for removing the char from the gasification apparatus 11 and combusting the removed char, the following advantages can be obtained:

• 1○ The char can be combusted under conditions (combustion temperature, residence time, etc.) suitable for the char combustion independently of the gasification apparatus 11.
• 2○ The gas to be turned into the product gas is not combusted by oxygen which is charged for the purpose of combusting the char.
• 3○ The combustible gas is not diluted by the char combustion gas (a high-calorie gas can be extracted).
• 4○ The combustible gas which has great value as the product gas and the combustion gas which has little value can be used independently of each other.
• 5○ In the case where the raw material A contains a large amount of fixed carbon, like coal or ligneous biomass, if the char C_X which is discharged in a large quantity is withdrawn and discarded, then the energy utilization ratio of the fuel is lower than that in complete combustion. When the char C_X is combusted by the char combustion apparatus 14 and its heat is used, the energy efficiency of the raw material A is improved.

If the raw material A such as coal or biomass, which contains a large amount of fixed carbon, is to be gasified, the above problem of the char produced in the gasification apparatus 11 can be solved by combusting the char C_X withdrawn from the gasification apparatus 11 with the char combustion apparatus 14, supplying the combustion exhaust gas G_C to the catalyst regenerating apparatus 13, and using the heat of the combustion exhaust gas G_C as the heat to regenerate the catalyst, thereby making it possible to regenerate the degraded catalyst C_A' without combusting part of the product gas G_B or using external energy.

It is difficult to gasify all the char C_X into the product gas G_B (because the reaction is complex or the gasification rate is low to cause imbalance between the char supply rate and the gas generation rate, though details are not known). Therefore, a conversion ratio of carbon (how much carbon in the fuel can be converted into a gas) is frequently used as an evaluation standard for the gasification of the raw material A which has a large fixed carbon content. However, the energy of fixed carbon which cannot easily be gasified or is difficult to be gasified can be used by combusting the fixed carbon in the char combustion apparatus 14 even though the fixed carbon is not gasified (if the fixed carbon is not combusted, such condition directly results in an energy loss.

According to the conventional idea of cogeneration based on gasification, the combustion exhaust gas G_C produced by combusting the char C_X can also be used by recovering its sensible heat with steam and using the recovered sensible heat for electric power generation. However, if a gasified gas is produced at a relatively low temperature with the catalyst C_A, then since high-temperature sensible heat is obtained in a limited portion, heat should be used for regenerating the catalyst (if the gas is heated with part of the recovered electric energy, then the consumption of external energy is suppressed, but the efficiency is lowered by a conversion loss caused by conversion from heat to electric energy).

FIG. 4 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 4 differs from the apparatus shown in FIG. 3 in that the apparatus includes a dust collector 15 for removing dust contained in the generated gas G_A supplied from the gasification apparatus 11, a sorting apparatus 16 for removing incombustibles I from a mixture of incombustibles I, ash J, and char C_X discharged from the gasification apparatus 11, and a dust collector 17 for removing ash J from the combustion exhaust gas G_C containing ash J and discharged from the char combustion apparatus 14.

Since the apparatus for reforming a combustible gas is constructed as described above, the ash J and the char C_X are removed from the generated gas G_A, containing the ash J and the char C_X, discharged from the gasification apparatus 11 by the dust collector 15, and then the generated gas G_A is supplied to the gas reforming apparatus 12 and the ash J and the char C_X which have been removed is supplied to the char combustion apparatus 14. The sorting apparatus 16 selectively removes incombustibles I from the mixture of the incombustibles I, the ash J, and the char C_X discharged from the gasification apparatus 11, and supplies the ash J and the char C_X to the char combustion apparatus 14. The dust collector 17 removes ash J from the combustion exhaust gas G_C discharged from the char combustion apparatus 14, and supplies the combustion exhaust gas G_C to the catalyst regenerating apparatus 13, where the sensible heat of the combustion exhaust gas G_C is used as the heat to regenerate the catalyst.

In the above apparatus for reforming a combustible gas, the char C_X discharged from the gasification apparatus 11 having a reducing atmosphere is combusted when the char C_X is withdrawn with retaining a high temperature and brought into contact with oxygen. Therefore, in order to withdraw the char C_X from the gasification apparatus 11, the following measures should be taken:

• a) The char C_X should be withdrawn with retaining a high temperature, while keeping a reducing atmosphere (e.g., nitrogen filling or steam purging).
• b) The char C_X should be withdrawn while being cooled (steam purging is needed to prevent the trouble of tar adhesion).

However, in the case of a), there is the possibility that oxygen leaks in from the exterior for various reasons, i.e., a shortage of the filled nitrogen or purge gas, a sealing failure in the feed path, and a pressure imbalance in the gasification apparatus (furnace). Even in a leakage of a small amount of oxygen, an abrupt temperature increase is caused by local combustion, resulting in an adhesion trouble and a blocking trouble caused by clinker.

Further, in the case of b), safety is ensured relatively with respect to the combustion of the char C_X. However, the tar which is present in the gasification furnace may possibly be accompanied by the char C_X, and may possibly be deposited and solidified, thus possibly causing a blocking of the path. Therefore, the path needs to be purged with steam to discharge the tar. The combustion of the discharged char to utilize its heat is not preferable from the standpoint of efficiency because the char has to be reheated after it is cooled.

Further, the flow rate of the char C_X that is transferred is also important. The char C_X has to be discharged such that it stays in a certain amount in the furnace. If the material to be gasified produces a large amount of char C_X, then the amount of char C_X that is transferred is very large, and the feeder to be used is large in scale. The amount of the char that is transferred is expressed as follows: The transferred amount of the char = generated amount of the char ÷ the concentration of the char in the furnace. If the char C_X in the gasification apparatus (furnace) 11 is of the same concentration, then the generated amount of the char and the transferred amount of the char are proportional to each other.

If the gasification apparatus 1 comprises a fluidized-bed furnace, then it is difficult to selectively discharge the char C_X (a certain amount of char can be selectively discharged based on the tendency of the char to stay on the surface layer). In most cases, the char is discharged together with the bed material. Therefore, it is necessary to provide an apparatus for sorting out the discharged bed material and the discharged char C_X from each other (by way of centrifugation, sieving, different specific gravities), or to employ a fluidized-bed furnace for the char combustion apparatus 14 and circulate the bed material between the gasification apparatus 1 and the char combustion apparatus 14.

