WO2014184923A1 - Method for gasifying solid organic raw material and gasification device - Google Patents

Abstract

Provided is a method for gasifying solid organic raw material that uses a relatively inexpensive gasification device to gasify a solid organic raw material at a low running cost. A solid organic raw material that has been dried and crushed is inserted from the upper end of a cylindrical reaction furnace (10) that is provided with a first circular cavity (11) and a second circular cavity (12) that are formed by expanding the inner diameter of an intermediate area, steam plasma that is generated by an electric arc plasma jet (30) within the first circular cavity (11) is injected, an oxidizing agent such as air that has been heated to 200-600 °C is injected into the second circular cavity (12), and the interior of the lower end section of the reaction furnace (10) is subjected to suction via an exhaust gas passage (21). Part of the organic component of the solid organic raw material within the first circular cavity (11) is gasified by the introduction of steam plasma, introduced into the second circular cavity (12), and combusted by reaction with the oxidizing agent. The synergy of the heat generated during combustion and the heating caused by the plasma cause the remaining organic component within the raw material to gasify. As a result, efficient gasification is possible.

Description

Method and apparatus for gasifying solid organic raw material

The present invention relates to a method for gasifying solid organic raw materials, and a gasifier for carrying out the method, and more specifically, an organic matter obtained in the form of solid matter such as various wastes, coal, wood, biomass and the like The present invention relates to a method for obtaining a fuel gas by gasifying the solid organic raw material by pyrolysis with a raw material (solid organic raw material) containing components as an object to be treated, and an apparatus for obtaining the fuel gas.

As a method of using solid organic raw materials, for example, coal as fuel, there is a method of burning coal directly and taking out thermal energy, and once combusting coal and gasifying it, a flammable fuel gas is obtained. There is a method of extracting energy by burning a fuel gas.

As an example, the case of using such coal as fuel for thermal power generation will be described by way of example. In the former method, coal is burned directly in the boiler and steam is generated by heat at the time of combustion, Power generation by rotating the steam turbine under the pressure of

On the other hand, in the latter example, coal is first pyrolyzed in the gasification furnace, and the gas turbine is rotated by the expansion power obtained when the fuel gas generated by the pyrolysis is burned in the gas turbine. Is done.

In this case, it is possible to perform combined power generation that recovers power also from exhaust heat from the gas turbine by generating steam using the exhaust heat from the gas turbine further and rotating the steam turbine with this steam. Therefore, more efficient energy recovery can be performed.

In the above example, thermal power generation using coal has been described as an example, but to obtain a fuel gas by gasifying a solid organic raw material by thermal decomposition is a process such as electric power or heat by incineration of wastes It is a technology that is expected to be used in zero-emission waste incineration facilities etc. that obtain energy.

Here, the combustion of raw materials such as wastes generally taking the form of solid phase is unstable, and when the solid organic raw material is directly ignited, the temperature rises to the temperature required for the gasification process in the reaction zone It is difficult to

In particular, in the case of combustion of waste containing a large amount of water, heat is taken away by evaporation of the water, so the calorific value becomes low and it becomes difficult to continue the combustion itself.

Also, in the direct incineration of solid waste, it is difficult to achieve the temperature to burn the harmful and toxic components efficiently in the thermal decomposition zone, and dioxins and similar at low burning temperature (as an example 850 ° C or less) There is a high possibility of discharging chlorinated benzofuran (hereinafter abbreviated as "furan") having a chemical structure, and from this point as well, it is possible to temporarily gasify and use the solid organic raw material without directly burning it. An advantage is pointed out.

A method of gasifying organic fuel components of wastes using plasma arc for the purpose of maximizing utilization efficiency of thermal energy and minimizing ash and slag residual amount for gasification of such solid organic raw materials And their devices have already been proposed (US Pat. No. 5,958,264: Patent Document 1).

In the present invention, waste is introduced into a shaft furnace provided with a heating zone using two or three variable electrodes, and air and water vapor whose flow rate and ratio are optimized so as to minimize electric input energy It supplies to the heating zone in the said blast furnace.

Here, the gasification rate, generated gas components, carbon removal from organic matter in the gasification process, vitrification of slag, etc. are influenced by the temperature of the heating zone, and the main factors for securing the temperature conditions required in the furnace The most important energy source is plasma arc, but the in-furnace energy input by the plasma arc calculated from the data published for the existing equipment is 0.1 to 1.2 kWh / kg of raw material, and the latest commercialization plant (described later) Also in the garbage processing facility in Hokkaido Ukushiri described in Non-Patent Document 1), the value is about 0.3 kWh / kg of raw material.

A plasma pyrolysis and vitrification system has also been proposed (US Pat. No. 7,665,407-2): Patent Document 2). In this invention, the plasma torch circulates the exhaust gas in the main reactor in order to reduce the amount of volatile ash that comes out with the gas generated by plasma pyrolysis. The particles of volatile ash melt and are adsorbed on the inner wall of the furnace by centrifugal force.

A plasma type gasification reactor has also been proposed (US Patent Application Publication No. 2010/099557 A1: Patent Document 3), in which a plasma is generated at the bottom of a solid organic raw material layer having a high calorific value, such as coke. There is disclosed a reaction vessel having a side wall shaped upper lid which is extended as it goes to the top. The present invention is characterized in three points relating to the shape of the reaction vessel, and the shapes of the product gas outlet pipe and the raw material feeding pipe.

U.S. Patent No. 5,958,264 U.S. Patent No. 7,665,407 [2] US Patent Application Publication No. 2010/099557 557 1

As described above, although various methods and devices for gasifying solid organic raw materials to obtain fuel gas have been proposed conventionally, industrial and commercial applications of such gasification methods and gasifiers Has not progressed yet.

The main reasons for the lack of progress in industrial or commercial use of such solid organic raw material gasification methods and gasifiers are the high cost of manufacturing the gasifier and the running cost of the gasifier, It is more than selling profit of electric energy and thermal energy obtained by using the obtained fuel gas [Reference: "Technical and economic analysis of Plasma-assisted Waste-to-Energy processes", Caroline Ducharme, Columbia University September 2010 (http://www.seas.columbia.edu/earth/wtert/sofos/ducharme_thesis.pdf#search='Technical+and+economic+analysis+of++Plasmaassisted+WastetoEnergy+processes+By+Caroline+Ducharme ') ].

