JP4593964B2 - Method for dry purification of pyrolysis gas - Google Patents

Description

  The present invention relates to a dry purification method of pyrolysis gas that can be effectively used in waste treatment technology and the like for the purpose of high-efficiency power generation while suppressing generation of substances harmful to the environment such as dioxins at low cost. Involved.

Waste is disliked as a source of dioxins, HCl, SO ₂ , NOx and toxic heavy metals, and is incinerated for reduction, and it is a therapeutic treatment for dioxins, HCl, SO ₂ , NOx and toxic metals generated at that time. Much effort has been devoted to the cleanup, but no technology has yet been developed to treat these centrally and to actively use waste as a useful resource.
As the ultimate treatment method for dioxin and fly ash / incinerated ash, it is recommended to treat at a high temperature of 1400-1500 ° C. For this purpose, waste is once pyrolyzed and converted into a gas with good combustibility. A method (gasification melting furnace method) that burns at an air rate and generates a high temperature of 1400 to 1500 ° C. has become common.

  However, this method has a complicated processing process and includes operation under severe temperature conditions of 1400 to 1500 ° C., so that the life of the furnace material is short and so-called de novo synthesis in the dust removal process is avoided. Therefore, it is necessary to perform a complicated operation such as rapidly cooling the exhaust gas temperature and then raising the exhaust gas temperature again to remove NOx. As a result, not only construction costs but also maintenance costs are high, which is more expensive than it seems.

  In recent years, there has been a movement to review from troublesome waste as an energy resource, but the biggest problem at that time is that the power generation efficiency is reduced to more than 10% due to high temperature corrosion of boiler heat transfer tubes by HCl generated from waste. It cannot be exceeded. Even in this gasification melting furnace system, the high temperature corrosion problem of the boiler heat exchanger tube is not improved, and it is an energy-intensive technology in order to forcefully suppress dioxin and incinerated ash.

Abstracts of the 12th Annual Meeting of the Japan Institute of Energy (30-31 July 2003) 216-217, 220-221, 404-405

  Gas purification (removal of hydrogen chloride, hydrogen sulfide and solids) after gasification of waste is indispensable in order to realize zero emission into the environment of hazardous substances such as dioxin and high-efficiency power generation. The obstacle to gas purification is the presence of high-boiling components and tar-like substances in the pyrolysis gas. The present invention aims to purify pyrolysis gas suitable for zero emission and high-efficiency power generation while overcoming this obstacle.

  The present inventor studied the mechanism of dioxin generation in an incinerator. The amount of dioxin generated was proportional to the second to third power of the HCl concentration in the furnace, and the high temperature corrosion of the boiler heat transfer tube by HCl in the combustion gas. It is well known that the power generation efficiency does not increase because of this, but the corrosion rate of the heat transfer tube was found to be proportional to the second to the third power of the HCl concentration like dioxin. When expressed in mathematical formulas, the relationship is as follows.

[Dioxin production] ∝ [HCl concentration] ^2-3
[Corrosion rate of heat transfer tube] ∝ [HCl concentration] ^2-3
In the gasification melting method, dioxin suppression is finally achieved at a level of 0.01 ng (TEQ) / m ³ N by forcibly burning out under severe temperature conditions of 1400 to 1500 ° C. According to this study, dioxin emissions were reduced to 0.01 to 0.001 and the life of the boiler heat transfer tube was 100 by simply reducing the HCl concentration in the furnace to 1/10 in an ordinary incinerator. Extend 1000 times. If this principle is applied to waste disposal, environmentally friendly waste recycling can be realized.

  In pyrolysis, hydrogen chloride, hydrogen sulfide, dust, high-boiling components, tar-like substances, metals, and other non-combustible substances are generated in addition to combustible pyrolysis gas. In order to use the pyrolysis gas as a fuel gas for high-efficiency power generation, it is necessary to remove these contaminants by a dry process that does not involve the burden of wastewater treatment costs and loss of heat energy.

  For removal of acid gases such as hydrogen chloride and hydrogen sulfide, alkaline substances such as bicarbonate soda, carbonate soda, quicklime and slaked lime are blown into the furnace, fixed as alkali salts, and removed with a dust collector together with soot dust. However, the biggest problem with this method is that it interferes with the dust removal operation due to the high boiling point components and tar-like substances contained in the pyrolysis gas.

