US1783259A - Process for cracking petroleum oil - Google Patents

Description

Dec. 2, 1930.

R. T. PoLLocK PROCESS FOR CRACKING PETROLEUM OIL Original Filed March 9, 1927 marce CoA/armste CONDE/V55( aww/nut Patented' Dee.y z, 193e ROBERT T. POLLOOK, OF vNEW' YORK, N. Y.,'ASSGNOR T0 'UNTVERSL OIL PRODUCTS param"- orifice COMPANY, F CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA PROCESS FOR @TRACKING PJTBOLEUM OEL Original application led March 9, 1927, Serial No. 173,921. Divided and this application filed November 14, 1929. Serial No. 407,203.

. Y Thls invention relates to lmprovements'ln process for cracking petroleum oil and refersv more particularly to that type of process in which the generated vapors are subjected to reflux condensing action and the reflux condensate, that is to say the incompletely con.-

verted oil constituents, subjected to further cracking reaction. 1 i

This application is a division of my c'opending application Serial No. 173,921, filed March 9, 1927, which latter case is a continuation in part of my application Serial No. 431,838, filed December 20, 1920.

With certain types of petroleum oil, the reflux condensate produced in the cracking operation is more ldesirablysubjected to further cracking reaction under different temperatures and pressures than is the original oil. By means of the present process, this reflux condensate can be separately cracked as part of a continuous process and under different i conditions of temperature and pressure than the raw'oil. As a further feature of the invention, the generated vapors are subjected to a double reflux condensing action in which the heaviest portions of the vapors are condensed and separately cracked while the intermediate portions of the vapors,'i. e., those lighter than the heaviest but not yet sufficiently cracked and therefore heavier than the lightest, are separately condensed, subjected to furtherJ cracking under 'still different conditions of temperature and pressure.

In the drawing, the single ligure shows a somewhat diagrammatic view partly in side elevation and partly in vertical section of my improved apparatus.

p Referring in detail to the drawing, A, B and C designate three separate furnaces. In the furnace A is mounted a heating coil 1, as'for example,la continuous coil of 2" to 6 pipe. This coil is fed from the charging pump 2, connected to the raw oil supply by inlet line 3 and delivering the raw oil to the heating element through the feed line 4 having throttle valve 5. The discharge side ofthe coil is connected by transfer line 6 having throttle valve 7 to vapor chamber 8. This vapor chamber 8 is provided with liquid to a partial condenser or redux condenser ,16.

rllhe vapor space of this condenser is connected by pipe 17 to throttle valve 18, nal condensercoil 19 seated in water condenser 20. The lower end of the coil 19 is connected to the upper part of receiver 21. This receiver 21 has liquid level gauge-22,v lliquid drawo pipe 23, having throttle valve 24 Referring back to the dephlegmator 13, to its lower end is connected a redux condensate pipe 27, which leads to the inlet side of the heating coil 28 mounted in the furnace C. A throttle valve 29 is interposed in the line 27.v There is likewise interposed in this line ya pump 30 provided at either side with valves 31 and 32, whereby the redux condensate may be pumped under increased pressure, if desired. A by-pass line 33having throttle valve 34 is provlded for -by-passing the pump, if desired. The discharge side of thecoil 28 is connected by transfer line 35 having throttle valve 36 to vapor chamber 37. This vapor chamber 37 is provided with liquid drawoff pipe 38 controlled by throttle valve A39. The upper end of the vapor chamber is connected by vapor pipe 40 and downwardly inclined pipe 41 having throttle valve 42, to the lower side ofa dephlegmator 43. This dephlegmater` 43 is provided with vapor outlet pipe 44 having throttle valve 45, which 'pipe 44 is connected to final condenser coil 46 seated in condenser box 47. f The lower end of the coil is connected by pipe 48 having throttle valve 49 to the upper part of receiver 50. This receiver 50 has liquid drawof pipe 51 controlled by throttle valve 52 and gas outlet ipe 53 controlled bythrottle'valve 54.l