Here, regardless of the economic conditions of each country or region, the production cost and running cost of the gasifier are proportional to the output of the plasma generator installed in the gasifier, and a high power plasma generator is used. The more it is equipped, the higher the cost and cost of manufacturing the gasifier, and the gasifier itself becomes larger.

Therefore, if a smaller, low-power plasma generator can be used as the plasma generator equipped in the gasifier without reducing the processing capacity of the entire gasifier, the manufacturing cost and running cost of the gasifier will be reduced. It is possible to realize not only the reduction but also the reduction in size and weight of the entire gasifier.

The average efficiency of gasification by plasma in existing equipment (ratio of the amount of thermal energy of the generated synthesis gas to the total amount of energy held by the raw material and the energy used for the synthesis gas generation) is 42% The average efficiency by general gasification outside plasma is about 72%, and there is still a large room for improvement.

Therefore, the present invention was made to eliminate the drawbacks in the above-mentioned prior art, and on the premise of the above-mentioned average efficiency in gasification, by enabling the efficiency to be increased, the conventional process Advantages of gasification by plasma method by enabling realization of processing capacity equal to or higher than that of equipment, using a smaller-sized, low-power plasma generator compared to conventional processing equipment The aim is to realize the reduction in size and weight of the entire device, and the control of manufacturing costs and running costs, while maintaining the capacity.

Hereinafter, means for solving the problems will be described together with reference numerals used in the mode for carrying out the invention. This code is described to clarify the correspondence between the description of the claims and the description of the mode for carrying out the invention, and, needless to say, is limited to the interpretation of the technical scope of the present invention. It is not used.

In order to achieve the above object, the gasification method of the solid organic material of the present invention is
The granular solid organic raw material dried from one end (upper end) side in the cylindrical reactor 10 is introduced, and the reactor is moved from the one end (upper end) side to the other end (lower end) side in the reactor 10 Form a raw material column that moves in the axial direction of 10,
The high temperature steam jet generated by the electric arc plasma jet 30 is injected in the middle region (the first circular cavity 11) of the reaction furnace 10 to partially gasify the organic component in the solid organic raw material to make the fuel gas Generate,
An oxidant (air, oxygen-enriched air, or oxygen) in the reactor 10 in the region (second circular cavity 12) near the other end (lower end) with respect to the region (first circular cavity 11) in which the fuel gas is generated B) to burn the fuel gas and heat the internal average temperature of the region (the second circular cavity 12) supplied with the oxidant to 1100 to 1600 ° C. to introduce the oxidant. In the region (second circular cavity 12) and the region (gasification promoting region 13) closer to the other end (lower end) with respect to the region, the organic component remaining in the solid organic raw material is completely gasified,
The inside of the reaction furnace 10 is sucked (through the exhaust gas passage 21) at the other end (lower end) side, and the fuel gas generated from the solid organic raw material is taken out at a temperature of 850 ° C. or higher, for example 850 to 1000 ° C. (Claim 1).

In the gasification of the solid organic material, it is preferable that the blowing of the oxidant be a mixture of fuel equivalent ratio of 0.7 to 3.0 (claim 2).

In the gasification of the solid organic raw material, the steam jet is a jet of superheated steam at 2000 to 3500 ° C., and the tangential line in the circumferential direction of the inner wall of the reactor 10 through one or more electric arc plasma jets 30 Forming a circulating flow of the steam jet circulating in the reactor circumferentially by blowing the steam jet in the direction;
The inner wall of the reactor (the inner wall of the first circular cavity 11) in the portion where the circulating flow is formed is heated to 1000 to 1600 ° C. (claim 3).

Furthermore, the oxidizing agent is blown into the reaction furnace 10 while being heated to 200 to 600 ° C. (claim 4).

Maintain the temperature of the solid organic material (the temperature of the solid organic material in the gasification promoting region 13) which has passed through the region (the second circular cavity 12) to which the oxidizing agent has been supplied in the range of 900 to 1100 ° C. The oxidizing agent consumption rate αo in the oxidation is maintained in the range of 0.90 to 0.95 (claim 5).

Alternatively, when superheated steam is mixed and introduced into the oxidizing agent in the region (second circular cavity 12) to which the oxidizing agent is supplied, the temperature of the solid organic raw material passed through the region (second circular cavity 12) (The temperature of the solid organic raw material in the gasification promoting region 13) is maintained in the range of 900 to 1100 ° C., and the oxidant consumption rate αo in gasification is in the range of 1.05 to 1.20 (claim 6).

In the region (second circular cavity 12) for supplying the oxidizing agent, the moving speed of the raw material column passing through the region is reduced (claim 7).

Moreover, the gasifier 1 for solid organic materials of the present invention
A first circular cavity formed by expanding the inner diameter of the reaction furnace 10 in an intermediate region in the cylindrical reaction furnace 10 in which the raw material introduced from one end (upper end) is moved to the other end (lower end) side 11 and,
A second circular cavity formed by expanding the inner diameter of the reactor at a position near the other end separated by a distance of 0.1 to 0.5 times the inner diameter of the reactor 10 with respect to the first circular cavity 11 Set 12 and
A vapor plasma introduction passage 22 for introducing a high temperature water vapor jet jetted by an electric arc plasma jet 30 disposed outside the reaction furnace 10 is communicated with a space in the reaction furnace 10 in the first circular cavity 11,
The oxidant introducing passage 23 for introducing a heated oxidant is communicated with the space in the reactor 10 in the second circular cavity 12,
An exhaust gas passage 21 for sucking the inside of the reaction furnace 10 is communicated with the inside of the reaction furnace 10 at the other end side (claim 8).

In the gasifier 1 for the solid organic raw material having the above configuration, the vapor plasma introduction path 22 makes the circulating flow of the water vapor jet along the inner wall surface in the tangential direction in the circumferential direction of the inner wall of the first circular cavity 11 It arrange | positions so that it may arise (Claim 9).

