US2040875A - Apparatus for the coking of bituminous or asphaltic liquids - Google Patents

Description

May 19, 1936. R. s. PETERSEN APPARATUS FOR THE COKING OF BITUMINOUS OR ASPHALTIC LIQUIDS Filed Feb. 23, 19-34 Patented May 19, 1936 UNITED STATES APPARATUS FOR THE COKING F BITU- MINOUS OR ASPHALTIC LIQUIDS Roy S. Petersen, San Antonio, Tex., assignor to Brassert-Tidewater Development Corporation, Chicago, 111., a corporation of Delaware Application February 23, 1934, Serial No. 712,460

2 Claims.

This invention relates to a new and improved apparatus for the coking ofbituminous or asphaltic liquids, pitches, petroleum residues, and other fluid or semi-fluid compounds which may or may not contain entrained solid fuels such as carbon, fine coal or the like.

In prior processes for coking materials of this character closed chambers have been used and vapors preheated to temperatures in excess of 850 F. have been admitted into the chambers in contact with the material being treated, which is usually heated to temperatures in excess of 600 F. The coking condition is brought about by mixture of these two heated streams in the chamber with a deposit of the coke formed in the lower portion of the chamber. In vertical chambers of ten foot diameter depositions of coke in excess of thirty feet in height have been carried on in actual operation. when the desired depth of coke has been reached the feed lines are shut off and steam introduced into the chamber until the coke has been cooled below the ignition point. Sections of the chamber wall or bottom are then removed and the coke is withdrawn by mechanical means suc for example, as cables or chains which have been placed in the chamber previous to the coking operation and have become embedded in the mass of coke.

In some instances rotary drills are used to break the coke sufiiciently to permit its removal. The difficulties of coke removal are increased as the amount of volatile matter in the coke is decreased, since the coking structure becomes denser and harder. 30 My present invention obviates these difliculties by placing the usual steel shell preferably in a horizontal position and building within it, of

refractory material, a cokingchamber of a shape which facilitates mass removal of the coke with- 40 out first cooling it and'this further serves to retain as much heat as possible by insulating the chamber.

the chamber proper, other insulating materials may be used between the walls and the shell or exteriorly of metal shell. The two ends of the chamber are equipped with insulated doors which are sealed to the shell proper and are removable when pushing out the hot coke after completion 50 of its formation.

The heat for the coking operation is supplied by the admission of hot gases and/or vapors into the chamber in suchquantity as to properly coke the available feed. These vapors aftenf 55 accomplishing their purpose are discharged into In addition to the refractory walls of suitable fractionating and condensing apparatus along with volatile portions of the feed.

It is an object of the present invention to provide a new and improved apparatus for the coking of materials of the character described. 5

It is "an additional object to provide a method whereby the coking operation is carried on without the necessity for the application of external heat to the coking chamber.

It is also an object to provide an insulated l0 horizontal chamber designed for the rapid and economical removal of the formed coke by means of a mechanical pusher or its equivalent.

Other and further objects will appear as the description proceeds. 5

I have shown certain preferred embodiments of my invention in the accompanying drawing, in which Figure 1 is an elevation showing one form of the coking chamber or oven, with the associated 20 quenching car and coke pushing apparatus;

Figure 2 is a cross section taken on line 2-4 of Figure 1;

Figure 3 is a cross section of a somewhat modi- Q fled form of construction and taken on the line 5 equivalent to 3-3 of Figure 1; and

Figure 4 is a. section similar to Figure 2 but showing a cylindrical coking chamber.

In the form of construction shown in Figures 1 w .and 2, the horizontal metallic shell I2 is sup- 0 ported on piers l3. This shell contains a refractory lining l4 and a refractory floor l5 which define a horizontally extending coking chamber. Doors l6 and I1 are provided to close the ends of the steel shell and the coking chamber. The hoist I8 is provided on the left end of the coking chamber for the purpose of raising and lowering the door l6. Floor extensions l9and 20 are provided on the opposite ends of .the shell for walkways and also for the purpose of supporting coke and coke moving apparatus during the removal of the coke layer.

The quenching car 2|, which may be of usual construction, is shown at the left end of the oven. The pusher machine 22 is shown at the right end of the oven, this pusher moving on tracks 23 if it is used in connection with a plurality of similar ovens. The pusher includes a push beam 24 having a pushing head 25, this beam being recip- 5 rocated into and out of the coking chamber as desired by means of a motor 26, drive connections and chain or rope 2B which is coupled to the push beam. The pusher machine 22 is also provided with a hoist 2% for use in raising in cross section,

2 and lowering the chamber.

