US1175079A - Continuous coking of liquids. - Google Patents

Description

R. P. PERRY.

CONTINUOUS COKING 0F LIQUIDS.

APPLICATION FILED MAY I9. 1915.

Patented Mar. 14, 1916.

7 P P a 1 z gvwewtoz @51 fitter/new RAY POTTER PERRY, 0F MONT'CLAIR, NEW JERSEY, ASSIGNOR TO BARRETT MANUFAC- TURING COMPANY, OF NEW YORK, N. Y., A CORPORATION OF WEST VIRGINIA.

CONTINUOUS COKING OF LIQUIDS. I

Specification of Letters Patent.

Application filed May 19, 1915. Serial No. 29,219.

To all whom it may concern:

Be it known that I, RAY POTTER PERRY, a citizen of the United States, and resident of Montclair, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Continuous Coking of Liquids, of which the following is a specification.

The object of my invention is to provide a new and useful improvement in the method of continuously coking various materials, such as coal tar, coal tar pitch, petroleum, asphalt, etc., which either are liquid in their normal condition or can be liquefied by heat to render them adaptable to my process of converting them into coke, by driving ofl by means of heat all or practically all of their volatile constituents.

Known methods of coking solids such as coal, wood, etc., in general consist in placing the material to be treated in a chamber, such as a gas retort, beehive coke oven or byproduct coke oven, and heating this material externally, or often internally, by combustion of a portion of the material, to such temperature and for such period as is required to drive off all or practically all of its volatile matter, leaving a coke residue. The use of such retorts or chambers has been attempted for the coking of such materials as coal tar pitch, but it presents certain disadvantages in addition to the evident ones incidental to any intermittent operation. An additional disadvantage for the coking of such a material as coal tar pitch, in an oven of this type is that at a certain stage in the process decomposition takes place with the rather sudden formation of a considerable volume of gas, which causes the material to foam and tend to overflow from the chamber, or oven, through the vapor pipe. The increase of volume incident to the decompo sition is so great that it is necessary to use a much smaller quantity of pitch in an oven of a given size than is customary in coking coal, and this results in requiring larger investment for a given output.

In the petroleum industry it has been usual to distil the petroleum oil in cylindrical steel stills, usually horizontal, to drive off the naphtha, gasolene, illuminating and lubricating oils, etc., leaving as a residue in the still a petroleum tar or pitch. If desired the heating of the still is continued until practically all of the volatile matter has been driven off, leaving a coke residue on the bottom of the still or the petroleum tar or pitch in a hot, liquid, condition is transferred to other smaller stills where the heating is continued until the desired coke is obtained. It has been found that the high heat necessary for coking in this manner burns out the still bottoms in a relatively short time, requiring frequent and expensive repairs. This burning of the steel forming the still bottom is hastened by the fact that the coke formed immediately adjoining the bottom on the inside surface acts as a heat insulator and requires the application of more intense heat in order to transmit suflicient heat to coke satisfactorily the tar or pitch not in contact with the still bottom. This burning action of the steel is somewhat similar to the burning of boiler plates when covered by a layer of scale. After the coke has been formed it is necessary to allow the still and setting to cool sufficiently so that the still can be opened and workmen enter with picks and shovels to loosen and remove the coke. This obviously results in a great waste of time as well as loss of heat.

To overcome the disadvantages necessarily incident to any of the processes heretofore employed, I have invented a continuous process by means of which I accomplish coking by heating the material in liquid form in comparatively thin films on a moving surface as hereinafter described and claimed.

One preferred form of apparatus for carrying out my invention is shown diagrammatically in the drawing forming part of this specification, in Which A is a chamber in which is mounted a hollow cylinder 2 revolving on a shaft 3 in the direction shown by the arrow. The material to be treated is delivered through the pipe 4 from a source of supply (not shown) into the pan 5 into which the cylinder 2 dips. As the cylinder revolves a thin film of the liquid 6 is carried along on the outer surface of said cylinder. The interior surface of the cylinder 2 is heated by any convenient means, as for example, gas jets 7. The chamber A is provided with a vapor pipe 8 which leads to a vapor condensing system (not shown). The scraper 9 is set in contact with the outer surface of the cylinder 2 and serves to remove the film of coke 10 which has been formed thereon depositing Patented Mar. it, was.

be opened when desired to allow the accumulated coke to drop into the storage chamber from which it is from time to time removed by openingthe bottom 14.

The operation is as follows: The cylinder is heated internally to the desired temperature, and is revolved slowly in the direction indicated by the arrow. The surface D of the cylinder 2 clips into the liquid 6 inthe pan 5 and continuously picks up a thin film of the liquid. The heat transmitted by the surface of the cylinder 2 causes the volatile matter, or a large part of the same, to be evaporated from the liquid, the vapors escaping through the vapor pipe 8 to the condensing system, (not shown). If desired vacuum may be applied to the condensing system to facilitate removal of the-vapors,

and to lower the temperature required for evaporating the volatile matter from the liquid. The two valves 12 and .13 are provided in order not to break the vacuum which may be employed in the process, each valve serving to prevent the admission of air to the cylinder when the other valve is opened to dump its contents.

As the liquid cokes decomposition takes place, causing the film of liquid to foam, as indicated by the increased thickness of the film at the top of the cylinder. By the time it reaches the scraper 9 the desired amount of volatile matter has been driven 0E by I heat and the scraper removes the film of coke which falls and accumulates on the valve 12. From time to time this valve is opened and all the accumulated coke falls to the lower valve 13 and from time to time is removed by opening this valve.

I may reverse the process and apply the heat to the outside of the cylinder and the liquid to be coked to the interior surface of the cylinder but this is a less convenient method and is not recommended in practice. Also instead of picking up a film by causing the surface of the cylinder to dip in a pan containing the liquid to be coked I may employ any other convenient means, as for example by causing the liquid to flow on to the surface of the cylinder from above or by spraying it on such surface, or any other convenient method'may be employed to supply a thin film of the liquid to be coked to the cylindrical or other moving surface.

The degree of heat necessary to reduce liquefied tar so as to gasify at least 85% of .the volatile material andreduce the residium to a coke, is in excessof 1000 F. under atmospheric pressure, which can of course be reduced materially by treatment under vacuum. As the liquid as itadheres to plementary steps, forming no part of this particular process.

Having thus described my invention what I claim and desire to secure by Letters Patent is 1. The method of heating tar in a thin film until decomposition takes place with evolution of gas and formation of coke.

2. The method of heating a continuously moving film of tar to a temperature above 1000 F. for a sufiicient time to produce decomposition with evolution of gas and, formation of coke.

3. The method of coking a liquid hydrocarbon, which consists inpassing the same in a continuously moving film through a zone of heat to substantially expel the volatile ingredients therefrom.

4:. The method, which consists in spread- I ing a film of liquid hydrocarbon upon a con-. tinuously moving surface, applying heat to said surface until the liquid has become coked, and automatically and continuously removing said film of coke.

5. The method, which consists in continuously spreading a film of liquid hydrocarbon upon a surface moving at uniform speed, applying suflicient heat to the opposite side of said surface to coke said liquid, and continuously cleaning said surface of the film of coke.

6. The method of heating tar in a thin film to a temperature of over 1000 F. for a suflicient time to eliminate at least 85% of the volatile matter.

7. Themethod of heating tar in a'thin film to a temperature of over 1000 F. .for a suflicient time to leave therein very little volatile matter.

Signed at New York, New York and State of day of May, 1915.

RAY POTTER PERRY.

in the county of New York, this 14-

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