Further, the oxidizing agent introduction path 23 is a tangential direction in the circumferential direction of the inner wall of the second circular cavity 12, and a circulating flow in the same rotational direction as the circulating flow of the steam jet generated in the first circular cavity 11 It arranges so that it may arise (claim 10).

Further, the above-mentioned exhaust gas passage 21 has a double pipe structure, and the inside of the reactor 10 is sucked through one passage (the inner passage 21a) of the exhaust gas passage 21, and the other passage (the outer The oxidant introducing passage 23 is communicated with an oxidant supply source (not shown) via the passage 21b) (claim 11).

The diameter of the second circular cavity 12 on the outlet (lower end) side is narrowed to a diameter 0.7 to 0.9 times the diameter on the inlet (upper end) side (claim 12).

Further, a region (gasification promoting region 13) from the outlet of the second circular cavity 12 to the other end of the reaction furnace 10 is from the outlet of the second circular cavity 12 to the other end of the reaction furnace 10 The inner diameter is formed to be gradually enlarged toward the end (claim 13).

According to the configuration of the present invention described above, according to the method of gasifying a solid organic raw material and the gasifier 1 of the present invention, the following remarkable effects can be obtained.

In the first circular cavity 11 provided in the middle region of the reactor 10, a portion of the organic component in the solid organic raw material is gasified by vapor plasma to generate a highly reactive fuel gas, and (2) By combining the circular cavity 12 with an oxidant (air, oxygen-rich air, or oxygen) and burning it, the heat of several times (about 2 to 5 times) the amount of energy by the steam plasma is generated, and these energies By performing the complete gasification of the organic components remaining in the solid organic raw material by the sum of the electric energy of the plasma and the heat energy obtained by burning the highly reactive fuel gas, Compared to the conventional plasma type gas generator, fuel gas can be generated efficiently even when using a small plasma generator.

As described above, according to the present invention, it becomes possible to use a smaller plasma generator, so that the manufacturing cost and running cost of the gasifier can be reduced, and the entire gasifier can be compact and lightweight. It was possible to

In addition, by keeping the manufacturing cost and running cost of the gasifier low, the sales profit of power and heat obtained by the fuel gas obtained by gasification is relatively increased, and as a result, it is industrial or commercial It is possible to provide a gasification method and a gasification apparatus for solid organic raw material that can ride on the base.

Front sectional drawing of the gasifier of this invention. II-II sectional view taken on the line of FIG. Side surface principal part sectional drawing of the gasification apparatus of this invention. IV-IV sectional view taken on the line of FIG. It is a correlation diagram of the temperature and the component of the fuel gas synthesized by the decomposition of the solid organic raw material, (A): air plasma 245 g, (B): air plasma 1200 g, (C): vapor plasma for decomposition per kg of raw material 64 g, (D) is an example using 314 g of vapor plasma. The graph which showed the power consumption with respect to the raw material per unit mass (1 kg). The graph which showed the output energy of the fuel gas obtained from the raw material of unit mass (1 kg). The correlation figure of the temperature and the product component at the time of gasifying wood with vapor plasma. The correlation diagram of the reaction gas temperature for every particle diameter of a raw material (wood), and the raw material particle surface temperature. The correlation diagram of the reaction gas temperature and the gasification rate for every particle size of a raw material (wood). The graph which showed the component and temperature change at the time of fuel gas combustion. It is a correlation diagram of the fuel equivalence ratio and the flame propagation velocity at the time of combustion of fuel gas, and as fuel gas, (A) is 5% CO + 95% H ₂ , (B) is 50% CO + 50% H ₂ , (B) is 75 example using% CO + 25% H _2.

Next, embodiments of the present invention will be described below with reference to the attached drawings.

[Configuration of gasifier]
Reference numeral 1 in FIGS. 1 to 4 is a gasifier according to the present invention. This gasifier 1 is a cylindrical reactor 10 made of a refractory material and surrounded by a heat insulating material 3; A supply device 40 for charging solid organic raw material inside, a plasma jet 30 for introducing vapor plasma into the reactor 10 (see FIGS. 3 and 4), and air, oxygen-rich air or oxygen in the reactor 10 And an oxidant source (not shown) for introducing the oxidant.

On the above-mentioned reactor 10, a supply device 40 with a motor 41 is provided. With this supply device 40, granular solid organic raw materials such as waste, wood, charcoal, coal, etc. crushed in the reactor 10 However, it is possible to supply a fixed amount each by the stirring blade 42 rotated by the motor 41.

A first circular cavity 11 formed by expanding the inner diameter of the reactor 10 is formed in an intermediate region of the reactor 10, and the inner diameter of the reactor 10 is set to 0 with respect to the first cylindrical cavity 11. 2. A second circular cavity 12 is provided at the lower side by a distance of 2 to 0.5 times and similarly formed by expanding the inner diameter of the reaction furnace.

The second circular cavity 12 is formed in a shape of gradually narrowing the diameter at its bottom, and the outlet of the second circular cavity 12 which becomes the narrowest part has a diameter of 0. 0 to the diameter of the inlet of the second circular cavity 12. It is narrowed to 7 to 0.9 times the diameter.

The outlet of the second circular cavity 12 mentioned above is in communication with the gasification promoting region 13 which is formed to expand in diameter downward from the diameter of the outlet of the second circular cavity 12.

At least one electric arc plasma jet 30 is provided outside the reaction furnace 10 thus formed, and the vapor plasma generated by the electric arc plasma jet 30 is introduced via the vapor plasma introduction passage 22. It can be introduced into the first circular cavity 11 described above.

The vapor plasma introduction passage 22 is provided on the inner wall surface of the first circular space 11 so as to be able to introduce the vapor plasma in a tangential direction with respect to the circumferential direction of the inner wall surface. The jet of superheated steam can be circulated in the first circular cavity 11 by introducing the vapor plasma into the first circular cavity 11 via 22.

At the bottom of the reactor 10, a circular exchanger 9 is attached which heats the introduced water by heat exchange to generate steam so that steam can be supplied into the reactor 10, where it is generated here When steam is generated by mixing the treated steam with the plasma jet and the oxidant introduced into the second circular cavity 12 if necessary, or by using it as the steam introduced from the lower part of the gasification promoting region 13 The lower portion of the reactor is cooled by heat exchange, and a residual ash discharging device 50 equipped with a motor 51 for forcibly discharging residual ash is attached under the circular exchanger 9.

