PROCEDURES FOR FORGOT FROM COAL AND FAR TREATING OF THE PRODUCT GAS.

The invention concerns a procedure for gases of coal, whereby the product gas prepares the condensate water to one or more resulting thereby from the product gas heat exchangers under production in from steam to under the point of condensation of the water vapour contained in it cooled down and separated, and in the Prozeß one leads back.

A procedure of this kind is from EP-A-0 202,428 well-known. The procedure is preferably accomplished with more allothermer, thus foreignheated coal gasification, whereby the Proze&szlig needed for the gasification; warm not by the gasification reaction won, but of auß EN by means of heat exchangers is supplied. To the production of the Prozeß can thereby one warms äuß ere heat source, e.g. a nuclear reactor, the Proze&szlig serves; can by burning a part of the produced product gas in addition, warms be won, as admits of the EP-A-0 mentioned from 202,428. The remainder of the product gas can industrially used or however for production of electricity by means of gas   and/or steam turbines a burn to be likewise supplied. One can in this way a combined gas   and Dampfturbinenprozeß create with integrated coal gasification, for which a substantial improvement of the utilization of primary energy makes possible. Auß erdem the advantage exists, da&szlig in relation to the direct burn of the coal; the product gas won by gasification very many more simply by environmentalharmful components to be cleaned knows than by coal combustion produced flue gas.

A substantial problem during coal gasification consists however of it, daß the raw gas a high water vapour portion won by the gasification contains, which is in particular with allothermer gasification over 40%. During the later cooling of the product gas to under the condensation temperature a high quantity of condensate water results. In this arrears of organic kind are as e.g. phenol, VTX u.dgl. as well as inorganic arrears contained. If the condensate water is into the environment will dismiss, so muß it over complex mechanisms so to be prepared, daß it is no longer environmentalharmful. From the EP-A-0 mentioned 202,428 is suggested preparing and using as boiler feeding waters for the steam generation the condensate water. A Kesselspeisewasseraufbereitung however already is when using e.g. usual Fluß water a complex and expensive Prozeß ; the production of boiler feeding water from the extremely polluted condensate of the product gas would not be justifiable technically and in view at the expense. Also the quantity of the resulting condensate water can substantially grö&szlig according to the kind of the procedure guidance; it its as the quantity of the feed water needed for the boiler oh supply.

The invention is the basis the task to train a procedure of the kind mentioned so daß the condensate water separated from the product gas in as simple and energetically favorable a way as possible prepares and in the Prozeß one leads back.

The solution of the task is indicated in the requirement 1. The Unteransprüche refer to further favourable arrangements erfindungsgemäß EN of procedure.

The advantage is obtained by the invention, daß the processing of the condensate water for its feedback in the Prozeß requires no additional energy source, but daß for this in simple way in the produced high pressure   and/or low pressure steam contained waste heat to be used can. There auß erdem the condensate water not as boiler feeding waters, but in steam form as Prozeß steam is led back, in it about still contained portions of organic impurities again with the produced product gas is combined. Against the purity obtained with the processing of the condensate water no particularly high demands are therefore made.

An execution form of the invention is more near described on the basis the design. This shows schematically the Fließ pattern for execution erfindungsgemäß e of procedure.

In the design with 1 way beginning of the product gas with a double line and the way of produced steam with a thick line is characteristic, in order to differentiate these ways from the thinly drawn lines for water od.dgl.

In a gas generator A, which is heated by means of a coil of pipe 11 allotherm, out with 13 of supplied fine-grained coal and with 15 a fluidised bed is produced for supplied water vapour, whereby the overheated water vapour serves as reaction and fluidization medium.

The product gas or raw gas produced in the gas generator A is led across a raw gas cooling stretch 1 and cooled down in the heat exchanger 17 of a high pressure steam generator B. High pressure steam is produced, whose pressure is preferably more highly as 100 bar and its burning temperature preferably higher than 450°C.

The cooled down coal gas is led across the line 2 by a gas scrubber 19 provided with a venturi tube and enters the separation container C, where itself in the gas contained impurities such as dust, salts (e.g. NH₄ Cl) and partial organic components separate.

3, so cleaned coal gas leaving the separation container C over in heat exchangers 21, 23, is continued to cool down, whereby in H low pressure steam is produced preferably within the range of 2 - 4 bar. The condensate water resulting thereby in the heat exchangers 21, 23, which essentially impurities of organic nature, contains as washing water in the gas scrubber 19 one uses and enters with the gas the separation container C.

From the separation container C the condensate water is taken off over the valve 5 and supplied to a stripper column D. In this the gaseous components contained in the condensate water become such as NH&sub3 under supply of low pressure steam; , H₂ S as well as volatile organic components driven out and are supplied, if necessary after cooling in the heat exchanger 25, to a vapour burn by way of the line 6.