- lieferring back lto the dephlegmator 13, I have heretofore stated that the redux condensate fromY said dephlegmator can be delivered through pipe 27 and pump 31 or line 33 to and gas outlet pipe 25, Ahaving throttle valvev the inlet side of the heating coil 28. It also may be delivered elsewhere, to wit, to a suitable Areceptacle (not shown) by means of branch 106 having throttle valve 107. In this case the valve 29 interposed in the end of ipe 27 will be closed.

eferring back to the dephlegmator 43, to its lower end is connected reflux return pipe in which is interposed a pump 56 having at eitherside valves 57 and 58. The pump may be by-passed by pipe 59 having valve 60. This line 55 connects to extension 55 leading to the heating coil 61 seated in furnace B. This coil may be of the same construction as the other two. The discharge side of this coil is connected by transfer line 63 having throttle valve 64 to an expansion or vapor chamber 65. This expansion chamber 65 has a liquid drawoi' pipe 66 controlled by throttle valve 67. It is also provided with the vapor outlet pipe 68 and connecting downwardly inclined pipe 69 furnished with throttle valve 70 and leading to the lower side of a dephlegmator 71. The upper end of the dephlegmator is connected by vapor pipe 72 having a throttle valve 73 to condenser coil 74 seated in condenser box 75. The lower end of the 'coil is connected by pipe 76 having throttle valve 77 to -the top of receiver 78. This receiver 78 has liquid drawoii' pipe 79 controlled by throttle valve 80 and gas outlet pipe 81 controlled by throttle valve 82.

The lower end of the dephlegmator 71 is connected by reiiux condensate pipe 83 having throttle valve 84 to a second return pipe 85 leading back to the pipe 55', whereby it may be returned to the heating coil 61. The line 83 is also provided with the branch pipe 86 having throttle valve 87 connected to any suitable receptacle (not shown), whereby the l reiux condensate may be led elsewhere than delivered to the coil 61. In this case a valve 88 in the line 85 can be closed and valves 84 and 87 regulated. In the pipe 85 is interposed a pump 89 having at either side, valves 90 and 91, whereby the reiux condensate may be returned to the pipe 55 under pressure. This pump may be by-passed by means of the pipe 92 having throttle valve 93. A throttle valve 94 is interposed in the pipe 55.

I have heretofore stated that the reflux condensate from the pipe 55 may be delivered to the pipe 55.. It also may be delivered elsewhere, to-wit :--to a suitable receptacle, (not shown), by means of branch 95 havin throttle valve 96. In this case the valve 9 interposed in the end of the pipe 55 will be closed.

, Referring back to the partial condenser 16, to its lower side is connected condensate return pipe 98. In this pipe line 98 is interposed a pump 99 .having suitable valves at either side thereof and also provided with the by-pass line 100 having valve 101. The lower end of the pipe 98 is connected as shown at 102 to the-,line 55, provided with control valve 103. The reflux condensate instead of being returned to the pipe 55 may be delivered to a suitable receptacle (not shown) by means of the branch 104 having throttle valve 105. l

The process may be operated as follows:

