US1885920A - Method of treating liquid hydrocarbons - Google Patents

Description

Nov. 1, 1932. A. s. KNOWLES ET AL METHOD OF TREATING LIQUID HYDROCARBONS Filed 001;. 27, 1928 .iiklvem Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE ALEXANDER S. KNOWLES AND CHARLES W. ANDREWS, OF CHICAGO, ILLINOIS, AS-

SIGNOBS TO TAR & PETROLEUM PROCESS COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS METHOD OF TREATING LIQUID HYDROCARBONS Application filed October 27, 1928. Serial No. 315,411.

This" invention relates to a new and improved method for the treatment of heavy hydrocarbon matter in liquid form, and more particularly to a method involving the complete distillation of materials such as coal tar, pitch, wood tar, and petroleum oils and res1- dues.

While our invention is adapted for use in connection with any such hydrocarbons, it is particularly adapted for use in connection with the treatment of residues from p pe stills, cracking plants or other stills in w 1ch the material being treated is reduced to a heavy residue with high specific gravlty and which in many cases is solid at atmospheric temperatures. This material may preferably be treated by our method while it is still liquid and highly heated from the preceding treatment. The material in many such plants is reduced to a density such that it is very near the coking point and in present practice the material is placed in large tank stills and further heated until it solidifies as petroleum coke. This coke is weak in structure, has an objectionable oily odor and tends to mass and stick together. Due to its undesirable features it is not of great commercial value. It is also expensive to produce as it must be removed by hand from the stills, which is a slow and costly process.

In a prior application Serial No. 218,453 filed September 9, 1927 there is disclosed another method and apparatus for treating hydrocarbons of this character. In this method and apparatus provision has been made for exposing the liquid being treated in thin films or layers to the action of the ascending heated gases. It has been found that while such method may be used it is not preferable with certain of the heavier residues as the material is so near the coking stage that it tends to clog the surfaces over whichthe material passes. This prior method and apparatus is most desirable for use where the material being treated has a large proportion of volatiles remaining in it before being sub jected to our treatment.

In our present method the heavy hydrocarbon in liquid form is subjected to the action of the ascending volatiles, preferably by means of bubble towers or other direct contact means in which the incoming liquid is further heated and in which the volatiles are brought in intimate contact with the liquid. Since the outgoing gases are hotter than the incoming liquid, some further distilling and cracking of the heavy hydrocarbon takes place. The incoming heavy hydrocarbon further serves to reflux heavier vapors from the ascending gases, resulting in a lighter product being derived from the vapors after they leave the apparatus.

The highly heated heavy hydrocarbon from the bubble tower or other contact apparatus may be introduced into the coking chamber in larger quantities and in fewer places than the lighter oils or residues. The hydrocarbon deposited on the highly heated floor of heat resistant material vaporizes very quickly until a thin film of coke is formed on the floor, after which it vaporizes somewhat more slowly from the top of the layer of coke. The feed of the liquid should be maintained at such a rate that the layer of liquid spreads substantially evenly over the floor or on the coke layer. If the liquid is permitted to accumulate in thicker layers the resultant coke will be somewhat similar to the petroleum coke formed by mass distillation in the large tank stills. If the layer of coking liquid is maintained thin the coke is hard and suitable for metallurgical purposes.

It is an object of the present invention to provide a new and improved method for the treatment of heavy hydrocarbon in liquid form whereby the volatiles are driven off and recovered and the residue formed into a metallurgical or domestic coke as desired.

It is a further'object to provide a method of treating material of this character to completely distill them on a floor of heat resistant material heated to orabove the coking temperature by so regulating the rate of input of' the material and of .the heat to the floor as to maintain a thin layer of uncoked material on the floor or on the coked mass.

It is an additional object to provide a 'method adapted for use with heavierresidues near the coking point whereby the material may be treated with the gaseous prodnot of the process and may becontinuously It is an additional obj set to provide a method in which the material treated is subjected to a cracking and distilling action by means of heat derived from and by contact with the volatile products of the process, preferably by means of bubble towers or like apparatus.

Other and further objects will appear as the description proceeds.

We have shown somewhat diagrammatically in the accompanying drawing, one form of apparatus adapted for carrying out our improved method.

In the drawing- Figure 1 is a vertical longitudinal section of the apparatus, and

Figure 2 is a transverse section taken on line 2-2 of Figure 1. i

In the drawing, the coking chamber 11 is provided with a floor 12 which is formed of heat resistant material. This floor may be made of material such as a brick formed of a refractory high in aluminum oxide, or it may be formed of metals or alloys adapted to resist high temperatures such as an alloy containing nickle and chromium. The corners 13 are rounded to facilitate the removal of the coke. 4

The floor 12 is heated by means of combustion flues 14 located below the floors which are shown as provided with the regenerators 15 and 16 for preheating air and gas for combustion in the fines. The details of these regenerators and flues form no part of the present invention. i

The chamber 11 is provided with the doors 17 at the ends, through which the coke may be removed as desired. The side walls 18 support the angular metal members 19 or Z-bars which have horizontal flanges which serve to support the pusher (not shown) in its movement through the chamber inpushing out the coke. The upper housing 20 of the chamber 11 is preferably formed of metal insulated on the outside and supported on the walls 18.

