US1319917A - Process of and apparatus for making coke and gas - Google Patents

Description

W. D. WILCOX. PROCESS OF AND APPARATUS FOR MAKING COKE AND GAS.

1,319,917. Patented Oct. 28,1919. 4 SHEETS-SHEET 1.

APPUCATION FILED .IUNE14, 1918.

-W. D; WILCOX.

mmus ron MA Patented Oct. 28, 1919.

4 SHEETS-SHEET 2.

W. D. WILCOX. PROCESS OF AND APPARATUS FOR MAKING COKE AND GAS.

Patented Oct. 28, 1919.

4 SHEETS-SHEET 3 APPLICATION FILED JUNE 14. 1918- W. D. WiL'COX. rnocess or AND APPARATUS FOR MAKING COKE AND GAS.

APPLICATION FILED JUNE 14. I918.

Patented Oct. 28, 1919.

4 SHEETS-SHEET 4.

WILLIAM J). wILcox, or CHICAGO, ILLIIvoIs.

PRdCESS OF AND APPARATUS FOR MAKING COKE AND GAS.

Specification of Letters Patent.

Patented Oct. 28, 1919.

Application filed June 14, 1918. Serial No. 289,969.

To all whom it may concern:

Be it known that 1, WILLIAM a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes of and Apparatus for Making Coke and Gas, of which the following is a specification.

My invention relates to improvements in process of and apparatus for carbonizing of carboniferous material and the obtaining of combustible gases and other by products therefrom. Although my invention, in some of its aspects, may be employed with advantage in numerous instances where minerals or analogous materials require tobe heated in order to obtain fuel gas or other valuable products therefrom, one of its principal applications is in the carbonization of bituminous coal for the production of coke and combustible gas.

The object of the invention is to provide an improved, simple, efficient, and economical, process and apparatus of the class described, in which the expenditure for bench fuel is reduced to a minimum, in which there results a comparatively 'large quantity of gas of high quality which may be used for fuel or other purposes, in which the valuable by-products of the distillation process are produced in compartively large quantities and of high quality, in which the process of distillation is carried out to a unlform degree throughout the material. without the necessity of heating unnecessarily any portion thereof, in which the degree of distilla tion to be effected may be accurately determined, in which the operation is substantially automatic and may be carried on rapidly and efiiciently with a minimum of labor and attention from skilled operatives, and, in general, to provide an improved process and apparatus of the character referred to.

According to present day commercial methods of carbonizing coal in by-product coke ovens, the coal to be carbonized is heated in a refractory retort, the walls of which are externally heated. Owing to the fact that the walls of the retort or oven are necessarily of considerable thickness and constructed of material which is a poor conductor of heat, the exterior of the retort must be heated to a considerably higher dcree than the temperature to which it is desired to raise the body of coal to be car- D. WILcox,

bonized, and the flue gases withdrawn at a high temperature; in addition to which, coal and coke are poor conductors of heat. These conditlons render it an extremely difficult matter to cause the heat to penetrate into the center of the body of material to raise it to carbonlzin temperature. It follows that the exterior layer of coke formed in the retort is heated to an unnecessarily high temperature and for an unnecessarily long perlod; as a matter of fact, it has been established that in an ordinary by-prodzict coke oven, most of the material becomes sufficlently carbonized long before the expiration of the time necessary to convert the entire body of coal into coke. Also, it will be observed that the extremely high temperature to which certain portions of the charge are raised, has a deleterious effect upon the by-products of the distillation process, these by-products being to a considerable extent cracked or deteriorated by coming in contact with the material in the highly heated zones of the oven.

I am aware that attempts have been made to effect carbonization of coal by what may be termed internal, as opposed to external,

heating of the charge, but, so far as I am' aware, such attempts have not gone into ex-' tended commercial use, as they involve certain disadvantages, which will be apparent to those skilled in the art. For instance, one process which has been proposed, involves the blasting of air across and through the coal which is to be carbonized. Such a process results in combustion of a portion of the coal or coke itself and in a consequent inferior quality of coke, by reason of the increased percentage of ash.

