US3736248A - Method for the manufacture of coke - Google Patents

Abstract

A METHOD OF AND AN APPARATUS FOR MANUFACTURING COKE FROM REDUCED CRUDE OIL WHEREIN SMALL DROPS OF OIL FALL THROUGH A VERTICAL CHAMBER FORMING A TALL, HEATED TOWER. THIS CHAMBER IS MAINTAINED AT COOKING TEMPERATURE, AND THUS, THE VOLATILE CONSTITUENTS IN THE OIL DROPS VAPORIZE WHILE THE REMAINDER IS COKED DURING THE FALL. THE VAPORS ARE REMOVED FROM THE TOWER THROUGH SIDE OUTLETS AND THE COKE IS COLLECTED AT THE BASE OF THE TOWER IN A POUND OR IN A FUNNEL.

Description

May 29, 1973 G. R. HUSSONG 3,736,348

METHOD FOR THE MANUFACTURE OF COKE Original Filed July 1, 1968 2 Sheets-Sheet 1 40 x 2/0-- l I v "'w' 62 L 60 q 55 4O 6. Richard Hussong WMWM WLR AT TORNE Y8 y 1973 G. R. HUSSONG METHOD FOR THE MANUFACTURE OF COKE Origiual Filed July 1, 1968 2 Sheets-Sheet 2 INVENTOR. 6. Richard Hussong ama 2% FIG. 9

A TTORNE Y3 United States Patent 1 3,736,248 METHOD FOR THE MANUFACTURE OF COKE George Richard Hussong, Godfrey, lll. 62035 Continuation of application Ser. No. 741,749, July 1,

1968. This application May 25, 1972, Ser. No. 257,003

Int. Cl. Cg 9/42 US. Cl. 208-46 4 Claims ABSTRACT OF THE DISCLOSURE A method of and an apparatus for manufacturing coke from reduced crude oil wherein small drops of oil fall through a vertical chamber forming a tall, heated tower. This chamber is maintained at coking temperature, and thus, the volatile constituents in the oil drops vaporize while the remainder is coked during the fall. The vapors are removed from the tower through side outlets and the coke is collected at the base of the tower in a pond or in a funnel.

This is a continuation of application Ser. No. 741,749, filed July 1, 1968, now abandoned.

This invention relates to methods and apparatus for the manufacture of coke, and more particularly to the production of coke from reduced crude oil.

In the refining of petroleum, the light, volatile constituents are removed by various processes and the residue, commonly referred to as reduced crude oil, is a thick, viscous mix containing asphalt, heavy oils, carbon particles and detritus. The content of such reduced crude oil may vary considerably depending upon the source of the petroleum and the manner in which it is refined. Some,- times this material may contain valuable asphalts or other substances which are useful and sometimes it will be of little value and not even useful as a fuel because it is so difficult to handle.

To utilize this reduced crude oil for an industrial fuel or the like, it is a common practice to subject it to high temperature, in the range of 1500 F., to completely break down the constituents thereof, to recover the volatiles, gas, oil and waxes, with the residue being a solid coke. This coke, which ordinarily will accumulate as a mass, as in the bottom of a tank, may be cooled and ground or otherwise comminuted and/or briquetted to form a valuable industrial material, for fuel and other purposes. As might be expected, considerable difficulty is encountered in handling the reduced crude oil and the coke formed therefrom at the high temperatures necessary for the coking operation in an oven or retort. Although improved processes for coking reduced crude oil have been proposed and used, they have not been completely successful for petroleum coke is still being manufactured by the basic method of heating the reduced crude oil in a container to coking temperature, and thereafter, cooling and manually removing the coke from the container.

It follows that there is a real and definite need for more economical and simplified methods of producing coke from reduced crude oil. The present invention, conceived and developed with such a need in view, comprises basically, a tower-like structure wherein the crude oil may fall a substantial distance as small drops through an intensely hot, gaseous environment to be stripped of all volatiles and converted to small globules of coke during the fall. These globules of coke may either be collected in a water basin at the base of the tower to be transported thence for briqueting or other treatment, or they may be directed into a converging exit at the base of the tower to be carried by a blast of fuel gas or the like into an industrial furnace.

A primary object of the invention is to provide a novel and improved method of producing coke from reduced crude oil as minute particles which may be easily handled and dispensed with.

