JPWO2014184923A1 - Gasification method and gasification apparatus for solid organic raw material - Google Patents

Abstract

Gasification of solid organic raw materials is performed at a low running cost using a relatively inexpensive gasifier. From the upper end of the cylindrical reactor 10 having the first circular cavity 11 and the second circular cavity 12 formed by expanding the inner diameter of the intermediate region, the dried and crushed solid organic raw material is charged, and the first circular cavity 11, vapor plasma generated by an electric arc plasma jet 30 is injected into the second circular cavity 12, and an oxidant such as air heated to 200 to 600 ° C. is injected into the second circular cavity 12. The inside of the lower end of 10 is sucked. Due to the introduction of the vapor plasma, the organic components in the solid organic raw material in the first circular cavity 11 are partially gasified and introduced into the second circular cavity 12 to react with the oxidant and burn, thereby generating heat and plasma during combustion. Efficient gasification was made possible by gasifying organic components remaining in the raw material by a synergistic effect with heating by means of.

Description

  TECHNICAL FIELD The present invention relates to a gasification method for solid organic raw materials and a gasification apparatus for carrying out the method, and more specifically, an organic material obtained in the state of solids such as various wastes, coal, wood, and biomass. The present invention relates to a method of obtaining a fuel gas by gasifying the solid organic raw material by pyrolysis using a raw material containing a component (solid organic raw material) 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 are a method of directly combusting coal to extract thermal energy, and a method of obtaining a combustible fuel gas by once pyrolyzing and gasifying coal. There is a method for extracting energy by burning fuel gas.

  As an example, the case where such coal is used as a fuel for thermal power generation will be described as an example. In the former method, the coal is directly combusted in a boiler, and steam is generated by the heat during combustion. It becomes a conventional thermal power generation that generates electricity by rotating a steam turbine at a pressure of.

  In contrast, in the latter example, coal is first pyrolyzed in a gasifier, and the gas turbine is rotated by the expansion force obtained when the fuel gas generated by the pyrolysis is burned in the gas turbine. Is done.

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

  In the above example, thermal power generation using coal was described as an example. However, to obtain fuel gas by gasifying solid organic raw material by pyrolysis, it is necessary to incinerate waste, such as electric power and heat. It is a technology that is expected to be used even in zero-emission type waste incineration facilities that obtain energy.

  Here, in general, combustion of raw materials such as waste in the form of solid phase is unstable, and when solid organic raw materials are directly ignited, the temperature is raised to the temperature required for the gasification process in the reaction zone. It is difficult to do.

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

  In direct incineration of solid waste, it is difficult to achieve a temperature that efficiently burns harmful and toxic components in the pyrolysis region. At low combustion temperatures (for example, 850 ° C. or lower), dioxins and similar substances can be used. Chlorinated benzofuran (hereinafter abbreviated as “furan”) with a chemical structure is highly likely to be discharged. From this point of view as well, solid organic raw materials can be used once gasified without direct combustion. Advantages have been pointed out.

  Regarding the gasification of such solid organic raw materials, a method of gasifying waste organic fuel components using plasma arc for the purpose of maximizing the utilization efficiency of thermal energy and minimizing the amount of ash / slag residue And its device have already been proposed (US Pat. No. 5,958,264: Patent Document 1).

  In this invention, waste and waste are put 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. Supply to the heating zone in the blast furnace.

  Here, the gasification rate in the gasification process, the generated gas components, the removal of carbon from organic substances, the vitrification of slag, etc. depend on the temperature of the heating zone, and are the main factors for ensuring the required temperature conditions in the furnace. The main energy source is plasma arc, but the energy input in the furnace by plasma arc calculated from the data publicly available for existing equipment is 0.1-1.2kWh / kg of raw material. The waste disposal facility in Hokkaido Utashi described in Non-Patent Document 1) is about 0.3 kWh / kg of raw material.

  A plasma-type pyrolysis and vitrification system has also been proposed (US Pat. No. 7,665,407 В2: Patent Document 2). In the present invention, the plasma torch circulates the exhaust gas in the main reactor in order to reduce the amount of volatile ash generated together with the gas generated by plasma pyrolysis. Volatile ash particles melt and are adsorbed on the furnace wall by centrifugal force.

  A plasma type gasification reactor has already been proposed (US 2010/0199557 А1 publication: Patent Document 3), where plasma is generated at the bottom portion where a solid organic material layer having a high calorific value, for example, coke is located. A reaction vessel having a side-wall-shaped top lid that expands toward the top is disclosed. The present invention is characterized by three points regarding the shape of the reaction vessel and the shapes of the product gas outlet pipe and the raw material input pipe.