Near the lower part in the reaction furnace 10, an exhaust gas passage 21 for discharging the generated gas (fuel gas) in the reaction furnace 10 is provided. The exhaust gas passage 21 is constituted by a double pipe in the illustrated embodiment, and can suck and discharge the fuel gas generated in the reaction furnace 10 through the inner passage 21a, and the outer passage 21b. Can be used to introduce an oxidant (air, oxygen-enriched air, oxygen) into the second circular cavity 12.

In order to make it possible to introduce such an oxidizing agent, an oxidant supply joint 21c is provided in the vicinity of the end opposite to the reaction channel 10 of the exhaust gas passage 21, and this joint 21c is illustrated By making it possible to connect piping etc. from a different oxidizing agent supply source, and by communicating the oxidizing agent introducing passage 23 for introducing the oxidizing agent into the second circular cavity 12 in the outer passage 21b at a position close to the reactor 10 The oxidizing agent supplied from the oxidizing agent source, not shown, is heated by heat exchange with the fuel gas passing through the inner passage 21a when passing through the outer passage 21b of the exhaust gas passage 21, and thus A heated oxidizer can be introduced into the second circular cavity 12.

The aforementioned oxidizing agent introducing passage 23 is opened in the inner wall surface of the second circular cavity 12 in a tangential direction with respect to the circumferential direction of the inner wall (see FIG. 2). By introducing it, a circulation flow of the oxidant having the same rotational direction as the circulation direction of the steam jet generated in the first circular cavity 11 described above is generated.

[Gasification method]
Gasification of a solid organic raw material is performed by the following method using the gasifier 1 of this invention comprised as mentioned above.

When the water content is dried to 15 to 20% and the crushed solid organic raw material is put into the supply device 40, the supply device 40 quantitatively determines the raw material by the stirring blade 42 rotated by the motor 41 into the reaction furnace 10 Supply.

The residual ash of the solid organic raw material generated by thermal decomposition in the reaction furnace 10 is forcibly discharged to the outside by the residual ash discharging device 50 provided at the lower part of the reaction furnace 10. The solid organic material introduced into the container is folded in a state where a gap is formed between the particles of the solid organic material by gravity, and passes through the inside of the reaction furnace 10 in the axial direction in a state similar to the porous body as a whole Form a raw material column.

The high temperature (2000-3500 ° C.) vapor plasma generated in the electric arc plasma jet 30 is introduced tangentially into the first circular cavity 11 through the vapor plasma introduction passage 22 and then the particles of the solid organic material are separated. Flow forward through the interstices to form a vortex-like flow circulating in the first circular cavity 11.

The inner wall surface of the first circular cavity 11 is heated to 1000 to 1600 ° C. by the swirling flow of the vapor plasma, and the solid organic substance in the first circular cavity 11 is directly heated by the vapor plasma and contacting with the red wall of the reactor. While a part (15 to 30% by mass) of the organic component in the raw material is gasified, it reacts with water vapor to generate a fuel gas by the reaction represented by the following general reaction formula.

In the case where steam plasma of 2000 ° C. or less is injected into the reactor 10, the heating temperature for the raw material column is reduced and the gasification rate is also reduced because the heating temperature of the reactor wall is reduced. When the temperature of the superheated steam to be introduced is set to 3500 ° C. or higher, dissociative recombination occurs and the heat conduction of steam rapidly rises, so that the loss for cooling the electric arc plasma jet 30 and the steam plasma introduction path 22 rapidly Because of the increase, as described above, the temperature of the vapor plasma introduced into the first circular cavity 11 is set to 2000 to 3500.degree.

Also, if the heating temperature of the reactor wall is less than 1000 ° C, the reaction rate of the organic matter decreases and the conversion rate decreases, while if the reactor wall temperature exceeds 1600 ° C, serious problems regarding the life and durability of the reactor The temperature of the vapor plasma introduced to the first circular cavity 11 is adjusted within the range of 2000 to 3500 ° C. mentioned above so that the heating temperature of the reactor wall is in the range of 1000 to 1600 ° C. .

Since the space in the reactor 10 is sucked from the outside via the exhaust gas passage 21, the fuel gas generated in the first circular cavity 11 by this effect reacts at a temperature of about 1100 to 1200 ° C. It moves downward along the inner wall of the furnace 10 and is introduced into the second circular cavity 12 (see FIG. 1).

The inside of the second circular cavity 12 is generated in the second circular cavity 12 so that a swirling flow in the same circulation (rotation) direction as the circulation (rotation) direction of the steam jet generated in the first circular cavity 11 described above occurs. An oxidant (air, oxygen-enriched air, or oxygen) is blown in a direction tangential to the circumferential direction of the wall through an oxidant introduction path indicated by reference numeral 23 (see FIG. 2).

This oxidizing agent is configured to be introduced into the above-described oxidizing agent introducing passage 23 through the outer flow passage 21b of the exhaust gas passage 21 configured as a double pipe through the joint 21c, and the exhaust gas passage In 21, the oxidizing agent heated to 200 to 600 ° C. by heat exchange with the fuel gas discharged through the inner passage 21 a of the exhaust gas passage 21, and thus the heated oxidant is introduced into the second circular cavity 12. The fuel gas generated in the first circular cavity 11 and then introduced into the second circular cavity 12 exceeds the ignition temperature (more than 650 ° C.) even after merging with the jet of the oxidant. In the second circular cavity 12, a flame flow with a local temperature of 2227 ° C. or more is generated.

If the heating temperature of the oxidizing agent is less than 200 ° C, the process of oxidation and gasification is hardly affected, and if it is heated to over 600 ° C, the heat of the fuel gas is removed by heat exchange and exhausted. After leaving the reactor after the temperature of the fuel gas falls below the allowable temperature of 850 ° C, there is a possibility that dioxins and furans may be generated by the combination of halogen and hydrocarbon, and the temperature of the oxidant to be introduced Was set to 200 to 600.degree.