Another object of the invention is to provide a novel and improved method of producing coke frm reduced crude oil as a continuous operation, eliminating repeated shutdowns and clean-up of the apparatus, and the subsequent grinding of the coke into small particles.

Another object of the invention is to provide a novel and simplified apparatus for the production of coke from reduced crude oil which does not require moving parts to handle the oil while it is being coked and which effects the coking without the oil clinging to surfaces of the structure or machinery where it could pile up as a thick, solid mass.

Other objects of the invention are to provide a novel and improved apparatus for producing coke from reduced crude oil, which is simple, economical and is especially suitable for operation as a part of a refining plant set-up without the need of specialized equipment and personnel.

With the foregoing and other objects in view, as will become apparent from the description hereinafter set forth, my invention comprises certain sequences, steps and operations, and constructions, combinations and arrangements of parts and elements, all as hereinafter described, defined in the appended claims and illustrated in preferred embodiment by the accompanying drawing in which:

FIG. 1 is an elevational view, diagrammatically indicating the fractionator of a refining plant and a coking tower associated therewith, constructed according to the present invention.

FIG. 2 is a sectional, elevational view of the coking tower per se, as taken from the indicated line 22 at FIG. 1, but on an enlarged scale.

FIG. 3 is a sectional, plan view of the tower as taken from the indicated line 3-3 at FIG. 1, but on an enlarged scale.

FIG. 4 is a sectional, elevational view of the upper portion of the tower, as taken from the indicated line 44 at FIG. 2, but on an enlarged scale.

FIG. 5 is a fragmentary sectional detail as taken from the indicated line 5-5 at FIG. 4, but on a further enlarged scale.

FIG. 6 is a sectional plan view of the lower portion of the tower, as taken from the indicated line 6-6 at FIG. 2.

FIG. 7 is a sectional, elevational view of the lower portion of the tower as taken from the indicated line 7-7 at FIG. 2, but on an enlarged scale.

FIG. 8 is a diagrammatic view symbolizing the action of drops of oil falling from the top of the tower and changing from a reduced crude oil to coke during their free fall within the tower.

FIG. 9 is a sectional elevational view of the lower portion of a tower, similar to a portion of the showing at FIG. 2, but illustrating a modified means of removing the coke from the tower.

FIG. 10 is a fragmentary, sectional, isometric view of the top portion of the tower showing a modified arrangement for dispensing the reduced crude oil into the tower.

Referring more particularly to the drawing, the reduced crude oil used in connection with the present invention is produced in a refinery fractionator R where it is heated or cooled to a temperature of from 600 to 675 F. The lower limitation of temperature is desirable to keep the reduced crude oil sufliciently fluid to flow from the fractionator while the higher limitation of temperature is the maximum at which the oil can be handled without forming deposits which would clog the fractionator. However, after the oil is discharged from the fractionator and directed into the improved coking tower T, it will eventually be heated to a temperature of approximately 1500 F.

At this increased temperature, any volatile components remaining in the reduced crude oil, such as gas, oil and heavy waxes, will be volatilized and the solid residue, primarily carbon, will be coke. When produced in the manner herein described, this coke will be a comparatively light, porous material which will actually float until it becomes saturated with water.

The present invention contemplates the conversion of reduced crude oil into coke within the coking tower T which will ordinarily be erected alongside the refinery fractionator R, as indicated at FIG. 1 of the drawing. So located, the discharge line 20 from the fractionator can be extended to the top of the tower T to provide a con tinuous supply of reduced crude oil with a minimum drop of temperature in the line 20. A pump 21 and'its filter 21a on the suction side of the pump, will ordinarily be required in this line 20 and the line may be jacketed with an insulator 22. This insulator can also include a heat exchanger, if necessary, to better control the temperature of the oil as it is delivered to the tower T. It is essential that this reduced crude oil be delivered to the tower T as fluid under pressure, and to reduce the viscosity of the crude oil it may be necessary to add a small amount of a lighter fraction such as fuel oil, to the reduced crude being pumped through the line 20. This may be accomplished by the use of a small auxiliary line 23 from the fractionator through which the lighter fraction is pumped, as by a pump 24, into the line 20.

The tower T is a tall, generally cylindrical structure having a cylindrical internal chamber C surrounded by a tubular, insulated furnace F. The base of the tower may be a concrete or steel platform of adequate strength to support it and this base is arranged to accommodate various conduits, as needed, and also to support a water tank under the tower which receives the coke as hereinafter described.