US Pat. No. 5,958,264 US Pat. No. 7,665,407 В2 US Application Publication No. 2010 / 0199557А1

“Achieving“ Zero Waste ”with Plasma Arc Technology” Louis J. Circeo, Ph.D. and others (http://www.slideserve.com/kaili/achieving-zero-waste-with-plasma-arc-technology)

  As described above, although various methods and apparatuses for obtaining fuel gas by gasifying solid organic raw materials have been proposed in the past, industrial and commercial use of such gasification methods and gasifiers. Is still not progressing.

  The main reasons for the lack of industrial or commercial use of such solid organic raw material gasification methods and gasifiers are the high production costs of gasifiers and the running costs of gasifiers. It is to exceed the sales profit of electric energy and thermal energy obtained by using the obtained fuel gas [Ref: "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 the high-power plasma generator is The more equipped, the higher the production cost and running cost of the gasifier, and the larger the gasifier itself.

  Therefore, the production cost and running cost of the gasifier can be reduced if a smaller and lower output plasma generator can be used in the gasifier without reducing the overall processing capacity of the gasifier. In addition to making it possible, it is possible to reduce the overall size and weight of the gasifier.

  In addition, the average efficiency of gasification by plasma in the existing equipment (ratio of the amount of heat energy of the generated synthesis gas to the sum of the amount of energy held in the raw material and the amount of energy used to generate the synthesis gas) is 42%. In addition, the average efficiency of gasification other than plasma is about 72%, and there is still much room for improvement.

  Therefore, the present invention has been made to eliminate the above-mentioned drawbacks of the prior art, and on the premise of the above-mentioned average efficiency in gasification, it is possible to increase the efficiency of the conventional processing. By realizing a processing capacity equal to or better than that of the equipment using a plasma generator that is smaller and has a lower output compared to conventional processing equipment, the advantages of gasification by the plasma method can be achieved. The objective is to reduce the size and weight of the entire device, and reduce manufacturing and running costs while maintaining the capability.

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

In order to achieve the above object, the gasification method of the solid organic raw material of the present invention comprises:
A granular solid organic raw material dried from one end (upper end) side in a cylindrical reaction furnace 10 is introduced, and the reaction furnace 10 moves from the one end (upper end) side to the other end (lower end) side. Forming a raw material column moving in the axial direction of 10;
In the intermediate region (first circular cavity 11) of the reactor 10, a high-temperature water vapor jet generated by the electric arc plasma jet 30 is injected to partially gasify organic components in the solid organic raw material, thereby generating fuel gas. Generated,
Oxidant (air, oxygen-rich 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 where the fuel gas is generated (first circular cavity 11). ), The fuel gas is combusted, and the internal average temperature of the region where the oxidant is supplied (second circular cavity 12) is heated 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,
At the other end (lower end) side, the inside of the reactor 10 is sucked (through the exhaust gas passage 21), 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 raw material, it is preferable that the oxidizing agent is blown into an air-fuel mixture having a fuel equivalent ratio of 0.7 to 3.0.

In the gasification of the solid organic raw material, the steam jet is a superheated steam jet of 2000 to 3500 ° C., and is tangential in the circumferential direction of the inner wall of the reactor 10 through one or more electric arc plasma jets 30. Forming a circulation flow of the steam jet circulating in the circumferential direction in the reactor by blowing the steam jet in a 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).

  While maintaining the temperature of the solid organic raw material that has passed through the region (second circular cavity 12) to which the oxidant has been supplied (the temperature of the solid organic raw material in the gasification promotion region 13) in the range of 900 to 1100 ° C., the gas The oxidant consumption rate αo in the conversion is maintained in the range of 0.90 to 0.95 (Claim 5).

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

  In the region where the oxidant is supplied (second circular cavity 12), the moving speed of the raw material column passing through the region is reduced (Claim 7).

Moreover, the gasification apparatus 1 of the solid organic raw material of this invention is
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 for processing while moving the raw material charged from one end (upper end) to the other end (lower end) side 11 and
A second circular cavity formed by expanding the inner diameter of the reaction furnace at a position near the other end that is 0.1 to 0.5 times the inner diameter of the reaction furnace 10 with respect to the first circular cavity 11. 12
A vapor plasma introduction path 22 for introducing a high-temperature steam jet jetted by an electric arc plasma jet 30 arranged outside the reactor 10 is communicated with the space in the reactor 10 in the first circular cavity 11;
An oxidant introduction path 23 for introducing a heated oxidant communicates with the space in the reaction furnace 10 in the second circular cavity 12, and
An exhaust gas passage 21 for sucking the inside of the reaction furnace 10 communicates with the inside of the reaction furnace 10 on the other end side (claim 8).

  In the solid organic raw material gasification apparatus 1 having the above-described configuration, the vapor plasma introduction path 22 circulates the water vapor jet flow 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).

