US2001214A - Art of coking hydrocarbons - Google Patents

Description

y 1935. H. 1.. PELZER ART OF 'CQKING HYDROCARBONS Filed May 1, 1951 ATTORNEYS,

3% Q 2 v m 2 m/ Z Q L 2 u 0 w m m M Patented May 14, 1935 nilvrrco smrcs ear or comm} HYDROCARBONS Harry L. Pelzer, Houston,lTeX., assignor to ,Sin--- clair Refining: Company, New- York, .N. Y., a.

corporation of Maine Application May 1, 1931, SerialNo; 534,285

3 Glaims.

' Thisinvention relatesto improvements in systemsfor carrying out the combined vapor phase cracking of oils,such as gas oil'or kerosene stocks, for the production of lower boiling oils, such as gasoline; and the coking of heavy. oils, such as crudes, topped. crudes, flux oils, and other residual stocks and the like,, by passing the hot vapor mixturefrom. avapor phase cracking operation, while still at high temperature, in intimate contact with a liquid, oilmixture to be reduced to coke in a-. receptacle adapted to receive an. accumulating charge of coke. thereby. coking this liquid, oil mixture by the heat of the hot vapor mixture from. the vapor phase cracking to either of two other lines,,for example, even where the legs of the T are very short and are connected directly to the gate valves, is not satisfactory for this purpose because, with the vapor mixture passing through either of the alternate passages, a deposit tends to form in the stagnant leg of the T rendering the operation of the valve system uncertain and irregular.

Two-way valves embodying plug-type closure members assist in the elimination of stagnant regions but in such service such valves tend to freeze in one position or to become locked in one position due to the development of bridges of hard coke between the closure member and the valve body. This invention relates particularly to improvements minimizing such difficulties when such valves are embodied in systems for carrying out such operations.

A system embodying the invention is illustrated, diagrammatically and conventionally, in Fig. 3 of the accompanying drawing, and details of the two-way valves embodied in this system are illustrated in Figs. 1 and 2, Fig. 1 being a section through the axis of the closure member of the valve and Fig. 2 being a section on line 22 of Fig. 1.

Referring to Fig. 3 of the drawing, the system illustrated may be operated as described in my application Serial No. 3412M. previously mentioned, the connections l5 and I. and the recep; tacles A, B; C and'Df corresponding to the con nections and receptaclesso designated in that application. The two-way valvesin this system are. shown in position topermit flow from the heater through connection. l6 throughfl'rece'pa tacles B and C in succession,toconnectionj "ii, To establish flow. through receptacles C andv Djjin succession, for example, two-way valves warm- 2! are first reversedand two-wayjvalves 22" and 23 are thenreversed. A similar operation estabe lishesfiow. through receptacles D. and run sue.- cession,, through receptacles A and B in..s'ucce'ssion-and so on.

These two-way valves, illustrated inldetail; in Figs. 1 and 2, comprise a frustr'oeconical rotatable plug t seatedin a body. 5. The body 5 isprovidedv with three ports. "5, 7 and-8; andthe plugfliis pro: vided with twocommunicating ports 9 and H11 arranged so that by rotation. of the plug. port .8, can beconnected either to port 6 or to' portilL A chamber H in the body 5,.not in. communication with any of the passages throughfthe valvebody and plug just describedor the connec tionsthereto. is closed on one side by thes'maller end of theplug l. A valved connection this pro,- vided through which. relatively cool oil may, be supplied to chamber H. under pressure sufiicient to lift the plug 4 free from its seat in the body. 5; The connection 12 enters directly the chamber I I, without passing through plug 4 or through more than a minimum of the body 5, so that oil supplied through this connection is subjected for but a minimum period of time to the temperatures prevailing in the valve. Set screws l3, l4,

l5, etc., are provided to assist in positioning and in maintaining in position the plug 4. To maintain the plug in position set screw i3 is withdrawn from engagement with the plug 4 and set screws M and I5, etc., are forced against the plug 3; to assist in releasing the plug 4 set screws l t and i5, etc., are withdrawn from engagement with the plug 4 and set screw I3 is forced against the plug 4.