The chamber C is a cylindrical steel shell 25 extending from the bottom to the top of the tower and it is capped by a flat lid 26 at its top. The reduced crude oil is pumped to the top of this chamber through line 20 and it is converted to small drops which fall through the tower to be coked as will be described. Accordingly, a means for forming such drops is necessarily located at the top of this tower.

In the arrangement illustrated at FIGS. 2 to 5, this means consists of a small compartment at the top of the chamber C above a circular floor plate 27 supported upon a circular ledge 28 about the shell 25. The floor plate 27 is foraminated by an array of small diameter passages 29 through which the oil flows to form as drops as the fall through the tower commences, as indicated at FIG. 8. The oil pumped into this compartment from line 20 will ordinarily be ejected through these passages 29 under the pressure of pump 21; however, from time to time, these passages may clog with sticky material or gunk in the reduced crude oil. Thus, a passage cleaning device is desirable and the unit illustrated at FIGS. 2 to provides for a multi-arm sweep 30 for this purpose.

The arm 30 is carried by a hollow, vertical, axiallycentered shaft 31 which projects upwardly through the lid 26 to be supported upon an adjustable thrust bearing 32 and rotated by a gear-reduced drive 33. A steam line 34 extends to the shaft 31 from a suitable high temperature, high pressure source, thence past a packer 35, thence into the passageway within the shaft 31 and thence to the arms of the sweep 30. Each arm of the sweep 30 is formed with opposing and enclosing skirts 36 which contact the surface of the plate 27, and each arm is hollow to provide a suitable passageway through it which communicates with the shaft passageway and includes orifices 37 from whence the steam is ejected downwardly against the plate and within the confines of the skirts 36, as in the manner illustrated at FIG. 5. A small amount of steam will be adeuate to keep the passages 29 clear and this steam wil assist in coking the oil within the tower by actually cracking or breaking down some of the constituents of the oil. If necessary, the temperature of the steam may be elevated to as high as 650 F. before being discharged into the tower, as by locating a coil within the furnace F or the flue thereof.

As the reduced crude oil falls through the tower, the temperature will be raised to a maximum in the range of 1500 F. to effect vaporization of the oils and waxes to form the coke. Accordingly, a substantial volume of vapor will be released as the crude oil falls through the tower. This vapor must be withdrawn from the tower in a manner which will prevent an imbalance of pressure within the tower. A primary vapor withdrawal manifold 40 is located at the lower reach of the tower. This manifold has a plurality of passageways 41 extending radially inwardly to the chamber shell 25, and the manifold 40 connects with a lead line 42 which extends to a vapor collecting apparatus. This apparatus may be the fractionator F as illustrated, and if necessary, a pump 43 may be used to pump the vapors into the fractionator. The apparatus may also be a condensor, of any suitable type, not shown. The intake of each passageway 41 is suitably protected by a deflector 44 and a screen 45 to prevent the movement of coke particles into these passageways.

The amount of gas formed in this tower will vary considerably depending upon the constituents of the reduced crude oil and any additive, such as a cutback in the oil. Accordingly, it is contemplated that additional vaporrelease manifolds such as 40a will be incorporated in the walls of the tower at any suitable location above the primary manifold 40. These additional manifolds may be constructed in the same manner as the primary manifold, using passageways 41a and a lead line 42a, as heretofore described. However, it is contemplated that the deflectors and screens at the entrance to the passageways 41a thereof may not be required, especially when the manifold is near the top of the tower.

The furnace F is formed by the shell 25 and an outwardly-spaced, concentric shell 50 a short distance above the bottom of the tower, and upwardly to a ring cap 52 a short distance below the top of the shell 25 and below the top compartment formed by the plate 27. To complete the arrangement, this furnace is enclosed within a shell 53 of insulation which lies about the shell 50 and under and over the end ring closures 51 and 52. The furnace F is fired in a conventional manner, as by a ring burner 54 at its base which receives a gas fuel and air supply from suitable lines 55 and intake gate 56 at the bottom portion thereof. The spent gases are discharged from a stack 57 at the top of the furnace and it is to be noted that the steam line 34, heretofore mentioned, may be coiled within this stack for preheating before being directed into the sweep, as heretofore described.