  In addition, the oxidant introduction path 23 is tangential in the circumferential direction of the inner wall of the second circular cavity 12, and has a circulation flow in the same rotational direction as the circulation flow of the water vapor jet generated in the first circular cavity 11. It arrange | positions so that it may arise (Claim 10).

  Further, the above-described exhaust gas passage 21 has a double pipe structure, and the inside of the reaction furnace 10 is sucked through one passage (inner passage 21a) of the exhaust gas passage 21, and the other passage (outer side). The oxidant introduction path 23 is communicated with an oxidant supply source (not shown) via the passage 21b).

  The second circular cavity 12 has a shape in which the diameter 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.

  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 connected to the other end of the reactor 10 from the outlet of the second circular cavity 12. It forms in the shape which expands an internal diameter gradually toward (claim 13).

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

  A part of the organic component in the solid organic raw material is gasified by vapor plasma in the first circular cavity 11 provided in the intermediate region of the reaction furnace 10 to generate highly reactive fuel gas. Two round cavities 12 are combined with an oxidant (air, oxygen-rich air, or oxygen) and burned to generate heat that is several times (approximately 2 to 5 times) the amount of energy generated by vapor plasma. By total gasification (total of electric energy of plasma and thermal energy obtained by burning highly reactive fuel gas), the organic components remaining in the solid organic raw material are completely gasified, Compared with the conventional plasma type gas generator, even when a small plasma generator was used, fuel gas could be generated efficiently.

  As described above, in the present invention, as a result of using a smaller plasma generator, it is possible to keep the manufacturing cost and running cost of the gasifier low, and to make the entire gasifier small and light. I was able to.

  In addition, by keeping the production cost and running cost of the gasifier low, sales profits such as electric power and heat obtained from the fuel gas obtained by gasification are relatively increased. As a result, industrial or commercial It was possible to provide a gasification method and gasification apparatus for a solid organic material that can be used as a base.

The front sectional view of the gasifier of the present 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 components of fuel gas synthesized by the decomposition of the solid organic raw material. (A) is the air plasma 245g, (B) is the air plasma 1200g, (C) is the vapor plasma. 64g, (D) is an example using 314g 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 a unit mass (1 kg). Correlation diagram of temperature and product components when wood is gasified with vapor plasma. The correlation diagram of the reaction gas temperature for every particle diameter of raw material (wood), and raw material particle surface temperature. The correlation figure of the reaction gas temperature and gasification rate for every particle diameter of a raw material (wood). The graph which showed the component and temperature change at the time of fuel gas combustion. A correlation diagram of a fuel equivalence ratio and the flame propagation speed at the time of combustion of the fuel gas, as a fuel gas, (A) is _{5% CO + 95% H 2} , (B) is _{50% CO + 50% H 2} , (B) 75 Example using% CO + 25% H ₂ .

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

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

  A supply device 40 with an electric motor 41 is provided on the reaction furnace 10 described above. By this supply device 40, granular solid organic raw materials such as waste, wood, charcoal, and coal crushed in the reaction furnace 10 are provided. However, a constant amount can be supplied by the stirring blade 42 rotated by the electric motor 41.

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

  The second circular cavity 12 is formed in a shape that gradually decreases in diameter at the bottom, and the outlet of the second circular cavity 12 that is the narrowest part is 0. 0 relative to the diameter of the inlet of the second circular cavity 12. It is narrowed to a diameter of 7 to 0.9 times.

  The outlet of the second circular cavity 12 described above communicates with a gasification promoting region 13 formed in a shape whose diameter increases 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 reactor 10 formed as described above, and vapor plasma generated by the electric arc plasma jet 30 is passed through the vapor plasma introduction path 22. It can be introduced into the first circular cavity 11 described above.

  The vapor plasma introduction path 22 is provided on the inner wall surface of the first circular space 11 so that the vapor plasma can be introduced in a direction tangential to the circumferential direction of the inner wall surface. By introducing the vapor plasma into the first circular cavity 11 through 22, the jet of superheated steam can be circulated in the first circular cavity 11.

  At the bottom of the reaction furnace 10, a circular exchanger 9 for generating steam by heating the introduced water by heat exchange is attached so that steam can be supplied into the reaction furnace 10. The generated water vapor is mixed with a plasma jet or an oxidant introduced into the second circular cavity 12 as necessary, or is used as a vapor flowing from the lower part of the gasification promoting region 13, so that water vapor is generated. The lower part of the reaction furnace is cooled by heat exchange, and a residual ash discharge device 50 equipped with an electric motor 51 for forcibly discharging residual ash is attached below the circular exchanger 9.

