US1898267A - Utilization of the perceptible heat of finished coke - Google Patents

Description

. calla fing I Peis. 21, 1933. J, SCHAEFER 1,898,267

UTILIZ'ATION QF THE PERCEPTIBLE HEAT OF FINISHED COKE Filed Feb. 24 1926 as fram g coke C Il:

0.41 z/ens sin bwer vte cooling uffi/zing its n.:

.smoke corrnining gases fooien/:matr corra/)11515 yases ca. 300 'C Patented Feb. 2l, 1933 PATENT OFFICE JOSEF SCHAEFER, OF DORTMUND, GEMM UTILIZATION OF THE PERCEPTIBLE HEAT F FmISHED COKE Application lpd February 24, 1926, Serial No. 90,419, and in Germany April 15, 1925.

This invention has reference to means of utilizing the perceptible and sensible heat of the finished coke freshly delivered from the coking ovens, retorts or the like, andit is in- 5 tended to utilize this heat in a highly economical manner as an element both in the 'heating of the coke ovens as Well as for other purposes, and in View thereof it is one of the important objects of the invention to increase the heating value of this great amount of caloric units present in the finished coke and of the combustible gases of high heating value retained therein by utilizing them in the dry cooling of the coke by means of so-called indifferent or rather inert neutral uninflammablc gases and by so conducting this procedure that the heating capacity of the perceptible heat is utilized and increased in such a manner as to produce additional heating gases by decomposition or chemical reaction. In the procedure of cooling the hot finished coke by means of so-called inert or neutral gases rich in carbon-dioxid which are caused to circulate through the coke and through any suitable means for the utilization of the heat referred to a partial conversion of the carbon-dioxid contained in the inert or neutral gases into carbon monoxid is effected in the hot portions of the mass of coke, and this carbon monoxid is transformed back again in part into carbon-dioxid upon the cooled gases reentering the cooled portion of the supply of coke to be cooled and in this operation the carbon is separated out from the carbon monoxid in pulverulent or dustlike condition in accordance With the formula 2CO=CO2+C. The carbon-dioxid in the course of circulation of the cooling gases through the coke is then partly reconverted ...into carbonmonoxid and so in successioinso that in the process of circulation referred to carbon is continuously Vprecipitated in pul- .verulent or dust-like condition. With a view of overcoming this difficulty and of attaining other important objects and advantages provision is made in accordance with this invention to mix and burn the cooling gases referred to With air of combustion before introducing them into the various devices which may be used for the utilization of their heat and after having passed them through the coke cooling chambers in which they have taken up a certain amount of combustible gases, both as a result of their becoming mixed with the carbon monoxid above referred to and of the absorption of the gases still contained or retained in the coke and furthermore than that in consequence of any possible subsequent coking ofl unfinished pieces of coke. By this means lthe gases referred to will undergo a combustion causing the carbon monoXid contained in them to be converted into carbon-dioxid, so that 'the gases may be made to reenter the coke-coolin chambers free from carbon monoXid an thereby to avoid the precipitation of carbon in the cooling chamber. Moreover, by working in this manner, not only the sensible heat, but in addition thereto the heat of combustion of the combustible gases which have been in view of the fact that, on account of the cooling action of the cold parts to be heated in the heat-utilizing means upon the flame, l

the combustion in such heat-utilizing means itself cannot be carried through at all, or at least net sa-tisfactorily without correspondingly preheated air of combustion. in the. treatment of the glowing hot pieces of toko with the cooling gases steam, as hasalready been suggested heretofore for the cooling of newly made coke, or water may be added,

which addition is also instrumental in counteracting the separation and precipitation of carbon inthe cooling chambers and in assisting the desulphurizing of the coke. In this connection it is a further object of my invention to produce and to assist the circulation and the revolving ofthe gases by the addition of steam, such steam or water vapors being for instance introduced by an injector or by equivalent means.

