US2005118A

US2005118A - Conversion process

Info

Publication number: US2005118A
Application number: US428398A
Authority: US
Inventors: Voorhees Vanderveer
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1930-02-14
Filing date: 1930-02-14
Publication date: 1935-06-18
Anticipated expiration: 1952-06-18

Description

UNIT-Eu STATE Patented June 18, 12935 CNVERSIQN PROCESS 'Vanderveer Voorhees, Hammond. Ind., assignor to Standard Oil Company, Whiting, Ind., a f

corporation of Indiana Application February 14,

.5 claims. V(c1. 19t-4s) f The present invention relates to improvements' in the production of lower boiling point hydrocarbon oils such as gasoline or other oil suitable as ,the numeral 5 indicates a furnace, in'which there isprovided a' suitable l'heating coil for Aimparting a desired cracking temperature to the oil under treatment. The oil issupplied to, the'coil in the 'furnace through the line 6 by the pump 'L'jand after being heated, leaves the furnace through the line Ia provided with a pressure release valve 3. The oil or vapors then pass through the line 3 into a manifold I0, from which the oil maybe ldischarged at a-selectedlev'el through line .line l2 or line I3, into the enlarged chamber Il.

The latter is preferably of a vertically elongatedform and is'provided at its bottom with a suitable .manhead.|5, permitting access' to its inte? rior for cleaning and removal of coke.

vapors pass out'of, the 'enlarged chamber I4 through'the line I6 provided'with valve I'Land enterA thelower portion of the tower I3. Theinterior of vthis tower is provided with suitable fractionating plates I3, such as baille plates or scen plates and in the upper portion thereof, 'a few' more emcient fractionating plates 20, such 'as bubble cap plates, maybe arranged. Oil may be discharged into this tower atone or more levels through the pipes 2 Il, 2 Ib, `2 Ic, 2 Id, which are supplied from the manifold 22. Oil thus supplied descends the tower'in countercu'rrent to the rising vapors, scrubs the latter,V and the resulting liquid visc'ollected in the lower portionv of the tower I6'. This liquid is removed from the tower I6 through the discharge line 23 by pump 24. It

' is then r'forced to the line 25, and a 'part 4of or all of it may be caused. to pass through the valved line 26 into the'line 3 before it enters the mani- .fold I6. Any remainder of oiliwithdrwn from the base of the columnl may be discharged from the system through the valved line `2I.

This line may also be employed for supplying additional oil to the line 26, when desired for pur-V poses' of temperature control. lF'or oil so supplied' it is preferred to use residual oils, which could..

`not otherwise be distilled without deposition of cok'e.

'1930, serial No; 428,398'

pass out 'through the vaporline 23 into an intermediate point in the fractionating -tower 23, which is suitably provided internallyl with fractionating. plates 30, illustrated as bubble cap! plates. The upper portion of the column may be cooled, for example, -by oil fed to the coil 3| in the top of the column from the oil vsupply line 32. By this means, a suitable reflux is es-v tablished in the column,` and. the oil passed through the coil 3| is preheated. This oil is disl0 charged from the coil 3| through theline 32,

by vwhich in is conducted tu the une as leading -to the suction side of pump -1 which feeds line 6 and the heating coil in furnacefli. A by-pass 32b'is provided` around coil 3|.

`Condensatie formedin the column 29 descends and vcollects in the. lower portion ofthe column, where it may be stripped, if desired, by steam supplied from line 34 to the distributing -pipe 35 in' the lower portion of the column.- The congo densate leaves the column through the line 36.

A portion of it may be taken up through valved line 3l by the pump 33 and fed to the manifold 22, from which it may be caused to enter the column I3 through the lines 2|, 2lb, 2|c and r2| g5 at one or more desired levels. The remainder of the oil or condensate withdrawn from the lower portion of the column 29 passes through the valved pipe 39 to the line 33 leading to the pump 'I which passes it. together with the oil preheated 30 in the coil 3|, into' the heating coil in the vfurnace.

The following illustrates a process conducted .in accordance with the ypresent invention.