  An exhaust gas passage 21 for discharging the generated gas (fuel gas) in the reaction furnace 10 is provided near the lower part in the reaction furnace 10. 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 can also discharge the outer passage 21b. It can be used to introduce an oxidant (air, oxygen-rich air, oxygen) into the second circular cavity 12 via.

  In order to enable the introduction of such an oxidant, a joint 21c for supplying an oxidant is provided near the end of the exhaust gas passage 21 opposite to the reaction path 10, and this joint 21c is not shown. By connecting a pipe or the like from the oxidant supply source, the oxidant introduction path 23 for introducing the oxidant into the second circular cavity 12 is connected to the outer passage 21b at a position near the reaction furnace 10. The oxidant supplied from the oxidant supply 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 in this way. A heated oxidant can be introduced into the second circular cavity 12.

  The aforementioned oxidant introduction path 23 is opened in a tangential direction with respect to the circumferential direction of the inner wall on the inner wall surface of the second circular cavity 12 (see FIG. 2), and the oxidant is passed through the oxidant introduction path 23. By introducing the oxidant, a circulating flow of the oxidizing agent having the same rotational direction as the circulating direction of the water vapor jet generated in the first circular cavity 11 is generated.

[Gasification method]
Using the gasifier 1 of the present invention configured as described above, gasification of a solid organic raw material is performed by the following method.

  When the moisture 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 puts the raw material into the reactor 10 by a fixed amount by the stirring blades 42 rotated by the electric motor 41. Supply.

  The residual ash of the solid organic raw material generated by thermal decomposition in the reaction furnace 10 is forcibly discharged out of the apparatus by a residual ash discharge device 50 provided at the lower part of the reaction furnace 10. The solid organic raw material charged in is folded in a state where a gap is formed between the particles of the solid organic raw material by gravity, and passes through the reactor 10 in the axial direction in a state similar to a porous body as a whole. Form raw material pillars.

  The high temperature (2000-3500 ° C.) vapor plasma generated in the electric arc plasma jet 30 is introduced into the first circular cavity 11 through the vapor plasma introduction path 22 in the tangential direction, and then between the particles of the solid organic raw material. A vortex-like flow circulating in the first circular cavity 11 is formed by flowing forward through the gap.

The inner wall surface of the first circular cavity 11 is heated to 1000 to 1600 ° C. by the vortex flow of the vapor plasma, and the solid organic matter in the first circular cavity 11 is brought into contact with the direct heat from the vapor plasma and the red hot wall of the reactor. A part (15 to 30% by mass) of the organic component in the raw material is gasified, and reacts with water vapor to generate fuel gas by the reaction shown by the following general reaction formula.

  When steam plasma of 2000 ° C. or less is injected into the reaction furnace 10, the superheat temperature of the reaction furnace wall is lowered and the amount of heating to the raw material column is also reduced. When the temperature of the superheated steam to be introduced is 3500 ° C. or higher, dissociation recombination occurs and the heat conduction of the water vapor rapidly increases, so that the loss for cooling the electric arc plasma jet 30 and the steam plasma introduction path 22 is rapidly increased. Since it increases, the temperature of the vapor plasma introduced into the first circular cavity 11 is 2000 to 3500 ° C. as described above.

  Moreover, when the heating temperature of the reaction furnace wall is less than 1000 ° C., the reaction rate of the organic matter is reduced and the conversion rate is lowered. On the other hand, when the reaction furnace wall temperature exceeds 1600 ° C., serious problems regarding the life and durability of the reaction furnace Therefore, the temperature of the vapor plasma introduced into the first circular cavity 11 is adjusted within the range of 2000 to 3500 ° C. so that the heating temperature of the reaction furnace wall is in the range of 1000 to 1600 ° C. .

  Since the space in the reactor 10 is sucked from outside the apparatus through the exhaust gas passage 21, the fuel gas generated in the first circular cavity 11 due to this influence 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).

  In the second circular cavity 12, a vortex flow in the same circulation (rotation) direction as the circulation (rotation) direction of the water vapor jet generated in the first circular cavity 11 is generated. An oxidant (air, oxygen-rich air, or oxygen) is blown in a tangential direction with respect to the circumferential direction of the wall surface through an oxidant introduction path indicated by reference numeral 23 (see FIG. 2).

  This oxidant is configured to be introduced into the oxidant introduction path 23 via the outer flow path 21b of the exhaust gas path 21 configured as a double pipe through the joint 21c. 21 is heated to 200-600 ° C. by heat exchange with the fuel gas discharged through the inner passage 21 a of the exhaust gas passage 21, and the oxidant thus heated is introduced into the second circular cavity 12. As a result, the fuel gas generated in the first circular cavity 11 and then introduced into the second circular cavity 12 exceeds the ignition temperature (650 ° C. or higher) even after merging with the oxidant jet. , Reacts violently with the oxidant and burns, thereby generating a flame flow having a local temperature of 2227 ° C. or more in the second circular cavity 12.

