DE1931166A1 - Gasification of coal with high moisture content - Google Patents

Description

Patent application

of the company

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

and the Lord

Prof. Dr.-Ing. Werner Wenzel, Aachen, Prinz-Heinrich-Str. 29

Gasification of coal with a high moisture content.

The gasification of coal in the fluidized state, a so-called Fluidized bed, has important advantages. The present invention relates to a further development of the fluidized bed gasification process with the aim of obtaining high-quality gases in a particularly simple and economical way, which are suitable for the reduction of iron ores and for gas synthesis.

The method according to the invention is based on the fact that the the gasification of coal with steam or carbon dioxide or mixtures of both gasification media required heat Process is supplied from outside from particularly cheap heat sources. As such a particularly cheap source of heat comes the heat production of a nuclear reactor in question, which is taken from the nuclear reactor by suitable heat transfer media and fed to the gasification apparatus.

000083/0972

In the known fluidized bed gasification processes, fluidization takes place, ie the fluidization of the gasification bed is carried out by the gasification medium, which in the case of external heating generally consists of steam and the fluid bed by means of openings in the Soil, which can be designed as a so-called /.nstrcrr.boden, is fed. Ler V / assa steam is to be regarded as a relatively expensive gasification medium, which has a considerable economic burden on the process. L) as method rä yfcirfcTyrel ^ Hhgfaig ^ Yhfyiiregr according to the invention is therefore based on the fact that it is particularly advantageous for such solid Erennotofi'e, that is: extraction state or as a result of their processing have a high moisture content, the The removal of the fuel evaporation caused by evaporation / water vapor to be used directly as a gasification medium. These requirements apply in particular to raw brown coal, which has a water content ν in the extraction state of about 55 - 60 ^r / o of slightly pre-dried coal, for example with a water content of about 4 & - 50 / a.

The inventive measure to achieve the aforementioned procedural elements consists in the fact that the coal is introduced into the heated gasification system in such a size that it is whirled up into a product due to the gases produced during the heating, in particular by the water vapor and its conversion , fluidized state device. In this way a Selbstfluidierung the coal to be gasified takes place with the self-generated from the coal comparison

009883/0972

medium.

This measure according to the invention has a considerable simplification of the gasification apparatus for the rim, because the natural soil and all devices which are useful for an equal distribution of the wind over the whole area are omitted. A further essential advantage of the "measure according to the invention - especially for the gasification of lignite" is that the coal is particularly ridden directly after the expulsion of the water and after further removal by the supply of a screen .ir itt üies affects cc of that from a given .leakticnsvc-liüsen one-hawser. Ur.. they sat Itemize achieved nn k ^ and that at relatively low temperatures see the -leakticr ier coal with the "Yasserd ampf can be done.

Oie supply of Frendwi-rnie, which for the coal drying, which Cabbage degassing and the gasification of what was left over afterwards Kchle constituents with the './asserdampf and the KohlensLuinre is required, can by V.'c.rme Transmissionvfiknde through to the reaction mixture. Sc can in that Fluidized bed a tube system can be arranged in which the Tubes arranged vertically or horizontally or otherwise are. The seed medium, for example from which the nuclear reactor coolant may consist of helium, can thereby be passed through the interior of the heat transfer tubes or the fluidized bed is located within

00988 3/0 97 2 ^BAD original

the tubes, which are heated from the outside by the heating chamber.

A particular difficulty with the arrangement of heat transfer walls within a fluidized bed is that a strong mechanical wear effect is exerted on the wall material. In order to keep this wear within economically acceptable limits, it is provided according to the invention that only a minimal vortex condition is maintained. In order to achieve this, ie _{: to} work as close as possible above the lower flow point, which is defined by the gas velocity at which the vortex state begins, it is provided that the grain size with which the coal is fed into the float bed is so on this »generated

ab ^ siifikt Wixx !, that the desired eddy state is maintained as far as possible in all areas of the fluidized bed in which there are heat transfer walls * This adaptation is carried out by controlling the dem Fluidized bed supplied amounts of heat on the amount and the Temperature of the heating medium carried per tent unit, The Control of these amounts of heat leads to a control of the per unit of time generated Kengen of water vapor and degassing products, and thus to a control of the gas velocity. On the other hand, it is provided that the gas too.

Cross-section of the fluidized bed flowing through at any height

existing gas quantities is adjusted so that the gas velocities are as optimal as possible.