The condensate water running off from the column D is supplied to one or more Koksgrusfiltern by way of the pump 7 an E, in which a Abtennung still in the condensate water contained of the solved or unresolved hydrocarbons takes place. Preferably remainder coke and/or airborne dust can be used in the filters E as absorption aids and filter auxiliary layer, which with the gasification in the gas generator A results and is delivered there as arrears over (not represented) an air-lock system. The use from Koksgrusfiltern to the separation of coal land on water open from waste water is from DE-A-36 35,461 well-known.

After going through the filters E the condensate water is transmitted to an evaporation container F there over the line 8 and evaporated. When heat source for the partial evaporation of the condensate in B produced and overheated high pressure steam used, which was led before by a steam turbine T (back-pressure steam turbine) to the work, in particular to propelling a generator G to the generation of current. That evaporate the steam turbine by a tube heat exchanger 27 of the evaporation container F one leads and until under the point of condensation one cools down there, so daß the condensation warmth of the Abdampfes for the evaporation of the condensate water coming from the filters E serves.

Steam won in the evaporation container F by evaporation the condensate water becomes over the line 9 and 15 as Prozeß steam the gas generator A supplied. If pressure and temperature of the Abdampfes of the gas turbine T are high enough, so that steam produced in the evaporation container F has a higher pressure than the pressure in the gas generator A, then steam can be fed over the line 15 directly into the gas generator A. Pressure and temperature of the Abdampfes from the steam turbine T are so low, daß the pressure of steam produced in the evaporation container F is lower than the pressure in the gas generator A, then it can be necessary to compress steam from that evaporation salaries F dashed by means of the suggested compressor 29 on the pressure necessary for the feed into the gas generator whereby the compressor 29 by the steam turbine T can be propelled.

In the heat exchanger 27 of the evaporation container F from evaporate the turbine D condensed water by means of a pump 31 and heat exchanger 33, 35 to the high pressure steam generator B one leads back.

If the quantity of the condensate evaporated in a steamer F is not sufficient, around the need of Prozeß steam in the gas generator A to cover, knows additional water of au&szlig into the evaporation container F; EN over the line 37 to be fed. This feed of Fremdwasser can take place also in other place, e.g. currentup the filter E.

The water residue remaining in a steamer F is taken off over the line 10 and cleaned in a filter 39 by solids and anschließ end by means of the pump 41 to the evaporation container F led back. The solids separated in the filter 39 can be dried and exhausted in usual way as filter cakes.

The special advantage of the descriptive procedure guidance is in it, daß in evaporate from the steam turbine T contained condensation warmth for the evaporation of the condensate water, i.e. for producing Prozeß steam to be used can and thus is not lost. Furthermore additional external cooling capacity is void by the evaporation process in F. The entire Vergasungsprozeß can work almost free of sewage, which is important in particular for the coupling of the gasification process with gas and steam turbine processes, thus in the power station range.

The heating of the gas generator A by means of the coil of pipe 11 is made via by the line 45 supplied heiß it heat distribution medium medium. This can be placed e.g. from a nuclear reactor to the order. In itself a closed and of äuß eren heat sources independent Prozeß one receives, if one burns at least one part of the product gas taken off over the line 4 and by way of the line 43 of the coil of pipe 11 supplies in such a way produced flue gas with a temperature of e.g. 850° or more. Before the entering the coil of pipe 11 the flue gas can flow through still another heat exchanger 45, around the Proze&szlig won in a steamer F; to overheat steam on temperatures from over 800° to. The coil of pipe 8 leaving flue gas can be used in a heat exchanger 47 still for overheating the steam turbine T of supplied steam.

35 heat exchangers represented with 25, the 33 and serve B and H for the preliminary heating in the steam generators of the boiler feeding water used.

Changes and arrangements of the represented execution form are possible in the context of the invention. So also low pressure steam produced in the steam generator H can be used e.g. for heating the evaporation container F up. In this case however steam taken off over the line 9 is only at a low pressure and muß e.g. by means of the compressor 39 to the high pressure necessary for the feed into the gas generator A by e.g. 35 bar to be after-consolidated. The stripper stage D and/or filter stage E planned for prepurifying the condensate before its evaporation can be theoretically also omitted, whereby then the impurities concerned remain in the condensate water and are led back together with steam produced in F again into the gas generator A. There is then however the danger, daß impurity materials determined themselves, how e.g. enrich perhaps the Amoniak removable in the stripper stage D or in the filters E separable phenol u.dgl. in the condensate water led in the cycle and for the enterprise of the plant and/or for the used materials can achieve critical concentration. The engagement of the stripper stage D and filter stage E is therefore as precautionary Maß to regard nahme.