In order to achieve the maximum value of the output by combustion of this fuel gas, the fuel equivalent ratio (mass of fuel gas / mass of oxidant) α f is set to 0.7 to 3.0, preferably 1.5 to 3.0. Combustion in the state of rich mixing. The general main reaction in oxidation is

It becomes.

By burning the fuel gas in this manner, an oxidation region is generated in the portion of the raw material column existing around the second circular cavity 12 of the reactor, and the internal average temperature of the second circular cavity 12 is 1100 to 1600. Reaching ° C.

Thus, under the influence of the heat generated in the second circular cavity 12, the entire raw column is heated to an average temperature of 1100 to 1600 ° C. under adiabatic filter combustion conditions, and then the second circular cavity It is introduced into the gasification promoting region 13 provided below 12.

In the gasification promoting region 13 located below the second circular cavity 12 in the reactor, the raw material from which excess oxidant and fuel gas combustion products not used for oxidation in the second circular cavity 12 fall The thermal decomposition of the main organic components remaining in the solid organic feedstock is performed, which is sprayed laterally to the columns.

The solid organic raw material heated in the second circular cavity 12 maintains the average temperature in the range of 900 to 11000 ° C., and the oxidant consumption rate α for the stoichiometry gasification in the range of 0.90 to 0.95 Do.

When the temperature of the solid organic raw material is less than 900 ° C., the residual carbon content increases, and when it exceeds 1100 ° C., the melted lump of the solid organic raw material remains, and the incineration performance of the organic impurities is deteriorated.

In addition, when the oxidant consumption rate α is less than 0.90, the power consumption for the thermal decomposition increases, and in the thermal decomposition stage, the incomplete combustion increases in the exhaust gas, while the oxidant consumption rate α is 0.95. If the temperature is exceeded, the temperature level of thermal decomposition may rise, and the grate provided at the bottom of the apparatus may burn.

As the oxidizing agent introduced to the second circular cavity 12, superheated steam may be introduced together with the above-mentioned oxidizing agent which is air, oxygen-rich air, or oxygen. In this case, the temperature at the thermal decomposition stage of the residual organic component in the gasification promoting region 13 is maintained in the range of 900 to 1100 ° C., and the oxidant consumption rate α is in the range of 1.05 to 1.20.

Below 900 ° C, unburned slag increases, and above 1100 ° C ash dissolution and lattice contamination occur.

When the oxygen consumption rate α is less than 1.05, the mass exchange with the residual carbon of the oxidant is deteriorated, and the incomplete combustion is increased. If the oxidant consumption rate α exceeds 1.20, this leads to an increase in energy consumption (fuel and power) for the process.

The reduction rate of the raw material column charged into the reactor 10 is proportional to the gasification rate, and the mass of the organic component of the gasified solid organic raw material is the separated amount of volatile components, the mass of the residual carbon gasified The raw material column moves downward with continuous decrease due to the decrease of solid organic material and the discharge of residual ash, and the generated fuel gas is ventilated through the exhaust gas passage 21 When it passes through the exhaust gas passage 21, it is aspirated, and heat exchange with the oxidant is performed, and the air is exhausted to the outside at a temperature of 850 to 1000 ° C.

It is supplied by superheated steam generated by plasma so that the average temperature range of the solid organic material in the second circular cavity 12 is 1100 to 1600 ° C., and the temperature range of the fuel gas at the outlet of the reactor is 850 to 1000 ° C. The ratio between the amount of heat and the amount of chemical heat from combustion of the fuel gas produced thereby is determined.

In the gasifier 1 of the present invention, a temperature zone is set along the moving direction of the raw material column (height direction of the reaction furnace), and the above-described process is performed in each temperature zone.

In the upper part of the reactor (above the first circular cavity 11), the average temperature inside is 100 to 250 ° C., and the solid organic raw material which is waste etc. is dried. Part of the raw material is gasified by steam plasma at ~ 1300 ° C, and heat generation by oxidation (combustion) of part of the fuel gas occurs at an internal average temperature of 1100-1600 ° C in the second circular cavity 12 below it. And in the gasification promoting region 13 below the second circular cavity 12, the residual organic component in the solid organic material is filtered and burned, and the inorganic component oxygen-free gasification produced by the decomposition of the solid organic material, synthesis gas production by reduction of the complete combustion products takes place, a predominantly CO + H ₂ components.

In the first circular cavity 11, the heat applied by the vapor plasma causes an endothermic reaction of the solid organic raw material, and a part of it is converted into fuel gas. The chemical energy of the solid organic feedstock is not lost here, but is converted into the chemical energy of the fuel gas and the thermal energy.

When the raw material is biomass, the energy generated is approximately three times the input power energy, this energy is generated in the second circular cavity 12, and the solid organic raw material is heated to a temperature of 1100 to 1600 ° C. Used for complete gasification of raw materials.

According to the gasification method of the present invention, the electric energy initially input to the electric arc plasma jet 30 and the power consumption during operation can be reduced to 3 to 5 times while maintaining the processing capacity of the solid organic raw material As compared with the existing industrial process (the treatment facility in Hokkaido Uzushi, previously introduced as non-patent document 1), the gasification apparatus 1 of the present invention can be reduced in the treatment apparatus of non-patent document 1 by The same processing capacity can be changed to the design of four 75 kW plasma jets, while four 300 kW plasma jets were used, and with the miniaturization of plasma jets, the cost of producing a gasification system Power consumption can be reduced to a quarter (75kW / 300kW = 1/4), which leads to a reduction in running costs, which is a large case for commercial use. Made with an advantage.

In the present invention, the novel communication structure, the shape, the size, and the combination thereof of the respective parts constituting the gasification device 1 are important features, and as described above, in the gasification device 1 of the present application, a cylindrical reactor A first circular cavity 11 is provided in the middle part of 10, and below the first circular cavity 11, the second circular cavity 12 is separated by a distance 0.2 to 0.5 times the diameter of the reactor. The diameter of the bottom of the second circular cavity 12 is gradually reduced to make the diameter of the narrowest part (the outlet of the second circular cavity 12) 0.7 of the diameter of the upper end (the inlet of the second circular cavity 12). Further, the shape of the gasification promoting region 13 formed below the second circular cavity 12 is configured to expand in diameter further downward from the narrowest portion. doing.