  When the heating temperature of the oxidant is less than 200 ° C, it hardly affects the oxidation and gasification process. When heating to over 600 ° C, the heat of the fuel gas is excessively removed by heat exchange and discharged. After the temperature of the fuel gas falls below the allowable temperature of 850 ° C and exits the reactor, dioxins and furans may be generated due to the combination of halogen and hydrocarbons. Was 200-600 degreeC.

となる。In order to achieve the maximum value of the output due to combustion of the fuel gas, the fuel equivalent ratio (mass of fuel gas / mass of oxidant) αf is 0.7 to 3.0, preferably 1.5 to 3.0 Combustion is performed in a dense mixed state. The overall 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. Reach ℃.

  In this way, the entire raw material column is heated to an average temperature of 1100-1600 ° C. under the insulated filtration combustion conditions under the influence of heat generated in the second circular cavity 12, and then the second circular cavity. 12 is introduced into the gasification promotion region 13 provided below the gas.

  In the gasification promotion region 13 located below the second circular cavity 12 in the reactor, the raw material from which excess oxidant and combustion products of fuel gas that have not been used for oxidation in the second circular cavity 12 fall. The main organic components remaining in the solid organic raw material are thermally decomposed, sprayed laterally to the column.

  The solid organic raw material heated in the second circular cavity 12 maintains an average temperature in the range of 900 to 11000 ° C. and an oxidant consumption rate α for stoichiometric gasification in the range of 0.90 to 0.95. To 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., a molten mass of the solid organic raw material remains and the incineration performance of organic impurities deteriorates.

  Further, when the oxidant consumption rate α is less than 0.90, the power consumption for pyrolysis increases, and in the pyrolysis stage, incomplete combustion increases in the exhaust gas, while the oxidant consumption rate α becomes 0.95. If exceeded, the temperature level of pyrolysis rises and the grate provided at the bottom of the device may burn.

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

  When the temperature is 900 ° C. or lower, unburned slag increases, and when the temperature is 1100 ° C. or higher, ash is dissolved and lattice contamination occurs.

  When the oxygen consumption rate α is less than 1.05, the mass exchange with the residual carbon of the oxidant deteriorates and incomplete combustion increases. When the oxidant consumption rate α exceeds 1.20, it leads to an increase in energy consumption (fuel and electric power) applied to the process.

  The rate of decrease of the raw material column introduced into the reactor 10 is proportional to the gasification rate, the mass of the organic component of the gasified solid organic material is the amount of volatile components separated, and the mass of residual carbon gasified. The raw material column moves downward as the solid organic raw material is reduced and the residual ash is discharged, and the continuous processing is performed, and the generated fuel gas is discharged by the ventilator through the exhaust gas passage 21. When it is sucked and passes through the exhaust gas passage 21, heat exchange with the oxidant is performed and discharged outside the apparatus 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 raw 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 generated by the combustion of the fuel gas produced thereby is determined.

  In the gasifier 1 of the present invention, the temperature zone is set along the moving direction of the raw material column (the height direction of the reactor), 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 internal average temperature is 100 to 250 ° C., and the solid organic raw material such as waste is dried. In the first circular cavity 11, the internal average temperature is 1000 Part of the raw material is gasified by vapor plasma at ˜1300 ° C., and heat generation due to oxidation (combustion) of part of the fuel gas occurs in the second circular cavity 12 below it at an internal average temperature of 1100 to 1600 ° C. In the gasification promotion region 13 below the second circular cavity 12, the residual organic component in the solid organic raw material is filtered and burned, and the inorganic oxygen-free gasification caused by the decomposition of the solid organic raw material and The synthesis gas is generated by the reduction of the complete combustion product, and mainly becomes a component of CO + H ₂ .

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

  When the raw material is biomass, the generated energy is approximately three times the input power energy. This energy is generated in the second circular cavity 12, and the whole solid organic raw material is heated to 1100-1600 ° 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 are reduced to 1/5 while maintaining the processing capability of the solid organic raw material. Compared to the existing industrial process (processing facility in Hokkaido Utashi introduced as Non-Patent Document 1 above), the gasifier 1 of the present invention is Although four 300kW plasma jets were used, the same processing capacity could be changed to the design of four 75kW plasma jets. Can be reduced, and the power consumption can be reduced to about one-quarter (75kW / 300kW = 1/4), leading to a reduction in running costs, which is large when considered on a commercial basis. Is an advantage.

