US2187872A - Gas producer for gasifying granular fuels - Google Patents

Description

Jan. 1940- F. WINKLER El AL. v

GAS PRODQCER FOR GASIFYING GRANULAR FUELS Filed Nov. 10. 1937 Fritz Wain/ 26?" Eduard Lame/(h INVENTORS BY Wk!) THE'IR ATTORNEYS Patented Jan. 23, 1940 Fritz Winkler and Eduard Linckh, Ludwigshafenv on-the-Rhine, Germany, assignors to I. G. Farbenindustrie Aktieng'esellschaft, Frankforton-the-Main, Germany Application November 10, 1937, Serial No. 173,818 In Germany December 2, 1936 1 Claim.

- The present invention relates to a gas producer for gasifying granular fuels.

In the gasification of fuels in granular or lumpy form, the throughput of fuel by the processes hitherto usual is relativelysmall. In the briquette gasification the throughput in the largest gas producers, as forexample those having an internal diameter of 3 meters (cross-section 7 square meters) is generally not more than from 1100 to 1200 kilogram per hour of briquettes. Gas producers are known in'which the throughput is much greater, for example those in which the layer of fuel is moved throughout the whole thickness of the layer by the gasifying 1 agent. In these gas producers,.working according to the so-called Winkler process, throughputs up-to about four times those described can be obtained. In this case, however, it is necessary for the coals to be in a finely granular state.

20 We have now found that the Winkler process may also be applied with advantage for the gasiflcation of granular or lumpy fuels which disintegrate on heating, by first heating the fuel outside thegasification chamber proper and above 5 the layer of fuel, as for example in the upper part of-the gas producer, by the hot gases produced in the gas producer, i. e., in its lower part, and then leading the fuel thus disintegrating at least in part, in the form of finely grained mate- 30 rialv downwards separate from the gasification chamber and introducing it with the'aid of regulatable conveyor devices into the lower part of the gas producer, preferably into the fuel bed itself,in which the fuel is kept throughout its whole 35 thickness in motion similar to a boiling liquid in known manner by the gasifying agent. As fuels which disintegrate by heating there may be mentioned in particular brown coals, brown coal briquettes, mineral coals from more recent geo- 40 glogical formations or low temperature carbonizationcoke. The so-called friable crude brown coal, which consists of a mixture of dust and more or less coarse grains, may also be gasified with advantage according to this invention. In this case the pulverulent portion may be separated from the coarsely grained portion before the preheating, only the latter portion being treated according to. this invention. The pulverulent portion, which by reason of its high water content 50 cannot be gasified or can only be gasifled with I difficulty, may be briquetted and gasified in the same manner. In the preheating, which takes place in the upper part of the gas producer and during which the fuel preferably slides downwards over an incline of a grate-like substratum through which flow the ascending hot gasiflcation products, a far-reaching pre-drying and in some cases a low temperature carbonization and degasiflcation and in some cases even a gasification takes place. The fuel disintegrated during 5 the heating then slides downwards into a chamber separate from the gasiflcation chamber, as for example into a tubular conduit arranged outside the gas producer and is introduced into the gasification chamber at a suitable height by mechan- 1o ical means, as for example rotating conveyor worm. It is preferable to work in such manner that the fuel forms a layer from the preheating chamber to the fuel bed. The process is very economical because the drying, preheating and disintegration of the fuel leads to a high yield of gas during the following gasification. When using oxygen for the gasification the quantity of oxygen applied is considerably smaller than that necessary when supplying the fuel to the fuel bed directly,

The nature of the invention will be further described with reference to the acompanying drawing which shows diagrammatically an example of apparatus according to this invention but the invention is not restricted to the particular example shown.

Brown coal briquettes in the so-called industrial form which contain 15 per cent of water and 6 per cent. of ashes and which yield 7 per cent of a tar upon low temperature carbonization are gasified in the gas producer shown in the drawing with the aid of 75 per cent oxygen. The crosssection of the lower part of the shaft is 0.95 square meter and that of the upper part is 1.8 square meters. The briquettes are introduced through the filling funnel A. They lie on the inclined refractory grate B and the refractory insertion C. Hot gases at a temperature ofv up to 1000 C. or more from the gasification chamber D pass up through slots in the grate B and cause the briquettes to disintegrate. In the gasification chamber itself, the fuel bed E consisting of finely grained fuel is gasified according to U. S. Patents Nos. 1,687,118 and 1,776,876, the fuel bed being in movement similar to a boiling liquid throughout its entire thickness. Thefinely grained coal, or more correctly the half-coke, is continuously supplied from the shaft F, in which the coal has When they have passed the lower end of the refractory grate (at about H), they have attained a temperature of 700 C. so that a degasification and even a gasification of the briquettes disintegrated for the most part into grains or of the coke formed therefrom takes place. Two gas outlets J and K are provided for the gas produced. Since the briquettes contain only 15 per cent of water, the greater part of the gas is withdrawn from the lower gas outlet J. This has the advantage that the gas withdrawn from the lower outlet is free from heavy hydrocarbons, while the gas withdrawn at K contains the whole of the tar.

