US2232290A - Protection of the walls of gasifying apparatus - Google Patents

Description

Feb. 18, 1941. e. S-ZIKLA EIAL, 2,232,290

PROTECTION OF THE WALLS 0f GASIFYING APPARATUS Filed July 30, 1938 GEZA SZlKL-A ARTHUR ROZINEK Patented Feb. 18, 1941 PATENT OFFICE 2,232,290 PROTECTION OF THE WALLS F GASIFYING APP ana'rus -G1a slim and Arthur nonnekmuaa est,

Application July 30, 1938, Serial No. 222,292

In Germany August 8'Claims.

tory lining. I

The present invention eliminates this drawback. Utilizing the particular conditions existing in the gasifying chamber, it eliminates in the most simple manner 'any disadvantageous wear and tear of the walls; at the same time it enables very favourable conditions to be created for the gasification of the fine-grained coke.

In accordance with the invention, tubes are arranged and spaced so that a backing of coke (coke wall) and/or of a mixture of coal andicoke, with an admixture of slag, is collected at the natural angle or slope -in such a manner, that jointly with the supporting tubes 9. wall or boundary of the furnace and/or gasifying chamber is formed.

The invention is of course not confined to the gasiiying apparatus for the gasification of fuel in a floating condition, according to our-previous patents; on the contrary the cokewall according-to the present invention can be employed in connection with all'gasifying chambers in which fine-grained fuel is'gasifled whilst being entirely floating condition with a restricted and in which temperatures above the melting point of the slag prevail.

The invention is based on the following considerations and reco 'tion of facts:

(1) Coke will resist which it is necessary to not melt and will not bake together, 1

(2) The admixture even of small quantities of or partly in a supply of air deal in such cases, it will coke dust will substantially increase the melting point of the mixture. Coke contents exceeding 20% of the ash will prevent the melting of the latter.

(3) The. accumulation of coke having a grain size of e. g. up to 5 mm. in the combustion chamber, for instance on a shoulder, following the natural angle of repose of the material. will due to the heat radiation to which it is exposed have on its surface a temperature approximately equal to the temperature of the chamber. 0n the other hand, the hot gas s granules will in consequence of the heat-absorbinadmissibly great wear and tear of the refracthe temperatures with dimming intothe deposit of ing chemical change undergone by them, be rapidly and eiliciently cooled, the C02 being reduced by thecoke to CO. Even if any free oxygen should, possibly still be contained in the gas, such oxygen will efiect the combustion of the coke. 5 on the surface layer and will increase the temperaturein this layer, but below the surface the cooling-down mentioned above of the gas will still take place.

These considerations are based on fine-grained coke, seeing that the fresh coal introduced will at the hightemperatures prevailing become converted into coke within a very short, time. All that is necessary is to make provisionfor ensuring that in the case of coal of a baking kind this 15 coal should be converted into coke in individual granules, which will be the case in the gasifying aparatus for the gasiflcation of fuel in a floating condition according to our prior patents as otherwise the small coal would bake together, into 20 lumps of coke. Coke dust itself will in the case of all kinds of coal behave in the same favourable manner in the sense of the present invention.

The invention results from the further development of the fundamental idea disclosed in .our 25 Patent No. 1,869,949 according to which an inverted flame develops 'in the interior of the crater of coke and ash which latter resists the highest temperatures as well as all detrimental influences of the liquid slag. 39

According to the invention this deposit of coke and ash is extended in the vertical direction so as to extend over the whole height of the gasifying chamber. This being done by arranging a number of tubes. above each other in'such a manner as to ensure that fuel deposits are formed on orbetween the said tubes, in a manner corre-" sponding to the natural angle of repose of the particular mixture of coke and slag. The tubes and the coke slope will build up to a wall in a 40 form resembling that of shutters. In order to in-' crease the length ofthe slope, the tubes are fitted 1 with fin-shaped extensions or two or more tubes are arranged so as to be in mutual contact. In

the case of the gasifying equipment according to 45 our Patent No. 2,099,968 mentioned above there will thus be formed behind the supporting group 0 tubes a backing of, coke and' slag which will permanently become supplemented from above by the .particles of' coke, and slag continuously becoming deposited irom the floating condition. It is however also possible to make provision for the said backing becoming continuously supplemented from the upper end of the row of tubes.