  In the present invention, the novel communication structure, shape, size, and combination thereof of each part constituting the gasifier 1 are important features. As already described, in the gasifier 1 of the present application, the cylindrical reactor A first circular cavity 11 provided in an intermediate portion of the first circular cavity 11 is formed, and a second circular cavity 12 is provided below the first circular cavity 11 with a distance of 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 so that the diameter of the narrowest part (the outlet of the second circular cavity 12) is 0.7 of the diameter of the upper end (the inlet of the second circular cavity 12). The diameter of the gasification promoting region 13 formed below the second circular cavity 12 is further expanded from the narrowest portion to the lower side by reducing the diameter to .about.0.9 times. 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 via the vapor plasma introduction path 22 to generate a circulation flow of the water vapor jet, and the second circular shape. The oxidant heated in the cavity 12 is introduced in a tangential direction via the oxidant introduction path 23 in a direction in which a circulation flow in the same rotational direction as the circulation flow of the water vapor jet flow in the first circular cavity 11 is generated.

By configuring each part in this manner, in the gasifier 1 of the present invention, a part of the granular solid organic raw material that is relatively incombustible mainly contains CO and H ₂ in the first circular cavity 11. After the fuel gas generated in the second circular cavity 12 burns in the second circular cavity 12, the entire solid organic raw material is heated intensely, thereby gasifying the organic components remaining in the solid organic raw material. Is done.

  Compared to the rate of gasification of granular solid organic raw materials in an acidic environment, that is, the rate of gasification only by combustion, in the present invention, partial gasification of organic components by vapor plasma and the fuel obtained by this gasification The gasification rate can be greatly improved because of the complete gasification of the organic components remaining in the solid organic raw material through a gas combustion mixing process, resulting in a chemical energy output of the solid organic raw material. As a result, the power consumption of the electric arc plasma jet 30 can be reduced to 3 to 1/5.

  The distance between the first circular cavity 11 for gasification by vapor plasma and the second circular cavity 12 for burning the generated fuel gas is selected within a range of 0.1 to 0.5 times the diameter of the reactor. The reason for this is that when it is provided at a distance less than 0.1 times, the steam jet flows into the second circular cavity 12 to suppress the combustion reaction, and when it is provided at a distance exceeding 0.5 times, This is because the fuel gas generated in the first circular cavity 11 flows into the gaps between the particles of the solid organic raw material, the fuel gas introduced into the second circular cavity 12 is reduced, and the calorific value is greatly reduced. .

  Also, 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 part is 0.7 to 0.9 times the diameter of the inlet of the second circular cavity 12. The gasification promoting region 13 having a shape that expands further downward from the outlet of the second circular cavity 12 is provided, so that the passage of the solid organic raw material through the second circular cavity 12 is restricted. As a result, the residence time of the solid organic raw material in the second circular cavity 12 having the highest heat output is prolonged, the heating of the raw material is promoted, and the amount of the solid organic raw material is one in the second circular cavity 12. Since the wall surface temperature becomes higher than the sludge melting temperature in the gasification promotion region 13 below the gasification promotion region 13, the sludge is removed from the furnace by widening the bottom of the gasification promotion region 13. Adhering to the inner wall It is prevented.

  In addition, by forming a circulating flow in which the jet direction of the superheated steam and the flame flow generated by the introduction of the oxidant and the direction of movement of the raw material are orthogonal to each other, As a result of this heating, filtration combustion can be performed efficiently in an adiabatic state where heat is confined in the raw material column.

  The maximum heat output region of the reactor, that is, the diameter of the bottom outlet of the second circular cavity 12 is adapted to the mass reduction rate of the solid organic raw material. (Falling) may become too late and heat burnout may occur. On the other hand, when the diameter exceeds 0.9 with respect to the diameter of the upper end portion, the progress of the raw material is accelerated, and the unreacted raw material portion increases and flows into the gasification promotion region 13.

[Comparison of gasification by vapor plasma and other methods]
Chicken manure, which is a solid organic raw material, was gasified by the method of the present invention. Table 1 shows the components of chicken manure 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.
The adiabatic combustion temperature was 1937 ° C.

  When chicken dung is used as a raw material, the oxidant consumption g (g / kg) used when pyrolyzing 1 kg of chicken dung is as follows.

  From the results in Table 3 above, the steam plasma type gasification consumes significantly less oxidant (oxygen) than the air plasma type gasification. It can be seen that it has a function as

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

  The reduction amount of the raw material column in the reaction furnace substantially corresponds to 0.25 which is a consumption ratio due to evaporation of moisture and volatile components in the raw material. As the raw material pillar is consumed, the whole raw material pillar moves downward, the solid organic raw material in the first circular cavity 11 approaches the second circular cavity 12, and the drying region above the first circular cavity 11. The solid organic raw material suitable for the above is introduced into the first circular cavity 11.

Next, the heterogeneous reaction between residual carbon and water vapor is performed by the following main reaction.