The gasification of the finely grained material according to the Winkler process takes place in known manner with the addition of steam and preferably while employing oxygen, part of the mixture of steam and oxygen being blown into the gas producer through nozzles L and MI. At the height of the. nozzle M, the coal dust carried up from the fuel bed with the gas is gasified. Steam is blown in through the nozzle N to reduce the temperature of the gas. In this way the refractory grate is protected from attack by slag which might in some cases occur by the gasification of dust at M. The steam naturally reacts in part with the hot coal at H and it is possible by adding large amounts of steam to increase considerably the hydrogen content of the final gas. The discharge pipe P is a discharge means for the removal of slags formed (slag outlet). The device O is a stirrer.

The gas producer may be operated for long periods without trouble and the throughput per hour may amount for example to 1065 kilograms of briquettes. This throughput is very high for so small a gas producer.

The consumption of oxygen is less than in the direct gasification of finely grained dry brown coal. The composition of the final gas may be varied according to desire, for example it may have the following compositions:

For carrying out the process it is not necessary to use briquettes of high strength such as are otherwise required in gas producers, because the briquettes, when they arrive at the inclined refractory grate disintegrate into small pieces. There may therefore be used briquettes of moist brown coal containing from 25 to 30 per cent of water and even crude brown coal may be used provided care be taken during the working of the latter in the mine that it is not disintegrated too much. With appropriate capacity for being shaped of finely grained crude brown coal, briquettes pressed therefrom may also be used for gasification. For the gasification of such moist fuels it is necessary also to provide the upper insertion with small slits through which are passed the hot gases which serve for drying the fuel. In this case the lower refractory grate B is preferably constructed as a roof over which the hot fuel slides down to both sides. There must then be provided two shafts F and, on the opposite side of the refractory insertion C, a similar insertion with slots must be symmetrically arranged.

These shafts may also be arranged directly adjacent to the gasification chamber in the brickwork of the gas producer itself. The inclined refractory grate may also be arranged in a coal bunker separate from the gas producer into which the hot gases from the gas producer are led and from which the coke is supplied to the gas producer. This arrangement may be suitable for example when it is desired to make use of an existing gas producer.

According to this invention salt-containing brown coals, the gasification of which is very difiicult, may also be gasified in the form of briquettes. The salts, as for example NaCl and Na2SO4, contained in the coal, at temperatures above 700 C., are removed from the coal in a vaporous state at least in part while flowing over the refractory grate B by the hot gases and the fine coal passing into the gasification chamber contains only slight amounts of salts.

Heating gas may also be prepared with the said gas producer with the aid of air.

Non briquetted initial materials, as for example crude brown coal or low temperature carbonization coke, such as lignite coke, may also be readily gasified by the process described.

For example lignite coke having 15 per cent of H20 and 18.5 per cent of ashes was gasifled in the gas producer described. The lignite coke consists of about 15 per cent of granules having a diameter up to 6 mm. 12 per cent of granules having a diameter of 6 to 8 mm. 30 per cent of granules having a diameter of 8 to 15 mm. 13 per cent of granules having a diameter of 15 to 20 mm. 30 per cent of granules having a diameter of 20 to 25 mm.

790 kilos of the said lignite coke were charged per hour into the filling funnel (A) from the top. The gasification was effected by means of a gas containing about 70 per cent oxygen with the addition of steam. The hourly output of gas amounted to 1670 cubic meters containing 27.8 per cent of CO2, 17.7 per cent of CO, 44.2 per cent of H2, 1.1 per cent of CH4 and 9.2 per cent of N2. The lignite coke was delivered to the grate (B) in the upper part of the gas producer, preheated thereon to about 630 C., by means of the waste heat resulting from gas produced, and then introduced into the gas producer at its bottom portion by means of the conveyor worm (G). The lignite coke, when introduced into the fuel bed, was chiefly composed of granules having a diameter less than 10 millimeters. As compared with the direct gasification of lignite coke by the process according to the U. 8. Patents 1,687,118 and 1,776,876 the consumption of oxygen, by the method of working according to the instant process, is reduced by about 3 per cent.

2050 kilos of crude lignite containing 55 per cent water and 3.5 per cent ashes and having a granular size of from 5 to 20 millimeters are hourly introduced from top into the gas producer. The gasification with a gas containing about 90 per cent oxygen with the addition of steam, yields an hourly output of gas per each square meter of the cross-sectional area of the shaft of 1300 cubic meters; the said gas contains 36.2 per cent of CO2, 0.3 per cent of Colin, 13.4 per cent of CO, 43.1 per cent of Hz, 0.7 per cent of CH4 and 6.3 per cent of N2.

Instead of crude lignite, briquettes made of peat having about 50 per cent of water may also with an equal result be gasified by the manner described above.

What we claim is:

A gas producer for gasifying granular fuel which dlslntegrates, upon'being heated, which comprises a gasiflcation chamber, the upper and lower portions of which are separated by at least one inclined grate, a shaft outside said gasiflcation chamber leading from said grate to the lower part of said gesification chamber, means for conveying hot gases from said gasification chamber through the openings in said inclined grate, means for conveying preheated and at least partially disinte rated fuel from the lower part of said shaft into the fuel bed in the lower part of said gasiflcation chamber, and means for introducing a. fluid gaslfying agent into said gasiflcation chamber.

FRITZ WINKLER.

EDUARD LINCKH.

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