US3033657A - Reactor with valve for expansion control and quenching - Google Patents

Description

R. E. SMITH May 8, 1962 REACTOR WITH VALVE FOR EXPANSION CONTROL AND QUENCHING 2 Sheets-Sheet 1 Filed July 29. 1958 INVENTOR ROBERT E. SMITH BY auwmfmdwvza,

ATTORNEY y 8, 1962 R. E. SMITH 3,033,657

REACTOR WITH VALVE FOR EXPANSION CONTROL AND QUENCHING Filed July 29, 1958 2 Sheets-Sheet 2 INVENTOR. ROBERT E. SMITH ATTORNEYS United States Patent Robert E. Smith, Flossmoor, 111., assignor to Sinclair Refining Company, New York, N.Y., a corporation of Maine Filed July 29, 1958, Ser. No. 751,703 3 Claims. (Cl. 23-284) This invention relates to a method and apparatus for use in a system where coke or other finely divided solid material is produced from a fluid stream. The method permits operation without plugging of the fluid feed lines by the formation of solids in the lines. This application is a continuation in part of my application Serial No. 537,245, filed September 28, 1955, now abandoned.

In cracking or similar processeswhere hot hydrocarbon gases flow from a higher pressure heater zone into a lower pressure reaction zone a control valve is presently employed in the conduit between the heater and the vessel. The opening of this valve to release the feed and the resulting pressure drop across the valve cause cracking of the feed and the formation of coke in the valve and feed line. This problem has always existed as a major source of troubleand failure in such feed systems. A common approach to a solution of this problem has been to keep the feed line between the valve and reaction vessel as short as possible. But even where this line has been kept to an absolute mirimum, the problem has persisted, with coke formed in the valve causing plugging, serious wear and replacement expense. In addition, this coking prior to the reaction chamber makes it difficult to introduce a quenching medium at the optimum areathe area of initial cracking. Past systems have performed the quenching operation either before the feed contacts the valve, right after this contact or within the reaction zone. The first and last methods are both inadequate since one is too soon and the other too late and the second method merely aggravates the coking and plugging problems.

The method of this invention introduces feed material to a reaction zone Without any significant pressure drop in the feed lines. The method quenches the hot feed material at a time when the resultant formation of coke or other finely divided solid is desired rather than at a time which presents new problems. Furthermore, it prevents coke from accumulating on the valve seat.

The method of this invention is applicable to any system wherein a change in temperature, or pressure, or the addition of a reagent causes an immediate deposition of finely. divided solids from a fluid stream. It finds its greatest application where these solids are of a soft cake-forming nature. The method comprises removing a fluid hydrocarbon from a higher pressure zone to an enlarged zone of lower pressure, and maintaining the higher pressure on the fluid in the conduit between the zones, allowing the pressure to drop only when the fluid is within the enlarged lower-pressure zone. The realm of higher pressure, that is, pressure higher than coke-forming pressure, therefore, includes the higher pressure vessel and the conduit. The pressure is reduced at the end of the conduit where the hydrocarbon is allowed to enter the lower pressure zone as a coneshaped stream. At approximately the same region where the pressure on the hydrocarbon is reduced past the coke-forming pressure a quenching fluid is caused to impinge on the hydrocarbon stream. Thus all of the coking takes place rapidly and within the enlarged lowerpressure zone. While the second fluid may be designed to lower the temperature, as described, it may also be a reagent or may be inert, being usedmerely to give the stream of first fluid suflicient velocity to carry oif from the area of deposition any solids which form. It is to be understood tha enlarged zone means a zone sig nificantly larger than the conduit.