  It is said that the high temperature dust collector is preferable to reduce the gas temperature to 500 ° C or less from the viewpoint of the reliability of the ceramic filter to the high temperature, but even when the temperature is reduced from the decomposition temperature of 650 ° C to 500 ° C or less, Possible damage due to tar-like substances. In addition, since a normal bag filter needs to lower the gas temperature to 200 ° C. or lower, there is a high boiling point component that condenses and mists in addition to tar-like substances, which hinders heat recovery and dust collection operations. .

  The present inventor has been studying a method of adsorbing with diatomaceous earth and pumice for the purpose of removing this high boiling point component and tar-like substance, but a similar study was recently presented at the Japan Institute of Energy (12th Japan). Abstracts of Annual Conference of the Japan Institute of Energy (July 30-31, 2003) 216-217, 220-221, 404-405).

  According to the summary of the lecture, the amount of tar-like substances generated can be suppressed by about 75% by using porous activated alumina or activated bauxite as the fluidized medium of the pyrolysis furnace in the thermal decomposition of biomass plastic. The coke deposited on the activated alumina can be removed by incineration in a regeneration tower. The exhaust gas is used as a heat source for the pyrolysis furnace. Porous materials other than activated alumina and bauxite have been described as having similar properties, but no specific experimental data has been shown. In the above technology, since the activated alumina / bauxite is used as a fluid medium in a high-temperature pyrolysis furnace in the hope of decomposing the tar-like substance with the catalytic activity of decomposition of the activated alumina / bauxite, It is estimated that the suppression rate of substances is only 75%. On the other hand, in the present invention, based on the oil absorption characteristics of the porous material obtained from the experiment described later, the porous material is filled in the heat recovery device and operated in a relatively low temperature range, and a high suppression rate of 99% or more is achieved. Is essentially different from the above technique.

The present inventor conducted experiments on the absorption characteristics of various porous materials using heavy oil and asphalt instead of high boiling point components and tar-like materials. As a result, activated alumina and zeolite have a low oil absorption rate and are accompanied by decomposition and coking. Regeneration usually requires a temperature close to 700 ° C, whereas diatomaceous earth has a high oil absorption rate. When heated, it raises flames at 500-600 ° C and burns to recover and recover the absorption capacity similar to that of virgin, and activated alumina, zeolite, diatomaceous earth, and pumice that have absorbed heavy oil and asphalt all have a dry surface. However, silica gel has a low oil absorption rate and has a solid surface with oil, and the activated carbon, zeolite, and silica gel have a low oil absorption rate and are not susceptible to decomposition and coking. This is because the pore size is in the molecular order (10 to 1 nanometer). In particular, silica gel has a particularly small surface because the pore size is particularly small. For the purpose of removing asphalt and tar-like substances with high molecular weight, activated alumina and zeolite with a small pore size, and diatomaceous earth with a pore size of micron order than silica gel are most suitable for the purpose of removing solid asphalt and tar-like substances. I found out.

  In addition, the oil absorption rate per unit weight of the porous material decreases remarkably with increasing temperature, while high boiling point component mist is generated more in the heat recovery process where the temperature is reduced to the dust collection temperature than in the high temperature pyrolysis process. It was clarified that the operation of removing high-boiling components and tar-like substances in the heat recovery process rather than the pyrolysis process is important.

  In other words, in order to eliminate the adverse effects on heat recovery and dust collection operations of high-boiling components and tar-like substances, heat is recovered with a heat recovery device in which a container equipped with a heat transfer tube is filled with an adsorbent composed of a porous material. Thus, it has been found that it is particularly important that the porous substance absorbs the high-boiling components and tar-like substances that condense while lowering the gas temperature.

  According to the method of the present invention, a completely clean fuel gas can be converted without loss of thermal energy. This enables high-efficiency power generation with waste without bothering with the dioxin problem. This technique is generally effective for dry purification of pyrolysis gas, and its ripple effect is very large.

  The present inventor removes tar-like substances by adsorption and removal of porous substances having pores on the order of microns rather than activated alumina, zeolite, silica gel, etc., such as diatomaceous earth, pumice, and pulverized coal fly ash. It has been clarified through experiments on oil absorption characteristics that oil-sintered materials are more suitable, and that the oil absorption rate decreases remarkably with increasing temperature, and a porous material is filled to make use of the oil absorption characteristics. We have devised a method for absorbing and removing absorption of high-boiling components and tar-like substances that condense while lowering the gas temperature with a heat recovery device.