FIG. 5 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 5 is constructed to solve the above problems of the apparatus shown in FIG. 4. The apparatus shown in FIG. 5 differs from the apparatus shown in FIG. 4 in that the gasification apparatus 11 comprises an integrated-type furnace including a gasification chamber 11-1 having a fluidized bed and a combustion chamber 11-2 having a fluidized bed, and there is provided a sorting apparatus 18 for separating incombustibles I from a mixture of incombustibles I, char C_X, and ash J withdrawn from the gasification chamber 11-1 and supplying the char C_X and the ash J to the combustion chamber 11-2.

Because the gasification apparatus 11 comprises the integrated-type furnace having the gasification chamber 11-1 and the combustion chamber 11-2, the gasification apparatus 11 has a function to gasify the raw material A and a function to combust the char. Since the char C_X is combusted in the same apparatus in which it is produced, the apparatus shown in FIG. 5 is free of the trouble relating to the feeding of the char C_X.

The interior of the gasification apparatus 11 is divided into a compartment (gasification chamber) for gasifying the raw material A and a compartment (combustion chamber) for combusting the char C_X, so that the generated gas G_A produced by gasifying the raw material A and the combustion exhaust gas G_C produced by combusting the char C_X can be taken out independently of each other. For example, the freeboard is divided by a partition plate to separate the compartments completely from each other. The compartments should preferably be isolated from each other not only in the freeboard but also in the furnace bottom to prevent oxygen supplied to the combustion chamber 11-2 for thereby combusting the char C_X from leaking into the gasification chamber 11-1.

As described above, the interior of the gasification apparatus 11 is divided into the gasification chamber 11-1 and the combustion chamber 11-2, and the char C_X is fed from the gasification chamber 11-1 to the combustion chamber 11-2 by a feeding medium, which should be a bed material M_X in the fluidized bed. The char C_X generated in the gasification chamber 11-1 is delivered together with the bed material M_X into the combustion chamber 11-2, and the char C_X is combusted in the combustion chamber 11-2. The bed material M_X that is heated with the combustion heat of the char C_X is returned again to the gasification chamber 11-1.

Since the bed material M_X is returned from the combustion chamber 11-2 to the gasification chamber 11-1, part of the heat of the combustion chamber 11-2 is used as a heat source for pyrolysis in the gasification chamber 11-1. In this case, both the compartments in the furnace bottom where the bed material M_X is present require a passage for moving the bed material. The presence of the bed material M_X and the maintenance of an appropriate fluidizing velocity make it possible to prevent oxygen from leaking from the combustion chamber 11-2 into the gasification chamber 11-1 to a certain extent. In addition, it is desirable that a bed in which the bed material moves be disposed between the gasification chamber 11-1 and the combustion chamber 11-2, like an internal circulating fluidized-bed gasification furnace, or the bed material be returned to the furnace bottom of the gasification chamber 11-1 where the concentration of the raw material is low.

If the raw material A contains a large amount of incombustibles, then a discharge mechanism (incombustible discharge apparatus, sorting apparatus) is needed for removing incombustibles from the gasification chamber 11-1 as with the conventional gasification apparatus. In FIG. 5, the sorting apparatus 18 is provided for separating incombustibles I from a mixture of incombustibles I, char C_X, and ash J discharged from the gasification chamber 11-1 and supplying the char C_X and the ash J to the combustion chamber 11-2. For handling the char C_X that accompanies the incombustibles I discharged from the gasification chamber 11-1, care should be taken to isolate the char from oxygen and prevent fouling. However, the danger of the trouble is reduced because all the amount of the char corresponding to the amount of char to be generated is not discharged from the gasification chamber 11-1.

The generated gas G_A containing the char C_X and the ash J and discharged from the gasification chamber 11-1 is passed through the dust collector 15, which removes the char C_X and the ash J. The removed char C_X is returned to the combustion chamber 11-2 (for the purpose of combusting the char C_X) and to the gasification chamber 11-1 (for the purpose of gasifying the char C_X), if necessary (if a large amount of char C_X is removed). The gas reforming apparatus 12 can be replenished with the catalyst (catalyst particles) C_A, and can be supplied with an oxidizing agent O_X (e.g. steam + oxygen) under certain catalyst reaction conditions for achieving higher temperatures.

FIG. 32 is a view of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 32 is another example of the apparatus shown in FIG. 5, and has a preferred construction for solving the problem which occurs if the char C_X generated when the raw material A1 is pyrolyzed is in a small quantity.

The above problem can be solved by supplying a raw material A1 to a gasification chamber 101 and supplying a raw material A2 to a combustion chamber 102 for thereby making up for a shortage of the quantity of heat given to the bed material in the combustion chamber 102. Specifically, the quantity of heat given to the bed material in the combustion chamber 102 can effectively be used as a heat source for gasifying the raw material A1 in the gasification chamber 101.

In the present embodiment, the integrated-type gasification furnace 100 is constructed such that the gasification chamber 101 and the combustion chamber 102 are supplied with the raw material A1 and the raw material A2, respectively.

A burner may be installed in an upper portion of the combustion chamber 102 to combust a combustible gas introduced as the raw material A2. Alternatively, the combustion chamber 102 may be supplied with a combustible gas as the raw material A2.

In the present embodiment, a generated gas G_A generated in the gasification chamber 101 is passed through a dust collector 103, a gas reforming apparatus 104, and a gas temperature reducing and cleaning apparatus 104, and then a product gas G_B is produced. On the other hand, a combustion gas G_D obtained from the combustion chamber 102 is passed through a waste heat recovery device 107 (e.g., a waste heat boiler), a dust collector 108, and an induced draft fan 109, and then the gas is discharged from a stack 110 into the atmosphere.

The dust collector 108 may comprise a bag filter or, in particular, an electrostatic precipitator if the concentrations of heavy metals and chlorine components contained in the raw materials A1, A2 are low. If the waste heat recovery device 107 comprises a boiler, then steam produced by the boiler may be used as a gas G_E introduced into the gasification chamber 101.

Further, part of the combustion gas G_D is introduced via a branch pipe 120 into the catalyst regenerating apparatus 115 to supply the quantity of heat which is necessary to regenerate the catalyst. The gas, from which the quantity of heat is removed, is returned from the catalyst regenerating apparatus 115 via a branch pipe 121 to a passage 111 of the combustion gas G_D.