The invention also includes a preferred apparatus for performing this process, although it will be easily seen that other types of apparatus can be devised for this purpose. This apparatus comprises a fluid controller for the first fluid having an integral fluid distributor for the second fluid. In the preferred apparatus the terminus of the conduit opening into the lower-pressure vessel forms a valve seat for stopping flow of the first fluid. The valve itself comprises a unitary, preferably metallic, plug. The plug has an elongated tapered nose which at one end is smaller than the terminus of the conduit and at the other end is larger than the terminus of the conduit. This larger end merges into a sloped face which is provided with orifices for the second fluid. This construction of the valve allows the valve to stopper the conduit at a mere circle of contact thus minimizing wear at the seat, and also prevents the orifices for the second fluid from contacting the walls of the lower pressure vessel surrounding the terminus of the conduit. For maximum ease of control, it is advantageous to provide means external of the lower pressure vessel to operate the valve assembly, for example, by attaching to the plug an operator rod extending into and across the lower pressure vessel. In this embodiment the operator rod, as well as the plug, advantageously is hollow and employed to conduct the second fluid to the orifices of the valve face.

The structure described effectively prevents a significant pressure drop in the conduit, and due to the shape which it gives the fluid hydrocarbon stream, allows the pressure drop and simultaneous coke formation to take place within the enlarged zone in a restricted space which is at least somewhat removed from the valve seat. The quenching medium is supplied in the present invention substantially directly to the region of pressure drop, the optimum point in the system. It therefore contributes to effective operation of processes where coke is produced rather than further aggravating a serious obstacle to sustained operations. Furthermore, the passage which conducts the second fluid from the hollow inside of the plug to the orifice in the sloped face of the valve may be arranged at such an angle that its impingement on the stream of hydrocarbon carries the solid particles in a direction away from the mouth of the conduit and the region of pressure drop.

It is obvious that in practicing the method of the invention other apparatus, wherein the valve and the orifice for the quenching fluid are independent of each other, may be used.

The invention will be described further in conjunction with the appended drawings in which FIGURE 1 is a horizontal view partly in section along lines 1-1 of FIGURE 3, showing the apparatus when the flow of hydrocarbon is stopped, and

FIGURE 2 is a detailed drawing of the plug valve means of the preferred apparatus; and

FIGURE 3 is a view of a reactor, with parts cut away, showing the plug valve means in operative position to allow'flow of the hydrocarbon fluid.

Referring to the drawings, the numeral 10 represents a reactor vessel in which a hydrocarbon conversion reaction is to take place at a pressure which is lower than the pressure maintained on the feed material which is to be introduced and at a conversion, e.g. coking, destructive distillation or cracking temperature of about 700 to 1000 F. Reactor vessel It is closed at each end and is provided with an effluent conduit 13 (refer to FIGURE 3) in its upper portion. A means 15, which can be a conventional reactor hand-hole closure, is provided in the lower end portion to facilitate coke cleanout. Alternatively the reactor vessel may be of the fluid coking type. Feed material is supplied to the reactor through a conduit 12 which is substantially smaller in cross-section than the lower-pressure vessel lid, communicating, for example, with a higher pressure heater (not shown). A valve means 14 is provided with a tapered nose 2i), which is adapted to be inserted into the terminus of conduit 12 from within the reactor 10. The nose can act as a self-guide in entering the conduit, has good self-cleaning characteristics and contacts the valve seat in a minimum area. The plug valve means is provided with an operator rod 16 extending, in the embodiment shown, across reactor 1t and through the wall opposite inlet conduit 12. to permit external operation of the valve means. Guide and support of the operator rod 16 is obtained with a bushing 13. A pressure tight seal is obtained, for example, with a seal composed of packing ring 21, packing 23, packing gland 25 and packing nut 27. For insertion and removal of plug means 14, the operator rod 16 can be provided with means, advantageously a handle 31, and suitable meshing gears 33 and 35, adapted to permit controlled adjustment of the rod 16.

The face, '41, of the plug is adapted to supply quenching medium, such as water, steam or another hydrocarbon to feed material entering the reactor when the plug means 14 is withdrawn from the seated position. To this end orifices 24 are provided in plug means 14 at a point which does not enter theconduit 12 of the assembly. Preferably this face is sloped away from the nose Ztl, so that when the flow of fluid hydrocarbon is stopped the orifices will not contact the Walls of the vessel lti or any coke which may have deposited thereon. The operator rod 16 advantageously is hollow and has a means 28 communicating with the rod 16 through which quenching medium is supplied to the system, i.e. through rod 16, through the bore 43 in plug means 14 and then to orifices 2.4. If desired, actuation of the means to supply quenching fluid can be made to occur automatical-ly upon removal of the plug means 14 from its seated position.