  According to this method, it can be expected that the removal rate of high boiling point components and tar-like substances is 99% or more. Thus, a dry refining technology for pyrolysis gas with no loss of heat energy was established.

Utilizing this principle industrially, when the waste is decomposed in a pyrolysis furnace in a reducing atmosphere at 400 to 650 ° C., the generated high-boiling components and tar-like substances are adsorbed and removed with a porous substance. After injecting an alkaline substance and fixing acidic gas such as HCl and H ₂ S, it is divided into clean gas and solid content not containing hydrogen chloride, hydrogen sulfide, etc. through a dust collector, and the obtained clean gas is used for power generation. In addition to generating electricity with an efficiency of 30% or more, solid materials are washed with water to remove alkali salts, and then used as raw materials for cement. Non-oxidized metals are recovered as resources. Efficient waste disposal methods are possible.

  In the present invention, the target pyrolysis gas is not particularly limited as long as it is a gas containing a high-boiling component / tar-like substance, and can be applied to any gas. In particular, waste pyrolysis gas is preferred.

  The target waste includes general municipal waste and industrial waste. Specific types of waste include rice cake, food waste, dust, fibers, papers, vegetation, wood, sludge, plastics, waste oil, and the like.

  Prior to the introduction into the pyrolysis furnace, these wastes are preferably fragmented and granulated in advance using a crusher or the like that is generally used, and made uniform in a regulating tank.

  The pyrolysis furnace may be a fluidized bed system, a kiln system, or a shaft furnace system, and a heat recovery unit (a heat exchanger filled with a porous adsorbent) is provided on the outlet side of the pyrolysis furnace. There are an indirect heating method and a partial combustion method in the furnace as the heating method of the pyrolysis furnace, but a simple partial combustion method is suitable.

  Pyrolysis gas generated by pyrolyzing waste usually includes high-boiling components and tar, in addition to acidic gases such as hydrogen, carbon monoxide, hydrogen chloride and hydrogen sulfide, and light flammable gases such as methane and ethane. Although high-boiling components and tar-like substances are obstructed when heat is recovered from the pyrolysis gas and the solid content is removed. In particular, when dust is removed with a normal bag filter, high boiling point components and tar-like substances must be removed.

  Therefore, in the present invention, high boiling point components and tar-like substances are porous substances such as diatomaceous earth, pumice, zeolite, activated alumina, preferably porous substances having a pore size of micron order, that is, diatomaceous earth, pumice, pulverized coal combustion. It is absorbed by an adsorbent mainly composed of sintered fly ash. Among these porous materials, diatomaceous earth is particularly preferable in terms of the ability to absorb high-boiling components and tar-like materials and their regeneration ability.

  The porous material that has absorbed the high-boiling component and tar-like material is regenerated by burning it with air in the regeneration process together with the char generated in the pyrolysis process. Regeneration is performed at 500 ° C. or higher, but the exhaust gas is preferably blown into a pyrolysis furnace and used as a part of the heat source of the pyrolysis furnace.

  There are fluidized bed, moving bed, and fixed bed as heat filling devices filled with porous materials, but moving bed has more machine operation than fluidized bed when considered as a component of pyrolysis gas purification system. However, it is excellent in terms of followability to load fluctuation, required power, wear of the absorbent, and high removal rate. In addition, the fixed bed has the disadvantage that the machine operation is more complicated than the moving bed. Although it is superior in terms of wear of the absorbent, it is equivalent in terms of followability to load fluctuation, required power, and high removal rate. Therefore, the moving bed type heat recovery unit is the best as the pyrolysis gas purification system. When the heat recovery unit is a moving bed, the regeneration process of the porous material is performed by a kiln method, etc., but in the case of a fixed bed, a plurality of fixed beds with heat transfer tubes are absorbed → regenerated → switched to the standby process While operating.

  The pyrolysis gas temperature is lowered to the operating temperature range of the dust collector, for example, 180 ° C. or less by the heat recovery device, and then guided to the dust collector to remove the fine particles. Fine particles such as fly ash and desalting agent collected by dust collectors are used as raw materials for cement after washing with water together with coarse incombustibles (other than metals such as Fe, Al, Cu, etc.) collected from the bottom of the pyrolysis furnace. Etc. can be used.