.-A suitable heavy oil, whichit 'is desired to 35 convert into-` gasoline, and which is preferably a distillate oil heavier than gasoline, is supplied by pump or other suitable device to the line 32 and is passed throughthe coil 3| 'in the 'upper portion of theA fractionating

column

26, 40

beingthere preheated by the rising vaporsy and cooling the latter toprovide condensate and reilux. Thefoil, thus preheated.' passes through line 32a and mingles with the condensate which collects in the lower. portion of the column 23 '45 and which passes out of the latter through the` lines 36 and 33. The mixedoil, whichis at a temperature below' that at which cracking 'to form gasoline takes place at an appreciable rate, is forced by pump.y 'l through lin'e6 finto 460 the 'heating coill in furnacei. l In the latter, the

oil is heated `to completely vaporize it vand bring the vapors to a rapid-cracking temperature.

1 AlthoughV any desired vaporphase cracking` conditions vmay. be employed in heating the oil 55.

-in the heating coil, it is preferred to cause it to -be rapidly vaporized pointed out -cracking and coking temperature therein matter. .The heavy outy through the line and brought to' a temperature of at least 850 F. with a relatively small amount of cracking to gasoline; preferably not more than 15% of the total amount of cracking to gasoline during the entire pass. In its continued travel through the heating coil, the oil vapors are maintained at a temperature above 850 F., and preferably brought to a temperature of 900 to 1000o F. with a pressure on the coil outlet of 100 to 400 lbs., maintained by the valve 8. Although such conditions are preferred, as they produce a desirable type of fuel product of the vapor phase type with relatively low loss, as in the Snow and Sullivan Patent 1,918,991, and other desired conditions for the production of vapor phase or liquid phasecracking, as preferred, may be employed. As will be apparent hereinafter, the temperature V,employed must be sufficiently high to effect the desired of the heavy tarry products introduced through the line 26, and must be substantially above the minimum (say by 50 to 100 F.) required -to secure the desired type of cracking.

InV passing through the valve 8, the pressure onthe hot oil vapors or oil products from the heating coil is reduced, say'to l0 to 60 lbs. gauge, or even to substantially atmospheric. The oil then passes through the line 9 to the manifold.

coke by their contained heat. In beginning operations, the chamber I4 may be preheated, for example, by the procedure described in the Thiele Patent 1,947,319. The oil products may be initially introduced from the manifold I0 through the lower pipe II. chamber I4 builds up, the line II may be closed and the oil products then introduced through the higher line I2. AOn further building up of the coke deposit in the o be closed off also, and the oil products allowed to enter through the line I3. It is preferred to employ a plurality of chambers such as chamber I4, which may be used alternately or in rotation as each is lled with coke. For simplicity of illustration, only one is shown.

The vapors from the chamber I4 pass out through the linejl. Coking or clogging of the outlet of the chamber may be avoidedv by supplying thereto a small amount of fresh oil, as through line 4I and'nozzle 42 directed' towards the opening of vapor line I8. The chamber I4 will ordinarily beat a temperature of 850 F. or higher, and 'may be so maintained by lagging or by the application of a mild-heat. A suitable is about 900"- F. The vapors coming off may be at 'a temperature of 800 F. or

higher, say 800,to 850 F. These'vapors pass into,

the scrubbing tower I8, wherein they are scrubbed with a small proportion of oil introduced into oneor more of the pipes 2 Il, 2 Ib, 2 Ie, 2ld at different levels to remove entrained heavy or tarry products thus entrained, together with the feed stock supplied into the tower I8, collect in the bottom of the latter and pass -23 to Athe pump 24, which forces them to the line 25 and the line 28 into vtop of the column.

As the coke deposit in the chamber I4, the line I2 may,

'the enlarged chamber completely to coke or to a non-liquid residuum.

the line 9, conveying the hot vapors and oil products from the heating coil to the enlarged chamber I4. If the proportion of heavy products thus supplied to the line 9 is excessive, sothat satisfactory reduction and conversion to coke does not take place in the enlarged chamber I4, a portion o f such heavy products maybe diverted through the line 21' to storage or 'used as fuel oil. The proportionof heavy Aproducts which may be then added to the hot vapors passing through the line 9 will not ordinarily-exceed about 10%. The vapors fromthe scrubbing tower I8 pass out through the vapor line 28 into the fractionating column 29, in which the heavier portions thereof, heavier than the desired gasoline product, are condensed, suitable cooling being effected byA the passage of suitably controlled proportions or all of the fresh oil throughthe coil 3I in the the vapors,` including the hydrocarbons in the gasoline point range, pass out 43 to the condenser 44.

vThe refluxcondensate formed in the Vcolumn ,29, which may be completely stripped of its lighter constituents by steam supplied to the distributing pipe 35 from the line 34, `passes out through the line 36, and a portion thereof is withdrawn through the line 31 by the pump 38 to be forced into the manifold 22, from which it passes into the scrubbing tower I9. The remainder of the condensate formedin the column 29 mixes. with the preheated fresh oil. If desired, instead of condensate from tower 29, fresh oil may be drawn by pump 38 from line 32a through line 4.0 and fed to the scrubbing tower I9.