Otherinventors have proposed the use of externally heated gases other than air, but, so far as I am aware, in such processes it has not been possible to remove more than ,a portion of the volatiles. According to my present knowledge, no one has ever succeeded commercially in producing high quality coke by internal heating.

In its approved embodiment. my invention involves the passing of a supply of material to be carbonized or distilled, progressively through an elongated insulated conduitpreferably vertical so as 'to utilize the force of gravity for effecting downward travel of the material-while causing a supply of highly heated gaseous fluid to flow through the conduit in contact with the material and in a direction opposing the direction of flow of material through the conduit. Preferably, the gaseous fluid whichI employ for this purpose is a mixture of carbon-monoxid and nitrogen, which is generated by passing a supply of preheated air through a. bed of incandescent carbonaceous fuel, preferably dry coke, contained in a producer furnace adjacent to, but distinct from, the conduit, the gas entering the conduit in a zone some distance above the delivery end of the conduit. The delivery end of the conduit is constructed of vmaterial having a relatively high conductivity, so that the sensible heat of the carbonized material may be conducted to and absorbed by the air used for producing the said gas, said air being thus pre-heated before entering the producer. The said air, before it is so heated, preferably is subjected to a preliminary warming in a recuperator through which are passed the hot gases which pass out of the conduit. Preferably, the conduit is extended to form a storage chamber above the point at which the distillation gases are removed from the conduit so as to permit, a continuous supply of the material, thereby insuring uniform and gradual heating of every portion thereof. Such uniform downward travel of the body of material in process of carbonization may be effected through the removal of the carbonized material by any convenientmechanism, such as a pair of constantly revolving toothed rollers which deliver the coke into a storage hopper beneath the conduit and in which the residual heat of the coke may be further reduced by the recuperator through which the distillation gases are withdrawn. This exhauster is capable of developing the necessary degree of vacuum which is required to draw the gases through the system, and its speed is capable of being varied according to the degree of heating required. Preferably, a thermostatic device is employed to automatically regulate the speed of the exhauster, this thermostat being acted upon by the gases flowing out of the top of the conduit.

In the drawings, which illustratea preferred embodiment of my invention as applied to the carbonization of bituminous coal Figure 1 is a transverse section taken vertically through the apparatus;

Fig. 2 is a section taken on the line 22 of Fig. 1;

Fig. 3 is a section taken on the line 33 of Fig. 1;

Fig. 4 is an enlargement of a portion of Fig. 2;

Fig. 5 is a diagrammatic view showing the thermostatic control for the exhauster;

Fig. 6 is a section taken on the line 6-6 of Fig. 1;

Fig. 7 is a section taken on the line 7-7 of Fig. 1;

And Fig. 8 is a section taken on the line 8-8 of Fig. 1.

Referring to the drawings, 20 represents the main vertical conduit, which is constructed of brick work, or other suitable material, and is lined with refractory material indicated at 21. The said conduit is supported by a suitable frame work of transverse I- beams 22 and 23, which also support the other instrumentalities constituting a complete oven unit, the whole being carried by a set of columns 24. At the top of the conduit 20 is a steel storage reservoir 25, the lower end of said reservoir fitting within the fireproof lining 21 of the conduit, while the upper end of the hopper or reservoir is closed by tight-fitting lid 26, the edges of which may be luted in order to prevent entrance of air and consequent deterioration of the fuel gas produced by the process. The capacity of the said storage reservoir or hopper 25 is large enough so that it will accommodate several hours supply of fuel, thereby rendering it unnecessary to open up the conduit except at widely spaced intervals. The body of coal within the storage reservoir or hopper 25 is not subjected to the action of the heating fluid until the material has traveled down below the gas exit pipe 27, which is located at the bottom of the hopper.

