US835506A - Art of generating gas. - Google Patents

Description

No. 835,506. PATENTED. NOV. 13, 1906.

' 0. ELLIS.

ART OF GENERATING GAS.

APPLICATION FILED JULY 1, 1905.

arm s UNITED STATES CARLETON ELLIS, OF NEW YORK,

PATENT OFFICE.

N. Y., ASSIGNOR To COMBUSTION UTILITIES COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

ART OF GENERATING GAS.

Specification of Letters Patent.

Application filed July 1,1905. Serial No. 267 .921.

Patented Nov. 13, 1906.

To all whom, it may concern:

Be it known that I, OARLEroN ELLIS, a citizen of the United States, and a resident of New York city, in the county of New York and State of New York, have-invented certain new and useful Improvements in the Art of Generating Gas, of which the following is a specification.

This invention relates to processes of mak- IO ing gas; and it consists in a method. of tproducing a complete partial combustion o the fuel in a gas-producer of the ordinary type, converting the fuel wholly into gaseous fuel without the eneration of comlpletely-burned [5 products, al as more fully ereinafter set forth, matters of novelty being particularly pointed out in the a pended claims.

The invention re ates more especially to that branch of the art wherein the gas-gener- 2o ator is functionally remote fromithe gas-consuming apparatus, although independence of structure isnot absolutelynecessary to the practice of my method, it being possible to unite gas-producing and gas-consuming alp- 2 5 paratus into a single structure, provided t e organization is such as to permit the application of the principles hereinafter laid down.

Gas-producers are structures wherein various mixtures ofgases are led throu h a bed of hot or glowing fuel and the com ustible gaseous products formed are collected and delivered for consumption. In the ordma operation of a gas-producer containing a su 'ficiently thick bed of fuel to insure normal re- 5 actions upon the gases going therethrough, there is a certain balance obtaimn between the carbon dioxid and the other bo ies in the gaseous roducts obtained. Under the phase rule or iiw of mass action its concentration 40 or partial pressure relative to other gaseous and vaporous bodies will always be a certain definite amount in the normal running of a given producer at given temperatures and under other given conditions. This amount 4 5 is independent of the composition of the gases fed to the producer. In one such producer I have found, for instance, that the gas delivered contains about five per cent, of carbon dioXid. While the producer is running at the same temperatures, &c., this five per cent. will be produced Whether the enterlng air used to support combustion in the pro ducer contains five per cent. of carbon diox d, ten per cent, or none, or whether it contains steam or does not, so long as the body ofreacting fuel-in the producer is sufiiciently deep to insure completeness of contact of, the gases passing through or is brought into thorough contact with said gases in any other way.

In the com lete combustion of carbon, speaking broad of every one hundred units of heat generated about thirtyare due to'the partial combustion to carbon monoxid and the remaining seventy to the further combustion of the monoxid to the dioxid. It is evi dent that the heat of formation of dioxid in the producer is wasted, as it appears as sensible heat in the gas produced and must generally be removed before use, and it is further detrimental in that it embarrasses the working of the producer by causing undue temperatures, clinkerin ,&c. It is also evident that the carbon t e dioxid contains is also wasted so far as any useful effect in the gas is concerned, and therefore re resents so much fuel thrown away. In t e prior practice of this art there has been an efiort to control the undue temperatures mentioned by an addition of steam to the entering gases, though I believe it has never heretofore been sought to obviate the wastes mentioned. Steam reduces the temperature, its reaction with glowing carbon being endothermic but it does not obviate the Waste of heat from the formation of carbon dioxid nor the waste of fuel to which it corresponds. The heat of formation of the dioxid is merely diluted, not doneiaway with. Producers are ordinarily run with air or steam, or mixtures; With steam alone it is necessary to blow up the producer with air occasionally to restore the temperature of the carbon, this being the well-known watergas process. With air alone at the high temperatures prevailing in a pure-air blow the oxygen is converted into carbon dioxid by the undermost layers of glowing fuel, thereby liberating a great deal of heat on the grate, where it is very detrimental, and the carbon dioxid in its upward passage through thefuel is converted partly into the monoxidthe useful ingredient in the gas produced. This conversion, however, as stated, is never complete, a certain proportion of dioXid inevitably remaining in the gas. With steam a certam amount decomposes with the hot carbon, forming carbon monoxid. Another portion 1 forms dioxid, and still another portiongoes through unchanged, the relative proportions in the gas of monoXid, dioxid, hydrogen, and steam depending on the laws of mass action. It has never hitherto been possible to bum the coal in the producer to carbon monoxid without production of carbon dioxid.