The raw material A2 may be the same as the raw material A1 or may be an auxiliary fuel. If the raw materials A1, A2 contain a large amount of incombustibles, then there may be provided not only an incombustible discharge mechanism for discharging incombustibles from the gasification chamber 101, but also an incombustible discharge mechanism for discharging incombustibles from the combustion chamber 102. The incombustibles discharged from the gasification chamber 101 and the combustion chamber 102 may be sorted by a common mechanism or respective separate mechanisms.

FIG. 6 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 6 differs from the apparatus shown in FIG. 5 in that a bed material of the fluidized bed of the gasification apparatus 11 comprises a mixture of a bed material (sand) M_X and a catalyst (catalyst particles) C_A; a mixture of char C_X, ash J, incombustibles I, a bed material M_X, and a catalyst C_A' discharged from the gasification chamber 11-1 or the combustion chamber 11-2 of the gasification apparatus 11 is introduced into the sorting apparatus 18; the incombustibles I are removed by the sorting apparatus 18; the char C_X and the ash J are returned to the combustion chamber 11-1; the catalyst C_A is returned through a feed passage 19 to the gas reforming apparatus 12; and the catalyst C_A' which has contributed to the gas reforming and has been degraded in the gas reforming apparatus 12 is returned to the combustion chamber 11-2.

Since the apparatus for carrying out the combustible gas reforming method is constructed as described above, the catalyst C_A' which has been degraded can be heated and regenerated by heat, for example, the combustion heat of the char C_X in the combustion chamber 11-2 of the gasification apparatus 11. Therefore, the catalyst regenerating apparatus 13 in the apparatus shown in FIG. 5 can be eliminated. The degraded catalyst C_A' is charged directly into the combustion chamber 11-2 to combust and remove deposited carbon which is one of the causes of the degradation of the catalyst, and hence the catalyst is regenerated. The feed passage 19 may be replenished with the catalyst C_A. The mixture of the char C_X, the ash J, the incombustibles I, the bed material M_X, and the catalyst C_A may be discharged from the gasification chamber 11-1 if the incombustibles I are present in a large amount, otherwise may be discharged from either the gasification chamber 11-1 or the combustion chamber 11-2.

FIG. 7 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 7 differs from the apparatus shown in FIG. 6 in that the combustion exhaust gas G_C containing the regenerated catalyst C_A and the ash J and discharged from the combustion chamber 11-2 of the gasification apparatus 11 is introduced into the dust collector 17, which removes the catalyst C_A and the ash J from the combustion exhaust gas G_C; the removed catalyst C_A and ash J are introduced into a sorting apparatus 20, which selectively removes the ash J; and the remaining catalyst C_A is returned via a feed passage 19' to the gas reforming apparatus 12. The gas reforming apparatus 12 is replenished with the catalyst C_A via the feed passage 19'.

FIG. 8 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 8 differs from the apparatus shown in FIG. 5 in that the catalyst C_A regenerated by the catalyst regenerating apparatus 13 is introduced into the gasification chamber 11-1 of the gasification apparatus 11; the raw material A is gasified in the gasification chamber 11-1 and the generated gas G_A is reformed (tar decomposition) in the gasification chamber 11-1; a mixture of reformed generated gas G_A', char C_X, ash J, and degraded catalyst C_A' which has contributed to the gas reforming is introduced into the dust collector 15, which removes the char C_X, the ash J, and the degraded catalyst C_A'; and the reformed generated gas G_A' is obtained as the product gas G_B.

The char C_X, the ash J, and the degraded catalyst C_A' which have been removed by the dust collector 15 are introduced into the sorting apparatus 20, which sorts the char C_X and the ash J, and the sorted char C_X and ash J are delivered to the combustion chamber 11-2, and the remaining degraded catalyst C_A' is delivered to the catalyst regenerating apparatus 13. The catalyst C_A heated and regenerated by the catalyst regenerating apparatus 13 is fed to the gasification apparatus 11-1 as described above. A feed passage for feeding the catalyst C_A to the gasification chamber 11-1 can be replenished with the catalyst C_A.

FIG. 9 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 9 differs from the apparatus shown in FIG. 8 in that the char C_X and the ash J removed from the reformed generated gas G_A' by the dust collector 15 are returned to the combustion chamber 11-2 of the gasification apparatus 11; and a mixture of the char C_X, the ash J, the incombustibles I, and the degraded catalyst C_A' discharged from the gasification chamber 11-1 of the gasification apparatus 11 is introduced into the sorting apparatus 18, which selectively discharges the incombustibles I; and the char C_X and the ash J are returned to the combustion chamber 11-2, and the degraded catalyst C_A' is transferred to the catalyst regenerating apparatus 13. The gasification chamber 11-1 can be replenished with the catalyst C_A.

FIG. 10 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 10 includes a gasification apparatus comprising a fluidized-bed furnace which employs catalyst particles as a bed material. Reference numeral 21 represents a gasification apparatus having a fluidized-bed gasification furnace which uses the catalyst (catalyst particles) C_A as a bed material. The gasification apparatus 21 gasifies the raw material A and at the same time reforms the gas (tar decomposition). The reformed generated gas G_A' is passed through a dust collector 22, which removes the char C_X, the ash J, and the degraded catalyst (catalyst particles used as the bed material and degraded) C_A', producing the product gas G_B. The char C_X, the ash J, and the catalyst C_A' removed by the dust collector 22 are delivered to a char combustion apparatus 24, which combusts the char C_X.

The mixture of the incombustibles I, the char C_X, the ash J, and the catalyst C_A' removed from the gasification apparatus 21 is delivered to a sorting apparatus 23, which selectively removes and discharges the incombustibles I by way of sieving, magnetic separation, and separation based on different specific gravities, etc. The remaining char C_X, the ash J, and the catalyst C_A' are supplied to the char combustion apparatus 24. In the char combustion apparatus 24, the supplied char C_X is combusted together with the char C_X supplied from the dust collector 22. The degraded catalyst C_A' is heated and regenerated into the catalyst C_A by the sensible heat produced upon combustion of the char. The catalyst C_A is removed from the furnace bottom of the char combustion apparatus 24, and delivered again to the gasification apparatus 21 for use as the bed material and the catalyst again.