Raw oil may be fed continuously to the heating tubes 1 where it is heated to a conversion temperature of say from 750 to 900 F., more or-less, and from the heating tubes 1 the hot oil is passed to the vapor chamber 8 where the vapbrs separate. The vapors pass thence to the iirst vdephlegmator 13 where they can be subjected to fractionation.- This fractionation may be helped by the introduction of a cooling medium .in the dephlegmator in a well known manner. The uncondensed portions are passed to the partial condenser 16, and the still uncondensed portions are passed to a condenser 19 Iand thence to the receiver 21. All of the i elements so far referred t'o may be maintained under the same pressure or, if desired, differential pressures may be maintained on said elements. The reux condensate from the dephlegmator 13 may be passed to the heating coil 28 by means of the pump 30, or of the by-pass line 33, according to the relative pressures maintained on the dephlegmator 13 and the second heating coil 28. In the second heating coil 2,8 the reiiux condensate from dephlegmator 13 is subjected to further conditions of conversion passing thence to the vapor chamber 37 and to the dephlegmator 43.. The condensed portions from dephlegmator 43 will pass into the condensing coil 46 and thence to the receiver 50. This part of the system from the coil 20 to receiver 50 may be maintained under the same pressure or each step of this part of the system can r`'be 'maintained under differential pressure. The pressure in this part of the system may be higher or lower than that maintained in the part of the system from heating coil 1 to receiver 21, and, if the differential pressures are maintained on these two parts of the system, the pressure on a step ofthe part of the system from coil 28 to receiver 50 can be higher or lower than the pressure on the corresponding step of the art of the system from coil 1 to receiver 21. n the' other hand, and according to the material treated in coil 1, and also to the characteristics of the reflux condensate passed from dephlegmator 13 through line 27 into the second heating coil 28, and also according to the characteristics of the product which it is desired 'to produce in the second partof the system from heating coil 28 to receiver 50, the ternperature to which the reflux condensate from dephlegmator 13 is subjected in the second heating coil 28 may be higher or lower, or the same as that to which the oil was subjected in heating coil 1.

y The reiux condensate formed in the dephlegmator 43 of the second part of the system may be passed to the heating coil 61 by means of pump 56 or by-pass 59 accoiding to` the relative pressures maintained on dephle mater 43 and heating coil 61. --Here the re ux condensate will jbe heated to such under diderential pressures. in thewsame ,A manner as has been heretofore described 1n relation with the first and second parts ci the system, the third part of the system from heating coil 61 to receiver -78 can be maintained under the same presure as either one of the irst or second parts of the system. ln other words, thepart oit the system from heating coil`61 to4 receiver 78 can be main- `tained under the same pressure as part of dit lthe system from coil 1 to-rec'eiver 21 and,if

inthe same operation, the second part of the system from heating coil 28 to receiver 5() -is maintained at a higher .or lower pressure than the tirst part ot the system from heating coil 1 to receiver 21, it will also be respectively at a higher or lower pressure than the third part of the system from heating coil 61 to receiver 7 8. lin another methvod ot operation, the third parteci the sysf y part oit the system, *from heating coil-1 to hlt receiver 21up to the second part oit the'system, irom'heating coil 28 to receiver 50, the

third part of the system` from heating coil 61 to receiver 78 Ibeing then at a pressure. intermediate those maintained on the two other partsoi the system. V

dll

'llhe temperature at which the various cuts` ci condensates are heated respectively in 28 being maintained at a higher temperature' thanthe heating coil 1.,' and the oil passed .through heating*v coil 61being subjected to a higher temperature than that passed through coil 28.

As another method of operation, thejredux condensate subjected to treatment in heating coil 28 can be subjected to a lower temperat'ure than that at which the oil is treated in heating coil 1, and, again, the redux condensate treated in heating coil 61 can be subjected to a lower temperature than that at' which i l the oil is treated'in 'heating coil 28.

ln another method of operation, it may be desirable to treat the oil in heating coil 61 at a temperature higher than that at which the redux condensate from dephlegmator 13 is subjected in heating coil 28, but, at the same time,lower than that at which the oil is subjected in heating coil 1. ln a further method of operation, the redux condensate from dephlegmators 16, d3, and ilmay be subjected in heating coil 61 to aftemperature lower than that at which the redux condensate from dephlegmator 13 is subjected in heating coil 28, and, at the same time, higher than that at which thefoil is subjected in heating coil 1. I lin the methods oi operation heretofore reierred to, and which are in no way limiting the scope oi the invention on account of the wide variations which canbe brought to the method ot operation adopted to carry out the process, l have preferably subjected to further treatment under independent conditions of temperatureand pressure, all the various cuts of redux condensate formed inthe operation of the recess.