It is the object of my invention to achieve this result.

The reaction between carbon dioxid and carbon to form carbon monoxid 1s a reversible one and is expressed b'y COH-CQZQCO, in which the arrows indicate that the reaction may progress in either direction according to circumstances. I determine this condi-tion of reversibility from the following reactions:

(1) C+02=C0z The principal reaction in the lower part or the producer.

The reaction of reduc tion occurring at 600 centigrade and upward.

The dissociation reaction investigated by Mail'lard and Le Qhatelier. ihispccurs at temperature varying from 300 to 800 centigracleu vim i we,

- with the laws or mass action pt" partial pressure of ce rho" d icon, and p t'hat c nass action m is neuende i where p the end, p tr reduce carbon irom an er;

2nd necess My invention consists in the institution by external means of the desired partial pressure 0 carbon dioxid in the gas-producerthat is to say, the normal balance. I aim to secure an equilibrium between carbon monoXid and carbon dioxid in an artificial manner, and I thus suppress the natural tendency of a portion of the coal to depart from the producer as carbon dioxid. The net result is complete combustion of the coal to carbon monoxid.

In the accompanying drawing I have illustrated more or less diagrammatically one form of apparatus of the many adapted to be used in my *rocless.

In the il usti'atlio n, 1 and 1 are two gasproducers of identical structure to be used independentlyo'r alternately, accordingto the modification of my process adopted. Each producer is provided with the usual coalinlets 3 "and gas 'ou-tl'ets (Show broken away.) Pipe 5 communicates with the t'wyers. This pipe is rovided yvith a branch pipe 6, having a vs vs 7 and an inductor '8, into 8 opens steam-pipe '9 with salve -10 and also another pipe 11 with valve 12. Pipe 11 oins pipe 13-. Pipe 13 is provided with valve 14 and 1S con-'r-rected with pipe 'r'hrougjh fan 15. Into it opens an airinlet pipe 16, provicled with v aive Beyond the airinlet is another valve 18 and a connection with a pipe 1-9 iead-ing to a source of products o'i' combustion. (Not shown?) Pipe 19 is'iurther connected with a pipe .20, leading from gas=outlet t of ti producer and provided with valve i ail'gas-outlet t is provided with valve 22 in operation, Where a mitt-triers of steam, produof combustion, and air'is desired "for the it-c nren't, steam imam 9 is used to lrav a mixture of products of eomhus'tion from and rrom "l6, valves i0, 1-2, and 18 being properly adjusted to centroi th proportions and valve 1 .1 closed to throw the ran out of circuit, or with valve 1 open and valve 12 ciosed the draft may be caused b: fan slight amour-its of steam added by opening 10. hen the steam is no; to be 7 is closed. and a m ureef products o co n nusti-on 'iroin end an rein i6 is r i flow by the fan. w en producers land i in processes Where an gas production, u

u air-bl e vaires 2i and 2 making: the a obvious tha valve i7 a (in-2e c as, for instance busti nced 1 amount Slifllifiiil ore jsru'e pa along m an or croonisteam, in case the latter is'desired.) Striking the lower part of the fuel-bed, the oxygen is burnedto carbon dioxid, and the mixture passes up through the incandescent fuel, where reduction to .carbon monoxid'takes place, down to that point where H partial pressure 7)., is realized. Thenceforth no fur-- Carbon dioxid 5 per cent. Carbon monoxid 20per cent. Hydrogen 15 per cent. -Hydrocarbons. 3 per cent. Nitrogen 52 percent. Steam.......... 5percent.