In what follows, the inventionwill be described with reference to Fig. l inwhichra gasifying equipment, approximately corresponding to our Patent No. 2,099,968, is assumed by way of example. Fine-grained coal I0 is introduced in a known manner by means of the centrifugal catapult apparatus 1 into the de-gassing chamber II, for instance, in such a way that the fine-grained coal accumulates in piles H on the cascade levels composed of tubes 13 from which it drops. During its downward movement, it is de-gassed and coked by the contact with the hot gases.- The fine-grained coke is accumulated in the mold l from which it is pulled by the stoker l6, moving in alternating directions, through the opening I! and is conducted in this way in the path of the gas stream rising upwards in the direction of arrow ll through the bottom opening I9 regulated bythe slide l8.

In chamber I the coke is gasified in a floating condition by means of the air entering from below. The gases pass then in the direction of arrow 20 to their further utilization.

In the gasifying chamber I supporting tubes 2 are provided which are preferably equipped with fins 3. Between each tube 2 and the next one a fuel deposit I! will be formed in accordance with the angle of repose 4 of the backing material (which latter may possibly be filled-in when setting the apparatus to work for the first time). These fuel deposits constitute, together with the tubes 2, the boundary walls 5. The particles of coke and slag floating about in the chamber II will partly drop behind the tubes onto the slope and will continuously make up for any diminution of the backing material.

It is, however, also possible to provide a construction in which the backing material is supplemented by the necessary supplementary quantities flowing down from above, as indicated for instance at 6. The material received here from the centrifugal catapult apparatus 1 will in accordance with the progress of the disappearance of the backing subside downwards. Naturally, the material deposited is in this case coal, which is converted into coke only during its downward progress. From what has been said above-the method of operation of theapparatus is self-explanatory. Inside these walls 5, 5 constituted by piles of coke and slag dammed up between tubes, even the highest temperatures are innocuous, and the liquid slag can not exert any disadvantageous efiects whatever. In case it is only the products CO2 and C0 of the pure gasification of coke which, in addition to N2, are present inside the gasifying chamber I, the gas diffusing into the layer of coke and slag will due to the heat-absorbing decomposition of C02 when entering into reaction with C exert a strong cooling efiect and at the same time an incineration will take place on the surface. The same process will take place in case the gas should moreover possibly also contain a certain quantity of O2, in which case this oxygen will effect the combustion of the incandescent coke on the surface, whilst the CO2 part of the gas will in the deeper layers again immediately enter into a heat-absorbing reaction with C and become converted into C0. In both cases the gas penetrating into the interior of the coke and slaglayer will exert a substantial cooling effect and will effect the chilling of the layer of coke. y

In view of the fact that the gasification in this apparatus takes place in the presence of an insuflicient amount of air, it will never be poss ble that the incandescent coke should be completely consumed and that only ash should remain as a backing material. What really happens is that the granules of coke floating and tripping about in the chamber will continue to drop on the pile and prevent any accumulation of ash. Pure ash as a backing material has already been proposed by other inventors, notably in connection with combustion in the presence of an excessive quantity of air, in which case only pure ash, due to the given conditions, would result, but experience shows that at the high temperatures in question the ash would melt and flow away so thatit would not be possible for any backing to be formed and, accordingly, any formation of a bordering wall for the gas would not bepossible.

Accordingly it is a fundamental condition that the gasifying chamber to be equipped with the apparatus according to the present invention should be'of the ln'nd claimed in our Patent No. 2,099,968 in which fine-grained coke is gasifld in a floating condition in the presence of aninsuflicient quantity of air.