The chamber is the door n at the adjacent end or provided, as best shown Figure 2,- with a. heavy hydrocarbon feed passage 30 in its upper portion and an opposedfeed passage 31 for use in introducing hot oil vapor or its equivalent which can be used in the 'coking operation. As shown in Figure 1 the upper portion of the chamber is also provided with an oiftake passage 32 which is connected with the oiItake header 33 for carrying off the volatile products of the process and for venting the chamber.

The form of construction shown in Figure 3 diil'ers from that shown in Figures 1 and 2 in that the steel shell 40 is oval rather than circular which affords a coking chamber 4| having a'wider floor 42.

A number of flues 43 are floor 42 and these flues may provided below this serve for the introduction of heated products of combustion, gases and/or vapors or the introduction of gas and air for heating the chamber floor from below. In carrying out my process by the use of apparatus of the general character, the material being treated will be introduced through the upper por- F. if feasible, and may be forced in under suitable pressure if it contains suflicient solids as not to flow readily under normal conditions. The hot oil vapor or its equivalent introduced through the passage 3| may consist of highly heated vaporized oil and/or heated fixed gases. In one method of carrying out the process a suitable gas oil fraction may be taken oil? a bubble tower .diii'ers only slightly from'that through through a preheater where perature. is preferably raised to above 900 F. This heated oil fraction is then discharged into the oven through passage 3| to serve as a'heating medium for carrying out the coking process.

By a method of this character the temperature in the oven the vapors coming in and therefore destructive heating of the vapors which are used as the heat transfer m um can be largely reduced. It will be understood that other oil vapors and/or fixed gases may be heated and introduced in similar manner.

The form of and passed construction shown in Figure 4 shown in Figure 2.

It comprises the cylindrical steel shell 50 with the refractory lining 5| which is also cylindrical and affords a cylindrical coking chamber with the arcuate bottom. The feed lines 52 and 53 are provided for introducing the material to be treated and the vapors and/or gases for supplying the heat for treatmen After a suflicient depth of coke has been formed in the oven the feed of the material being treated is stopped. The feed of the heating medium may stopped immediately or may be continued for a period to substantially complete the coking of the last portion of the material introduced.

During the last period vapors are operation. As these are not desirable fractionation, .we prefer to vent the oven and gradually introduce air into the oven suitable openings to burn such undesirablevapors in the oven, thus increasing the temperature of the walls and also at the same time heat the coke charge. If desirable, suf- "which the volatile matter is "that of having sufllcient creases the throughput need not exceed the temperature L if the top is too cool,

ficient air will be admitted to also burn part of, the coke and thus reduce the volatile content of that remaining to whatever point may be desired. The additional heat will also have the eflect of reducing the friability of the coke and making it a better selling product. The product of. this coking and subsequent beehive operation is of a different quality from any now on the market and I also claim this material as a new article of manufacture whose physical properties are much superior to the ordinary chamber coke and in maintained at a percentage best suited for domestic use. This will usually be from 3% to It will be observed that in my method of operation the coke is .not cooled before removal from the oven and, on account of the insulation, the brick work maintains a temperature which corresponds to the coking temperature used in the oven, it building up during the burning off which is deposited on it. This being the case,

the problem of pushing the oven becomes only power to overcome'the frictiorroi tlfe coke with the containing floor and walls. This naturally saves time and thus inof-a given chamber. After the desired point is reached the doors are removed and the coke is pushed or drawn by mechanical means such as the pusher shown in the drawing. After the coke is removed the doors are again closed and the operation isrepeated. By the use of an approximately flat floor the first push on the hot coke breaks the nearby coke free from the floor and usually causes numerous vertical fractures, sometimes to the extent that the coke will roll up rather than push out in a flat sheet. In this way the mass of coke successively breaks away from the floor. A further advantage of pushing the coke hot is that it breaks up into more suitable sizes when dropping into the coke car than it usually would if it were allowed to cool and'be pushed out in a solid mass.

Under some conditions of operation the tem perature of the feed material may be such that it" is possible to introduce into the chamber a substantial depth of liquid and to thereafter agitate the liquid by passing gases through it to an extent suflicient to dnitiate coking. The operation may be continued by the addition of more hot charging stock and gasesuntil the desired coking is obtained. If the heat of the charging stock is sufficient, it may be unnecessary to add heat through the gases, which may simply serve for agitation.