The carbonizing section of the conduit is the insulated portion extending between the bottom of the reservoir 25 and a series of horizontal apertures 28 through which the heating fluid is conducted into the conduit and into the material inclosed therein. The conduit is insulated for a short distance below the said series of holes 28, but the lower end 29 of the conduit is not insulated but is made of material such as steel or castiron which will readily radiate or conduct heat away from the body of carbonized material as it descends into the coke storage hopper 30. Said coke storage hopper 30, which is shown best in Fig. 2 of the drawings, is closed at its lower end by a suitable gate or valve 31, the coke being controlled in its downward movement into said hop-per by means of a pair of cylinders 32 and 33, each having a set of spirally arranged fingers or teeth 3%, said rollers 32 being constantly driven so as to effect a gradual downward movement of the material into the hopper.

The driving means for the said feed rolls 32 and 33 comprises a pair of worm gears 35 and 36 which are engaged by a right-hand and a left- hand worm 37 and 38 keyed to the constantly running power-driven shaft 39. Said shaft 39 may be driven by an electric motor, or other suitable form of power.

The coke hopper is of suflicient capacity to accommodate a large amount of carbonized material so that the Valve or gate 31 may be opened at periodic intervals in order to fill a waiting coke car 40 which runs on tracks 41 under the hopper. Since it is not possible to draw all of the sensible heat out of the coke while it is passing down through the conducting portion 29 of the conduit, in some cases it may be desirable to still further cool the coke with a limited quantity of water, the quantity of water used being slightly less than is required to reduce the temperature of the coke to that of the boiling point of water, so that the coke is delivered free of moisture.

The gases which pass out of the top of the insulated portion of the conduit consist of a mixture of the distillation gas and the heating fluid, said gases passing out through the pipe fitting 27, previously referred to, on the end of the horizontal gas pipe 44. In order to prevent contamination of the gas with air when the reservoirs 25 and 30 are being filled or emptied, I prefer to insert a gate valve 45 in the pipe 44, this valve being closed at such' times in preference to shutting down the motor-driven exhauster 46. The pipe 44 discharges into the header 47 of a recuperator 48, being of any desired shape.

in cross-section and having a series of vertical circulating pipes 49 extending between the headers 47 and 50, said pipes 49 constituting the means through which the distillation gases are induced to give up a considerable portion of their sensible heat to the air which is used to feed the furnace, hereafter to be described. Said air enters the recuperator shell through a side opening 51 and passes up through the said casing 48 and around the heater tubes 49 before it enters the air feed pipe 52. The valuable byproducts contained in the distillation gases are removed therefrom by the usual methods and apparatus, which it is not necessary to describe in this application, since such matters are well understood by those skilled in the art.

I will now describe the heating fluid used in my process and the manner in which said heating fluid is produced and raised to the required temperature. Referring to Fig. 1, it will be observed that at the side of the conduit 21 there is located, adjacent to the wall of the conduit, a producer furnace designated as a whole 53, said furnace being of the slagging type and embodying a bed of incandescent carbonaceous fuel, preferably dry coke, through which air is conducted to form a mixture of carbon-monoxid and nitrogen. Such a mixture of carbonmonoxid and nitrogen is the heating fluid which is preferably employed to effect the actual carbonization of the material fed through the main insulated conduit 21.

The producer furnace, as shown best in Fig. 3, comprises a producer proper 53 and an upper storage chamber 54 which contains a supply of reserve fuel sufiicient to run the furnace for several hours, while maintaining a suflicient height of fuel to insure the substantially complete conversion to C0 of any CO which. may be present. The gas is conducted away from the top of the producer section 53 through a pair of side apertures 55, the bottom portions of which are inclined, as shown at 56, in order to prevent the producer fuel from blocking the furnace. Said side openings or recesses 55 communicate through passages 57 with a series of apertures 28, previously referred to, leading into theinsulated conduit 21. The air supply for the pro 'lucer 53 is the same air which undergoes a preliminary heating in the 'recuperator 48, and this same air is also given a still greater pre-heating by causing it to pass around the lower or uninsulated section 29 of the conduit, so that the sensible heat of the carbonized material'is utilized to supply heat to the air usedfor feeding the furnace. This is accomplished by leaving a hollow space 58 around the conducting section 29 of the conduit, the pipe 52 discharging into said space through a horizontal limb 59 near the lower end of the conduit.