It is only on the surface of the coke piles that any ash or slag will be formed, which at the high temperature prevailing will become molten, whilst after its penetration into the layer of coke it will in consequence of its cooling-down assume a pasty condition, and will accordingly wet the granules of coke and 'agglomerate them into 'lumps, in consequence whereof a pasty compound pasty mixture of coke and slag may be held firm under a steeper angle of e. g. 50 and even 60. The angle of repose finally resulting for practical construction will be different according to the quantity and melting point of the slag contained in the mixture and according to the magnitude of the temperature in the gasifying pit.

The spacing of the tubes supporting the slope of coke and slag depends in the case of the same tube diameter on the factors enumerated below. The number of supporting tubes will be lower,

(1) The steeper the angle of repose,

(2) The more the angle of inclination of the surface laid through the tube centre line approximates the angle of slope of the backing material and (3) The greater the length of the fines.

The serviceable slope is, as experiments have proven, in general 45. If the coke becomes pasty on account of the fluidity of the slag, it may be 55.

of good insulation also consists in the presence of granules of coke by which the structure is held firm. Slag alone would become molten into a compound. Even if this compound should keep the thickness of the backing can be kept at avery low figure. The external boundary may consist of ordinary brickwork or possibly of a metal shell.

It is also possible for the structure of the tube wall to be vertical or overhanging. A vertical arrangement is shown by the tubes 8 placed in such a manner that each pair of tubes will be in immediate contact. At the same time it is shown in connection herewith that between two rows of supporting tubes, which in this case consist of the tubes'Z and 8, it is possible to form a separating wall for instance in such a manner that from the centrifugal catapult apparatus 1 fine-grained coal is fed also at l0 between these two rows of tubes. Accordingly there exists in this case a backing between two rows of tubes. It should be added that it'would be possible to employ such a backing'on any desired other parts of gasifying equipments also,.e. g. as a baflle wall, a wall for the reflection of radiation, etc.

An overhanging arrangement of tubes placed at close mutual distances is represents at 9 below the admission of fine-grained coal at 6. In the case of this overhanging arrangement it may be necessary, as a particular case, that the tubes should be placed as indicated, not only close to each other, but in immediately mutual contact, seeing that it is not possible for any slope of coke to be formed between the tubes. This arrangement also, however, is applicable to a backing with the mixture of slag and coke or coal.

Double tubes, like the tubes 8 can be arranged in lieu of the fin tubes, as described above. It is, however, also possible to manage with single tubes not fitted with any fins, if provision is made for these tubes being so arranged relative to each other as to ensure that with due regard to the angle of repose an unbroken backing should become formed. This is indicated in Fig. 2 in which a sloping wall has been assumed and in substantially horizontal tubes spaced apart one above the other, a retaining wall spaced from the seriesof tubes, and a filling of a high melting point mixture of coke and ash between said series of tubes and retaining wall, said tubes being spaced apart a distance depending on the angle of repose of the mixture and the inclination of the series of tubes relative to the vertical.

2. An apparatus according to claim 1, in which the tubes are spaced apart in an askewldirection, the slope of which giving the desired slope of the composite wall.

3. In an apparatus of the character described having a gasifying chamber in which gasification of floating fuel is effected in the presence of a restricted quantity of ,air, said chamber being provided with walls each comprising a series of substantially horizontal tubes spaced apart one above the other, a retaining wall spaced from the series of tubes, a filling of a high melting point mixture of coke and ash between said series of tubes and retaining wall, said tubes being spaced apart a distancedepending on the angle of repose of the mixture and the inclination of the series of tubes relative to the vertical, and radial fins extending longitudinally of the tubes and projecting radially from the tubes substantially perpendicularly to the exposed surface of the filling between tubes to enable the spacing between the tubes of the series to-be increased.