The furnace F may be heated to a temperature of from 1500 F. to as high as 1800 F. so that the walls of the shell 25 will radiate suflicient heat as to heat the vapor within the tower and to react upon the drops of reduced crude oil falling through the tower to effect the necessary vaporization of volatiles and the formation of coke by these drops. A tower having a height of approximately feet may be effectively used for this purpose whenever the drops of oil are kept to a diameter of less than approximately 0.10 inch.

Once the height of the tower is established, the fundamental consideration involved in the operation in a given tower is the drop size. The reaction of converting the drops of reduced crude oil into small globules of coke must take place while the drops are falling through the tower. The smaller the drops, the quicker will be the reaction with the heat, and also, the smaller the drops, the more effectively they will be retarded during their fall by vapor resistance. Therefore, large drops of oil are not suitable except in an excessively high tower. For example, a drop having a diameter greater than A iuch can fall through the 100-foot tower in less than 3 seconds without being heated sufficiently to form coke. On the other hand, smaller drops may require 5 seconds or longer to complete the fall because they are retarded in their float downward by vapor resistance. Also, as these drops form into coke near the bottom of the tower, the product will become a lightweight, fluffy globe which is very considerably retarded by vapor resistance. Accordingly, the necessary limitations for operation of this process may be easily established by providing an environment where-through the drops of oil will fall which is capable of heating such drops to the desired temperature approximating 1500. Then, the size of the drops may be selected, depending upon the height of the tower from a diameter approximately M inch as a maximum, to droplets considerably less than 0.025 inch in diameter, and even to the point where the reduced crude oil is practically atomized when the height of the tower is restricted, say to approximately 30 feet. The variation of the size of the droplets can be regulated by varying the diameter of the passages 29 through the floor plate 27 of the compartment and by increasing the pressure of the reduced crude oil pumped into the compartment through line 20. Also, the droplets can :be decreased in size and more effectively atomized under any given pressure by adding a small amount of a cutback, such as diesel oil, to the reduced crude as through the auxiliary line 23 heretofore mentioned. The cutback will be almost immediately vaporized and can be returned to the fractionator. The manner of producing drops of a selected size is possible through simple tests which can be made by any refinery technician skilled in the art.

The coke falling to the bottom of the tower remains in the form of small globes, which are reduced somewhat in their diameter and considerably in their weight from that of the reduced crude oil drops originally formed and dropped through the tower. This coke is continuously removed from the tower by various means, it being important, however, to maintain the chamber C under a pressure of at least several pounds per square inch to seal it oif from the atmosphere and to thus prevent the possibility of a combustive explosion of the hot vapors within the tower. If the coke is to be cooled and stored and subsequently briquetted or otherwise processed, it is desirable to seal the base of the tower by a water pond P which can also receive and cool the coke as it is formed. If the coke is to be used immediately as a fuel, it may be effectively carried from the tower through a conduit by a blast of gas as will be hereinafter described.

The base of the tower, a short distance below the furnace, is formed as a pond P, by container walls 60 within the tower which also extend outside the tower as illustrated. It is contemplated that the water level outside the tower will be several feet higher than that within the tower as indicated at h at FIG. '7, the differential being caused by the vapor pressure within the tower. Also, a submerged lip 61 divides that portion of the pond which is within the tower, from the portion outside the tower to constitute an effective .seal barrier even when the water level in the tower flucturates.

It is contemplated that a continuous flow of Water will pass through the tower as from a supply line 62 which includes a pressure-level control 63 to automatically regulate the flow through the line 62 to maintain a proper water level in the tower.

The coke globes will be lightweight particles which will float as they fall onto the water surface, and they must be removed as fast as they accumulate in the tower. A belt conveyor 64 is provided for this purpose. This conveyor 64 consists of a belt 65 with an array of paddles 66 which is mounted upon end drives 67 and 68 at each end and moves along a path formed by guides 69 to extend across the chamber with the paddles 66 at the normal water level. Thence, the belt turns underneath itself, at one end of the tower, to move in a constricted passageway 70 to extend to the exterior of the tower as in the direction of the indicated arrows at FIG. 7, and to the discharge point 71 at the end of the pond. The discharge point 71 is formed as a lip over which the coke may drop as it is ejected from the pond by the conveyor.