009883/0972

An important further development of the invention consists in the fact that the coal gasification is carried out in several series Fluidized beds is distributed. Here, at least one of these fluidized beds works, in which the drying of the coal or the Drying and degassing take place according to the principle of self-fluidization. The downstream fluidized beds into which the dried and fully or partially degassed coal is fed will work as normal fluidized beds with or without an inflow base, with a fluidizing gas supplied from the outside work. Either the gas generated in the preceding fluidized bed is used as the fluidizing gas or the most inert gas is used Gasification residue with the most salable gas in countercurrent.

Since the internal heating of fluidized beds by heat-transferring walls makes the process more difficult, the above-mentioned division of the entire gasification process into several beds according to the invention is advantageously carried out in such a way that only the self-fluidizing bed _{t. In} which the coal is dried and, if necessary, degassed # with; Internal heating through heat transfer walls are provided. On the other hand, the heat required for gasification is introduced into the downstream gasification beds by the fluidizing gas, in which the gas is heated in suitable heat exchangers outside the fluidized bed. With this method according to the invention, the difficulty of wear and tear on the heat transfer walls in the self-fluidizing bed is largely eliminated.

00 9883/0972 ^ßAD

»Boil. When drying, the coal remains relatively -, / calibrated and has a relatively low wear effect; on the walls only when the coal is at a higher temperature is converted to coke, the wear effect becomes greater. During the gasification of this coke in fluidized beds without heat transfer installations this wear effect is practically completely avoided.

Another application of the invention is in a direct one The fluidized bed is heated by means of liquid or solid heat transfer media. These heat carriers enter the fluidized bed from above given or sprayed or sprinkled on the surface of the same * They sink due to their severity under the release their heat content down through the fluidized bed, collect on the floor and are cooled from here in the Condition removed again. They are then re-heated in the circuit and returned to the fluidized bed from above. as Liquids are particularly suitable for metal melts, such as liquid / Sige's lead, kls solid heat transfer media look like bodies refractory materials, such as corundum balls. Γ

The invention also includes hatred for segregation the solid gasification residues from the fluidized bed. This can be done according to the invention so that the raw coal or the little pre-dried raw coal on the ground in the self-fluidizing bed is entered «The gas development within the fluidized bed is controlled by the heat supply

009883/0972

BATH ORIGINAL

-rerefelt that the resulting from the amount of gas generated Gas velocity after drying 'or after Drying and degassing or after drying, degassing and gasification in the various areas of the fluidized bed v: riiegt, the leaded solid gasification residues of the Coal is removed substantially upward from the fluidized bed. This process can also be done in such a way that the lumpy Rohl: ch? .E is entered into the fluidized bed at the top and, as a result of its heavy load, sinks to the bottom and loses weight here, so that the solid residues are conveyed upwards with the gas flow and finally discharged from the vessel.

The invention also takes into account the fact that, for economic reasons, it may not be expedient to gasify the coal with external heating until the carbon bound with the ash has been completely or almost completely gasified. Thus, it can be technically and economically advantageous be to achieve the gasification level of the coal with external treatment only up to a considerably, lower level, for example 8öf A gasification mixture of oxygen and water vapor or air and water vapor is advantageously used.

0.09883 / 097.2

⁵ BATH

Exhaust gas originating from the heating system can be removed.

A particular difficulty in using self. fluid beds are there at the start-up the same no gas for whirling up the charge is available. This difficulty is in accordance with the invention thereby eliminating the need for fluidization to start up the apparatus for performing the self-fluidization process initially takes place in the normal way with the help of foreign gases. Air in particular can enter the bed as such a foreign gas are express blown, the conversion of which with the coal advantageously leads to rapid heating of the system. The air addition is expedient after the onset of self-fluidization, d. h, switched off when the required drying temperature is reached. But there is also the possibility that you can go to Maintaining an advantageous fluidization state constantly blows some auxiliary air into the bed or when it occurs If fluidization difficulties temporarily add auxiliary air.

The measure of the supply of foreign gas into the fluidized bed can a? valuable help for the constant regulation of the air flow condition and the temperature level to ensure constant, continuous operation *

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. BATH

The invention finally makes use of the fact that when introducing raw lignite and other coking coals with a high gas content in hot fluidized beds exerted a strong explosive effect within the coal pieces as a result of the spontaneous formation of gas will. There is therefore the possibility that in such a new Fluidized bed is given relatively coarse-grained coal, which comminutes itself within the bed to the required grain size.

