US2347076A

US2347076A - Method for the production of coke

Info

Publication number: US2347076A
Application number: US384667A
Authority: US
Inventors: Arthur J Boynton; Urban H Stallings
Original assignee: KNOWIES FUEL PROCESS CORP
Current assignee: KNOWIES FUEL PROCESS Corp
Priority date: 1941-03-22
Filing date: 1941-03-22
Publication date: 1944-04-18
Anticipated expiration: 1961-04-18

Description

Aprn 18, 1944. A. J. BOYNTON ETAL METHOD FOR THE PRODUCTION OF COKEv 3 Sheets--Sheecl 1 Filed March 22, 1941 QN. NN

pl'l 18, 1944 A. J. BOYNTON ETAL 2,347,076

METHOD FOR THE PRODUCTION OF COKE Filed Maranza. 1941 s sheets-sheet 2- 5? iu#- @==om r# 55 Fa BY Urban/176i@ .A

Ap E8, 1944. A. J. BOYNTON Em. 2,347,076

METHOD FOR THE PRODUCTION OF COKE Filed March 22, 1941 3 sheets-sheet :s

mu/ 4 HYDEOCAEBONE mw METER/AL @EPRocE VULAT/LEE A nml/EN Co/fE 1/EN OFF PER/00 I.

TEMPERATURE /NcEE/lS//v HEAT EN@ a/FEEEEA/m/L r/L/Eoua/ 70 COKE .SOLE

f/E/IT 70 /:ACE offE v C '0 EN ,45m/E co/rE PER/00 E.

TEMPERATURE H/GH @No HEAT A l/N/Fo//f #waz/@Hour come To OLE HARD. UEMEE Enom/cr 0E PffocES HECTHOE CME INVENTORE. @mr J Qg/ZZorz, WZ/Eben HazZZL/Zg l square millimeter of cross section.

Patented Apr. 18, 1944 METHOD FOR THE PRODUCTION F COKE Amm- J. Boynton, winnetka, and Urban n. Stallings, Glenwood, lll., assignors to Knowles Fuel Process Corporation, New York, N. Y., a

corporation or Delaware .Application March 22, 1941, Serial No. 384.667

2 Claims.

This invention relates to a new and improved method for the production of coke of high density. It relates particularly to the production of coke from liquid hydrocarbons in a coking chamber, the coke being formed of a density suitable for electrode manufacture directly in the coking chamber without subsequent processing after removal from the chamber;

The requirements for carbon for the manufac# ture of carbon electrodes include a specification with regard to the amount and character of ash, with which We are here not concerned, the moisture content, the content of volatile matter and the true density. The ash is a matter of composition of the charging stock; the other requirements are matters of processing. The moisture content is determined by methods of cooling the coke after the coking process is complete. The volatile content may be reduced to a point below one-half of one percent by continued heat-v ing at temperatures which are not diiicult to create within any high temperature coking oven.

The true density of carbon for electrode manufacture is required to be above 2.00 and preferablyabove 2.05. The reason for this is found in the great decrease in electrical -resistivity which accompanies the higher density. 'Ihe measure of this quantity in coke made at 1112 F. has been found to be 154,000,000 ohms per meter length per This ilgure of resistivity is reduced to 33 1 ohms by. heating to 1710" F. and to 136 ohms by further heating to 2012 F. In order to obtain a true density of 2.05, however, a temperature between 2300 F. and 2400 F. is required, a temperature not usually possible to obtain `in a coke oven. It has heretofore been customary to vsubject coke intended for electrode manufacture to a further processing known as calcination. This consists in heating the coke after removal from the oven, to high temperatures produced by burning additional fuel, by burning a part of the coke or both.

In carrying out the present process we prefer to use a coking chamber of the type known as a Knowles oven. This is a rectangular chamber, composed of refractory material within a steel shell, provided with combustion ues for heating, these ues located beneath a flat floor on which the charge is placed. The oven is also provided with doors at each end by means of which a pusher ram is introduced and the coke pushed from the oven. 4 Gases and vapors of distillation are removedby means of an overhead uptake.

`The charge is introduced in liquid form through one or more inlets.

The process of coking is one in which very rapid distillation of the initial part of the charge occursl with the formation of about an inch of coke on the floor, accompanied by severe cracking of distilled gases and vapors. This phase of charging is succeeded by one in which the liquid charge is added much more rapidly than it is coked. 'Ihe result is that above the initial coke formation just described, the charge remains liquid until after it has all been placed in the cokingV chamber. It then gradually increases in temperature with ebullition of successively higher boiling fractions as the process continues. The coke nally forms almost at once. It is then for most purposes, necessary to superheat it for the sake of hardness and for the reduction of the volatile content. Continued heating will, however, not bring the entire mass of the coke up to a density of 2.05. This results from the fact that the space above the coke is colder than the coke itself, with the result that an equilibrium is reached at which the radiation from the upper surface of the coke is equal to the heat conducted to the upper surface from the flues. This equilibrium temperature is very considerably below that required for the desired density.

It is an object' of the present invention to provide a new and improved method for producing dense coke. l

It is a further object to provide methods by which the coke is increased in density by a heating step carried on in the cokingchamber subsequent to the coking of the charge.

It is an additional object to provide methods of this character for producing dense coke from liquid hydrocarbons such as petroleum residues.