The operating temperature of the pyrolysis furnace takes into account the characteristics of impurities in the pyrolysis gas, such as the melting point of Al (660.2 ° C), the reaction temperature of Na and K with the furnace SiO ₂ (about 800 ° C). Although it should be determined, in order to reduce the amount of organic chlorine to 1% or less, the thermal decomposition temperature is preferably 450 ° C. or higher. Therefore, the operation temperature is particularly preferably 450 to 650 ° C. The conventional method of avoiding obstacles due to high boiling point components and tar-like substances was to perform thermal decomposition at a temperature close to 1000 ° C. In the present invention, a heat recovery device filled with an adsorbent made of a porous substance is used. By incorporating it, high boiling point components and tar-like substances can be removed without any loss of heat energy. This greatly improves the cold gas efficiency.

  On the other hand, in the dust collection operation, technical restrictions of the dust collector (reliability of the filter at high temperature, fusing trouble of solid substances), gas handling amount (related to the capacity of the dust collector), and hydrogen chloride removal rate (Ca-based alkaline substance) The lower the temperature, the more advantageous in terms of In other words, when a normal bag filter is used as a dust collector, the temperature must be 180 ° C. or less and the dew point of the pyrolysis gas (70 ° C. when the water vapor concentration in the pyrolysis gas is 30%) or more. Even in this case, 500 ° C. or less is preferable.

  Therefore, in the present invention, a heat recovery device in which a porous material is filled in a container equipped with a heat transfer tube for the purpose of removing high boiling point components and tar-like substances in the pyrolysis gas is provided at the outlet of the pyrolysis furnace at 400 to 650 ° C. The pyrolysis gas temperature is lowered to 70 to 500 ° C. With this heat recovery device, heat recovery and removal of high boiling point components and tar-like substances can be achieved simultaneously.

  In the case where the pyrolysis gas is a gas containing an acidic gas such as hydrogen chloride gas, it is preferable to add an alkaline substance in the form of an aerosol to the pyrolysis furnace or its outlet in order to effectively suppress the generation of dioxins. In addition, the addition method of an alkaline substance is not limited to this.

  Alkaline substances include sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium bicarbonate, potassium carbonate, potassium hydroxide, calcium oxide and calcium hydroxide, alkali metal carbonates, hydroxides and oxides that exhibit alkalinity. These may be used not only alone but also in a mixture of several kinds, and further may be a mineral resource containing them, such as limestone, dolomite, natural soda, and the like.

Further, by replacing a part of the porous material with iron ore grains, H ₂ S in the pyrolysis gas can be removed as iron sulfide according to the reaction of the formula (1).

FeO + H ₂ S = FeS + H ₂ O (1)
Furthermore, trace amounts of Zn, Pb, Mn, Cu, Cr, Ni, Cd, etc. contained in the waste are volatile chlorides in conventional waste incinerators, so they must be removed with a normal dry HCl removal system. However, in the dust collector where H ₂ S is present, the HCl concentration is low, and the temperature is relatively low, for example, volatile lead chloride is a non-volatile sulfide like the formulas (2) and (3) Becomes lead and lead oxide.

PbCl ₂ + H ₂ S = PbS + 2 HCl (2)
PbCl ₂ + H ₂ O = PbO + 2 HCl (3)
Zn, Mn, Cu, Cr, Ni, and Cd can also be removed as dust by a dust collector because they become non-volatile sulfides and oxides in the same reaction as in formulas (2) and (3). In order to reduce the release amount of these heavy metals into the atmosphere, the temperature of the dust collector is preferably as low as possible, that is, close to 70 ° C. (decomposition point of pyrolysis gas).

  The solid content recovered from the pyrolysis gas contains decomposition residue, powdered porous material, and unreacted alkaline material and alkali salt when an alkaline material is added for the purpose of removing acidic gas. This unreacted alkaline substance and alkali salt can be removed and used as an industrial raw material.

  The method for removing the alkali salt is not particularly limited, but since these are water-soluble, they can be removed by washing with water. The washing method is not limited at all and may be carried out by setting appropriate conditions. The solid content from which the alkali salt has been removed can be used as a raw material for cement.

  Coarse incombustibles recovered from the bottom of the pyrolysis furnace must be recovered from non-oxidized metals as resources, then washed with water in the same manner as fly ash recovered from pyrolysis gas and used as raw materials for cement. I can do it.

