JP2003260454A - Biomass pyrolysis method and apparatus - Google Patents

Abstract

(57) [Summary] [Problem] To provide a biomass pyrolysis apparatus that can obtain a product gas obtained by drying and pyrolyzing high-humidity biomass as a high-calorie and clean pyrolysis gas for fuel. The drying pipe 2 and the carbonization pyrolysis pipe 3 are installed in the combustion gas of
Is dried, and carbonized and pyrolyzed by the carbonization and pyrolysis tube 3 at the subsequent stage to generate carbides such as the pyrolysis gas 11 and the char 12. In the present invention, the steam generated in the drying step of the drying pipe 2 is taken out, and this steam is again converted into the most effective zone for the water gasification reaction to occur in the pyrolysis step of the carbonization pyrolysis pipe 3. It was made to supply. By this steam activation, it is possible to obtain a high-calorie and clean pyrolysis gas which is reduced in tar content and which can be effectively used as fuel for a high-efficiency engine such as a gas turbine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for pyrolyzing biomass, and more particularly to highly moist biomass (for example, wood-based, sludge, manure, food residues, food waste, organic waste such as rice husk). The present invention relates to a pyrolysis technology for effectively utilizing methane in a power generation system.

[0002]

2. Description of the Related Art Conventionally, it has been known that pyrolysis of biomass produces pyrolysis gas, char, tar and the like. The amount and composition of each of these differ depending on the operating temperature of the gasifier based on heating.

As a technique of this kind, Japanese Patent Laid-Open No. 10-330 is known.
Japanese Unexamined Patent Publication No. 760 describes a continuous carbonization device for organic substances. The structure of this device mainly includes a drying furnace, a charcoal furnace, a deodorizing drum, a hopper, and a screw feeder.

[0004]

In the above conventional example, the steam generated in the drying furnace is fed as it is to the carbonization furnace together with the dried product, mixed with the gas generated in the carbonization furnace, and finally used. The produced gas was only used as a heat source for the deodorizing furnace.

That is, since it is a low-calorie gas and a dirty fuel containing dust and tar,
It was unsuitable as a fuel for high-efficiency heat engines such as gas engines and gas turbines.

On the other hand, in conventional steam power generation, it was difficult to establish biomass power generation due to its low power generation efficiency (20% or less at most due to wet substances). Therefore, it has been desired to use the gas produced by the thermal decomposition of biomass as the fuel for high-efficiency engines such as gas turbines and gas engines.

An object of the present invention is to provide a biomass pyrolysis apparatus which can obtain a gas produced by drying and pyrolyzing highly moist biomass as a high-calorie and clean pyrolysis gas for fuel.

[0008]

In order to achieve the above object, a method for pyrolyzing biomass according to the present invention comprises a drying step of drying biomass and pyrolysis of the dried biomass by pyrolysis to produce pyrolysis gas and char. And a steam obtained by drying the biomass in the drying step, and the steam is concentratedly activated in the water gasification reaction in the carbonization pyrolysis step. And

Further, the biomass thermal decomposition apparatus of the present invention is
In a heating casing, a drying pipe for drying biomass and a pipe for carbonization and pyrolysis that is installed in a subsequent stage of the drying pipe to carbonize and pyrolyze the biomass to generate pyrolysis gas and char The steam obtained by drying the biomass in the drying pipe body is taken out, and the steam passage for supplying the steam to the carbonization pyrolysis pipe body is installed in the carbonization pyrolysis pipe body. And a steam supply nozzle for supplying the steam in the steam passage to the water gasification reaction accelerating zone in the carbonization pyrolysis tube.

The operation of the present invention will be described below. When biomass is pyrolyzed, gases such as CO, CO ₂ and H ₂ are generated by a combination of various reactions as shown in the following chemical reaction formulas (1) to (6).

[0011] _{C + O 2 ⇔CO 2 ......... (} 1) C + CO 2 ⇔2CO ......... (2) 2C + O 2 ⇔2CO ......... (3) C + 2H 2 O⇔CO 2 + 2H 2 ......... (4) C + H 2 O⇔CO + H ₂ ……… (5) CO + H ₂ O⇔CO ₂ + H ₂ ……… (6)

The above chemical formula does not always proceed in one direction, and complicated elements such as moisture, temperature, fuel type, and residence time are intertwined. However, the presence of H ₂ O in the gas has been shown to be extremely important.

