DE1943080A1 - Method and device for gasifying coals with a high water content - Google Patents

Description

s Kötif'22. DIFL. HNTG. HELMUT KOEPSELL _{AM HOF} , _e

PATENT ADVOCATE. raiMON MMM

fli / 324

REÖ.-NH. BITTB ANGBBEIf

"* ■" * 194308C

Patent application

of the company

Rheinische Braunkohlenwerke AG., Cologne, Kaiser-Friedrich-Ufer

Method and device for gasifying coals with high

Water content. Addition to patent application P 17 96 05O ₀ 8

In the main application a procedure is described and is a device is specified for carrying out this procedure, in the case of the hydrous coal in the form of a runway or in some other fluidized state into one from the outside or inside heated reaction chamber is pressed in, in which the gasification takes place with the evaporated own water of the coal .. The heat required for the gasification of the coal with the EigenWöLWser or for the evaporation of this water and the The reaction mixture was heated to the reaction temperature here by external heat, in which, for example, the Pipes through which the coal paste was pressed, heated from the outside by the reactor coolant of a nuclear reactor will.

It was found that the basic process described in the parent application performed particularly beneficial to those who can, if the sensible heat of the gasified coal to

194308C

Heat generation is used.

The method according to the invention is characterized in particular by that the hydrous coal is only partially gasified with the own water it contains. The gassing will to such an extent that there is a gasification residue with still considerable Remaining calorific value results. This calorific value of the gasification residue should be at least so high that: Combustion with air for heating, the gasification process the required heat is generated.

Assuming raw lignite with a water content of around 56 to 59 % , the coal is first pre-dried to a water content of around 40% residual water before it is introduced into the actual gasification room. The water vapor generated in this way is wholly or partially discharged in such a way that it does not get into the gasification chamber. At the end of the feed, the pre-dried raw lignite is fed into a tube gasifier, the walls of which are heated with flue gas. When the coal moves through the gasifier, the residual water is first evaporated, then the volatile components are expelled and the coal is finally heated to a gasification temperature of around 800 to 900 ° C. The water vapor, which is passed through the tubes in cocurrent with the coal, reacts with the coal and with the degassing gases of the coal and a high-quality gas is produced, which essentially consists of carbon monoxide and water.

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there is hydrogen. The length of time the coal remains in the gasification tubes, the gasification temperature and the amount of water vapor available for gasification are measured in such a way that when the coal is discharged from the tubes at the discharge end of the gasification device, there is about a degree of gasification of $ 60, i.e. about $ 60 of the with The calorific value added to the coal has been converted into gaseous form. This results in a residual coal with a correspondingly high calorific value. The remaining coal is then burned, if possible without cooling, whereby it is advisable to carry out the combustion with preheated air. The heat generated during the combustion of the coal is used to heat the gasification process, in which, for example, the flue gases are passed through the tube gasifier in such a way that they heat the tubes from the outside. -.:■;.?■■■. - .. ". * ·." .. '. ·

For a good heat economy of the process it is advisable to to preheat the combustion air for the remaining coal in the countercurrent by means of the ductile gases of the gasification process to be cooled. ·. .

It has proven to be useful as a tube gasifier straight lines arranged at a suitable distance from each other To use tubes that have an inclination of up to 10 to 30 ° relative to the horizontal. Since the pre-dried raw lignite is in a powdery crumbly state · ,, can for charging the gasification tubes at the top, end of the

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inclined tube bundle according to various known per se. Methods are done. So it is possible to add a To provide a throw-in device in the manner of the known slinging apparatus, with which the coal is thrown into the pipe openings will. Furthermore, there is the possibility of providing distribution devices in the manner of rake arms, so that the shovel-like rake arms are moved over the pipe openings and fill this with the coal in the shovel.

Instead of a tube gasifier, you can basically also other known gasification devices for can be used for the present purpose. Special advantages also has a metal bath gasification device in which, for example the heat is transferred to the gasification process through liquid lead. The powdery to 'crumbly coal is blown into the lead bath by means of a carrier gas and when Rise together with the steam gas released from the coal. Recirculated production gas is expediently used as the carrier gas. The lead that has cooled down becomes a adjacent heating bath supplied, in which the heating means

d it · * the flue gases blown into the lead bath takes place / are generated by the combustion of the residual coal with air.