If the catalyst particles from the char combustion apparatus 24 are broken into smaller particles or particles of the catalyst C_A are originally small, then since the catalyst particles tend to be scattered in a large quantity with the combustion exhaust gas G_C, the catalyst particles are delivered to the dust collector 25, which traps the catalyst C_A and the ash J and thus removes them from the combustion exhaust gas G_C. The trapped and removed catalyst C_A and the ash J are fed to a sorting apparatus 26, which separates the catalyst C_A and ash J from each other. The ash J is selectively removed and discharged from the sorting apparatus 26, and the catalyst C_A is delivered to the gasification apparatus 21. In the gasification apparatus 21, the catalyst C_A is used as the bed material and the catalyst as with the catalyst C_A supplied from the char combustion apparatus 24. The sorting apparatus 26 sorts out the catalyst C_A and the ash J from each other by way of sorting based on different specific gravities or centrifugation, depending on the state of the particles of the catalyst C_A.

With the apparatus shown in FIG. 10, the handling of the particles including the char C_X is required, and oxygen blocking is required. Since the tar is decomposed by the catalyst at the same time that the raw material is gasified, the trouble of tar adhesion is less liable to occur even if the feed passage is cooled, and the particles including the char C_X can be cooled and fed. However, cooling the catalyst C_A and returning the catalyst C_A to the gasification apparatus 21 leads to a reduction in the thermal efficiency.

FIG. 11 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 11 is constructed to solve the above problems of the apparatus shown in FIG. 10. The apparatus shown in FIG. 11 is different from the apparatus shown in FIG. 10 in that the gasification apparatus 21 comprises an integrated-type furnace including a gasification chamber 21-1 having a fluidized bed and a combustion chamber 21-2 having a fluidized bed. At the same time that the raw material A is gasified in the gasification chamber 21-1, the generated gas G_A is brought into contact with the catalyst C_A serving as the bed material and is reformed. The reformed generated gas G_A' is passed through the dust collector 22, which removes the char C_X, the ash J, and the catalyst (degraded catalyst) C_A' contained therein, producing the product gas G_B. The char C_X, the ash J, and the catalyst C_A' removed by the dust collector 22 are delivered into the combustion chamber 21-1 and combusted therein.

The catalyst (bed material) C_A' containing the char C_X and discharged from the gasification chamber 21-1 is introduced into the combustion chamber 21-2, and the catalyst C_A' is heated and regenerated by the combustion heat of the char C_X in the combustion chamber 21-2. The regenerated catalyst C_A is delivered again into the gasification chamber 21-1. Further, the mixture of the incombustibles I, the char C_X, the ash J, and the catalyst C_A' removed from the gasification chamber 21-1 is delivered to the sorting apparatus 23, which selectively removes and discharges the incombustibles I. The remaining char C_X, ash J, and catalyst C_A' are sent to the combustion chamber 21-2, and the char C_X is combusted to contribute to the heating and regeneration of the degraded catalyst C_A' in the combustion chamber 21-2. The exhaust gas G_C containing the ash J and the char C_X discharged from the combustion chamber 21-2 is sent to the dust collector 25, which removes and discharges the ash J and the catalyst C_A. The removed ash J and catalyst C_A are delivered to the sorting apparatus 26, which separates the ash J and the catalyst C_A from each other. The separated catalyst C_A is delivered again into the gasification chamber 21-1.

The particulate catalyst C_A as the bed material is directly moved in the same fluidized-bed furnace. As with the internal circulating fluidized-bed gasification furnace, the bed material (catalyst C_A) is moved based on the difference between the fluidizing velocities of the bed material in the gasification chamber 21-1 and the combustion chamber 21-2. As with the apparatus shown in FIG. 10, if the catalyst C_A can easily be scattered because it tends to be broken into smaller particles or it is originally in the form of small particles, then the catalyst C_A should be sorted out by the sorting apparatus 26 from the mixture of the ash J and the catalyst C_A trapped by the dust collector 25, and returned to the gasification chamber 21-1. Further, the gasification chamber 21-1 and the combustion chamber 21-2 should be isolated from each other, and a means for preventing oxygen from leaking from the combustion chamber 21-2 into the gasification chamber 21-1 should be provided, as with the above embodiments.

If the bed material for use in the fluidized-bed furnace of the gasification apparatus 21 comprises catalyst particles (CaO, Al₂O₃Ni, FeSiO₂, MgSiO₂, etc.) for decomposing tar, then the gasification of the raw material A and the tar decomposition based on the catalytic action can simultaneously be performed. Since CaO or the like functions as a desulfurizing agent and a dechlorinating agent, desulfurization and dechlorination can also be carried out simultaneously.

FIG. 12 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. In the apparatus shown in FIG. 12, a raw material A such as biomass, municipal wastes, industrial wastes, RDF, waste plastics, etc. is gasified in a gasification apparatus 31, and dust collecting of a generated gas G_A and reformation of the generated gas are performed by a dust collecting and catalytic reaction apparatus 32, thus producing a product gas G_B.

The generated gas G_A discharged from the gasification apparatus 31 contains tar, dust, and char, as described above, which need to be removed. If the gas has been reformed (tar decomposition), then the dust and char can be removed from the gas by a wet-type gas cleaning. Because the gas before decomposition of tar causes the problem of tar deposition upon cooling of the gas, the tar has to be decomposed before the gas is cooled. The dust collecting of the gas should preferably be performed in a stage prior to the catalytic reaction apparatus in order to prevent the catalyst which decomposes the tar at a low temperature from being degraded and contaminated.

A ceramic filter has been used as a high-temperature dust collector for use in a temperature range for gasifying the raw material A. When dust collecting is performed in such a state that the tar is not decomposed, no problem arises when the apparatus operates at a high temperature. However, when the apparatus is stopped, oxygen and tar may react with each other, causing the damage due to local high temperatures or the trouble of clogging due to tar deposition.

In order to solve the above problems, the system shown in FIG. 12 employs the dust collecting and catalytic reaction apparatus 32 disposed in a stage subsequent to the gasification apparatus 31. Specifically, the dust collecting and catalytic reaction apparatus 32 includes a filter section of a dust collecting apparatus which carries a catalyst or a particulate filter filled with catalyst particles. When the generated gas G_A passes through the filter which has a catalytic function, the dust collecting of the generated gas G_A is performed by the filter, and the decomposition of the tar is accelerated by a catalytic reaction.

FIG. 13 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 13 employs an arrangement which is a development of the apparatus shown in FIG. 12. As shown in FIG. 13, the degraded catalyst C_A' which has contributed to gas reforming (tar decomposition) in the dust collecting and catalytic reaction apparatus 32 is removed from the dust collecting and catalytic reaction apparatus 32, and delivered to a catalyst regenerating apparatus 33, which regenerates the degraded catalyst C_A'. The regenerated catalyst C_A is supplied again to the dust collecting and catalytic reaction apparatus 32.