Therefore, if the biomass treatment process is divided into a drying process and a carbonization pyrolysis process, the involvement of H ₂ O in the carbonization pyrolysis process is minimized and the production of hydrogen in the produced gas is hindered. Therefore, there is a risk that high-calorie gas cannot be obtained.

In the pyrolysis process of pyrolysis, pyrolysis begins at around 150 ° C., gas containing hydrocarbon as a main component, tar and char are produced, and the pyrolysis rapidly starts at around 300 ° C. When tar is cooled, it becomes a highly viscous liquid and has an adhesive property. Therefore, in general, the gas cannot be used as a fuel for a gas turbine or a gas engine.

The pyrolysis gas containing the tar content discharged from the carbonization pyrolysis process is steam (by drying) during the pyrolysis of carbonization when the polymer substance forming the tar content is vapor. By supplying the generated steam) and activating the steam, the tar content in the gas generated from the furnace can be suppressed as much as possible, and high calorie gas can be taken out, and the gas cleaning load in the downstream can be reduced.

If even a small amount of tar flows to the downstream equipment, it accumulates and the equipment becomes difficult to operate. Therefore, the tar is washed off by cleaning, the reformed decomposition product gas is cleaned, and clean and high calorie gas can be supplied to the high efficiency engine as fuel.

As a result, the biomass pyrolysis gas, which has been impossible in the past, can be applied to a high-efficiency engine such as a gas turbine, and high-efficiency power generation can be performed. In the present invention, biomass can be dried in advance by waste heat of a gas turbine or the like, or char generated in the carbonization pyrolysis process can be used as a fuel for a boiler.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The outline of the embodiment of the present invention is that the steam obtained in the drying step of biomass is taken out, and this steam is used in the subsequent carbonization and pyrolysis step, which is most effective immediately before the water gasification reaction occurs. It is designed to be supplied centrally to the zone. By this intensive steam activation, it is possible to obtain a high-calorie and clean pyrolysis gas with reduced tar content.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of the configuration of the biomass thermal decomposition apparatus of the present invention. In FIG. 1, a casing 1 is provided with a tube 2 for drying and a tube 3 for pyrolysis of carbonization.

Combustion gas (800 to 850 ° C.) is fed to the casing 1 from the hot air stove 4 to heat the drying pipe body 2 and the carbonization pyrolysis pipe body 3. Further, screw feeders 6 and 7 are mounted inside the drying pipe body 2 and the carbonization pyrolysis pipe body 3 so that the biomass moves at a speed that maintains an arbitrary residence time.

Thus, in the drying tube body 2, the biomass 10 charged from the charging port 5 is dried while being sent to the downstream side by the screw feeder 6. Biomass is generally highly moist and produces steam in the process of being heated and dried.

In the present example, this vapor is once taken out from the drying pipe body 2 and is again supplied to the subsequent carbonization pyrolysis pipe body 3. By passing the inside of the casing 1, the steam passage 8 maintains a high temperature and prevents liquefaction.

A tube 3 for pyrolysis of carbonization is installed in the latter stage of the tube 2 for drying, and the supplied dry biomass is conveyed to the downstream side by the screw feeder 7 while the casing 1 is being conveyed.
It is heated by the combustion gas inside and produces pyrolysis gas and carbides such as char. This pyrolyzed gas contains a tar component, and as described above, when accumulated in the devices in the subsequent stage, various problems will be caused.

Therefore, in the present embodiment, the steam taken out from the drying pipe body 2 is supplied from the steam supply nozzle 9 into the carbonization pyrolysis pipe body 3 so that the water gasification reaction during the biomass carbonization pyrolysis process is performed. It was made possible to obtain a high-calorie pyrolysis gas with a reduced tar content by steam activation by intensively supplying it to the most effective zone when it occurs.