ln accordance with another feature of my invention the employment of the inert or neutral gases referred to for cooling purposes, both without as well as in the presence of steam or water vapors, may extend to part of the mass of the freshly discharged coke only, and by this means additional important advantages will be realized, particularly in the case of coke ovens which are heated with the so-called lean or poor gases, that is to say, gases comparatively low is heating value, such as producer gas or blast furnace gases, for instance. In the case of coke ovens heated by the gases referred to and which hereinafter will be designated broadly as lean or poor eases there is the difficulty that, incase the g owing hot coke in the coke-cooling chambers is employed for preheating only said lean gases, but not for preheating the air of combustion, large amounts of waste heat will result for which, as heretofore practised, it is frequently not possible to provide sufiicient means of utilization. On the other hand, however, if the air of combustion would also be preheated in these ovens, the amoumL of heating gas would be relatively reduced in such cases and they would not sufiice for the complete absorption of the heat of the glowing mass of coke. Now, in order to overcome this difliculty in the successful utilization of the perceptible and sensible heat and of the cooling of the freshly prepared coke in the case of ovens heated with lean or poor gases, the perceptible and sensible heat of the coke in this case is more intensely utilized in accordance with my invention by making use of neutral gases for withdrawing the sensible heat of only part of the newly made and freshly discharged finished coke and in this operation water vapors, steam or water. if so desired, may be admitted to these gases before their admission to the cooling chamber. Another portion of the hot quantity of coke is employed foi-,the preheating of said lean or poor gases, while the air of combustion is preheated on the regenerative or reeuperative principles. In further pursuance of this feature of my invention the heating gases which have thus been heated by the newly made coke may have their heat further considerably increased by suitable heat-exchanging means. When working in this manner, the raising of the ternperature of the heating gases to the degrees of heat commonly employed in regenerative and recuperating furnaces in combination with the preceding increase of the heating value of the gases resulting from their passage through the glowing pieces of coke will result in a reduction in the consumption of gas as compared with the preheating of the heating gas by means of the `glowing coke exclusively, or as compared with the preheating of the gas by regenerative and recuperating means exclusively. The neutral gases obtained, be-

fore parting with their heat, may, moreover, be mixed with a, portion of the gases of combustion or smoke gases produced in the oven and particularly with the smoke gases directly discharged therefrom or with smoke gases which have passed through the gasreheating means. The mixing of the smo re gases discharged from the oven with the neutral gases heated by the coke presents the advantage of an increase of the heating value of this mixture in consequence of the excess of air contained in the smoke gases escaping from the oven.

These and other objects and advantages of my invention may find expression in different embodiments and will be further described with reference to the accompanying drawing showing various forms of exemplilication thereof which have been found suitable for the purposes of the invention. In the drawing Fig. l illustrates diagrammatically and in plan view a coking plant embodyin;l the principles, of this invention. Fig. 2 is likewise a vertical elevational view of the plan referred to seen at right angle to Fig. l and Fig. 3 illustrates diagrammatically a modification of the plant for the carrying out of the process, particularly in connection with ovens heated with the lean or weak gases referred to.

The coke ovens indicated particularly at c in Figs. l and 2 are provided in the well known manner with the cooling chambers 7; for the coke, which may be disposed underneath the ovens or at an inclination in front thereof, as indicated in Fig. 2 of the drawing and into which the finished glowing pieces of coke are discharged from the ovens. Into these coke cooling chambers c neutral gases as above referred to, including, for instance,

smoking gases, are introduced from below by a distributing channel a and preferably by means of a steam injector 8. The gases heated by the coke are withdrawn from the top of the chambers 7c and are conducted, as indicated by the arrows, into the collecting channel b and are then introduced into one or a plurality of combustion chambers i) (Fig. l) in` which they are mixed with air of combustion, for instance, by means of a grate or the like in very tine distribution. As the air of combustion I may employ, for instance, the hot air withdrawn from the air heaters of the coke ovens or preheated by waste heat in any other manner, so that in the combustion chambers the temperature required for the combustion may be sure to be obtained. From the combustion chambers e the gases pass to the station or device for the utilization of the heat, which may, for instance, comprise a steam boiler heated by waste heat and adapted to produce the cooling of the gases; thereupon the gases are again conducted by the channel a to the several cooling chambers k `for the coke which happen to be charged from the ovens. The excess of gases resulting fromthe admission of steam and the taking up of gaseous constituents from lthe coke may be withdrawn at the rear of the heat-utilizing means or station w and may be led into thechimney f, and Whenever necessary or desired,"-may be submitted to any further treatment-of utilization of valuable constituents. In vie'wof the fact that the gases leave the heat-utilizing means or station lw With a temperature which vis mostly above the boiling pointof Water,"

they may be mixed With Water which is vaporized thereby, instead of mixing them With steam.