A mixture of incombustibles I, char C_X, and ash J removed from the gasification apparatus 31 is sent to a sorting apparatus 34, which selectively removes the incombustibles I, and the remaining char C_X and ash J are fed to a char combustion apparatus 35 in which the char C_X is combusted. A combustion exhaust gas G_C containing the ash J is delivered from the char combustion apparatus 35 to a dust collector 36, which removes the ash J, and the remaining combustion exhaust gas G_C is delivered from the dust collector 36 to the catalyst regenerating apparatus 33. The degraded catalyst C_A' is heated and regenerated with the sensible heat of the combustion exhaust gas G_C by the catalyst regenerating apparatus 33. The degraded catalyst C_A' which has contributed to gas reforming (tar decomposition) in the dust collecting and catalytic reaction apparatus 32 may be charged into the catalyst regenerating apparatus 33, and the heated and regenerated catalyst C_A may be sorted and returned to the dust collecting and catalytic reaction apparatus 32.

FIG. 14 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention, the apparatus being developed from the apparatus shown in FIG. 9. The apparatus shown in FIG. 14 is different from the apparatus shown in FIG. 9 in that a gasification apparatus 31 comprises an integrated-type furnace which includes a gasification chamber 31-1 having a fluidized bed and a combustion chamber 31-2 having a fluidized bed. Because the gasification apparatus 31 comprises the integrated-type furnace having the gasification chamber 31-1 for gasifying the raw material A and the combustion chamber 31-2 for combusting the char, the gasification apparatus 31 has a function to gasify the raw material A and a function to combust the char.

For example, the freeboard is divided by a partition plate to separate the compartments completely from each other, so that the gasification chamber 31-1 and the combustion chamber 31-2 in the gasification apparatus 31 can take out the generated gas G_A produced by gasifying the raw material A and the combustion exhaust gas G_C produced by combusting the char C_X, independently of each other. The compartments should preferably be isolated from each other not only in the freeboard but also in the furnace bottom to prevent oxygen sufficiently supplied to the combustion chamber 31-2 for combusting the char C_X from leaking into the gasification chamber 31-1.

As described above, the interior of the gasification apparatus 31 is divided into the gasification chamber 31-1 and the combustion chamber 31-2, and the char C_X is transferred from the gasification chamber 31-1 to the combustion chamber 31-2 by a bed material M_X in the fluidized bed. Specifically, the char C_X generated in the gasification chamber 31-1 is delivered together with the bed material M_X into the combustion chamber 31-2, and the char C_X is combusted in the combustion chamber 31-2, and then the bed material M_X that is heated with the combustion heat of the char C_X is returned to the gasification chamber 31-1.

Since the bed material M_X is returned from the combustion chamber 31-2 to the gasification chamber 31-1, part of the heat of the combustion chamber 31-2 is used as a heat source for pyrolysis in the gasification chamber 31-1. In this case, the compartments in the furnace bottom where the bed material M_X is present require a passage for moving the bed material M_X. The presence of the bed material M_X and the maintenance of an appropriate fluidizing velocity make it possible to prevent oxygen from leaking from the combustion chamber 31-2 into the gasification chamber 31-1 to a certain extent. In addition, it is desirable that a bed in which the bed material moves be disposed between the gasification chamber 31-1 and the combustion chamber 31-2, like the internal circulating fluidized-bed gasification furnace, or the bed material M_X be returned to the furnace bottom of the gasification chamber 31-1 where the concentration of the raw material is low.

If the raw material A contains a large amount of incombustibles I, then an incombustible discharge mechanism (incombustible discharge apparatus, sorting apparatus) is needed for removing the incombustibles I from the gasification chamber 31-1 as with the conventional gasification apparatus. In FIG. 14, a sorting apparatus 34 is provided for separating the incombustibles I from a mixture of the incombustibles I, the char C_X, and the ash J removed from the gasification chamber 31-1 and supplying the char C_X and the ash J to the combustion chamber 31-2. For handling the char C_X that accompanies the incombustibles I removed from the gasification chamber 31-1, care should be taken to intercept oxygen and prevent a blocking. However, the danger of the trouble is reduced because all the amount of char corresponding to the amount of char to be generated is not removed from the gasification chamber 31-1 unlike the conventional process.

The char C_X removed by a dust collecting and catalytic reaction apparatus 32 is returned to the combustion chamber 31-2 (for the purpose of combustion) or to the gasification chamber 31-1. (for the purpose of gasification), if necessary (if the amount of char C_X is large). In the above example, a catalyst C_A' degraded in the dust collecting and catalytic reaction apparatus 32 is heated and regenerated by a catalyst regenerating apparatus 33, and returned again to the dust collecting and catalytic reaction apparatus 32. The combustion chamber 31-2 may be used to regenerate the catalyst. That is, the degraded catalyst C_A' which has contributed to gas reforming (tar decomposition) in the dust collecting and catalytic reaction apparatus 32 may be charged into the combustion chamber 31-2, and the heated and regenerated catalyst C_A' may be selected and returned to the dust collecting and catalytic reaction apparatus 32.

FIG. 15 is a view of an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention, the apparatus being developed from the apparatus shown in FIG. 13. The apparatus shown in FIG. 15 includes a gasification, combustion, dust collecting and reforming apparatus 40 for performing, in a single fluidized-bed furnace, the gasification function of the gasification apparatus 31 shown in FIG. 13, the char combustion function of the char combustion apparatus 35 shown in FIG. 13, and the dust collecting and reforming function of the dust collecting and catalytic reaction apparatus 32. Specifically, the gasification, combustion, dust collecting and reforming apparatus 40 comprises a gasification chamber 40-1 for gasifying the raw material A, a combustion chamber 40-2 for combusting the char C_X, and a dust collecting and catalyst reaction chamber 40-3 for dust collecting and reforming (decomposing tar) the generated gas G_A.

As shown in FIG. 13, if the dust collecting and catalytic reaction apparatus 32 is provided and employs a particulate filter comprising catalyst particles, then a fixed bed (packed bed) may be used. With respect to the handling of the catalyst particles, the handling of the catalyst particles is facilitated by using the fluidized bed as shown in FIG. 13.