After passing through the hollow space 58 .around the pre-heating or conducting section 29 of the conduit, the air'which has thus been pre-heated passes out through a pair of horizontally extending apertures 60 leading into a pair of vertical conduits 61, the lower ends of which 62 are inclined and discharge into the bottom of the producer section 53 of the furnace. The bottom of the furnace extends below the air inlets a sufficient distance to permit of an accumulation of slag without danger of stopping up the air-openings, the slag being removed through a suitable horizontal opening 63 normally closed by a suitable cover 64. It should be understood that no air is allowed to enter the producer, except such air as has been pre-heated by passing through the space 58 surrounding the conducting section 29 of the conduit, the top of the storage portion of the producer being normally closed by cap or door 65, and opened only at such times as it is necessary to re-charge the furnace.

In Fig. 4 the part 66 is a plug or cap used for normally sealing an aperture at the top. of the conduit, said aperture being provided to facilitate inspection and to permit the insertion of a rod, if for any reason the material develops a tendency to arch or clog in its passage down the conduit. At 67 is indicated the position of a thermostatic element which is subjected to the heat of the distillation gases at the top of the conduit. Such thermostatic element 67 is employed to regulate the speed of the exhauster @6 which is preferably driven by a direct current motor 68, the field winding 69 of said motor be ing placed in'series with a resistance coil 70, normally short-circuited by a pair of contact springs 71 and 7 2, the lower contact 7 2 being adapted to be depressed or elevated by means of the moving element 73 of the thermostat diagrammatically indicated at 7 4.

The arrangement is such that when the temperature of the exhaust gases drops below that to which the thermostat 67 is set, the latter, by means of mechanism well known to those skilled in the art, will depress the part 73 and open the contacts 72 and 71, thus effecting an increase in the speed of the shunt-wound motor 68. By reason of such increase in the speed of the motor, the blower 46 will pull a greater volume of gas through the system, there by causing more active combustion in the producer section 53, the generation of a greater Volume of producer gas, and consequently a more rapid flow of heating fluid through the insulated section of the conduit. By reason of the increased flow of heating fluid, the material to be carbonized is heated faster and hence the lowering of temperature of the material undergoing carbonization is arrested and automatically corrected. When the temperature reaches the desired degree, the thermostat automatically closes the contacts and slows down the motor in an obvious manner.

The advantages of my invention in its various aspects will be apparent to those skilled in the art, after careful consideration of the conditions affecting the successful carrying out of such a process. A factor which contributes to a large extent to the success of the process is the fact that the heating fluid which I employ to raise the temperature of the material to effect carbonization, is incapable of endothermic reactions with the material which is being treated. Nitrogen is inert in every sense, and carbon-monoxid, the other constituent of the heating fluid, is incapable of combining with other elements without the generation of heat. This property of my heating fluid is in sharp contrast with such gases or mixtures of gases as contain carbon-di or steam. As is well known by those skilled in the art, carbon-dioxid when it comes in contact with a highly heated body of carbon or coke is converted into carbon-monoxid, a substantial amount of heat being absorbed in the process, with a corresponding reduction in the temperature of the coke and of the gas itself, Steam, in the presence of incandescent carbon, decomposes, hydrogen and oxids of carbon being produced, this reaction being accompanied by a very serious loss of heat. It will be noted that in my process none of the heat which is imparted to the treating fluid before it enters the conduit, is consumed or wasted through undesirable endothermic reactions, nor is there any combustion of the material being treated, since oxygen i excluded.

The efficiency of the process and apparatus is materially enhanced by the pre-heating of the air before it enters the producer. As a matter of fact, certain tests and cal culations which I have .made seem to indicate that unless the producer air supply is pre-heated to a considerable extent, it is im possible to obtain a temperature of carbonization high enough to produce satisfactory coke of the higher grades; for instance, metallurgical coke, the carbonization of Which must be carried to a high degree in order to produce a coke of the required density. Incidentally, the extremely high temperature to which I am enabled to raise the heating fluid before it enters the conduit, renders it possible to conduct the process with a comparatively limited amount of fluid, thus minimizing the quantity of producer fuel required, and also reducing the consumption of power for operating the exhauster. In this connection, it will be understood that the power required to operate the exhauster increases in a rapidly ascending ratio, according to the amount of fluid which must be drawn through the conduit per unit of time.

