JPS6254357B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention makes raw coal into a slurry with a high concentration of 60 to 90%, uniformly disperses a gasification catalyst, and supplies the slurry to a gasifier to obtain synthesis gas with high gasification efficiency. The present invention relates to a coal gasification method that can be used to gasify coal.

Conventionally, in the process of partially oxidizing coal to obtain synthesis gas, a wet feeding method has been proposed by pulverizing raw coal to prepare a coal/water slurry and supplying it to the gasifier, but the slurry concentration is 50%. Since the water content is low, a large amount of water must be evaporated in the gasifier, resulting in a low gasification efficiency.

As a result of extensive research in order to solve the above problems, the present inventors have found that a mixture of pulverized coal and a small amount of water is coated with a foaming dispersant or water with a slight surface tension (0.1 to 5 dyne/cm). When a dispersant that has the effect of lowering is added and thoroughly mixed, the air bubbles created when a foaming dispersant is added are interposed within the coal particle layer, creating fluidity and slightly reducing the surface tension of water. When a dispersant is added to lower the coal particle surface, water adheres uniformly to the surface of the coal particles, making them slippery and creating fluidity.Additionally, by adding a gasification catalyst during slurry preparation, It was discovered that the catalyst can be uniformly dispersed and the gasification efficiency can be improved.

The present invention has been made in view of the above points, and includes a method for supplying coal to a gasification furnace and partially oxidizing the coal to obtain synthesis gas. Coal can be gasified with high gasification efficiency by preparing a highly concentrated slurry of 60 to 90% coal with a gasification catalyst uniformly dispersed therein and supplying this highly concentrated slurry to the gasifier. The aim is to provide a method that can be used.

Hereinafter, the configuration of the present invention will be explained based on the drawings. FIG. 1 shows an example of an apparatus for carrying out the method of the invention. Raw coal (either coking coal or non-caking coal may be used) is coarsely crushed in advance to about 10 mm or less, and then further crushed by dry pulverizer 1 to a 200 mesh passing rate of about 10 to 80 degrees Celsius, preferably 30 to 70 degrees Celsius. Finely grind to %. The pulverized coal, gasification catalyst, water, and a foaming dispersant or a dispersant that has the effect of slightly lowering the surface tension of water are supplied to the kneader 2 and thoroughly kneaded to create a fluidized high concentration. A slurry is prepared. The amount of dispersant added at this time is 0.01 to 3% by weight, preferably 0.3 to 1.5% by weight based on the coal.
The concentration of the slurry (coal content) is 60-90% by weight on a dry basis, preferably 65-80% by weight.
It is. Also, the viscosity of this slurry is 300 to 3000 c.p.
That's about it.

Suitable gasification catalysts used in the present invention are metals of the periodic table group such as iron, or alkaline earth metals of group a of the periodic table, and these metals can be used in the form of nitrates, chlorides, sulfates, etc. Or added in oxide form with water during slurry preparation.

In addition, the foaming dispersant used in the present invention is suitably a metal of the periodic table group such as iron, or an alkaline earth metal of group a of the periodic table, and these metals are It is added in salt or oxide form along with water during slurry preparation.

The foaming dispersant used in the present invention may be anionic, nonionic, cationic surfactants, etc., used alone or in combination, and is appropriately selected depending on the type of coal. Specifically, anionic surfactants include alkylbenzene sulfonates, alkyl sulfate ester salts, polyoxyethylene alkyl (alkylphenol) sulfate ester salts, alkyl phosphate ester salts, dialkyl sulfosuccinate ester salts, acrylic acid and/or and maleic anhydride copolymers, polycyclic aromatic sulfonates, formalin compounds, etc. are used, and as cationic surfactants,
Alkyl amine salts, quaternary amine salts, etc. are used, and nonionic surfactants include polyoxyalkyl ethers, polyoxyethylene alkyl phenol ethers, oxyethylene/oxypropylene block polymers, polyoxyethylene alkyl amines, and sorbitan fatty acids. Ester, polyoxyethylene sorbitan fatty acid ester, etc. are used. As the amphoteric surfactant, alkyl betaine and the like are used, and amine compounds such as 1,2,3 monoamine and diamine are used. In addition, the dispersants that have the effect of slightly lowering the surface tension of water used in the present invention include:
Anionic, nonionic, and cationic surfactants are used alone or in combination, and are appropriately selected depending on the type of coal. Specifically, anionic surfactants include fatty oil sulfate salts,
Higher alcohol sulfate salts, nonionic ether sulfate salts, olefin sulfate salts,
Alkylaryl sulfonates, dibasic acid ester sulfonates, dialkyl sulfosuccinates, acyl sarcosinates, etc. are used, and nonionic surfactants include polyoxyethylene fatty acid esters, fatty acid alcohol polyoxyethylene ethers, Alkylphenol polyoxyethylene ether, polyhydric alcohol fatty acid ester, fatty acid ethanolamide, etc. are used, and as cationic surfactants, alkyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride, alkylpyridinium salt, etc. are used, and amphoteric surfactants are used. As the surfactant, higher alkyl amino acids and the like are used.