For heating and regenerating the catalyst particles of a degraded filter for reuse, if the degraded catalyst particles are regenerated with the heat of combustion of the char C_X and the regenerated catalyst particles are supplied to the filter, then the handling of the catalyst particles is needed in many situations, e.g., when the catalyst particles are removed from the filter and supplied to the regenerating apparatus, and when the regenerated catalyst particles are supplied to the filter. Unlike the method of removing the catalyst particles with batch processing in the fixed bed, using the gasification apparatus 31 and the gasification-combustion-dust collecting-reforming apparatus 40 which utilize the fluidized-bed (moving bed) technology as shown in FIGS. 14 and 15 makes it possible to continuously remove and supply the catalyst (catalyst particles) C_A.

In the catalyst regenerating apparatus 33, the fluidized bed is effective to increase the ratio of contact between the combustion exhaust gas G_C serving as a heat source and the catalyst C_A, and makes it easier to remove the regenerated catalyst C_A from the catalyst regenerating apparatus 33 than in the case where the combustion exhaust gas G_C is brought into contact with the catalyst C_A in the packed bed.

With a cyclone-type dust collector or a centrifugal-separation dust collector, after the catalyst particles are introduced to reform the combustible gas in a stage prior to the dust collector, the catalyst C_A is trapped together with the char C_X and the dust in the generated gas G_A, separated from the generated gas G_A, and delivered to the char combustion chamber (catalyst regeneration chamber). In this manner, the gas can simultaneously be dedusted and reformed (tar decomposition).

FIG. 16 shows an example of a construction wherein the catalyst is regenerated by a combustion chamber 31-2, rather than being regenerated by the catalyst regenerating apparatus 33 in FIG. 14. As shown in FIG. 16, the gasification apparatus 31 has a fluidized-bed furnace with a fluidized bed 31a, and the fluidized-bed furnace is divided into a gasification chamber 31-1 and a combustion chamber 31-2 by a partition wall 31b. A region of the fluidized bed 31a beneath the lower end of the partition wall 31b serves as a passage for moving the bed material therethrough. The dust collecting and catalytic reaction apparatus 32 has a filter 32a, and a catalyst C_A is charged on the filter 32a.

When a generated gas G_A containing char C_X and ash J from the gasification chamber 31-1 is supplied to a region below the filter 32a of the dust collecting and catalytic reaction apparatus 32, the char C_X and the ash J are trapped and removed by the filter 32a, and the generated gas G_A is injected from a distributor nozzle 32c into a fixed bed (packed bed) 32b of the catalyst C_A and reformed (tar decomposition) while passing through the fixed bed 32b of the catalyst C_A, thus producing a product gas G_B. The char C_X and the ash J which have been trapped and removed by the filter 32a are supplied, if necessary, to the combustion chamber 31-2 and the gasification chamber 31-1.

The mixture of the incombustibles I, the ash J, the char C_X, and the catalyst C_A serving as a bed material, which is removed from the fluidized bed 31a in the gasification chamber 31-1, is supplied to the sorting apparatus 34. The incombustibles I are selectively removed from the sorting apparatus 34, and the ash J, the catalyst C_A, and the char C_X which remain in the sorting apparatus 34 are returned to the combustion chamber 31-2. The degraded catalyst C_A' (whose catalytic function has been lowered) which has contributed to the reforming of the generated gas G_A in the dust collecting and catalytic reaction apparatus 32 is delivered to the combustion chamber 31-2. In the combustion chamber 31-2, the degraded catalyst C_A' is heated and regenerated into a regenerated catalyst C_A that is returned to the dust collecting and catalytic reaction apparatus 32. The catalyst C_A which has been heated and regenerated in the combustion chamber 31-2 is delivered to the gasification chamber 31-1. A combustion exhaust gas G_C from the combustion chamber 31-2 passes through a heat recovery apparatus 37, and hence heat recovery is performed. Thereafter, the combustion exhaust gas G_C passes through a dust collector 38, which removes dust from the combustion exhaust gas G_C, and is then discharged from the dust collector 38.

FIG. 17 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The system construction shown in FIG. 17 performs the gasification function, the catalyst regenerating function, the dust collecting function, and the gas reforming function illustrated in FIG. 11 in a single fluidized-bed furnace. As shown in FIG. 17, a gasification-combustion-dust collecting-reforming apparatus 40 includes a fluidized-bed furnace which has a fluidized bed 40a and is divided into a gasification chamber 40-1, a combustion chamber 40-2, and a dust collecting and catalyst reaction chamber 40-3 by partition walls 40b, 40c. Regions of the fluidized bed 40a beneath the lower ends of the partition walls 40b, 40c serve as passages for moving the degraded catalyst C_A' as a bed material therethrough.

A dust collecting chamber 41 is disposed below the dust collecting and catalyst reaction chamber 40-3. A filter 41a is provided in the dust collecting chamber 41. A generated gas C_A containing char C_X and ash J and produced by gasification of a raw material A in the gasification chamber 40-1, is introduced into a region below the filter 41a of the dust collecting chamber 41. The char C_X and the ash J are trapped by the filter 41a, whereas the remaining generated gas G_A is injected through distributor nozzles 41b into the fluidized bed 40a and reformed (tar decomposition) by the catalyst C_A as a bed material of the fluidized bed 40a, thus producing a product gas G_B that is discharged from the dust collecting and catalytic reaction chamber 40-3. Air L, serving as a fluidizing gas and an oxidizing agent, is usually introduced into the bottom of the fluidized bed 40a.

The degraded catalyst C_A' which has contributed to the reforming of the generated gas G_A (tar decomposition) in the dust collecting and catalyst reaction chamber 40-3 is delivered to the combustion chamber 40-2. In the combustion chamber 40-2, the degraded catalyst C_A' is heated and regenerated, and the regenerated catalyst is returned through a feed passage 40d to the dust collecting and catalyst reaction chamber 40-3. A combustion exhaust gas G_C from the combustion chamber 40-2 passes through a heat recovery apparatus 37, and hence heat recovery is performed. Thereafter, the combustion exhaust gas G_C passes through the dust collector 38, which removes dust from the combustion exhaust gas G_C, and is then discharged from the dust collector 38. The catalyst which has heated and regenerated in the combustion chamber 40-2 is returned through a feed passage 40e to the gasification chamber 40-1.