  Since the heterogeneous reaction takes place in the diffusion kinetic mode, the reactant (steam) is sent to residual carbon and the gasification product is discharged by the turbulent / vortex flow of the steam.

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

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

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

  6 shows the power consumption (MJ / kg) required for processing the raw material per unit mass (1 kg) in Examples 1 and 2 and Comparative Examples 1 and 2, and FIG. 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 shown in FIGS. 5A to 5D, in the gasification method of the present invention using vapor plasma, a fuel gas of the same component can be obtained with a smaller amount of plasma than when air plasma is used. I was able to confirm.

  The consumption of vapor plasma required for processing per kg of raw material in gasification varies depending on the material of the solid organic raw material that is the raw material, but 64 g / kg when the above-described chicken manure is used as a processing target (Example 1). ), 326 g / kg when dry wood was treated, and 1.2 kg / kg when waste tire was treated.

  Also, from FIGS. 6 and 7, the gasification of the present invention using vapor plasma shows that a fuel gas with higher output energy can be obtained with less power consumption than when air plasma is used. It has been confirmed that when gasification is performed using vapor plasma, the efficiency can be improved up to about 3 times compared to gasification using air plasma. (Comparison between Example 2 and Comparative Example 2 in FIG. 6).

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

From the results shown in FIG. 8, the generation amount of H ₂ and CO reaches a peak when the temperature exceeds about 1300 K (1026.84 ° C.), and then the generation amount of H ₂ and CO hardly changes as the temperature rises. Therefore, it is advantageous to heat the solid organic raw material under the condition that the heating temperature of the solid organic raw material is 1100 ° C. or higher. Such a temperature is 2,000 in the tangential direction in the first circular cavity 11. It can be realized by blowing water vapor heated to ˜3500 ° C.

[Effect of particle size]
FIG. 9 shows the change in the surface temperature of the wood particles for each particle diameter with respect to the temperature change of the reaction gas, and FIG.

  As is clear from FIGS. 9 and 10, even when the temperature of the reaction gas (superheated steam) is the same, as the particle size of the wood to be treated decreases, the surface temperature of the wood increases and gasification occurs. It can be seen that the rate increases, and that gasification by superheated steam can be promoted as the surface area of the raw material increases as the particle size decreases.

In order to improve the generation rate of carbon oxide (CO) and hydrogen (H ₂ ) in the generated gas component on the particle surface of the solid organic raw material which is the raw material, the heat flow from the reactor wall toward the particle surface is increased. Since the heat flow by radiation is proportional to the surface area, this can be achieved not only by increasing the wall temperature, but also by increasing the surface area as the particle size of the solid organic material decreases (see FIGS. 9 and 10). ), The advantage of using a crushed solid organic raw material as a processing target is confirmed.

[Mixing ratio with oxidant during combustion (fuel equivalent ratio)]
Since the combustion speed, heat generation speed (see FIG. 11), and flame propagation speed (see FIGS. 12A to 12C) during the combustion of the fuel gas are sufficiently fast, the second circular cavity 12 is caused by the combustion of the fuel gas. Heat output heats the raw material without delay.

12 (A) to 12 (C) show fuel equivalent ratios (mass of fuel gas / oxidizer) for three samples having different blends of carbon oxide (CO) and hydrogen (H ₂ ) under conditions close to that in the reactor. It is the result of having measured the change of the flame speed accompanying the change of the mass).

  The flame propagation speed decreases as the carbon oxide (CO) content increases, and as the initial temperature rises, the propagation speed increases. In either case, the fuel equivalent ratio αf is a high concentration of about 2 The velocity of propagation reaches a peak in this gas, and the fuel equivalent ratio αf including the range before and after this value should be in the range of a rich mixture with a value of 0.7 to 3.0, preferably 1.5 to 3.0. In any case, it can be seen that a high heat transfer rate can be obtained [FIGS. 12A to 12C].

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

[Effect confirmation test]
Test example 1
Using the experimental apparatus, the solid organic raw material was gasified by the method of the present invention under the conditions shown in Table 4 below. Table 5 shows the components of the fuel gas generated by this gasification.

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

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

That is, in the gasification of biomass described above, the chemical energy generated by the combustion of the generated gas is 2.3 kW for a power consumption of 0.55 kW. Therefore, the total heat capacity input to the reactor is “0.55 + 2.3 = 2.85 kW”, and the increase with respect to the input heat quantity (0.55 kW) is “2.85 / 0.55≈
5.2 times ", and gasification with high efficiency was achieved.