4. An apparatus of the character described, comprising a large chamber confined within refractory walls having an air inlet in the bottom thereof and an outlet in one of said walls near the bottom, means below the top of said chamber for feeding fuel into the upper portion of said chamber, a series of horizontal tubes extending across said chamber between the air inlet and said outlet, said series of tubes being spaced one above the other and extending from said bottoin upwardly to a point above said outlet and terminating below said fuel feeding means, a second series of similarly spaced and arranged tubes positioned between the first-recited series and the outlet, a third series of similarly spaced and arranged tubes positioned between the air inlet and a wall of the chamber, a loose filling of coke and ash between the first and second series of tubes, and a loose filling of coke and ash between the third series of tubes and the adjacent chamber wall, said first and third series of tubes defining between them a gasifying chamber.

5. An apparatus of the character described, comprising a large chamber confined within refractory walls having an air inlet in the bottom thereof and an outlet in one of said walls near the bottom, means below the top of said chamber for feeding fuel into the upper portion of said chamber, a series of horizontal tubes extending across said chamber between the air inlet and said outlet, said series of tubes being spaced one above the other and extending from said bottom upwardly to a point above said outlet and terminating below said fuel feeding means, a second series of similarly spaced and arranged tubes positioned between the first-recited series and the outlet, 2. third series of similarly spaced and arranged tubes positioned between the air inlet and a wall of the chamber,a loose filling of coke and ash between the first and second series of tubes, a loose filling of coke and ash between the third series of tubes and the adjacent chamber wall, said first and third series. of tubes defining between them a gasifying chamber, and means associated with each tube and extending into the filling in contact therewith for preventing the outflow of the filling between said tubes.

6. An apparatus of the character described, comprising a large chamber confined within refractory walls having an air inlet in the bottom minating below said fuel feeding means, a second series of similarly spaced and arranged tubes positioned between the first-recited series and the outlet, a third series of similarly spaced and arranged tubes positioned between the alr inlet and a wall of the chamber, a loose filling of coke and ash between the first and second series of tubes, a loose filling of coke and ash between the third series of tubes and the adjacent chamber wall, said first and third series of tubes defining between them a gasifying chamber, and a fin extending downwardly and inwardly from each tube into the filling in contact therewith for preventing the outflow of the filling between said tubes.

'7. An apparatus of the character described, comprising a large chamber confined within refractory walls having an air inlet in the bottom thereof and an outlet in one of said walls near the bottom, means below the top of said chamber for feeding fuel into the upper P rtion of said chamber, a series of horizontal tubes extending across said chamber between the air inlet and said outlet, said series of tubes being spaced one above the other and extending from said bottom upwardly to a point above said outlet and terminating below said fuel feeding means, a second series of similarly spaced and arranged tubes positioned between the first-recited series and the 'outlet, a third series of similarly spaced and arranged tubes positioned between the air inlet and a wall of the chamber, a loose filling of coke and ash between the first and second series of tubes, a loose filling of coke and ash between the third series oi tubes and the adjacent chamber wall, said first and third series of tubes defining between them a gasifying chamber, and a tube positioned alongside of each tube of the series below and inwardly thereof so as to extend into the filling for preventing the outflow of the filling between tubes of the series.

8. An apparatus of the character described, comprising a large chamber confined within refractory walls having an air inlet in the bottom thereof and an outlet in one of said walls near the bottom, means below the top of said chamber for feeding fuel into the upper portion of said chamber, a series of horizontal tubes extending across said chamber between the air inlet and said outlet, said series of tubes being spaced one above the other and extending from said bottom upwardly to a point above said outlet and terminating below said fuel feeding means, wall defining means extending across said chamber spaced from and substantially parallel to said series of tubes, said wall defining means being located between said series of tubes and the chamber outlet, a loose filling of coke and ash between said series of tubes and the wall defining means, another series of similarly spaced and arranged tubes positioned between the air inlet of said chamber and an adjacent parallel wall of said chamber, and a loose filling of coke and ash between said second recited series of tubes and the adjacent parallel wall of the chamber, the two series of tubes defining between them a gasifying chamber.

GEZA SZIKLA.

ARTHUR ROZINEK.

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