FIG. 18 is a view showing an example of a construction of the dust collecting and catalytic reaction apparatus 32. As shown in FIG. 18, the dust collecting and catalytic reaction apparatus 32 has a filter 32a housed therein. A generated gas G_A containing ash J and char C_X is introduced from a gas inlet 32-1 into the filter 32a, and the ash J and the char C_X are separated from the generated gas G_A by the filter 32a. The generated gas G_A from which the ash J and the char C_X have been removed by the filter 32a is reformed (tar decomposition) while passing through the packed bed 32b of the catalyst C_A formed on the filter 32a. The reformed gas is then discharged as a product gas G_B from a gas outlet 32-2. The filter 32a comprises a ceramic filter or a metal filter. The ash J and the char C_X which have been separated are discharged from an outlet 32-3.

The dust collecting and catalytic reaction apparatus 32 may be constructed such that as shown in FIG. 19, a packed bed 32c which is filled with sand or ceramic particles as a filler O_X, instead of a filter, is provided, and a generated gas G_A containing ash J and char C_X is introduced from the gas inlet 32-1 into the dust collecting and catalytic reaction apparatus 32, and then the ash J and the char C_X are separated from the generated gas G_A by the packed bed 32c. In the packed bed 32c, the filler O_X moves by flowing-down or the like. When the generated gas G_A containing the ash J and the char C_X passes through the packed bed 32c, the particles of the filler O_X in the packed bed 32c contact and trap the ash J and the char C_X, thus separating the ash J and the char C_X from the generated gas G_A. The generated gas G_A which has passed through the packed bed 32c is reformed (tar decomposition) while passing through a packed bed 32b of the catalyst C_A that is disposed in a flow passage from the packed bed 32c to the gas outlet 32-2. The reformed gas is discharged as a product gas G_B from the gas outlet 32-2. Since the catalyst C_A is used in the form of a mixture of the catalyst C_A and the filler O_X, the filler O_X may be replaced in its entirety with the catalyst C_A.

The filler O_X, the ash J, and the char C_X which are discharged from the outlet 32-3 are classified by a gravity separator based on the different specific gravities of the filler O_X, the ash J, and the char C_X. The classified filler O_X is returned to the packed bed 32c of the dust collecting and catalytic reaction apparatus 32. The ash J is recovered after it is cooled. The filler O_X, the ash J, and the char C_X are classified in a reducing atmosphere.

As shown in FIG. 20, the dust collecting and catalytic reaction apparatus 32 may comprise a cyclone-type centrifugal separator for separating, under the centrifugal forces of swirling flows, ash J and char C_X from a generated gas G_A which contains the ash J and the char C_X and is introduced from the gas inlet 32-1. A catalyst (catalyst particles) C_A is introduced into the generated gas G_A within the dust collecting and catalytic reaction apparatus 32 or near the gas inlet 32-1 through an apparatus, such as a lock hopper 42 or the like, which isolates the atmosphere of the generated gas G_A and the external atmosphere from each other, whereby tar contained in the generated gas G_A is decomposed by the catalyst C_A due to a mixing and stirring action of the swirling flows. In the dust collecting and catalytic reaction apparatus 32, after decomposition of the tar, the ash J, the char C_X, and the degraded catalyst C_A' are separated from the generated gas G_A, and discharged from the outlet 32-3. After decomposition of the tar, the generated gas G_A is discharged as a product gas G_B from the gas outlet 32-2.

The dust collecting and catalytic reaction apparatus 32 may be constructed as shown in FIG. 21 such that the filter 32a is housed within the apparatus; a generated gas G_A containing ash J and char C_X is introduced from the gas inlet 32-1 into the dust collecting and catalytic reaction apparatus 32; and then the generated gas G_A is passed through the filter 32a to trap and separate the ash J and the char C_X from the generated gas G_A, and the separated ash J and char C_X are discharged from the outlet 32-3.

Tar contained in the generated gas G_A is decomposed by the catalyst C_A that is filled in a flow passage from the filter 32a to the gas outlet 32-2, and the generated gas G_A that has been reformed is discharged as a product gas G_B from the gas outlet 32-2. The filter 32a comprises a ceramic filter or a metal filter.

After the catalyst C_A is used to decompose the tar, the catalyst C_A is degraded. In order to regenerate the catalyst C_A, a distribution means such as distributor nozzles 32b or the like are disposed above the filter 32a. The generated gas G_A is ejected through the distribution means to fluidize and move the catalyst C_A, thereby discharging the degraded catalyst C_A' from a catalyst outlet 32-4. The filter 32a in the dust collecting and catalytic reaction apparatus 32 should preferably have a slanted surface which is progressively lower toward the catalytic outlet 32-4 for effectively discharging the degraded catalyst C_A'.

FIG. 22 is a view showing an example of another construction of the dust collecting and catalytic reaction apparatus 32. As shown in FIG. 22, the dust collecting and catalytic reaction apparatus 32 has a packed bed 32c filled with sand or ceramic particles as a filler O_X, instead of a filter to separate the ash J and char C_X from the generated gas G_A. In the packed bed 32c, the filler O_X moves by flowing-down or the like. A generated gas G_A containing ash J and char C_X is introduced from the gas inlet 32-1 into the dust collecting and catalytic reaction apparatus 32. When the generated gas G_A containing the ash J and the char C_X passes through the packed bed 32c, the ash J and the char C_X are contacted and trapped by the particles of the filler O_X of the packed bed 32c, and are thus separated from the generated gas G_A. The ash J and the char C_X that have been separated by the packed bed 32c are discharged from the outlet 32-3 to the outside.

The dust collecting and catalytic reaction apparatus 32 also has a catalyst packed bed 32d filled with a regenerated catalyst C_A. In the catalyst packed bed 32d, the catalyst C_A moves by flowing-down or the like as with the packed bed 32c. When the generated gas G_A passes through the catalyst packed bed 32d, the catalyst C_A decomposes tar contained in the generated gas G_A, and the degraded catalyst C_A' is discharged from a catalyst outlet 32-5.

In the dust collecting and catalytic reaction apparatus 32 constructed as shown in FIG. 22, the catalyst C_A may be in the form of particles as with the filler O_X and mixed with the filler O_X, or the filler O_X may be replaced in its entirety with the catalyst C_A. In this case, the ash J and the char C_X which have been separated by the packed bed 32c are classified by a gravity separator based on the different specific gravities of the filler O_X (the catalyst C_A), the ash J, and the char C_X.

In the case where the catalyst C_A is in the form of particles as with the filler O_X and mixed with the filler O_X, or the filler O_X is replaced in its entirety with the catalyst C_A, if the temperature in the dust collecting and catalytic reaction apparatus 32 is in a high temperature range from 900°C to 1000°C, then since salts are volatilized and do not remain in the ash J, the ash J and the char C_X which have been separated by the packed bed 32c can be supplied together with the filler O_X and the catalyst C_A to the char combustion apparatus or the combustion chamber.