It is also an object to provide methods by which heat is directed upon the upper layer of coke vformed in the coking oven.

It is another object to provide methods whereby such heat may be directed upon the upper layer of coke by introducing oxygen containing gases into the chamber above the coke to cause combustion therein, this combustion being supported by a portion of the upper layer of coke, by additional fuel, or by both the coke and additional fuel.

It is a further object to provide methods by which the additional heat is supplied substantially uniformly to the sheet of coke.

It is an additional object to provide methods whereby coke may be treated at temperatures in the range of 2400 F. and coke or carbon produced having a density of the order of 2.05.

Figure 4 is a diagrammatic representation of the process. i

Referring ilrst to Figure 1 of the drawings, the oven chamber II is formed by the refractory floor I2, the side walls I3 and arched roof I4. The heating flues I5 are located below the floor I2 and may be provided with burners or have heated products of combustion passed thereover in any desired manner. The entire oven is preferably enclosed in a metallic housing supported and held in place by means of the structural steel framework I6. The roof of the chamber is enclosed by the steel roof plates Il supported from this frame I6, the plates being spaced from the brick arch. The brick arch is also shown as covered by a layer of heat resisting, insulating material I8.

The nozzles or burners I9 and 20 are located upon opposite sides of the upper portion of the oven and extend downwardly through the roof cover plates and through the brick arch, so as to discharge into the upper portion of the chamber directly below the arch. As shown in Figure 3, they are preferably spaced along the two sides of the furnace so that those on one side are located intermediate the burners or nozzles upon the opposite side. This insures more uniform distribution of the material flowing vfrom the nozzles, so that the effect is substantially uniform throughout the floor area of the oven.

The series of nozzles 20 is fed with air through a header 2|, which is fed from a riser 22 connecting to .the air main 23. This air main 23 also feeds the nozzles I9 through a riser 24 and header 25. If it is desired to introduce fuel, as Well as air, under pressure through the nozzles, this fuel may be introduced through the pipes 26 and 21, one of which connects to each nozzle, as indicated in Figure 1. These pipes 26 and 21 may be connected in any desired manner to a source of fuel. As shown in Figure 3, the air main 23 is connected to the blower or fan 28, driven by motor 29 and having the air intake 30. The oven is provided with the oiftake 3|, also shown in Figure 3, which carries olf the volatile products of the rst part of the coking process and the products of combustion formed in the second step of the process. It will be understood that the showing of the nozzles or burners is somewhat diagrammatic and that any well-known type of nozzle or of burner, adapted for burning liquid, gaseous or finely divided solid fuel, may

be used.

The oven itself may be of a standard type known as a Knowles oven and provided with the usual doors at the end, which may be opened for the removal of carbon or highly condensed coke, which is removed by pushing from one end out through the opposite end, in the well-known manner.

It will be apparent from the foregoing description that our invention comprises a coke oven of the Knowles type provided with means whereby heat may be added to the coke at its upper surface, thereby increasing its temperature to a point such as vto provide a very hard dense carbon. This temperature may be raised to the order of 2400 F. to produce a coke having a true density of 2.05. During this heating of the top of the coke layer additional heat is also preferably supplied to the bottom of the layer through the sole fiues of the oven.

'I'he air feed pipes or burner nozzles located in the roof of the oven directoxygen containing gases downwardly adjacent the side of the oven, which gases may be air alone or may be products of combustion from burners utilizing additional fuel. The entire surface of the coke layer is contacted by the air, flame or products of combustion which raise the temperature of the coke substantially uniformly throughout its area. Only a small portion of the coke itself is consumed in any such method of operation. Radiation upward from the coke takes place but conduction downward through the coke layer also occurs with the result that the temperature of the upper portion of the coke layer equals that of the lower portion and the coke reaches the desired density throughout the layer.

While we have shown and described certain preferred embodiments of our invention, it is capable of variation to meet diiering conditions and requirements, and, we contemplate such modifications as come within the spirit and scope of the appended claims.

What is claimed is:

1. The process of treating liquid hydrocarbons to produce a coke of high density, which comprises placing the liquid hydrocarbons in a broad, relatively thin layer in a closed chamber, heating the liquid from below to drive off vol'atiles and coke the residue, introducing oxygen containing gases into the upper portion of the chamber to cause substantially uniform combustion throughout the upper face of the coke layer and, during said period of combustion in said upper portion of said chamber, supplying additional heat to the bottom of said layer to heat the coke from above and below to maintain the entire layer at a temperature of approximately 2300 F. until it reaches a density of not less than 2.00, stopping the introduction of the gases and removing the hardened coke.

- 2. The process of treating liquid hydrocarbons to produce a coke of high density, which comprises placing the liquid hydrocarbons in a broad, relatively thin layer in a closed chamber, heating the liquid from below to drive off volatiles and coke the residue, continuing the application of heat from below,introducing oxygen containing gases into the upper portion of the chamber to cause substantially uniform combustion throughout the upper face of the coke layer whereby heat applied from above and below serves to heat substantially the entire layer of the coke to a temperature of from 2300 to 2400" F. until the coke is brought to a* true density of approximately 2.05, stopping the introduction of the gases, and removing the hardened, unburned coke.

ARTHUR J. BOYNTON. URBAN H. STALLINGS.