The invention is illustrated below with reference to the " provided embodiment explained.

Hydrous carbon carriers are placed in the heated fluidized bed 1 7 introduced, ζ. B. raw lignite with its own natural pit moisture, possibly from stoichiometric Reasons, may have dried down to approx. 42% moisture content. The heating takes place by means of a heat-transferring medium which is introduced into the heating tube system 17 through the feed 8 and is removed therefrom through the discharge 9.

In the fluidized bed 1 is the carbon carrier, due to a high heating rate, its moisture and its volatile constituents quickly and gets by this gas development into the state of self-fluidization. The self-fluidizing effect is intensified by the grain disintegration at a high drying rate.

BATH

009883/0972

- ίο -

From the fluidized bed 1 the dried, iluidated and partially gasified Carbon carriers (e.g., partially gasified dry coal) introduced successively into the gasification fluidized beds 2 and 3. These Vergasungsfluidattetten 2 and 3 can become one. Aggregate summarized './erden, öas withdrawn from the fluidized bed 1 Gas is in the gas heater 6, with the ./armezufuhr 13 and the waste heat transfer line 14, reheated and introduced into the fluidate bed 3. The withdrawn from the fluidized bed 2 dry Partially gasified carbon carriers are produced by the gas that is diverted from the fluidized bed 1 and reheated in the gas heater 6 implemented further.

In the gas heater 5 with the heat supply 10 and the Abwo.rmefortleitung 11, the gas emerging from the fluidized bed 3 is reheated and fed into the gasification fluidized bed 2. A product gas 12 with a GO / H ₂ ratio of approximately 1: 1 emerges from this. ·.

The still ungased carbon discharged from the fluidized bed 3 is' in the high-temperature fluidized bed 4 with air Ιό, the can be highly enriched with oxygen, converted completely exothermically. The axis 15 is withdrawn from the fluidized bed 4. 0er air 16 can be a partial gas flow from the fluidized bed be fed for incineration. A product gas 18 with a high CO content is withdrawn from the high-temperature fluidized bed 4. By mixing the product gas 18 with fractions of the product gas 12 and subsequent partial conversion

009883/0972

Din

ORIGINAL

- li -

By adding CO ₂ from reduction aggregates (e.g. iron ore reduction), the product gases can be released, especially with a low supply, at a temperature level that is not sufficient to carry out the Bouduuard reaction 12 , partially converted back to CO. In order to get to hydrogen-rich synthesis gases, the product gases 12 and 14 can be converted to ground with KjO.

The V / arms required in the fluidized beds 1, 2, 3 for implementation the energy-intensive drying, degassing, comminution and gasification reactions can in particular high-temperature nuclear reactor heat which is introduced into units 1, 5 and 6 through feed lines 8 or 9, 10 and 13. the The tubular heat exchanger (17) in the fluidized bed 1 can also be heated with the waste heat 11 and / or 14 from the heat exchangers 5 and / or 6 take place.

Ö09ÖB3 / Ü972

Claims (1)