Referring particularly to FIGURE 2, the plug means 14 advantageously comprises a tapered nose portion 20 extending toward the terminus of the conduit from the shoulder portion 22. Between the base of the nose and the shoulder is a face portion 41, sloped at about a 45 angle to the plane of the terminus of the conduit and the shoulder 22. By tapering the nose 20 of the plug valve means, seating can be made to occur at any portion of the nose Zil. The taper of nose portion 20 need be but slight, for example, about 2 to so that good withdrawal characteristics and superior cleaning action of the valve and valve seat are obtained. The operator rod 16 can be fixedly connected to shoulder means 22 by suitable means 26, for example a lock nut. Stem 16 is hollow and communicates by means of a bore 43 and passages 45 in the valve with the orifices 24 and the quench fluid supply means 28 advantageously located externally of the reactor it).

It will appear from an observation of this preferred apparatus that the fluid hydrocarbonleaving the terminus of conduit 12 will spray into reactor 1% in a generally conical shape, which as each molecule of fluid hydrocarbon approaches the base of this cone, causes less pressure to be exerted on the molecule. Under the conditions in which the process of this invention is designed to operate, this pressure reduction causes coking of some of the molecules. When the preferred apparatus is used, the tapered and sloped parts of the valve body serve as a conical core to this cone of fluid hydrocarbons, slowing the drop in pressure on the individual molecule. The preferred apparatus, therefore, makes it possible to prevent the molecule from reaching the pressure at which coking occurs until the molecule is within the enlarged lower-pressure zone. At the region where this pressure occurs, the quenching fluid is supplied to complete the coke formation in this very same region. In the preferred apparatus the passages 45 are arranged at such an angle to the hollow conical fluid hydrocarbon stream that the quenching fluid will blow away, as they are formed, substantially all of the coke particles, in a direction radially away from the orifice and the valve. may then be removed through the opening 15.

In operation, for example in a viscosity breaking reaction, a reduced petroleum crude oil hydrocarbon feed material was heated in a pressure heater (not shown) to a temperature of approximately 875 F. At the beginning of the feed operation, the plug valve was seated in the terminus of the conduit and the quenching supply cut off. The heated feed, at a pressure of 265 p.s.i.g. and a rate of about 51 pounds per hour was thenintroduced into the reactor by withdrawing the valve from its seat, allowing flow through the conduit at this pressure. Simultaneously with the withdrawal of the valve from its seat quench oil, gravity API of 22.6, at a temperature of about 625 F. was introduced into the valve stem under a pressure adequate to force it through the four orifices in the face of the valve. As the feed material entered the reactor, it was sprayed in the shape of a cone to the reactor at 50 p.s.i.g. As the quench oil contacted the feed, coking, under the effects of reduced pressure and the quenching medium, occurred in a region radially removed from the terminus and the valve. The coke formed fell to the bottom and walls of the reactor while the vaporous efiiuent including cracked gasoline and gas oil passed upwardly and out of the reactor to a conventional recovery system which is not shown.

The process of this invention is applicable to liquid or gaseous hydrocarbons whether from a petroleum source or from the destructive distillation of coal.

I claim:

1. An apparatus comprising a closed-end reactor, a feed inlet conduit opening into said reactor at an intermediate portion, an elongated plug valve in the reactor having a tapered nose and a face surrounding and slopingly arranged with respect to said nose and facing the plane of the terminus ofsaid conduit and an enlarged shoulder portion, the end of said nose opposite said face being smaller than the terminus of said conduit, and the end of said nose adjacent said face being larger than the terminus of said conduit and preventing contact between the face and the terminus when the valve is seated, a hollow operating rod attached to said shoulder and extending across and out of said reactor opposite said feed conduit for inserting part of said nose into said terminus such that a centrally located lateral surface of said nose sealingly engages with said terminus when the valveis seated, the direction of movement of the rod in seating the valve be-- ing opposite to the direction of feed traveling in the con-- duit, and means to supply a second fluid, said means com-- prising the inside of the operating rod, a bore in the valve,. a passage from the bore to the face of the valve and anorifice in the face of the valve, said passage being at such an angle to said face that the second fluid is directed out-- side the conduit and in the reactor in a region radially removed from the terminus.