With a flow of water through the pond P in the base of the tower, the water will ordinarily remain sufficiently cool as to receive and cool the hot coke particles. If necessary, however, a spray line 72 having nozzles 73 may be directed across the chamber immediately above the normal water level of the pond to pre-cool the coke particles to some extent before they drop into the pond.

The alternate arrangement for dispensing with the coke particles as they fall to the bottom of the chamber is illustrated at FIG. 9. 'In this arrangement, the chamber C converges as a funnel 75 at its bottom having a central intake 76 whereinto the coke particles fall. This funnel base intake 76 connects with a gas fuel line 77 which extends to a furnace, not shown. The fuel line 77 is a low pressure gas line, and is provided with gas from a high pressure line 78, and a jet nozzle 79 is located at the intake 76 to permit a high velocity jet to pick up the coke particles and eject them through the fuel line 77. This arrangement is especially suitable for high temperature blast furnaces or the like because the hot coke particles preheat the gas with which they are mixed.

A modified mode of supplying the reduced crude oil to the top of the tower T is illustrated at FIG. 10. In this arrangement, the compartment at the top of the tower chamber C" is dispensed with and a rotating sprayer 80 is used which is adapted to extend downwardly into the chamber C. This sprayer 80 is formed as a vertical, hollow shaft 81 mounted upon a suitable bearing 82 at the top of the tower. The shaft is rotated by a slowspeed drive 83 mounted upon the top of the tower. The shaft 81 extends through its drive and the top of the shaft is connected with the end of the line 20 through a packer 84. This arrangement permits the reduced crude oil to flow from the line 20 to the shaft. The sprayer 80 at the lower end of the shaft is provided with an array of arms 85 arranged in an even, symmetrical pattern as illustrated. These arms are hollow, communicate with the passageway in the shaft and are provided with nozzle outlets to spray downwardly directed drops of oil as the arms are slowly rotated.

To provide information for operative use, time data for coking drops of reducedcrude oil initially heated to approximately 675 F. and thereafter heated to a temperature approximating 1600 F. is submitted in the following table.

Drop diameter, Coking time, inches seconds 0.100 4 0.050 2% 0.025 2 To establish a suitable tower height, the time required for such drops to fall from various heights is indicated in the following table.

Time of fall, seconds Drop diameter Heigalt of fall, feet: y y 1 g 1 2 e0 2% 3y: 5 3% 6 7% 4 5% 7% computed on the basis of simple assumptions; however, as the drops change to coke, they become very light and fiufiy and the vapor resistance in the tower will reduce the speed of fall to increase the falling time and thereby render the computations conservative.

I have now described my invention in considerable detail.= However, it is obvious that others skilled in the art can devise, build andoperate alternate and equivalent constructions which are nevertheless within the spirit and scope of my invention. Hence I desire that my protection be limited, not by the constructions illustrated and described, but only by the proper scope of the appended claims.

I claim:

1. A method for producing coke from reduced crude oil including the steps of:

(a) heating the oil to a temperature in the approximate range of 600 to 675 F. to render the same liquid, but below the cracking temperature;

(b) ejecting the oil from a dispenser as small drops with most of the drops having a diameter of not more than 0.10 inch or less than 0.025 inch in the presence of steam to maintain said temperature;

() providing and maintaining a coking zone at an elevated temperature in excess of 1500 F. by indirect heating;

(d) permitting the drops to fall through this coking zone whereby to be heated to coking temperature, approximating 1500 F., to vaporize the volatiles within the oil and to convert the non-volatile components to small globules of coke; removing a substantial portion of the formed vapors from the lower portion of said coking zone and (e) collecting andremoving the globules of coke as they complete the fall from the said coking zone.

2. The method defined in claim 1, wherein the vaporous environment is of an extent, vertically, sufiicient to permit the fall of the drops to continue therethrough for at least two seconds.

3. In the method defined in claim 1, wherein the globules of coke are collected in a water pond as they complete their fall through said vaporous environment. 4. In the method defined in claim 1, wherein the gloubles of coke are collected in a funnel at the base of. the environment and the further step of diverting them into a flowing stream of gas.

References Cited UNITED STATES PATENTS 3,130,146 4/1964 Plaster 208-106 2,751,334 6/1956 Scott 208-46 2,366,057 12/ 1944- Russell 208-106 2,366,055 12/ 1944 Rollman 208-129 HERBERT LEVINE, Primary Examiner US. Cl. X.R. 23284; 423-450

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