It will be recognized that at times the temperature in the top of the oven may be 'high enough to cause destructive heating of the lighter hydrocarbons in the gases and vapors. Therefore it is one of the purposes of this invention to so control this heat by feeding in the proper amount of the charging stock which is at the lower temperature to reduce the top temperature to a safe point before introducing the heating gases. Likewise, more of the heating gases can be introduced and In some special cases it may prove desirable to use the ordinary she still or vertical coking chamber types, horizontally placed, with or without insulating lining, as shown in Figure 4. In this case the pusher would be made to conform to the curvature of the .bottom of the chamber and the coke would ever depth was best adapted for pushing the same. In this way, as in the previous ones, the

be allowed to form to whatcoke would be preferably pushed hot, as I have found that this method is far preferable to quenching the coke in the chamber and thus reducing the-chambcrs temperature so materially.

My process fits in very nicely with the ordinary cracking operations of a refinery where the coking chamber is an integral part of the cracking apparatus. If desired, vapors and bottoms can be fed into my coking chamber instead of into the usual evaporators or coking chambers which constitute an integral part of the cracking unit. In thislevent, my coking chamber would be operated under the regular coking pressure and no liquid residues would be formed as a result of the cracking process.

In the case where charging stock is passed directly through a heater it may be found that the transfer line can be discharged directly into my oven instead of into the usual reaction chamher. In this event the size of the oven would preferably be so proportioned that the soaking or reaction time required for best operation of the cracking unit would be attained in the chamher, which in this casewould receive the heavy residue and coke it without further handling. In such an operation a sufficient number of coking ovens would be installed to assure that the operation of the cracking unit would continue without interruption, the stream of vapors being transferred from one coking unit to another as required.

In my method the temperature in the coking oven is not reduced by the quenching of the coke therein, therefore my coking oven is ready to go back on the line immediately upon its being emptied and sealed up again. If its temperatureis either higher or lower than that of the charging stock which will be admitted to it I can bring the oven to the desired temperature either by cooling with steam, for-example, or raising its temperature by bringing in hot vapors or buming vapors and/or gases in it.- This is a very important element of my invention as it relieves the operator of the delicate operation of raising the temperature in the coking chamber to permit the entrance of hot vapors without causing operating difliculties and serious strains on the equipment where the chamber is cooled.

While I have stated that the coke mass is preferably pushed or pulled from the oven while hot, it will be understood that this is not always essential and that under some circumstances it may be desirable to first cool the coke before discharging it.

It will be understood that the process is not limited to the exact form of apparatus shown in the drawing. The form shown in Figure 3 may be used or other means may be provided for heating the floor from below if desired. This heating of the floor may be carried on only when starting up the oven or may be used throughout the process, as desired. It will also be understood that the method itself will be modified to meet varying conditions and requirements, and I contemplate such changes and modifications as come within the spirit and scope of the appended claims.

I claim: 1

1. Apparatus for coking heavy hydrocarbons in fluid form, which comprises a metallic outer casing entirely surrounding a refractory lining, said metallic casing serving to prevent infiltration of air through said lining, said lining forming a horizontal coking chamber therein, said casing having openings at each end thereof, removable sealing means covering said openings, a substantially flat refractory floor for said chamber and heating flues below the floor and within the metallic casing, means for introducing into the chamber the heavy hydrocarbons to be coked, means for removing from the chamber vapors produced by the coking operation, a pusher ram and means for forcing it through the chamber to push out the coke, and means for receiving the coke after it is discharged from the chamber.

2. Apparatus for coking heavy hydrocarbons in fluid form, which comprises a metallic outer casing entirely surrounding a refractory lining, said metallic casing serving to prevent infiltrationof air through said lining, said lining forming a' horizontal coking chamber therein, said casing having openings at each end thereof, removable sealing means covering said openings, a substantially flat refractory floor for said chamber and heating-flues below the floor and within the metallic casing, means for introducing into the chamber the heavy hydrocarbons to be coked,

means for providing heated gases and vapors heated to above a-coking temperature and for introducing them into the chamber, means for removing from the chamber vapors produced by the coking operation, a pusher ram and means for forcing it through the chamber to push out the coke, and means for receiving the coke after it is discharged from the chamber.

' ROY S. PETERSEN.

Images