The partial pressures of these constituents will be denoted hereinafter by the expression p 1),, p p p and p respectively. The partial pressure of carbon dioxid, or P I call the partial-pressure efficiency factor of the generator. The total pressure of the gas is P and thepartiahpressure equation for the gaseous constituents is Now p the partial pressure of carbon dioxid, provided no reaction-producing carbon dioxid other than that embraced in these partial-pressure considerations exists, is represented by five per cent. in the above state ment, or five per cent. (30, represents the pan calculated in thermal value into terms of car-' bon monoxid, be equivalent to about fortyfive parts of the latter. The thirty-eight 7 arts of the total combustible matter in one iiundred parts of the gas may therefore be expressed as forty-five parts carbon monoxid. The carbon completely burned, as shown by the carbon dioxid, is five parts, and this, expressed in terms of carbon monoxid, remains the same nuinerically namely,five parts. The total fuel value is therefore represented by fifty parts carbon monoxid, and the fuel allowed to go to waste in this manner is five-fiftieths, or ten per cent, of the total. By my process this fuel is saved. Endothermic reactions conducted in the producer with steam or otherwise do not succeed in converting the excess of heat developed in the formation of this carbon dioxid into latent gaseous energy, as shown by the fact, hereinbefore mentioned, that hydrogen does not increase in' increases.

forth above is considered only for the purpose of elucidating the points which I desire to makevevidentnamely, that the percentage of carbon dioxidstands as a measure of efficiency of a gas-generator intended for the a production of a gas rich in combustible matter and that a'very substantial economy may be effected by means which tend to re duce the amount of carbon dioxid formed from the fuel. I have therefore shown theoretically why it is that the institution by external means of the desired partial pressure of carbon dioxid will result in economy owing to the production. of the maximum quantity of carbon monoxid.

In certain cases where the generator is efficiently designed, so as to largely complete reactions within the thick uniform fuel-bed, particularly where no steam is used or where the amount of steam is not too large, thepartial pressure of carbon dioxid required in operating by my process may be obtained by the introduction of an amount of carbon dioxid which may be determined with approximate accuracy by making it equal in weight to the amount of carbon dioxid normally, present in the combustible gaseous product. In other cases the determination of the amount of carbon dioxid required may be found approximately by making a deterproportion as carbon dioxid- I 7 It will be understood that the example set mination of the percentage of carbon dioxid in the gas produced by an air-blast contain ing no endothermically-reacting agent, care being taken that the bed of fuel during this determination is of such depth that practically no free oxygen passes through the'fire unchanged. Under such conditions the percentage of carbon dioxid represents fairly well the partial-pressure requirement of the gas for this constituent. termination of the normal partial pressure p of carbon dioxid scientific measurements of a high degree of refinement and complexity must be resorted to. So'exact an adjustment is unnecessary and, in fact, in practice is scarcely possible. When steam in considerable uantity passes unchanged throu h the fue-bed and the gas is not coole immediately on evolution, the follow- .ing reaction occurs: CO-i-HzO COR -H2 For the precise deofiafuel a maximum of combustible gas, and

therefore my process is scarcely applicable to such gas-making operations as t use which normally give rise to a try-product gas very low in combustible matter and which have primarily as their object the production of distillation or decomposition productssuch, for instance, as ammonia.

As a source of carbon dioirid the products of combustion or wwte gases from any suit able furnace may be employed. These contain, beside carbon diox. -,.ordin=arily oxygen, nitrogen, Water rapor, and, in small amount, carbon monoxid. The products of combustion of producer-gas generally are the most convenient sources of carbon dioirid for producer operation, as the gas is usually burned in. furnaces located near producer. When the presence of nitrogen is not objection-able, Water-gas generators may often be supplied with carbon dioxicl from the airblow, Waste gases, or from a steam-boiler furnace. The Waste gases evolved in the calcination of lime or cement are especially suited for this per sec, owing to their high content ofcarbon ioxid. l -Iaste gases contai-ning large quantities of dust may be fil producer tempeature is lowered. i

tered before use. Vl hen the generator is used for the operation of internal-explosion engines, the products of explosion of the engine may be entered into the producer in suchan amount as Will suffice to regulate the combustion in the desired manner. the manufacture of producer cooling medium, such as steam, may no ntroduced into the fuelbed, whereby on contact with ignitedcarbon an endothermic action occurs on the ls furthermore often desirable when the products of combustion are derived from a furnace at a high temperature to-sub iectthese a cooling influence prior introduction into the generator, for at high temperatures the velocityof reaction of oxygen with carbon is greatly accelerated over that at normal temperatures, and the oxygen may combine so rapidly with carbon to produce exces ively high or clinkering teleratures the lower portion of the fuel-bed.