. However, .in one ot the preferred methods of carrying out the process, it may be desirable to subject to further treatment only selected fractions of the redux condensate;

u, formed in the process while'the other tracjtions are withdrawn trom the apparatus and ldischarged to storage.. To this edect l have ica heretofore referred to valve-controlled drawl ed lines 166, 10i, 95, and 86, connected respectively to the redux draw-od lines from dephlegmators 13,16, i3, and ,71. By the proper manipulation oi the valves shown on llO these branch lines, the redux trom each oi i closing valve 29 on line 27., the redux from v dephlegmator 13 can be withdrawnmto storage, and in this case the second part of the system from heating coil 28 to receiver 50 will be cut od from the operation, -`Valve 97 on line 55 will also be closed. At the same time,

part of the system from heating coil 28 to receiver 50 and againvsubject the redux condensate from the dephlegmator 43 of said second part of the system to further treatment in heating coil 61, while the reux con densate from the pressure condenser 16 Will be withdrawn from the process by opening valve 105 on branch line 104 and closing valve 103 on line 55.

In another method of operation, the reflux condensates from dephlegmators 13 and 16 can be respectively treated in heating coils 28 and 61, while the reflux condensate from dephlegmators 43 and 71 are Withdrawn from the process through lines 95 and 86 respectively.

Is is not deemed necessary nto describe herein all the various methods of operation which can be utilized to carry out the process as regards the treatment of reflux condensate from the various dephlegmators of the process upon further conditions of conversion. It is believed that the above description of the process, together with the drawing, will enable any one skilled in the art to adopt the method of operationl best suited to the result desired.

No specic illustration of .the pres sure and temperatures of the various parts 'of the system have been heretofore given since they may be varied widely-from one operation to another. The various fractions of oil can be subjected in the various portions of the system to pressures from 100` which comprises subjecting oil to a cracking.

with the oil in one of the pressure zones.

3. The process of converting heavy hydrocarbon oils into oils of lower boiling point which comprises subjecting oil to a cracking temperature and pressure` 1n a pressure zone, separating the high boiling fractions of the .evolved vapors from the lower boiling fractions in the form of a condensate, subjectin the condensate while still hot to increase cracking temperature and pressure, simultaneously distilling another independent body of oil, separating the evolved vapors according to their boiling points, charging the condensate thus formed while still hot into one of the pressure zones to co-mingle with the oil therein, and subjecting the remaining vapors while still hot to further fractionation to form additional condensate for the next succeeding pressure zone.v

A 4. The process of converting heavy hydrocarbons into oils of low boiling point which comprises subjecting oil to a temperature and pressure sufficient to effect cracking thereof, separating the high boiling fractions of the evolved vapors from the low boilin fractions inthe form of condensate, `forclng the condensate so separatedv into a succeeding zone for further cracking at an increased temperaturev and pressure, and mixing with the condensate an additional charge of preliminarily treated oil substantially lighter than `said oilt initially subjected to temperature and. pressure sufficient to effect crackingthereof and obtained from a source other than said evolved vapors.

In testimony whereof I aHiX my signature.

ROBERT T. POLLOCK.

temperature and pressure 1n a pressure zone,

separating the 'high boiling fractions of the evolved vapors from the low boiling fractions 1n the form of a condensate, then subjecting the condensate while still hot to increased cracking temperature and pressure, simultaneously distilling. another independent body of oil, separating the evolved vapors according to their boiling points, and comingling the condensate thus formed with the oil in one ofthe pressure zones.

2. The process of converting heavy hydrocarbon oils intol oils of lower boiling point which comprises, subjecting oil to acrackmg temperature and pressure in a pressure zone, separating the highboiling fractions of the evolved vapors from the lowerboiling

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