Further, the vapor plasma generated by the electric arc plasma jet 30 is introduced into the first circular cavity 11 in the tangential direction through the vapor plasma introduction passage 22 to generate a circulating flow of the water vapor jet, and the second circular shape The oxidizing agent heated in the cavity 12 is introduced tangentially via the oxidizing agent introducing passage 23 in such a direction that a circulating flow in the same rotational direction as the circulating flow of the steam jet in the first circular cavity 11 is generated.

By configuring each part in this manner, in the gasifier 1 of the present invention, a portion of the granular solid organic raw material that is relatively incombustible, mainly contains CO and H ₂ in the first circular cavity 11. It becomes a reactive combustion gas, and then the entire solid organic raw material is vigorously heated by burning the fuel gas previously generated in the second circular cavity 12, whereby the organic components remaining in the solid organic raw material are gasified Be done.

In the present invention, partial gasification of organic components by vapor plasma and fuel obtained by this gasification are compared with the gasification rate of particulate solid organic raw materials in an acidic environment, that is, the gasification rate by combustion alone. The gasification rate can be greatly improved by performing complete gasification of the organic component remaining in the solid organic raw material by the mixed process of gas combustion, and as a result, the chemical energy output of the solid organic raw material Power consumption of the electric arc plasma jet 30 can be reduced to three to five times.

The distance between the first circular cavity 11 that performs gasification with vapor plasma and the second circular cavity 12 that burns the generated fuel gas is selected in the range of 0.1 to 0.5 times the diameter of the reactor The reason is that if the distance is less than 0.1 times, the steam jet flows into the second circular cavity 12 to suppress the combustion reaction, and if the distance is more than 0.5 times, (1) The fuel gas generated in the circular cavity 11 flows into the gaps between the particles of the solid organic raw material, and the fuel gas introduced into the second circular cavity 12 is reduced, and the calorific value is significantly reduced. .

In addition, the bottom diameter of the second circular cavity 12 is gradually narrowed, and the diameter of the outlet of the second circular cavity 12 which is the narrowest portion is 0.7 to 0.9 times the diameter of the inlet of the second circular cavity 12 And the provision of the gasification promoting region 13 having a shape of expanding the diameter further downward from the outlet of the second circular cavity 12, the outlet passage of the second circular cavity 12 of the solid organic raw material is restricted. As a result, the residence time of the solid organic raw material in the second circular cavity 12 is lengthened and the heating of the raw material is promoted, and the amount of solid organic raw material in the second circular cavity 12 is one. Since the wall temperature becomes higher than the slug melting temperature in the gasification promoting region 13 below the partial gasification and the gasification promoting region 13 in the lower part of the furnace, the sludge is a furnace by expanding the tail of the gasification promoting region 13 Attach to the inner wall Thereby preventing the door.

Also, from the outer peripheral side to surround the raw material column by forming a circulating flow in which the jet flow direction of the superheated steam and the jet flow direction of the flame flow generated by the introduction of the oxidizing agent and the moving direction of the raw material mutually cross By performing the heating, it is possible to efficiently perform the filtration combustion in an adiabatic state in which the heat is confined in the raw material column.

The maximum heat output area of the reactor, ie the diameter of the bottom outlet of the second circular cavity 12 is adapted to the mass loss rate of the solid organic feedstock, and if less than 0.7 with respect to the diameter of the inlet, the advancement of the feedstock (Falling) may be too late and thermal burnout may occur. On the other hand, if it exceeds 0.9 with respect to the diameter of the upper end portion, the advance of the raw material will be quick, and the unreacted raw material will flow into the gasification promoting region 13 in a state of being increased.

[Comparison of vapor plasma and gasification by other methods]
Chicken manure, a solid organic material, was gasified by the method of the present invention. Table 1 shows the components of chicken feces before treatment, and Table 2 shows the components of fuel gas obtained by gasification.

The lower heating value (LHV) of the combustion gas obtained by the method of the present invention is 12.09.
It is MJ / kg, and the adiabatic combustion temperature is 1937 ° C.

When chicken manure is used as a raw material, the amount of oxidant consumption g (g / kg) used when thermally decomposing 1 kg of chicken manure is as follows.

From the results in Table 3 above, in the vapor plasma type gasification, the consumption of the oxidant (oxygen) is significantly reduced compared to the air plasma type gasification. It can be seen that it has the function of

That is, by applying vapor plasma to the raw material layer in the first circular cavity 11 of the reactor, the raw material is heated, and water and volatile components are gradually converted from the solid phase into a gaseous state, that is, evaporated. At the same time, homogeneous conversion of gaseous volatile components is performed by the following main reaction.

The amount of reduction of the raw material column in the reactor substantially corresponds to 0.25, which is the consumption ratio of water and volatile components in the raw material due to evaporation. As the raw material column is consumed, the whole raw material column moves downward, and the solid organic raw material in the first circular cavity 11 approaches the second circular cavity 12 and the drying area is above the first circular cavity 11 The solid organic raw material present in is introduced into the first circular cavity 11.

Next, the heterogeneous reaction of residual carbon and water vapor is carried out by the following main reaction.

In the diffusion kinetic mode, since the heterogeneous reaction is performed, the reactant (vapor) is sent to the residual carbon by the turbulent flow and swirling of the vapor, and the gasification product is discharged.

By examining the concentration profiles of hydrogen (H ₂ ) and carbon monoxide (CO) in the outer layer part of the raw material column in the first circular cavity 11, the mutual between their concentration and mass concentration change of carbon in solid phase The important fact that it is related was found. That is, it can be seen that, in the method of the present invention, the main cause of the change in mass concentration of hydrogen and carbon monoxide is that carbon contained in the solid organic raw material is vaporized.

Therefore, by adjusting the molar flux ratio of water vapor to the molar flux of carbon atoms, the composition of the gasification product can be determined, and in the first circular cavity 11, close to the stoichiometric ideal value Gasification can be performed.