The gases are cooled down considerably by their utilization in the heat-utilizing means or station lw, and a further cooling is eiiected by the introduction of steam from the injector s, so that their temperature may, for instance, be as low as, say about 150 C. upon entering the coke cooling chambers 7c from Which they escape at a temperature of for instance approximately 750 C. A further increase oftemperature is produced by the combustion at "v and the entire amount of carbon monoxide is thereby'converted into carbon-dioxid.

In case it is desired to obtain Water gas in the cooling chambers 7c a special steam conduit d maybe provided in the exemplification under consideration, this conduit being connected with the bottom part of the several cooling chambers I; which, in this case, are provided at their top portion With a special collecting conduit e 'for the carrying olf of the Water gas produced. In this case `the chambers 7c which happen to be freshly charged with hot-finished coke are iirst fed with steam and after the coke has become suiiiciently cooled down, the connections are changed, so as to put the chamber in communication with the channels a andb.

By Working in this manner from about 3 l to 4 percent by volume of Water gas in the total amount of the circulating gases may be obtained.

In the modification shown by Way'of example and diagrammatically in Fig. 3 of the drawing and which is particularly of advantage in connection 'with coke ovens heated with lean or poor gases, as above referred to, the cooling chambers for the coke are subdivided into a section k1 and a section lo?. Through this section lol and a heat utilizing station or device w neutral gases are caused to circulate as above described to which may be added steam at s in the manner set -forth with reference to the other exemplification, thus, for instance, by means of a steam injector for effecting the circulation. Instead of steam Water may be added which is vaporized by the gases and the excess of gases produced may be discharged through the chimney f,

as set forth With reference to the other exempliication.

Into the other section la? of the coke-cooling chambers and likewise charged with glowing hot coke, lean or poor gas employe-l for the heating of the coke oven. such as, for instance, producer gas or blast furnace gases may be introduced by way of a conduit 7e.. The heating value of the gases is-thcreby increased by the partial conversion of the carbon dioxid contained therein into carbon monoxid and by the partial trans/formation of the Water contained in the gases to Water gas' as Well as by the taking up of the gaseous constituents still remaining in the coke, and the coke. is, moreover, desulphurized to a large extent. The thus preheated heating gases are then introduced intol one of the gas heaters, the heater g1, for instance, such heat- `ers being constructed on the regenerative or has been preheated in the air heaters Z1, like- Wise comprising one or two or more compartments. The smoke carrying gases resulting from the combustion are divided, one part passing through the air heaters, regenerators or recuperators Z2 of the other side of the battery of ovens and, after having been cooled down therein very lovv, are discharged through the chimney f, While another portion of the said smoke carrying vgases or gases of combustion passes through the gas heater g2 or gas regenerators that are to .be employed in a succeeding stage'and escape therefrom with a still comparativly high temperature, inasmuch as the preheated heating gases upon the reversal of the damper for the change ot direction of the gases are made to pass through the gas generators g2 With a rather high temperature. This portion of the smoke carrying gases or gases of cornbustion which are discharged at Im from the section g2 of the oven and which do not pass through the hot coke in the section 7a2 are mixed in the exemplication of Fig. 3 With the neutral gases circulated through the section cl and discharged therefrom in the heated condition, before the gases are passed into the heat-utilizing device or station w. The combustible gas constituents which have been taken up by these gases from the coke will then be burned by the excess of air which is always present in the smoke carrying lgases from the ovens and the heat liberated there- 'by becomes available in the heat-utilizing discharged from the utilizing means w may`l then be reintroduced into the coke-cooling portions, mixing air with part of the gaseous products obtained. thereby, burning the mixture, and preheating the heating gases by heat exchange with the products of combustion obtained.

