US1894438A - Coking process - Google Patents

Description

Jan. 1211933. G P. BARTHQLOM-Ew 1,894,438

COKING PROCESS Filed OC'C. 20. 1928 gnou/obo@ 351g abme/1t www Patented Jan. 1.7, 1.933

UNITED STATES PATENT OFFICE GEORGE POMEROY BARTHOLOMEW, OF ESSEX FELLS, NEW JERSEY, ASSIGNOR TO AMERICAN SMELTING & REFINING COMPANY, OF NEW YORK, N. Y., A CORPORATION or NEW JERSEY COKIN G PROCESS Application led October 20, 1928.A Serial No. 313,816.

constituents are-removed and the residue isformed into coke.

The present invention provides for the efficient treatment of tar for the production of creosote and coke in one operation. The operation is carried on cyclically and includes subjecting the tar in a finely divided condition to a temperature sufficiently high to drive oil" the desired percentage of creosote and to initiate coking of the residue. This residue may be further treated at appropriate temperatures to complete the coking operation. The re uired heat may be obtained during completion of the coking operation and suitably stored for use in treating the next portion of tar. The cycle of operation accordingly comprises treating the. tar in a hot chamber to produce creosote vapor and initiate cokin of the residue. The cokin operation is thzen completed in the same c 1amber and the heat derived therefrom is utilized for treating further uantitiesV of tar.`

The process is re erably carried out in a chamber having t ick refractory walls which are capable of withstanding a comparatively high temperature and of absorbing a considerable amount of heat during the coking operation.

The invention also consists in certain new and original 'features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointedout in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may bc better understood by referring to the following description takenin connection with the accompanying drawing form .names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

The oven which is disclosed in the figure is of conventional design and comprises walls 9 of refractory material which are held in position by any desired means. A thick coating 10 of clay or other heat resisting material is applied over the oven for the purpose of conserving and storing heat. Charging door 13 is provided for removing the resultant coke and for cleaning. The admission of air may be regulated by varying the opening of said door 13 as by fiuting with clay in a manner well known in the art. Pipe 14 is located at theupper portion of the oven and is utilized for removing the creosote vapor to suitable condensing mechanism (not shown). A damper or valve 15 may be included in said pipe for controlling the vapor iiow. Pipe 16 enters the center of the oven preferably through pipe 14'and terminates ina spray nozzle 17. Pipe 16 may be supported in any desired manner and is utilized for the admission of liquid tar into the chamber.

The oven, as shown, is essentially of the conventional bee-hive coke oven type, par-4 tlcularlyadapted for the preparation of metallurgical-coke in massive form. Such massive coke, as prepared in this type of oven, has been thev standard metallurgical coke since the earliest days of the industry, due to its physical structure and resulting strength, being particularly adapted for use in blast furnaces.

A pitch coke, prepared in the manner to be hereinafter described, in addition to havin l the desired structure and strength of ordinary metallurgical coke, is characterized by a freedom from gangue or slag-formin constituents, as it is composed essentially o pure carbon.

In carrying on the present process the oven is first heated by any desired means, as lfor reaches a temperature of example,by burning a quantity of pitch coke. rll`he heating is continued until the oven some 700 C. to 750 C. and large quantities of heat are absorbed and stored in the walls and in the clay Covering. After this temperature is reached the oven is entirely closed with the exception of damper 15 increosote pipe 14. .Coal tar is then admitted through pipe 16 and sprayed into the heated space through nozzle 17 The coal tar spray is introduced in a finely divided condition and is immediately heated by the latent heat contained within the furnace and in the walls 'thereof to a temperature sufficiently high to drive 0H a large part of the volatile constituents as creosote vapor which is withdrawn through pipe 14 to a suitable condensing apparatus, not shown. r1`he spraying operation is continued until a bed of semi-coke of substantial thickness is formed and the heat absorbed by the tar re (luces the temperature of the furnace to, say, approximately 400 C. i

The residue remaining after the creosote vapor is driven off is partly coked and falls to the bottom of the chamber. At the end of the spraying or tar charging period, the residue is allowed to stand in the chamber for an additional period of time during which further quantities of vapor are driven off and removed and the ,coking operation is continued, the temperature of the oven being maintained at approximately 200o C. to 500 y C. Durin this period only a small quantity of heat is eing withdrawn from thel oven. Hence the total quantity of heat therein and in the heavy refractory walls is sufficient to prevent a substantial lowering of the temperature.

At the end of this second period; the

creosote vapor pipe is closed and a small amount of air is admitted through door 13 or by removing a portion of the clay fluting. This air is utilized for supporting combustion within the coking bed andy burning a portion of the coke whereby a sufiicient quantity of heat is derived to complete the coking of the residue and to again raise the temperature of the oven to some 800 C. to 900 C.