FIG. 23 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 23 has a gasification apparatus 43 comprising a fluidized-bed furnace which is divided into a gasification chamber 43-1 and a combustion chamber 43-2 by a partition wall 43a. A bed material (sand) M_X, a degraded catalyst C_A', and char C_X move from the gasification chamber 43-1 in a reducing atmosphere into the combustion chamber 43-2 in an oxidizing atmosphere. In the combustion chamber 43-2, the char C_X is combusted, and the degraded catalyst C_A' is heated and regenerated into the catalyst C_A. The regenerated catalyst C_A moves again into the gasification chamber 43-1, and a combustion exhaust gas G_C is discharged.

A fluidized bed 43-1a in the gasification chamber 43-1 contains the bed material (sand) M_X and the catalyst C_A, and the raw material A is gasified and simultaneously reformed (tar decomposition) by the catalyst C_A. The reformed generated gas G_A is introduced into a dust collecting and catalytic reaction apparatus 32 which comprises a cyclone-type centrifugal separator that is of essentially the same structure as the cyclone-type centrifugal separator shown in FIG. 20. A mixture of incombustibles I, the degraded catalyst C_A' including unreacted components, the bed material M_X and the ash J, which is removed from the fluidized bed 43-1a in the gasification chamber 43-1, is delivered to the sorting apparatus 34, and the incombustibles I are selectively separated out by the sorting apparatus 34, and the catalyst C_A', the bed material M_X, and the ash J which remain in the sorting apparatus 34 are supplied to the dust collecting and catalytic reaction apparatus 32.

In the dust collecting and catalytic reaction apparatus 32, as with the arrangement shown in FIG. 20, the generated gas G_A is further reformed by a gas-phase mixture of the generated gas G_A and the catalyst C_A, thus producing a product gas G_B. The catalyst C_A', the bed material M_X, and the ash J from the dust collecting and catalytic reaction apparatus 32 are returned to the combustion chamber 43-2 of the gasification apparatus 43.

FIG. 24 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. The apparatus shown in FIG. 24 has a gasification apparatus 31 which is of substantially the same structure as the gasification apparatus 31 shown in FIG. 12 and a dust collecting and catalytic reaction apparatus 32 which is of substantially the same structure as the dust collecting and catalytic reaction apparatus 32 shown in FIG. 20. A mixture of incombustibles I, catalyst C_A' and ash J, which is removed from the fluidized bed 31a in the gasification chamber 31-1, is delivered to the sorting apparatus 34, and the incombustibles I are selectively removed by the sorting apparatus 34, and the catalyst C_A' and the ash J which remain in the sorting apparatus 34 are returned to the gasification chamber 31-1. In the gasification chamber 31-1, the raw material A is gasified and the generated gas G_A is reformed by the catalyst C_A. The mixture of the generated gas G_A, the ash J, and the char C_X from the gasification chamber 31-1 is delivered to the dust collecting and catalytic reaction apparatus 32.

In the dust collecting and catalytic reaction apparatus 32, as with the arrangement shown in FIG. 20, the generated gas G'_A is further reformed by a gas-phase mixture of the generated gas G_A and the catalyst C_A, thus producing a product gas G_B. The catalyst C_A', the char C_X, and the ash J from the dust collecting and catalytic reaction apparatus 32 are returned to the combustion chamber 31-2 of the gasification apparatus 31.

FIG. 25 is a view showing an example of a system construction of an apparatus for carrying out a combustible gas reforming method according to the present invention. As shown in FIG. 25, the apparatus employs a fluidized-bed catalytic reaction apparatus 56 as a catalytic reaction and catalyst regenerating apparatus. The fluidized-bed catalytic reaction apparatus 56 uses catalyst particles as a bed material, and has a furnace divided into a reaction chamber 56-1 where the catalyst C_A reacts and a regeneration chamber 56-2 where the degraded catalyst C_A' is regenerated. The reaction chamber 56-1 is in a reducing atmosphere, and the regeneration chamber 56-2 is in an oxidizing atmosphere. The reaction chamber 56-1 and the regeneration chamber 56-2 are divided from each other by a partition plate (not shown) to allow gases to pass independently through the reaction chamber 56-1 and the regeneration chamber 56-2, respectively. The divided compartments are designed depending on the amount of a generated gas G_A to be processed, thereby keeping an appropriate fluidizing velocity between the compartments. The catalyst C_A as the bed material circulates between the compartments.

A raw material A including coal, biomass, municipal wastes, industrial wastes, RDF, waste plastics, etc. is gasified by a gasification apparatus 51, and a generated gas G_A is delivered to a dust collector 52. The dust collector 52 removes char C_X and ash J contained in the generated gas G_A, and delivers the generated gas G_A to the reaction chamber 56-1 of the fluidized-bed catalytic reaction apparatus 56. In the reaction chamber 56-1 which is in the reducing atmosphere, the generated gas G_A is reformed (tar decomposition) while fluidizing the catalyst C_A by the generated gas G_A, thus producing a product gas G_B.

A mixture of incombustibles I, the char C_X, and the ash J from the gasification apparatus 51 is delivered to a sorting apparatus 53, and the incombustibles I are selectively removed by the sorting apparatus 53 and a remaining mixture of the char C_X and the ash J is supplied from the sorting apparatus 53 to a char combustion apparatus 54. In the char combustion apparatus 54, the char C_X is combusted. A combustion exhaust gas G_C including the ash J from the char combustion apparatus 54 is delivered to a dust collector 55, which removes the ash J. The combustion exhaust gas G_C is then delivered to the regeneration chamber 56-2 of the fluidized-bed catalytic reaction apparatus 56.

The catalyst C_A' which has contributed to the tar decomposition and whose catalytic function has been lowered is delivered from the reaction chamber 56-1 to the regeneration chamber 56-2. In the regeneration chamber 56-2 which is in an oxidizing atmosphere, the degraded catalyst C_A' is regenerated by the heat of the combustion exhaust gas G_C. If the catalyst C_A' delivered from the reaction chamber 56-1 contains a large amount of char C_X, then the regeneration chamber 56-2 is charged with an oxygen-containing gas for combustion (such as air) to combust the char C_X. The catalyst C_A which has been regenerated by the sensible heat of the combustion exhaust gas G_C and the heat of combustion of the remaining char C_X is supplied again to the reaction chamber 56-1.

In the reac