In applying my new p to the facture of watengas Z in en-oral the or dinary methods, such oiasting hot fuel with mixtures of air and steam, a the former in amounts su-llicient to keen upthe heat, or the alternate blasting with steam and With air; but in each case inject, together With the steam, an amount carbon sllO-Xid or of products of combustion contain the same that will suii'ice to supp y the amount of carbon dioxid normal totne gas formed in the producer. With the mixed air-steam blow the amount of steam can of course be as great or as little as de ire l, though Where it exceeds a certain amount an occasional interruption the to season store heat to the fuel by an air-blow Will be necessary. /Vhere the alternating blast is employed, the products of combustion to be supplied With the steam can be very conveniently derived from the air-blow.

in the manufacture of Water-gas by my process the loss of fuel ordinarily incurred by the formation of carbon dioxid in the producer is obviated, the inevitable amount of carbon dionid in the gas being supplied from products of combustion which cost practically nothing. The gas is richer in combustible elements, and it is farmore uniform in quality than prior Water-gas, for the reason that one variable reaction in its formation. is eliminated.

I regard my process as generally applicable to any producengas method blowing gases or vapors or mixtures of both through glowing fuel for the manufacture of combustible gas. l have found it particularly applicable to making watengas by the described method and also to making producer-gas by air inj ection alone; though the latter specific process I do not herein claim, as it forms the subject matter of Patent No. 795,790, granted me July 25, 1905, upon a copend-ing application, Serial No. 240,626, filed January 11, 1905.

Briefly stated, my invention consists, broadly, in the art of semi-oxidizing carbon in a gas-producer Without production. of can bon dioxid therein or the complete oxidation of the carbon by supplying to the draftcurrents sent through such a producer the amount of carbon dioxid normal to issuing therefrom, thereby suporessing completely the formation of such dioxid or oompletely-onidized carbonin the producer itself. These draf -currents may be oxygen, air, steam, or m xtures thereof Within purview of my broad invention.

hat I claim is l. The process of making gas which conslots in contacting With a bed of hot fuel a carbon oxidizing draft current containing an amount of carbon dioxid equal to that normally present in the gas from said fuel.

2. The process makinggas which consists in contacting with a of hot fuel carbonoxidizing draft current containing products of combustion in quantity sullic ient to furnish amount of carbon equal to that normally present in the gas iroin said. fuel.

3. The process of semi-oxidizing carbon Without formation of carbon dionid therefrom ivl'iich consists in contacting with said carbon in heated state a draft-current of air containing endothermic agents in quantity sufficient to repress undue rise in temperature, said endothermic agents comprising a quantity of carbon dioxid equal to that normally found in the gas resulting from the which consists in contacting with a bed of hot fuel a draft-current containing air, steam and carbon dioxid, the carbon dioxid being equal in amount to that normally present in the gas from said fuel.

5. The process of manufacturing gas which consists in contacting-with a bed of hot fuel a draft-current containing air, steam and products of combustion, said products being contained therein in amount sufficient to furnish an amount of carbon dioxid equal to that normally present in the gas from said fuel.

6. The process of manufacturing gas which consists in contacting with a bed'of hot fuel a draft-current comprising steam and carbon dioxid, the carbon dioxid being equal in amount to that normally present in the gas from said fuel.

7. The process of manufacturing as which consists in contacting with a bed of ot fuel a j draft-current comprisin steam and products of combustion, said pro nets-being contained therein in quantity sufficient to furnish an amount of carbon dioxid equal to that nor- WARREN E. DIXON, JAB. K. CLARK.

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