5 (A) to 5 (D) are graphs showing the temperature at the time of gasification of chicken manure with plasma and the component change of the synthesized fuel gas, and FIG. 5 (A) shows 245 g of air plasma. The example used (Comparative Example 1), FIG. 5 (B) is an example using 1200 g of air plasma (Comparative Example 2), and (C) is an example using 64 g of steam plasma (Example 1), (D) is a steam The example (Example 2) which used plasma 314g is each shown.

Fig. 6 shows the power consumption (MJ / kg) required to process the raw material per unit mass (1 kg) in Examples 1 and 2 and Comparative Examples 1 and 2. Fig. 7 further shows Examples 1 and 2 and The output energy (MJ / kg) of the fuel gas obtained from the raw material of unit mass (1 kg) in Comparative Examples 1 and 2 is shown.

From the results of FIGS. 5 (A) to 5 (D), according to the gasification method of the present invention using a vapor plasma, a smaller amount of plasma can be used to obtain a fuel gas of the same component as compared to the case using an air plasma. That was confirmed.

The consumption of vapor plasma required for treatment of 1 kg of raw material in gasification varies depending on the material of the solid organic raw material which is the raw material, but 64 g / kg when the above mentioned chicken manure is treated (Example 1 The dry wood was treated at 326 g / kg, and the waste tire was treated at 1.2 kg / kg.

Also, according to FIG. 6 and FIG. 7, in the gasification of the present invention using steam plasma, it is possible to obtain fuel gas with higher output energy with less power consumption compared to using air plasma. It has been confirmed that when gasification is performed using vapor plasma, it is confirmed that an improvement in efficiency of about 3 times at maximum can be obtained as compared to the case where gasification is performed using air plasma (Comparison of Example 2 and Comparative Example 2 in FIG. 6).

In addition, in the gasification by the vapor plasma which used the crushed wood as a raw material, the result of having measured what kind of difference arises in the component of the gas produced | generated by the change of process temperature is shown in FIG.

According to the results shown in FIG. 8, the generation of H ₂ and CO peaks at about 1300 K (1026.84 ° C.), and then the generation of H ₂ and CO hardly changes with the increase of temperature. It is advantageous to carry out heating under the condition that the heating temperature of the solid organic raw material becomes 1100 ° C. or higher, since such a temperature is 2000 ° C. in the tangential direction in the first circular cavity 11. This can be realized by blowing in steam superheated to -3500 ° C.

[Influence of particle size]
The change in surface temperature of wood particles by particle size with respect to the temperature change of the reaction gas is shown in FIG. 9, and the change in gasification rate by particle size with respect to the temperature change in the reaction gas is shown in FIG.

As apparent from FIGS. 9 and 10, even if the temperature of the reaction gas (superheated steam) is the same, the surface temperature of the wood rises and the gasification becomes more pronounced as the particle size of the wood to be treated becomes smaller. It can be seen that the rate increases, and it can be seen that the gasification by the superheated steam can be promoted as the surface area of the raw material increases with the decrease of the particle size.

In order to improve the generation rate of carbon monoxide (CO) and hydrogen (H ₂ ) in the gas component generated from the particle surface of the solid organic raw material which is the raw material, increase the heat flow from the reactor wall toward the particle surface Needed, because the heat flow due to radiation is proportional to the surface area, this can be achieved not only by the temperature rise of the wall, but also by the increase of the surface area with the decrease of the particle size of the solid organic raw material (see FIGS. The advantage of using solid organic raw materials in the crushed state as a processing target is supported.

[Mixing ratio with oxidant at the time of combustion (fuel equivalent ratio)]
Since the combustion rate, heat generation rate (see FIG. 11), and flame propagation rate (see FIGS. 12A to 12C) at the time of combustion of the fuel gas are sufficiently fast, in the second circular cavity 12, by the combustion of the fuel gas The heat output heats the raw materials without delay.

12 (A) to 12 (C) show fuel equivalent ratios (mass of fuel gas / oxidant) for three samples different in the composition of carbon monoxide (CO) and hydrogen (H ₂ ) under conditions close to the inside of the reactor. It is the result of measuring the change of the flame speed accompanying the change of the mass of.

The flame propagation speed decreases as the content of carbon monoxide (CO) increases, and when the initial temperature rises, the propagation speed also increases, but in all cases, the fuel equivalence ratio α f is as high as about 2 Propagation velocity reaches a peak, and the fuel equivalence ratio α f is in the range of concentrated air-fuel ratio of 0.7 to 3.0, preferably 1.5 to 3.0, including before and after this value. For example, it can be seen that a high heat transfer rate can be obtained in any case (FIGS. 12A to 12C).

The fuel equivalent ratio was calculated by determining the amount of fuel gas generated in the first circular cavity 11 based on the stoichiometry of the solid organic raw material remaining without gasification in the first circular cavity 11.

[Effect confirmation test]
Test Example 1
Using the experimental apparatus, the gasification of the solid organic raw material according to the method of the present invention was performed under the conditions shown in Table 4 below. The components of the fuel gas produced by this gasification are shown in Table 5, respectively.

In the above test example, when the fuel equivalence ratio is 1, the combustion temperature of the combustion products achieves the maximum value, and the maximum combustion temperature of the combustion products when the biomass is processed is 1900 ° C., and the waste mixture model is The maximum combustion temperature of the combustion product when treated was 1700 ° C. The carbon monoxide (CO) in the combustion product was less than 0.5%.

In the test example in which biomass was gasified, a fuel gas with a calorific value of 11.03 MJ / m ³ was output at 12.5 liters / minute. The heat output at the time of combustion of this fuel gas in air was 2.3 kW.

That is, in the gasification of biomass described above, the chemical energy generated by the combustion of the produced gas is 2.3 kW while the power consumption is 0.55 kW. Therefore, the total heat capacity input to the reactor is “0.55 + 2.3 = 2.85 kW”, and the increase relative to the input heat quantity (0.55 kW) is “2.85 / 0.555
The gasification could be performed with high efficiency.

In the test example in which the mixture model was gasified, a fuel gas with a calorific value of 8.17 MJ / m ³ was output at 10.0 liters / minute. The heat output at the time of combustion of this fuel gas in air was 1.36 kW.