Another important feature of my invention is the fact that the gas which is pro duced by the distillation process is not seriously deteriorated by the admixture of the heating fluid, since the producer gas, which is a mlxture of carbon-monoxid and nitrogen, is in itself a gas of substantial heating value. Hence, the gaseous mixture which is produced by my process is of high heating value and can be transported considerable distances with" economy.

Another important feature of the invention is the fact that as the material passes down the conduit, its temperature increases gradually and the distillation takes place fractionally. ny gas or product which is given off by the material when it reaches a certain temperature, immediately ascends to a higher and cooler level of the conduit where it is not subjected to the action of a higher temperature than is required to effect its distillation, and is thus prevented from cracking or being decomposed into less desirable products.

By reason of the marked efliciency of my process, a comparatively small amount of bench fuel is required. This of course results in high efliciency and a marked'ecmiomy in operation; also, the coke produced by my invention is of exceptionally uniform grade, by reason of the even heating throughout the cross-section of the conduit, due to the direct transmission of heat to the coal from the heating fluid and the regularity of withdrawal; in addition to which, by reasonfurnish heat for the furnace, the percentage of ash is not more than necessarily results from the character of the material being treated.

Although the details of the process and the apparatus for carrying it out may of course be changed materially without departing from the spirit of the invention, the embodiment which I have shown and described has some advantages where it is desired to employ a battery type of construction. In this connection, it should be noted that my improved process is such that no external heating of the conduit is required, thereby enabling the conduit to be made perfectly air-tight, and thus excluding air or flue gas, with the attendant evils. In most forms of coke ovens, the alternate heating and cooling has an unfavorable effect upon the comparatively thin oven wall, causing leaks todevelop which admit fiue gas into the oven, with a corresponding degradation of the distillation gases. With my in vention, there is nothing in its operation which limits the thickness of the walls of the conduit, which may be made of great strength and high insulating efiiciency, thereby efi'ecting a considerable economy by preventing losses due to radiation, while excluding air or flue gases with their accompanying bad effects.

I claim 1. The improvement in the art of carbonizing coal, which consists in causing the coal to travel uni-directionally through an insulated conduit, introducing into said conduit a supply of moisture-free producer gas composed of one volume of carbon-monoxid and two volumes of nitrogen and heated to a temperature not less than the temperature to which it is desired to heat the coal, and causing the said fluid to flow through said conduit in contact with the coal in a direction cOntrary to that in which the coal moves.

2. The improvement in the art of carbonizing coal, which consists in producing a gas inherently incapable of endothermic reaction with the material to be treated by passing pr'e-heated air through carbonaceous fuel in a furnace, passing the resultant heated gas through and in direct contact with the coal to be carbonized in a chamber from which air is excluded. whereby said coal is heated and removing the resultant products.

3. The improvement in the art of carbonizing coal, which consists in causing a supply of heated air to pass through a bed of incandescent carbonaceous fuel, whereby a moisture free gas composed substantially of a mixture of carbon-monoxid and nitrogen is produced, causing said gas to flow in contact with the coal, whereby the latter is raised to the desired carbonizing tempera ture, and removing the carbonized coal substantially as soon as it is carbonized, while utilizing the sensible heat of the carbonized coal to heat the said air.

4:. The improvement in the art of distilling volatiles from solid hydro-carbons. which consists in effecting unidirectional movement of a supply of hydro-carbonaceo'us material, introducing into said material a supply of highly heated gaseous fluid which is substantially inherently incapable of endothermic reaction with the material to be treated, causing said fluid to flow in contact with the material in a direction contrary to the direction of movement of said fuel, and cooling the treated fuel during the period of its travel after it has lost contact with the said fluid, while Withholding air and moisture from the material while it is heated, whereby the fuel during its travel is subjected to a temperature not in excess of the temperature of the inflowing gas.