Other inventions to which the present invention is applied are as follows.
1. When waste is decomposed in a pyrolysis furnace under a reducing atmosphere at 400 to 650 ° C., an alkaline substance is added to fix acidic gas such as hydrogen chloride contained in the pyrolysis gas as an alkali salt, while pyrolysis gas The high boiling point components and tar-like substances in the pyrolysis gas are adsorbed and removed with a porous substance while collecting the thermal energy by introducing it into a heat recovery device, and the temperature is raised to the operating temperature range of the dust collector at 70 to 500 ° C And then removing solids in the pyrolysis gas using a dust collector, and using the obtained clean gas component as fuel for power generation, high-efficiency power generation is performed. It is.

  2. 1. A moving bed with a heat recovery heat transfer tube filled with a porous material at the outlet of the pyrolysis furnace is installed. This is a waste recycling method described.

  3. 1. A fixed bed with a heat recovery heat transfer tube filled with a porous substance at the outlet of the pyrolysis furnace is installed. This is a waste recycling method described.

4). The porous material is a porous material having a pore size on the order of microns, which is described in 1.2. Or 3. This is a waste recycling method described.
5). Porous material that adsorbs high-boiling components and tar-like substances is regenerated by burning with air (oxygen-enriched air) at 500 to 750 ° C., and the generated high-temperature combustion exhaust gas is used as the heat source for the pyrolysis furnace. The above 1.2.3. Or 4. This is a waste recycling method described.

  A conceptual diagram of a pyrolysis gas purification system when a fluidized bed heat recovery unit is used as an application example of the present invention is shown in FIG. Moreover, the conceptual diagram of the pyrolysis gas purification system at the time of using a moving bed type | mold heat recovery device is shown in FIG.

  Compared with the conventional waste incineration system, the combustion process is divided into two stages, the pyrolysis section (low temperature section) and the main combustion section (high temperature section), and the mechanism is somewhat complicated. Since the recovery unit is provided to cool the pyrolysis gas to 70 to 200 ° C., and the excess air ratio is much smaller than that of a conventional stoker furnace, the equipment becomes compact. Therefore, in the method of the present invention, the construction cost of the equipment is not so different from the conventional stoker furnace system.

On the other hand, the feature of the present invention is that the amount of dioxin, HCl, SOx, Zn, Pb, Mn, Cu, Cr, Ni, and Cd emitted to the environment is extremely low and the energy recovery efficiency is high.
Waste contains various types of contaminants other than combustible components, but the heat generated from waste containing substances (Cl, S, Pb, Zn) that are considered particularly harmful to the environment and energy recovery. A method for purifying cracked gas has been described. However, as a matter of course, some of the above operations are unnecessary for wastes that do not contain such harmful substances or contain only a very small amount. For example, in the case of fibers not containing chlorine, papers, vegetation, wood, sludge, plastics, and waste oil, the operation of blowing an alkaline substance into the pyrolysis furnace or its outlet is not required.

Experiments on oil absorption characteristics experimental method
Oil (heavy oil + asphalt) is injected into a Pyrex (registered trademark) test tube having a diameter of 30 mm and 200 mm, and the test tube is placed in an annular electric furnace and heated to a predetermined temperature. A weighed adsorbent (porous material) is placed in a wire mesh cage, dipped in oil in a test tube, pulled up after a certain time, and a sample that has absorbed oil is weighed. The sample amount was about 3.5 g.
2. Experimental conditions (1) Type of adsorbent (porous material) Diatomaceous earth CG4A (made by Isolite Industry, molded into approximately 4mm and fired at 1150 ° C,
Bulk specific gravity: 0.68g / cm ³ )
Diatomaceous earth CG4 (made by Isolite Industry, molded into approximately 4mm and fired at 1000 ° C
Bulk specific gravity: 0.55 g / cm ³ , pore volume: 0.57 cm ³ / g, average pore diameter: 1000 nm)
Porcelain fine powder sintered product (manufactured by Iwao Porcelain Kogyo, crushed and sieved to about 4 mm, bulk specific gravity: 1.65 g / cm ³ , pore volume: 0.27 cm ³ / g, average pore diameter: 210 nm)
Silveed N (Mizusawa Chemical, approx. 2mm spherical silica gel, bulk specific gravity: 0.82g / cm ³ ,
Pore volume: 0.30cm ³ / g, average pore diameter: 2nm)
Activated alumina (Spherical activated alumina KHO-46 manufactured by Sumitomo Chemical, size: approx. 4 mm,
Bulk specific gravity: 0.80 g / cm ³ , pore volume: 0.43 cm ³ / g, average pore diameter: 10 nm)
(2) Type of absorbing oil Heavy oil (vacuum distilled distillate desulfurized) + 10% asphalt mixture Heavy oil (vacuum distillate desulfurized) + 20% asphalt mixture (3) Test temperature 180 ° C, 2600 ℃, 350 ℃, 420 ℃, 460 ℃
3. Experimental results The experimental results are summarized in Tables 1 to 4.
Calculation method of oil absorption rate Oil absorption rate (B-A) / A = [After oil absorption B (g)-Adsorbent A (g)] / Adsorbent A (g)