P a t β η t a η s ρ r üc h e 1. Process for gasifying coal with a high moisture content, in particular of raw lignite or raw lignite that has not been dried to a great extent, in which the heat requirement of the gasification process is wholly or primarily as sensible heat from the outside is supplied and can be taken from the heat production of a nuclear reactor, among other things, characterized in that that the coal is introduced into the heated room with such a lump size that it is due to the Gases generated by heating, in particular due to the water vapor and its reaction products, in a whirled up, fluidized state device. 2. The method according to claim 1, characterized in that the Heat is supplied to the gasification bed through heat transfer walls, such as through a pipe system with internal heating or outside heating. 3. The method according to claim 1 and 2, characterized in that that the cross-sectional conditions in the gasification space are adapted to the grain size and gas volume conditions, that the fluidization takes place just above the lower flow point. . · 009883/0972 BATH 4. The method according to claims 1 to 3, characterized in that the coal with a larger grain size in the fluidized bed given "as required for fluidization under Exploitation of the explosive effect on such grains when subjected to shock heating. 5. The method according to claim 1 to 3, characterized in that the coal gasification on several one behind the other Beds is distributed, with at least one of the beds in which the drying or drying and - in whole or in part - The degassing of the coal takes place on the principle of self-fluidization, while the downstream beds work as normal fluidized beds with or without an inflow tray and an externally supplied fluidizing gas, and in which the gas generated in the first bed forms the fluidizing gas. 6. The method according to claims 1 to 4, characterized in that only the self-fluidizing bed with internal heating is provided by heat transfer walls, while the downstream gasification beds by reheating of the fluidizing gas in suitable heat exchangers overheated v / ground and introduce the heat required in the gasification process as sensible heat into the gasification bed. BATH 00988 3/0972 7. The method according to claims 1 to 5, characterized -ekennsoicL-net, that the liohkohle or the little predried raw charcoal is added to the yellow fluidizing bed at the bottom, or that they with such a grain size above the soil in the Bed is given, because it sinks mainly to the floor, while the gas evolution is controlled by the supply of heat is that as a result of the gas velocity generated after drying or drying and degassing or drying and gasifying remaining solid residue of the coal substantially with the gas flow upwards out of the vessel be carried out. 8. The method of claim 1 and suitable others foregoing Claims, in which the heat supply into the upper drying, crushing, degassing and gasification beds by liquid or solid heat transfer medium, which is carried out from above put in the bed and peeled off again at the bottom. 9. The method according to "claim 1 and suitable others preceding them." Claims, characterized in that the gasification with external heating only up to a technical and economical Usable degree of gasification of the coal operated as $ 80 is, while for gasification of the residual carbon content the coal is fed to the gasification bed or the mixture of gasifying agent and residual coal oxygen, such as by adding the appropriate kengen air. 009883/0972 10. The method of claim 1 and suitable others foregoing Claims, characterized in that a partial flow of the production gas is primarily used for drying Self-fluidizing bed is fed to the last gasification stage in a mixture with oxygen. 13. Procedure for commissioning an apparatus for the Implementation of the method according to claims 1 to 9 »characterized in that the fluidization is initially carried out with foreign bases, especially with air, while after * onset the auxiliary air completely or partially shut off the Celbstfluidierung will. 12. The method of claim 11 and suitable others foregoing Claims, characterized in that the G external gas supply for constant regulation of the fluidization state and the temperature level. 13. Device for carrying out the method according to claims 1 to 10, ä characterized by a shaft-like vessel as a drying fluidate bed or as a drying and degassing fluidate bed with tubular internals (17), with feed openings and feed organs for hydrous coals (7) just above the ground of the vessel (1) and gas discharge soff openings with gas discharge openings on the ceiling of the vessel, and associated gas lines, with supply lines (8, 9) and discharge lines for a heating medium BAD ORKaWAL 009883 /097.2 v: ir heat transfer media for nuclear reactor heat to the tubular internals, and with openings for dried and, if necessary, relieve coal, " 14. The device according to claim 13, characterized by one or more further shaft-like vessels (2, 3, 4) as Vergacungsfluidat Betten with a gas-permeable inflow base for a fluidizing gas, with feed openings for predried, possibly predried and predegassed and optionally also pregassed coal, with gas discharge openings (12, IS ¹ on the ceiling of the vessel and associated gas lines, and with openings for the gasification residues. 15. Device according to claim 13 or IU ₃ identified through a shaft-like geffess as oxygen gasification fluid bed with a gas-permeable inflow tray and a supply line for an oxygen-containing gas v / ie air in the -Geciisch r.it H ^ O or ΙΙ, -Ο / ΰΓι _to dieeera inflow tray, with supply ports for pre-gassed cave, with Gas discharge openings ur.I on the ceiling ac-s Gel '.: r; co £ and associated gas ■ ~. eitunger, and ■ r.it, - ff r.unger. Door * locked, unrestricted items. .It:. 'Yorricl'-v.-iv-: r ^ ch a üc-i ¹ ;.? - r; .i'Uche 13 to. 15, c: ek '; nn ^ ϊ ί-ύϊΐΐβζ Ι ": ■ ,;' .. · ■: *: - ~ ^{J, ir:} jäi ¹ (G -:;..... -. : - '! r: r) (5, ^) for the Lr- ' :: l \ z - :: \ r , 'iA-r ..'■; £ ....: - ; -u: den rroci: -r. ·:. ":. ■■:; -, \ .zvi. Desrasing, hz ~: i * V'ir: asu ·;.;: ..:. ": ■: -. ·: - · .ot ^J _ ^: \ _" jr your ^ vl'Uhrung in a gassing ' 009883/09 7 2 fluidate bed by means of a heating medium, such as a heat transfer medium for kereactor heat and through connecting pipelines and, if necessary, conveying, regulating and measuring devices between the above-mentioned system parts. BATH ORIGINAL. 4 * Blank page