The water gasification reaction begins to occur at about 300 ° C. Depending on the temperature of the dry biomass supplied to the carbonization pyrolysis tube 3, the temperature of the combustion gas in the casing 1, and the like,
It is possible to identify the location where the water gasification reaction occurs. By activating steam immediately before the occurrence of the water gasification reaction, the reaction is most effectively promoted and the tar content can be reduced.

Particularly, by positively advancing the equations (4) to (6) among the above-mentioned chemical reaction equations (1) to (6), reduction of tar is also achieved at the same time, and high calorie gas is produced. Has the effect of contributing to.

The steam and biomass produced in the conventional drying process are sent together to the subsequent carbonization and pyrolysis process, and the pyrolysis gas produced there and the steam previously taken out according to the present embodiment are subjected to the charcoal pyrolysis process. It was found that the tar content in the pyrolysis gas can be reduced by about 50% in the present embodiment when it is supplied to the most effective zone.

As described above, according to this embodiment, the pyrolysis gas produced by the pyrolysis in the carbonization pyrolysis tube 3 becomes a high-calorie gas, and the tar content is suppressed and carbonization occurs. It is discharged from the pyrolysis tube 3. The pyrolysis gas discharged from the carbonization pyrolysis tube 3 can be effectively used as a fuel for a high-efficiency heat engine such as a gas turbine.

Further, the char generated in the carbonization and pyrolysis tube 3 can be supplied to the power generation system as a fuel for the hot stove 4 or a boiler fuel. Reference numeral 13 in the drawing denotes combustion exhaust gas in the casing, and 14 denotes combustion air of the hot stove 4.

[0030]

As described above, according to the present invention, the steam collected in the biomass drying process is taken out and supplied to the most effective zone when the water gasification reaction in the biomass carbonization decomposition process occurs, By activating, it is possible to obtain a pyrolyzed gas that has a high calorie content with reduced tar content and is clean, and that can be effectively used as a fuel in a highly efficient engine such as a gas turbine.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a biomass thermal decomposition apparatus according to the present invention.

[Explanation of symbols]

1 casing 2 Drying tube 3 Carbonization pyrolysis tube 4 hot stove 5 slot 6, 7 screw feeder 8 steam passages 9 Steam supply nozzle 10 biomass 11 Pyrolysis gas 12 char

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10J 3/00 C10J 3/00 ZABA ZAB C10L 5/44 C10L 5/44 F02B 43/10 Z F02B 43/10 F02C 3/28 F02C 3/28 B09B 3/00 303M F-term (reference) 4D004 AA02 AA03 AA04 AA12 BA03 CA26 CA27 CA42 CB36 CB42 CB45 4D059 AA01 AA07 AA08 BB03 BB18 BD01 BJ02 CB06 CB07 CC03 4H012 HA03 HA05 4H015 AA01 AA03 AA12 AA13 AA14 AB01 BA12 BB03 BB04 CB01

Claims (5)

[Claims] 1. A drying step of drying biomass, and a pyrolysis step of pyrolyzing the dried biomass to produce pyrolysis gas and char, which are obtained by drying the biomass in the drying step. A method for pyrolyzing a biomass, characterized in that the steam is collected, and the steam is concentratedly activated for a water gasification reaction in the carbonization pyrolysis step. 2. A drying pipe for drying biomass, and a pipe for pyrolysis for carbonization, which is installed in a subsequent stage of the pipe for drying to pyrolyze the biomass to produce pyrolysis gas and char. A steam passage which is provided in a heating casing, takes out steam obtained by drying biomass in the drying pipe, and supplies the steam to the carbonizing pyrolysis pipe, and the carbonizing pyrolysis pipe And a steam supply nozzle for supplying the steam in the steam passage to a water gasification reaction promoting zone in the carbonization pyrolysis tube, the biomass pyrolysis apparatus. 3. The biomass thermal decomposition apparatus according to claim 2, wherein the steam passage is arranged in the heating casing. 4. The pyrolysis gas collected from the carbonization pyrolysis tube is used as a fuel for a gas turbine of a power generation facility or a gas engine, according to any one of claims 2 to 3. Biomass pyrolyzer. 5. The char collected from the carbonization pyrolysis tube is used as a heat source of the heating casing and a boiler fuel of a power generation facility, according to any one of claims 2 to 4. Biomass pyrolyzer.