At the end of this coking period the door is opened and the coke removed. The removal of the coke cools the oven to a slight extent and reduces the temperature thereof to some 700 C. to 750 C. at which temperature a further quantity of tar is ucharged through pipe l'and another cycle of operation carried out in the manner above set forth.

1n a particular example the tar was sprayed for a period of from-8 to 10 hours, the residue was allowed to remain in the closed chamber for some 39 additional hours and the coking operation required a further period of 28 hours.

ln accordance with the above described process, the coal tar is treated for the production of creosote and coke without intermediate handling: and without the use of external fuel. The coke supplies the heat required for driving off the crcosote vapor from subsequent charges of tar. lVhen the residue is completely coked it may be removed through the door ofthe furnace and is in saleable coudition without further treatment.'

A comparatively'high percentage of creosote recovery is obtained by reason of the efficient heat treatment of the tar. By introducing the same in a finely divided condition it is possible to rapidly raise the temperature thereof to the required value and thereby prevent substantial quantities of intermediate products from beingy formed.

The process has been described as applied to the treatment of coal tar by way of example only. lt is understood that other hydrocarbon oils may be similarly treated at appropriate temperatures for driving off the lighter constituents and leaving the heavy residue.

Although certain novel features of lthe invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the several steps of the process and in its operation may be made by those skilled in the art without departing` from the spirit of the invention.

That is claimed is:

1. rlhe `process for treating coal tar, which comprises introducing said tar in a finely divided, condition into a chamber heated to a temperature of from 400 C. to 900 C. whereby the volatile constituents are removed as vapor and the coking of the residue is begun, collecting said residue as a mass in the bottomv of said chamber, admitting small quantities of air to said chamber for burning a portion for completing the colring of the'residue and for again raising the temperature of said chamber to between 7 00o C. and 900 C., utilizing the walls of said chamberv for storing excess heat, removing the coke from said chamber while maintaining the temperature of the chamber at an operative minimum, and distilling volatiles from a further portion of said tar in the chamber by the so-stored heat.

2. The process for treating coal tar, which comprises introducing said tar in a finely divided condition into a chamber heated/to a temperature of approximately 700 C. whereby the volatile constituents are removed as vapor and the coking of the residue is begun, collecting said residue as a coherent mass in said chamber,y continuing the introduction of tar until the temperature is reduced to approximately 400O 0.5 discontinuing the introduction of tar and maintaining the residue at approximately 400 C. for a further period of time whereby additional quantities of vapor are driven off, admitting of coke whereby heatA is .produced v small quantities of air to said chamber whereby a portion of coke is burned and heat is produced to complete the coking of the residue and to raise the temperature of said chamber to approximately 900 C., utilizing the walls v of said chamber for storing excess heat thus produced, removing the coke from said chamber while maintaining the temperature of the chamber at an operative minimum, and distilling volatiles 'from a further portion of said tar in the chamber by the so-stored heat.

3. The process for treating coal tai', which comprises introducing said tar in a finely divided condition into a chamber heated to chamber, discontinuing the spraying of tar A a temperature of from 400 C. to 900 C.

whereby the volatile constituents are removed as vapor and the coking of the residue is begun, collecting said residue as a coherent mass in said chamber, maintaining a temperature of from 200 C. to 500 C. therein for a further period' of time whereby additional quantities of vapor are driven ofi', then admitting v small quantities of air to said chamber whereby a portion of the coke is burned and the coking of the residuev completed, utilizing the heat thus produced for again raising the temperature of said chamber to between 700 C. and 900 C., utilizing the walls of said chamber for storing excess heat, removing the coke from said chamber while maintaining the temperature of the chamber at an operative minimum, and distilling the vola'- tiles from a further portion of said tar in the chamber by the so-storedheat.

4. The process for treating coal tar which comprisesspraying said tar into a chamber heated to a temperature of from 400 C'. to 900 C. whereby the volatile constituents are removed as vapor and the coking of the residue is begun, collecting said residue on the bottom of said chamber, continuing the spraying until a homogeneous'mass of substantial thickness has been deposited and the temperature falls to approximately 400 C., then admitting small quantities of air to said chamber whereby a portion of coke is burned, utilizing the heat therefrom for completing the coking' of the residue and again raising the temperature of said chamber to between 7 00 C. and 900 C., utilizing the walls of said chamber for storing excess heat, removing the coke from said chamber while maintaining the temperature of the chamber at an operative minimum, and distilling volatiles from a furtherportion of said tar in the chamber by the so-stored heat.

5. lin the treatment of coal tar for the production of coke, the process which comprises spraying said tar into a closed chamber preheated to a temperature sucient to eect simultaneous distillation of creosote and other volatiles and initial coling of the residuum, the heat for said simultaneous distillation and initial coliingiactions being derived from heat stored in the Walls of said preheated

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