4). Discussion (1) Heavy oil-In the experiment to absorb 10% asphalt in diatomaceous earth CG4A, it was measured at four temperatures of 180 ° C, 260 ° C, 350 ° C, 420 ° C, 460 ° C. -The amount of asphalt absorbed was significantly reduced. The relationship between temperature and absorption is shown in FIG. It was also found that the oil absorptivity values of 180 ° C., 260 ° C., 350 ° C., 420 ° C. and 460 ° C. are on one line regardless of the asphalt percentage.
(2) Absorption characteristics of porous materials Absorption of heavy oil-asphalt to diatomaceous earth reaches the saturation point in 1 to 3 minutes. The absorption rate at 180 ° C. reaches about 49% for diatomaceous earth calcined at 1000 ° C. and reaches about 33% for diatomaceous earth calcined at 1150 ° C. (high wear resistance). Activated alumina and silica gel have a slow absorption rate and do not reach the saturation point even after 20 minutes, but the equilibrium absorption rate is estimated to be about 30%. The relationship between time and absorption is shown in FIG. The surfaces of the diatomaceous earth and activated alumina that had absorbed the oil were not sticky and smooth, but the surface of the silica gel was sticky.

This difference in the absorption characteristics of diatomaceous earth, activated alumina, and silica gel seems to be due to the fact that the pore diameter of diatomaceous earth is on the order of microns (meters), whereas the pore diameter of activated alumina and silica gel is on the order of nanometers. The surface of the silica gel after oil absorption is considered to be sticky because the pore diameter is particularly small and the absorption rate is low.
(3) Effect of oil type It was found that the absorption characteristics of heavy oil + 10% asphalt and heavy oil + 20% asphalt did not change. In other words, at 180 ° C or higher, asphalt has sufficient fluidity as heavy oil.
(4) Regeneration The pores of activated alumina and zeolite are on the molecular order (10 to 1 nanometer), whereas the pores of diatomaceous earth are on the order of microns. Activated alumina and zeolite have a large chemisorption weight and are accompanied by decomposition and coking. Regeneration of activated alumina and zeolite with coke deposited on the surface usually requires temperatures close to 700 ° C, but diatomaceous earth that has absorbed heavy oil and asphalt burns with a flame at 500-600 ° C when heated in air. It was found that the regeneration was completed after recovering the weight and absorbency of the virgin. This seems to be due to the fact that diatomaceous earth is mainly based on physical adsorption with weak chemical adsorption.

Application example of the present invention: Conceptual diagram of a pyrolysis gas purification system using a fluidized bed heat recovery device Application example of the present invention: Conceptual diagram of a pyrolysis gas purification system using a moving bed heat recovery unit Diagram showing the relationship between temperature and oil absorption Diagram showing the relationship between time and oil absorption

Claims (5)

The pyrolysis gas containing high-boiling components and tar-like substances is led to a heat recovery unit filled with a porous material having an average pore diameter of 210 nm or more, and the temperature of the pyrolysis gas reaches the operating temperature range of the dust collector. Dry purification of pyrolysis gas, characterized in that high-boiling components and tar-like substances that condense while being lowered are adsorbed and removed by a porous substance, and then fine particles in the pyrolysis gas are removed using a dust collector. Method.   A porous material that adsorbs high-boiling components and tar-like substances is burned in a regenerator together with a char generated in a pyrolysis furnace, and the heat generated by the combustion is used as a heat source for the pyrolysis furnace. The method for dry purification of pyrolysis gas according to claim 1. The method for dry purification of pyrolysis gas according to claim 1 or 2, wherein the pyrolysis gas and an alkaline substance are brought into contact with each other, and the acidic gas in the pyrolysis gas is fixed as an alkali salt.   The method for dry purification of pyrolysis gas according to claim 1, wherein the heat recovery unit is a moving bed type heat recovery unit.   The method for dry purification of pyrolysis gas according to claim 1, wherein the porous material is a porous material having an average pore size on the order of microns.

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