The slurry prepared by the kneading machine 2 is once stored in a collection tank 3, and then pumped by a high-pressure slurry pump 4 at a linear velocity of 0.5 to 5 m/sec, preferably 2 m/sec.
It is force-fed to the gasifier 5 at a rate of ~4 m/sec, and is ejected into the gasifier 5 together with oxygen and water vapor. The coal particles are gasified while flowing downward in the gasifier 5 by high-temperature partial oxidation, water gasification reaction, and the like.
The temperature inside the gasifier 5 is 1100 to 1700°C, preferably
The temperature is 1400-1600℃ and the pressure is maintained at 10-90 atm. When the slurry is ejected into the gasifier 5, there is almost no aggregation between coal particles, it has good dispersibility, quickly mixes with oxygen, and is gasified with high gasification efficiency to mainly produce hydrogen and carbon monoxide. It is converted into syngas as a component. The main reaction formula at this time is as follows.

C+2H ₂ →CH ₄ C+H ₂ O→CO+H ₂ C+2H ₂ O→CO ₂ +2H ₂ C+CO ₂ →2CO CO+H ₂ O→CO ₂ +H ₂ C+O ₂ →CO ₂ 2C+O ₂ →2CO Note that 6 is a lock hopper and 7 is a waste heat boiler. , 8 is a settling tank, and 9 and 10 are heat exchangers.

FIG. 2 shows another example of an apparatus for carrying out the method of the invention. That is, raw coal is crushed in advance into particles of about 10 mm or less, and then supplied to the wet crusher 11.
At the same time, water, a dispersant, and a gasification catalyst are added, and the raw coal is pulverized in the wet pulverizer 11, and the catalyst is uniformly dispersed by thoroughly kneading the raw coal, water, dispersant, and gasification catalyst. Prepare a fluid, highly concentrated slurry. The coal particle size after pulverization is 200 mesh passing rate 10 to 80%, preferably 30 to 70%, and the viscosity of the slurry at the outlet of the wet pulverizer 11 is about 300 to 3000 c.p. The other configurations are the same as in the case of FIG.

Next, embodiments of the present invention will be described.

Example 1 Australian sub-bituminous coal was crushed in advance and then crushed using a dry crusher. This crushed charcoal,
Water, a dispersant that lowers the surface tension of water (1.0% by weight based on coal), and a gasification catalyst were supplied to a kneader and thoroughly kneaded to prepare a highly concentrated slurry.
Fe ₂ O ₃ was used as a gasification catalyst and was added so that the Fe weight was 0.5% by weight based on the coal. The properties of Australian sub-bituminous coal were as follows.

Moisture 7.0% Ash 7.1% Volatile content 26.2% Fixed carbon 59.7% Fuel ratio 2.27 The properties of the slurry at the exit of the kneader are as follows: particle size is 1 mm or less, 200 mesh passing rate is 25%, and slurry concentration is 70%.
(dry base), viscosity 1400 c.p. This slurry is then supplied to a gasifier to reduce the pressure
It was gasified by blowing oxygen as an oxidizing agent at 25 atm and 1400°C. The composition of the resulting gas was as follows.

H ₂ 37.1% CO 46.3% CO ₂ 16.0% N ₂ 0.4% CH ₄ 0.03% H ₂ S 0.13% Example 2 Sub-bituminous coal from China was crushed in advance and then crushed using a dry crusher. This pulverized coal, water, foaming dispersant (1.0% by weight based on coal), and gasification catalyst were supplied to a kneader and thoroughly kneaded to prepare a highly concentrated slurry. Fe ₂ O ₃ was used as a gasification catalyst and was added in an amount of 1.0% by weight based on the coal. The properties of sub-bituminous coal produced in China were as follows.

Moisture 7.2% Ash 8.9% Volatile content 28.2% Fixed carbon 60.0% Fuel ratio 2.13 The properties of the slurry at the exit of the kneader are as follows: particle size is 1 mm or less, 200 mesh passing rate is 30%, and slurry concentration is 76%.
(dry base), viscosity 3900c.p. This slurry is then supplied to a gasifier to reduce the pressure
It was gasified by blowing oxygen as an oxidizing agent under the conditions of 10 atm and 1400°C. The composition of the resulting gas was as follows.

H ₂ 35.2% CO 52.1% CO ₂ 12.3% N ₂ 0.30% CH ₄ 0.04% H ₂ S 0.02% As explained above, according to the method of the present invention,
Because the slurry concentration is high, the drop in gasification efficiency due to water evaporation is small, and by adding a gasification catalyst to the water when preparing the slurry,
Since the catalyst can be uniformly distributed in the slurry, the gasification efficiency can be increased and the amount of catalyst added can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an example of an apparatus for carrying out the method of the present invention, and FIG. 2 is a flow sheet showing another example. 1...Dry crusher, 2...Kneader, 3...Collect tank, 4...High pressure slurry pump, 5...Gasifier,
6... Lock hopper, 7... Waste heat boiler, 8... Sedimentation tank, 9, 10... Heat exchanger, 11... Wet crusher.

Claims (1)

[Claims] 1 In a method of supplying coal to a gasification furnace and partially oxidizing the coal to obtain synthesis gas, pulverized coal, water, a dispersant, and a gasification catalyst are sufficiently mixed to form a mixture of 60 to 90% coal with a gasification catalyst dispersed therein. A coal gasification method characterized by preparing a highly concentrated slurry of and supplying this highly concentrated slurry to a gasification furnace.