2. The apparatus of claim 1 in which the face slopes at an angle of about 45 to the plane of the terminus.

3. An apparatus comprising a reactor, a feed inlet conduit opening into said reactor, a plug valve in the reactor and for said conduit opening having a tapered nose adjacent said conduit opening and a face with orifices surrounding and slopingly arranged with respect to the said nose and facing the plane of the terminus of said conduit, the end of said nose adjacent said conduit being smaller than the terminus of the conduit, and the end of said The coke nose opposite said conduit being larger than the terminus of the conduit to prevent contact between the face and the terminus when the valve is seated on the terminus, a hollow rod attached to said valve and means to supply a fluid through the inside of the hollow rod and the plug valve and out the orifices of said face so that the fluid is directed outside the conduit and in the reactor in a region radially removed from the said terminus, the said rod moving in a direction opposite to the direction of feed travel in the conduit when seating said valve.

References Cited in the file of this patent UNITED STATES PATENTS Ringgenberg Aug. 23, 1932 Tifit Aug. 23, 1932 Kaplan Nov. 3, 1936 Forward Sept. 21, 1937 [Farrell June 13, 1939 Dahl Sept. 2, 1941 Watts June 19, 1945 Maguire June 8, 1948

Claims (1)

1. AN APPARATUS COMPRISING A CLOSED-END REACTOR, A FEED INLET CONDUIT OPENING INTO SAID REACTOR AT AN INTERMEDIATE PORTION, AN ELONGATED PLUG VALVE IN THE REACTOR HAVING A TAPERED NOSE AND A FACE SURROUNDING AND SLOPINGLY ARRANGED WITH RESPECT TO SAID NOSE AND FACING THE PLANE OF THE TERMINUS OF SAID CONDUIT AND AN ENLARGED SHOULDER PORTION, THE END OF SAID NOSE OPPOSITE SAID FACE BEING SMALLER THAN THE TERMINUS OF SAID CONDUIT, AND THE END OF SAID NOSE ADJACENT SAID FACE BEING LARGER THAN THE TERMINUS OF SAID CONDUIT AND PREVENTING CONTACT BETWEEN THE FACE AND THE TERMINUS WHEN THE VALVE IS SEATED, A HOLLOW OPERATING ROD ATTACHED TO SAID SHOULDER AND EXTENDING ACROSS AND OUT OF SAID REACTOR OPPOSITE SAID FEED CONDUIT FOR INSERTING PART OF SAID NOSE INTO SAID TERMINUS SUCH THAT A CENTRALLY LOCATED LATERAL SURFACE OF SAID NOSE SEALINGLY ENGAGES WITH SAID TERMINUS WHEN THE VALVE IS SEATED, THE DIRECTION OF MOVEMENT OF THE ROD IN SEATING THE VALVE BEING OPPOSITE TO THE DIRECTION OF FEED TRAVELING IN THE CONDUIT, AND MEANS TO SUPPLY A SECOND FLUID, SAID MEANS COMPRISING THE INSIDE OF THE OPERATING ROD, A BORE IN THE VALVE, A PASSAGE FROM THE BORE TO THE FACE OF THE VALVE AND AN ORIFICE IN THE FACE OF THE VALVE, SAID PASSAGE BEING AT SUCH AN ANGLE TO SAID FACE THAT THE SECOND FLUID IS DIRECTED OUTSIDE THE CONDUIT AND IN THE REACTOR IN A REGION RADIALLY REMOVED FROM THE TERMINUS.

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