5. The improvement in the art of carbonizing coal, which consists in causing the coal to travel uni-directionally through an insulated conduit, introducing into said conduit a supply of gaseous fluid heated to a temperature not less than the temperature to which it is desired to heat the coal, causing the same to flow through said conduit with the coal in a direction contrary to that in which the coal moves, and subsequently cooling the carbonized coal, air and moisture being excluded from the conduit throughout the period of heating.

6. The improvement in the art of carbonizing coal, which consists in causing a supply of heated air to pass through a bed of incandescent carbonized fuel. whereby a gas composed substantially of a mixture of carbon monoxid and nitrogen is produced. causing said gas to flow in contact with the coal to be carbonized, whereby the latter is raised to a carbonizing temperature, air and moisture being withheld from the coal to be carbonized during the period of heating. removing and cooling the carbonized coal substantially as soon as it is carbonized. andutilizing the sensible heat of the carbonized coal to heat the said air.

7. The improvement in the art of carbonizing coal, which consists in causing a supply of heated gaseous fluid to travel in contact with the said coal, and causing progressive movement of the coal in a contrary direction, while automatically cOntrolling the temperature to which the coal is raised by accelerating or retarding the flow of said gaseous fluid, the rate of flow being automatically varied in a direction reverse to the variation in the temperature of the gaseous fluid at the point of withdrawal.

8. The improvement in the art of carbonizing coal, which consists of pre-heating air, drawing same through a body of incandescent carbonized fuel whereby a gas composed substantially of carbon-monoxid and nitrogen is produced, drawing the gas through a body of coal, causing said body of coal to move in a direction contrary to the movement of said gas, automatically varying the rate of flow of said gas in a direction the reverse of any variation in the temperature of the gas at the point of withdrawal.

9. The improvement in the art of carbonizing coal, which consists in passing air through a body of highly incandescent carbonized fuel, passing the resultant hot gas through a body of coal, moving the coal in a direction contrary to that in which the gas is moved, controlling the temperature of the coal by varying the rate of flow of the gas in a direction reverse to any variation in the temperature of the gas at the point of withdrawal.

10. In apparatus for distilling volatiles, the combination of a vertical conduit provided with an upper insulated section in which the material to be treated is heated and a lower cooling section in which the sensible heat of the treated material may be removed and absorbed by air, and a producer furnace communicating with the lower end of the heating section of said conduit and receiving the said air for delivering into said conduit a supply of heated gas substantially inherently incapable of endothermic reaction with the material to be treated.

11. In apparatus for distillin volatiles, the combination of a vertica conduit rovided with an upper insulated section 1n which the material to be treated is heated and a lower cooling section in which the sensible heat of the treated material may be removed and absorbed by air, a producer furnace communicating with the lower end of the heating section of said conduit and receiving the said air for delivering into said conduit for treating said material a supply of heated gas substantially inherently incapable of endothermic reaction with the material to be treated, means for maintaining a supply of fuel at the upper end of said conduit, and means for. withdrawing the treated material at the lower end of said conduit.

12. In apparatus for distilling volatiles, the combination of a vertical conduit provided with an upper insulated section in which the material to be treated is heated and a lower cooling section in which the sensible heat of the treated material may be removed and absorbed by air, a producer furnace communicating with the lower end of the heating section of said conduit and receiving the said air for delivering into said conduit for treating said material a supply of heated gas substantially inherently incapable of endothermic reaction with the material to be treated, means for maintaining a supply of fuel at the upper end of said conduit, means for withdrawing the treated material at the lower end of said conduit, and means for producing a partial vacuum at the upper end of said conduit for drawing said heated gasupwardly through the material being treated.

13. In apparatus of the class described, the combination of a vertically disposed conduit through which coal to be carbonized is moved progressively downwardly, means for producing a highly heated gas and delivering same into the lower end of said conduit, means for causing said gas to travel upwardly through the coal in sa1d conduit for carbonizing the same, and means for automatically accelerating or retarding the said flow of gas upon decrease or lncrease of the temperature in the upper end of said conduit.

WILLIAM D. WILCOX.

Images