4. The process of treating fresh incandescent coke to recover the heat values thereof, which comprises dividing the supply of coke into separate portions, passing different kinds of carbonaceous heating gases, each possessing different degrees of thermal v 'alues and carrying different amounts of carbondioxide into direct heat-exchanging contact with the respective coke portions, raising the heat of certain portions of the then resulting gaseous products, and mixing them with air, burning the air-mixture abstracting the heat from the burning mixture and causing air and certain of the carbon-containing heating gases to pass Vin heat-exchanging relation with the products of combustion.

5. The process of treating fresh incandescent coke to recover the heat-values thereof, which comprises dividing the supply of coke into two portions, passing lean fuel gases of low thermal value into direct heatexchanging contact with one portion and passing inert fuel gases containingr much carbon-dioxid into heat-exchanging direct contact with the other portion, raising the heat of the then resulting gaseous products of the v first mentioned portion, uniting therewith gaseous products from the other portion, and burning the united products, and abstracting the heat generated by the burning.

6. The process of treating fresh incandescent cole to recover the heat values thereof, which comprises dividing the supply of coke into two portions, passing fuel gases of different low degrees of thermal value and carrying different amounts of carbon-dioxide into direct heat-exchanging contact with said coke portions, uniting the then resulting gaseous products, adding air to such united products, burning the resulting mixture, and

'passing the products of combustion in heatexchanging contact with the air, and with portions of the fuel gases and of the said gaseous products.

7. The process of treating fresh incandescent coke to recover the heat values thereof, which comprises dividing the supply of coke into two portions, circulating fuel gases of comparatively low thermal value and containing carbon-dioxide in direct heat exchanging contact with one of said portions', thereby producing carbonaceous fuel gases of higher thermal value, passing lean carbonaceous gases of low thermal value different from t-he first-mentioned fuel gases into direct heat-exchanging contact with the other portion of coke, thereby raising the thermal value and the carbonaceous contents of the lean gases, thereupon additionally heating said resulting lean gases, adding air thereto, passing the yresulting gas-and-air mixture over material capable of coking and burning the gas-and-air mixture in direct heat-exchanging relation therewith, thereby abstracting heat from said gas-and-air mixture, and uniting the resulting gases of combustion with the fuel gases first mentioned.

8. The process of treating fresh incandescent coke and recovering the heat values thereof which comprises causing a supply of said incandescent coke to act directly upon carbonaceous lean fuel gases of lower temperature than the coke, thereby cooling said supply` mixing the then resulting gases with air, burning the gas-and-air mixture in heat exchanging relation with coke-forming carbonaceous material, thereby producing gases of combustion and coke, passing said gases of combustion in heat-exchanging relation with fresh supplies of lean fuel gases intermediate the coke-cooling stage and the coke-producing stage, treating another supply of glowing fresh coke with oarbonaceous fuel gases of lower temperature, uniting the then resulting gases with a portion of the gases of combustion referred to and abstracting the heat from the gas mixture.

9. The process of treating freshly prepared incandescent coke and recovering the `heat values thereof, which comprises acting with a supply of fresh hot coke upon carbonaceous fuel gases of lower thermal value than said coke, thereby cooling said coke and heating the gases, additionally heating the resulting fuel gases, mixing heated air with said resulting heated fuel gases, burning said resulting gas-air-mixture in indirect heatexchanging relation with carbonaceous, coke-forming material, thereby producing hot, incandescent coke and gases of combustion, causing part of said gases of combustion to flow in heat exchanging relation with air, Aand causing another portion of said gases of combustion to flow in heat-exchanging relation with a fresh supply of carbonaceous fuel-gases intermediate the coke-cooling stage and the coke-forming stage, and then abstracting the remaining heat of said last-mentioned portion of gases of combus- E tion.

l0. The process of treating freshly prepared highly heated coke and recovering the heat values thereof, which comprises causing a supply of said hot coke to act in direct heat exchanging contact upon inferior fuel gases of lower thermal value than said coke, thereby cooling said coke and producing enriched and heated carbonaceons fuel gases, acting with another separate portion of said hot coke upon lean carbonaceous gases of lower thermal value than said last-mentioned coke portion, mixing the thereby enriched'lean gases with hot air, burning the gas-and-air mixture in heat exchanging relation with cokable material, thereby producing highly heated means.

JOSEF SCHAEFER.

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