The pre-drying of the coal can be directly related with the gassing, in which, for example, a previously described tubular gasifier is used that is whipped directly with the brown coal cake. You cn

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speaking vote of the pressure in the room in which the pipes on the feed side flow with the pressure in the room into the the pipes open out on the discharge side, it is ensured that a controlled amount of the water vapor produced during the drying of the coal in the first part of the tube device into the feed area flows away and is thereby withdrawn from the gasification.

The predrying of the raw lignite can, however, according to the invention can also be carried out in a special pre-drying device, a fluidized bed dryer being used in particular. Heating tubes run through this fluidized bed dryer, through which the heating exhaust gas from the tube gasification device flows are, possibly increased by additional room gases from direct combustion of residual coal. This indirectly heated The fluidized bed dryer is charged with the raw lignite, wherein the fluidization process is wholly or partially maintained by the water vapor produced during drying will. Appropriate dimensioning of the flow cross-sections in the fluidized bed dryer enables the in the Drying resulting pre-dried coal is discharged with the upwardly flowing water vapor and from this with methods known per se can be deposited.

A major advantage of the invention is that in the actual gasification process only the relatively easy gasifiable components of the coal must be converted with water vapor, while the more difficult to gasify residual components

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completely and quickly through the combustion with oxygen be exploited.

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Claims (8)

Claims 1. Process for gasifying coals with a high water content, especially of red brown coals or coals that have been dried to such an extent that the core water content is used as a gasification agent for the carbon sufficient, according to patent application r 17 96 050.8, characterized in, that the coal is gasified to such an extent that the calorific value of the solid gasification residue is required for heating the gasification process sufficient. 2. The method according to claim 1, characterized in that raw lignite is pre-dried to a water content of about kOfo residual water, that the pre-dried coal is fed to a tube gasifier, metal bath gasifier or the like for the purpose of gasification up to a degree of gasification of about 60 / & and that the gasification residue with air - if necessary, preheated air - is burned and the heat for heating the gasification process and, if necessary, for pre-drying the coal is taken from this combustion process. 3. Process according to Claims 1 and 2, characterized in that that after pre-drying the crumbly coal into the gasification pipes provided with an incline of about 10 to 30 ° on their End of loading through throw-in devices such as slingers, or distribution devices, such as rake arms will. 1 0 9 8 1 1/0 8 /, 0 - ■; 1343 08 4. The method according to claims 1 to 3, characterized in that that - especially when using a metal bath gasifier or a fluidized bed gasifier, the pre-dried Coal with a carrier gas - how recycled production gas is blown into the metal bath or onto the fluidized bed. 5. Device for performing the method according to claims 1 to 3, characterized by a tubular heat exchanger serving for coal gasification, the straight tubes of which are inclined at an angle of about 10 to 30% to the horizontal, with a feed device for powdery to small-grain predried coal into the upper end of the pipes, like a rake arm that periodically guides the coal past the pipe opening, with a collecting vessel for the gasification residue that emerges from the pipes at the lower end of the same and with a heating device for the external heating of the pipes with hot combustion gels characterized by a burner for the combustion of the gasification residue with preheated air Γ '""'" 6. Apparatus according to claim 5, characterized by a heat exchanger for the transfer of the heat from the generated Gas to the combustion air to preheat it. 7. Apparatus according to claim 5 or 6, characterized by a pre-dryer for raw lignite, e.g. B. a fluidized bed dryer with heating tubes in the coal bed. 1 0 9Ü 1 ^{1/034 0 C0PY} 8. Device according to one of the preceding claims 5 to 7 »characterized by" connecting lines for dried coal from the pre-dryer an object side of the gasification device, for residual coal from the discharge side of the V _e rgasungsgerätes to the pre-drier, for hot produced gas to the air preheater, ν for preheated air to the burner of the gasification device, for hot immersion gas from the burner to the gasification device, for partially cooled flue gas from the gasification device to the pre-dryer. 109811/0840