The contact chamber or bubble tower 21 is located above the central portion of the housing 20. The passage .22 extendsfrom the top of the chamber 21 and serves for the removal of the volatile products of the process. The

tower 21 is provided with the horizontal partitions or trays 23 and 24. These trays are provided with the upwardly extending sleeves 25 and 26 which carry the hoods or caps 27 and 28. The hoods have their edges spaced from the sleeves and serrated. The overflow pipe 29 has its upper end located above the lower edge of the serrations on the hoods 27 so as to maintain the liquid on the tray 23 above that level. The overflow pipe 30 has its upper end similiarly located in regard to the hoods 28 of the tray 24.

The inlet pipe 31, controlled by valve 32, leads into the chamber 21 above the tray 23. The outlet 30 is connected to a cross pipe 33 which has its ends connected to the headers 34 which are in turn connected to the downwardly extending pipes 35 which lead into the chamber 11 at a plurality of spaced points and serve to deposit the material being treated onto the floor 12.

In the operation of the apparatus in carry ing out our improved method, the heavy hydrocarbon in liquid form is introduced through pipe 31, the rate of flow being con trolled by valve 32. The fioor 12 is heated from below to a coking temperature. liquid fills up the tray 23 to the level of the top of the overflow pipe 29 and the excess flows down through pipe 29 to be deposited upon tray 24. On tray 24 the liquid rises to the level of the top or the overflow pipe 30 and flows through pipe 30 to cross pipe 33 and through the headers 34 to the discharge pipes or nozzles 35. It will be understood that these pipes and headers may be so designed and proportioned as to insure a substantially uniform distribution of the material, but these details form no part of the present invention.

The first liquid deposited on the floor is heated rapidly and the volatilesdriven off and residue coked to form a thin film of coke on the floor. The deposit continues at such a rate as to maintain a thin layer of uncoked material on the layer of coke. To secure the best coke and secure liquid and gaseous products of satisfactory quality and specific gravity, it is important to maintain a proper balance between the input of the material and of heat so as to have a coking layer of desired thickness. It will be understood that the layer of coke gradually built up on the floor acts to some extent as an insulator and that therefore the heat input should be increased or material input decreased or both varied as the depth of coke demands. When the coke reaches the desired thickness, the introduction of material is temporarily suspended, the doors soon opened and the coke layer pushed out of the chamber.

During the operation, the volatiles, which consist of condensible vapors and fixed gases, pass upwardly into the chamber 21 and upwardly through the sleeves 26. From the sleeves 26 the gases bubble through the serrations on the under edge of the hoods 28, in contact with the liquid in the tray 24. The gases similarly pass up through the tray 23, and those portions not taken up by the liquid pass out through passage 22. They may be suitably treated to separate and condense out The i assaaao fractions as desired, and the fixed gases may be further treated or used. The volatiles in passing through and in contact with the liquid serve to give up much of their heat and to raise the liquid to almost a coking temperature.

It will be understood that our method may be carried out in other forms of apparatus than the specific form shown by way of illustration. The liquid hydrocarbon may be deposited at few or more points than those shown. It may be sprayed into the chamber or may be deposited intermittently rather than continuously, it being understood, however, that the deposit should be at such rate as to maintain an approximately uniform layer of liquid on top of the formed coke. It will be understood that the bubble tower or contact apparatus may vary in its construction.

The variation in amount of the liquirfl hly- 4 drocarbon fed in, the temperature liquid, the temperature of the floor and of the formed coke on the floor, determine the extent of the cracking of the hydrocarbon and the quality of the products of the crackiriifg. The presence of the hot coking mass a acts the cracking action depending upon the depth of the coked and of the uncoked layers. A thin coked layer increases the of a closed chamber, the material passing down through the chamber in contact with gases given ofi below and falling upon a floor heated to a coking temperature, coking the solid residue of said liquid upon said floor, and refluxing some of the gaseous products of the coking process by passing said gaseous products in counter current contact through the entering liquid, said contacts serving to heat the incoming liquid to near a' coking temperature.

Signed at New York City, New York, this 25th day of October, 1928.

ALEXANDER S. KNOWLES. CHARLES W. ANDREWS.

rapidity of the action while a thicker layer decreases the rapidity of the action.

The method as described above has proven' a quick, safe and economical method for the extraction of solid matter as coke which may be made suitable for metallurgical purposes, from heavy hydrocarbons in liquid form and at the same time to crack the material and to drive off the volatile constituents.

Hydrocarbons suitable for suchtreatment include all hydrocarbons in liquid form or capable of liquefaction by heat such as acid sludges, pitch and residues from distilling,

topping and cracking operations. It has proven in actual use to be particularly adapted for treatment of the heavy residues of the more modern oil cracking processes.

While we have shown one form of apparatus for can 'ng out our invention, and disclosed certain preferred manners of carrying out the improvedmethod, both apparatus and method are capable of modification and we contemplate such variations and changes as come within the spirit and scope of the appended claim.

With some oils which are corrosive in their action, it has been customary to neutralize them with lime or other agents. In such 4 The method of treating heavy hydrocarbon material in liquid form, which comprises introducing the liquid into the upper portion

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