That is, in the gasification of the mixed model described above, the chemical energy generated by the generated gas combustion is 1.36 kW while the power consumption is 0.55 kW. Therefore, the total heat capacity input to the reactor is “0.55 + 1.36 = 1.91 kW”, and the increase with respect to the input (0.55 kW) is “1.91 / 0.55 ≒ 3.47 times”. Even when using any of the raw materials, gasification could be performed with high efficiency.

Test example 2
Plasma jet input -100kW. Processing capacity of waste (medical waste)-53 kg / h, water flow-27 kg / h. Plasma jet temperature-2800 ° C. Reactor internal temperature -1100 ° C. Product gas components,% by _{weight: Н 2 - 65, СО- 35} . Calorific value-11, 42 MJ / mn3. Generated gas output (1, 5 mn3 / kg)-80, 0 mn3. Heat quantity at the time of gas combustion-253 kW. Total amount of heat in the furnace 353 kW. Depending on the chemical energy of the raw material, the total amount of heat is 3, 53 times the input power. In the above, “mn3” is a cubic meter of gas at a temperature of 20 ° C.

1 gasification device 3 heat insulating material 9 circular exchanger 10 reaction furnace 11 first circular cavity (zone 1)
12 Second circular cavity (zone 2)
13 Gasification promotion area (zone 3)
21 Exhaust gas passage 21a Inner passage 21b Outer passage 21c Joint 22 Steam plasma introduction passage 23 Oxidizing agent introduction passage 30 Electric arc plasma jet 40 Supply device 41 Motor 42 Stirring blade 50 Residual ash discharge device 51 Electric motor

Claims (13)

1. A granular solid organic raw material dried from one end side in a cylindrical reaction furnace is introduced, and a raw material column moving in the axial direction of the reaction furnace from the one end side to the other end side is formed in the reaction furnace ,
   In the middle region of the reactor, a high temperature steam jet generated by an electric arc plasma jet is injected to partially gasify the organic component in the solid organic raw material to generate a fuel gas,
   An oxidant is blown into the reaction furnace in a region near the other end with respect to the region where the fuel gas is generated to burn the fuel gas, and the raw material column is heated in the region where the oxidant is supplied. Completely gasify the organic component remaining in the solid organic material in the region where the oxidizing agent is introduced and the region closer to the other end with respect to the region,
   A method of gasifying a solid organic material, comprising: drawing the inside of the reaction furnace at the other end side and taking out a fuel gas generated from a solid organic material at a temperature of 850 ° C. or higher.
2. The method for gasifying a solid organic raw material according to claim 1, wherein the blowing of the oxidizing agent is performed so that the fuel equivalent ratio becomes a mixture of 0.7 to 3.0.
3. The steam jet is a jet of superheated steam at 2000 to 3500 ° C., and the steam jet is blown in a tangential direction in the circumferential direction of the inner wall of the reactor through one or more electric arc plasma jets. Forming a circulating flow of the steam jet circulating in the circumferential direction,
   The method for gasifying a solid organic raw material according to claim 1 or 2, wherein the inner wall of the reactor in the portion where the circulating flow is formed is heated to 1000 to 1600 ° C.
4. The method for gasifying a solid organic raw material according to any one of claims 1 to 3, wherein the oxidizing agent is blown into the reaction furnace while being heated to 200 to 600 属 C.
5. Maintain the temperature of the solid organic raw material passed through the region where the oxidizing agent is supplied in the range of 900 to 1100 ° C., and maintain the oxidizing agent consumption rate in the gasification in the range of 0.90 to 0.95 The method for gasifying a solid organic raw material according to any one of claims 1 to 4, characterized in that
6. Superheated steam is mixed and introduced into the oxidizing agent in the region where the oxidizing agent is supplied, the temperature of the solid organic raw material passed through the region is maintained in the range of 900 to 1100 ° C., and the oxidizing agent consumption in gasification The method for gasifying a solid organic raw material according to any one of claims 1 to 4, wherein the rate is in the range of 1.05 to 1.20.
7. The method for gasifying a solid organic raw material according to any one of claims 1 to 6, wherein the moving speed of the raw material column passing through the area is decreased in the area where the oxidizing agent is supplied.
8. A first circular cavity formed by expanding the inner diameter of the reaction furnace in an intermediate region in a cylindrical reaction furnace in which a raw material introduced from one end is moved to the other end and processed,
   A second circular cavity is formed by expanding the inner diameter of the reactor at a position near the other end separated by a distance of 0.1 to 0.5 times the inner diameter of the reactor with respect to the first circular cavity. ,
   A vapor plasma introduction passage for introducing a high temperature steam jet jetted by an electric arc plasma jet disposed outside the reactor is communicated with the space in the reactor at the first circular cavity,
   The oxidant introducing passage for introducing the heated oxidant is communicated with the space in the reactor in the second circular cavity, and
   An apparatus for gasifying a solid organic raw material, wherein an exhaust gas passage for drawing the inside of the reaction furnace is communicated with the inside of the reaction furnace at the other end side.
9. 9. The solid organic raw material according to claim 8, wherein the vapor plasma introduction path is arranged in a tangential direction in a circumferential direction of the inner wall of the first circular cavity so as to generate a circulating flow of water vapor jet along the inner wall surface. Gasifier.
10. The oxidant introduction path is disposed tangentially in the circumferential direction of the inner wall of the second circular cavity so as to produce a circulating flow in the same rotational direction as the circulating flow of the steam jet generated in the first circular cavity The gasifier of the solid organic material according to claim 9, characterized in that.
11. The exhaust gas passage has a double pipe structure, and the inside of the reaction furnace is sucked through one of the exhaust gas passages, and the oxidant introduction passage is communicated with the oxidant supply source through the other passage. A gasifier for a solid organic material according to any one of claims 8 to 10, characterized in that
12. The solid according to any one of claims 8 to 11, wherein the diameter of the outlet side of the second circular cavity is narrowed to a diameter 0.7 to 0.9 times the diameter of the inlet side. Gasification method of organic raw materials.
13. A region from the outlet of the second circular cavity to the other end of the reactor is formed in such a shape that the inner diameter is gradually expanded from the outlet of the second circular cavity toward the other end of the reactor A gasifier for a solid organic raw material according to any one of claims 8 to 12, characterized in that
    

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