In the test example in which the mixed model was gasified, fuel gas with a calorific value of 8.17 MJ / m ³ was output at 10.0 liters / minute. The heat output during combustion of the 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 product gas combustion is 1.36 kW for the power consumption of 0.55 kW. Therefore, the total heat capacity input to the reactor is “0.55 + 1.36 = 1.91kW”, and the increase with respect to the input (0.55kW) is “1.91 / 0.55≈3.47 times”. , No matter which raw material was used, gasification could be performed with high efficiency.

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

DESCRIPTION OF SYMBOLS 1 Gasifier 3 Heat insulating material 9 Circular exchanger 10 Reactor 11 1st 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 Oxidant introduction passage 30 Electric arc plasma jet 40 Supply device 41 Electric motor 42 Stirring blade 50 Residual ash discharge device 51 Electric motor

Claims (13)

A dry granular solid organic raw material is introduced from one end side of a cylindrical reactor, and a raw material column that moves in the axial direction of the reactor from the one end side to the other end side is formed in the reaction furnace. ,
Injecting a high-temperature steam jet generated by an electric arc plasma jet in an intermediate region of the reactor to partially gasify an 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, the fuel gas is burned, and the raw material column is heated in the region where the oxidant is supplied. , And completely gasifying the organic component remaining in the solid organic raw material in the region where the oxidant has been introduced and the region closer to the other end relative to the region,
A gasification method for a solid organic material, wherein the inside of the reaction furnace 10 is sucked on the other end side, and a fuel gas generated from the solid organic material is taken out at a temperature of 850 ° C. or more.   2. The method of gasifying a solid organic raw material according to claim 1, wherein the oxidizing agent is blown so as to be a mixture having a fuel equivalent ratio of 0.7 to 3.0. The steam jet is a superheated steam jet of 2000 to 3500 ° C., and the reactor is formed by blowing the steam jet in the tangential direction in the circumferential direction of the inner wall of the reactor through one or more electric arc plasma jets. Forming a circulation flow of the water vapor 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 reaction furnace in the portion where the circulating flow is formed is heated to 1000 to 1600 ° C.   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 ° C.   Maintaining the temperature of the solid organic raw material that has passed through the region where the oxidant has been supplied in the range of 900 to 1100 ° C., and maintaining the oxidant consumption rate in the gasification within the range of 0.90 to 0.95. The gasification method of the solid organic raw material of any one of Claims 1-4 characterized by these.   In the region where the oxidant is supplied, superheated steam is mixed and introduced into the oxidant, and the temperature of the solid organic raw material passing through the region is maintained in the range of 900 to 1100 ° C. The gasification method according to any one of claims 1 to 4, wherein the rate is in the range of 1.05 to 1.20.   The method for gasifying a solid organic raw material according to any one of claims 1 to 6, wherein in the region where the oxidant is supplied, the moving speed of the raw material column passing through the region is reduced. A first circular cavity formed by expanding the inner diameter of the reaction furnace in an intermediate region in a cylindrical reaction furnace that is processed while moving the raw material charged from one end to the other end;
A second circular cavity formed by extending the inner diameter of the reaction furnace at a position near the other end that is 0.1 to 0.5 times the inner diameter of the reaction furnace with respect to the first circular cavity is provided. ,
A steam plasma introduction path for introducing a high-temperature steam jet jetted by an electric arc plasma jet arranged outside the reactor is communicated with the space in the reactor in the first circular cavity;
An oxidant introduction path for introducing a heated oxidant communicates with the space in the reactor in the second circular cavity,
An apparatus for gasifying a solid organic material, wherein an exhaust gas passage for sucking the inside of the reaction furnace is communicated with the inside of the reaction furnace on the other end side.   9. The solid organic raw material according to claim 8, wherein the vapor plasma introduction path is arranged in a tangential direction in the circumferential direction of the inner wall of the first circular cavity so as to generate a circulation flow of a water vapor jet along the inner wall surface. Gasifier.   The oxidant introduction path is arranged so that a circulation flow is generated in the tangential direction in the circumferential direction of the inner wall of the second circular cavity and in the same rotational direction as the circulation flow of the water vapor jet generated in the first circular cavity. A gasifier for a solid organic raw material according to claim 9.   The exhaust gas passage has a double pipe structure, and the inside of the reaction furnace is sucked through one passage of the exhaust gas passage, and the oxidant introduction passage is communicated with the oxidant supply source through the other passage. The gasification apparatus of the solid organic raw material of any one of Claims 8-10 characterized by the above-mentioned.   12. The solid according to claim 8, wherein a diameter of the second circular cavity on the outlet side is narrowed to a diameter of 0.7 to 0.9 times the diameter on the inlet side. Gasification method for organic raw materials. A region from the outlet of the second circular cavity to the other end of the reactor is formed in a shape that gradually increases the inner diameter from the outlet of the second circular cavity toward the other end of the reactor. The gasification apparatus of the solid organic raw material of any one of Claims 8-12 characterized by these.

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