Again referring to Fig. 3, immediately in advance of each of the two-way valves on the entrance side of the coking receptacles, in connecnection 24 with respect to valve 22 for'example, an auxiliary valved connection, 25 for example, is advantageously provided for the introduction of relatively cool oil into the vapor mixture entering the valve. Similar auxiliary connections may be provided in advance of the valves on the discharge side of the coking receptacles, valve 20 for example, but their provision is less important at this point.

The operation of the invention as embodied in the system illustrated in Fig. 3 will be illustrated by specific reference to the operation of valve 22. Assume a mixture of oil vapors at a temperature of 1000-1020 F. flowing from the heater through connections I6 and 24, through valve 22 and through connections 26 and- 21 to the coking receptacle B, set screw I3 being loose and set screws I4 and I5 being tight and valved connections I2 and 25 being closed, toreverse the position of the valve 22 so that the vapor mix ture will pass through connection 28 instead of connection 26, the set screws I4 and I5-are loos ened and the set screw I3 is tightened, cool oil, gas oil for example at a temperature of -80 F. for example, is forced under pressure 500- 15 00 pounds per square inch for example, through connection I2 into chamber II and, advantageously, the introduction of cool oil, of similar character and at a similar temperature for example, through connection 25 is initiated. The oil supplied to the chamber beneath the plug operates to lift the plug from its seat in the valve body and, as the plug is lifted from its seat in the valve body, to cool and lubricate the plug and seat. The oil introduced through connection 25 is vaporized thus cooling the vapor mixture by the absorption of both sensible heat and latent heat of vaporization. The oil so introduced thus assists incooling the valve and, to the extent that this cooling is abrupt, assists in freeing the valve plug from its seat. Gas oil or similar oil introduced into the system through connection 25 or flowing into the system from the chamber 1 I between the valve plugand its seat in the body of the valve joins the oil undergoing treatment in the system As soon as the valve plug is free, it is rotated to the desired position, valved connections 25 and I2 are closed, set screw I3 is loosened, and the setscrews I4 and I5, etc., are tightened.

By introducing cool oil immediately in advance of the two-way valves just before changing their position insuiiicient volume to cool them quickly over a substantial range of temperature, the valve plug may be freed from its seat in some operations without requiring the application of fluid pressure beneath the smaller end of the valve plug.

I claim:

1. In a system for reducing heavy oils to coke comprising a heater in which oil is heated to a cracking temperature upwards of 950 F., a coking receptacle adapted to permit the reduction of heavy oil to coke therein by the heat of the hot oil products discharged from said heater and a connection for discharging such hot oil products from said heater into said coking receptacle, a valve positioned in said connection comprising a frustro-conical rotatable plug seated in a body provided with ports communicating with said connection, a chamber not in communication with said ports or said connection and closed on one side by the smaller end of said plug when and only when said plug is seated, and means for supplying relatively cool oil to said chamber under pressure; p

2. In a system for reducing heavy oils to coke comprising a heater in which oil is heated to a cracking temperature upwards of 950 F., a coking receptacleadapted to permit the reduction of heavy oil to coke therein by the heat of the hot oil products discharged from said heater and a connection for discharging such hot oil products from said heater into said coking receptacle, a'valve positioned in'said connection comprising a frustro-conical rotatable plug seated in a body provided with ports communicating with said conmotion, a chamber not in communication with said ports or said connection and closed on one side by the smallerend of said plug, means for supplying relatively cool oil to said chamber under pressure, and means for introducing relativelycool oil into said connection immediately in advance of said valve.

3. In a system for reducing heavy oils to coke comprising a heater in which oil is heated to a cracking temperature upwards of 950 F., a coking receptacle adapted to permit the reduction of heavy oil to coke therein by the heat of the hot oil products discharged from said heater and a connection for discharging such hot oil products from said heater into said coking receptacle, a valve positioned in said connection comprising a frustro-conical rotatable plug seated in a body provided with ports communicating with said connection, and means for introducing relatively cool oil'into said connection immediately in advance of said valve.

HARRY L. PELZER.

Images