Although 'it is preferred to maintain vapor phase crackingconditions in the heating coil, suitable temperatures and pressures may be employed, as is well knownfin the art, to retain a part or all of the oil in the liquid phase at the outlet thereof. The pressure conditions in the coil, which may be at 100 to 1000 lbs. pressure or higher, and the supply of heavy oil products to The lighter constituents of .2.0

through the linev the products from the heating coil as they enter l areso controlled as to sev In the event thatany liquid residuum collects e therein, it may be kept at a high temperature so as to be substantially completely converted into a solid residuum or coke vby causing apart or all of the highly heated products from the heating coil to enter the enlarged chamber through a lower. inlet.

The proportion of tarry liquid scrubbed out of the vapors`from the chamber I4 in the tower I8 is relatively small, and the products soremo'ved are of a tarry nature unsuitable of itself as a cracking stock'.- Atmospheric pressure or pressure only slightly higher, say not more than 2 5 to 30 lbs.,is preferably maintained. inthe scrubbin'g'tower Il. The fractionating plates or baille plates employed in the lower portion thereof are preferablyI` of a character suc'h as baffle plates, 4which may be readily cleaned of accumulations of cke `or carbonaceous material.

I' claim: `1. The method of boiling hydrocarbon oils into lower boiling'products such as gasoline which comprises' heating in a confined stream a substantially comlpetelyvaporizable hydrocarbon oil charging stock con sisting substantially entirely of a petroleum distillate to substantially completely vaporize the oil and bring the vapors to a high cracking temperature-of at least 900 F., passing the stream of heated oil vapors into an enlarged chamber wherein they undergo substantial cracking in the .vapor phase by their contained heat, removing in a stream the cracked vapors from said chamber and passing the stream of vapors directly to and through a scrubbing tower, continuously introducing into said tower a small proportion of the said vaporizable charging distillate stock supplied to the cracking operation and intimately contacting the said vapors owing through said tower only with said completely vaporizable distillate charging stock which is added in a volume just suilicient to scrub from the said cracked vapors substantially only entrained heavyand tarry products of cracking, passing only liquid products comprising said heavy tarry products from said tower into said enlarged chamber while excluding from said chamber heavy residual stocks from external sources, and

intimately contacting them with the aforesaid stream of highly heated oil vapors entering the said enlarged chamber, retaining the said heavy products in said chamber at a cracking temperature until they are substantially completely converted to solid residuum, separately withdrawing the scrubbed vapors from said scrubbing tower and passing them directly to a fractionating operation wherein undesired higher boiling constituents thereof are separated in the form of reflux condensate, and separately removing and collecting the fractionated vapors.

2. The method of converting relatively high boiling hydrocarbon oils into lower boiling products such as gasoline which comprises heating in f a. confined stream a substantially completely va- 40` porizable hydrocarbon oil charging stock consisting substantially entirely of a petroleum distillate to substantially completely vaporize the oil and bring the vapors to a high cracking temperature, passing the stream of heated oil vapors into an enlarged chamber wherein they undergo substantial cracking in thevapor phase by their contained heat, removing in a stream the cracked vapors from said chamber and passing the stream of vapors directly to and through Aa scrubbing tower, continuously introducing Vinto said tower a small proportion of the said vaporizable charging distillate stock supplied, to the cracking operation and intimately contacting the said vapors owing through said Atower only with said completely vaporizable distillate charging stock which is added inv volume just suflicient to scrub from the said cracked vapors substantially only entrained heavy and tarry products of cracking, passing only liquid products comprising said heavy tarry products from said tower into said enlarged chamber while excluding from said chamber heavy residual stocks from external sources, and intimately contacting them with the aforesaid stream of highly heated oil vapors entering the said enlarged chamber, ,the proportion of r the returned heavy products being not above relative to thetotal material charged to said lenlarged chamber, retaining the said heavy products in said chamber at a cracking vtemperature until they are substantially completely converted to solid residuum separately withdrawing the scrubbed vapors from said scrubbing tower and passing them directly to a fractionating operation wherein undesired higher boiling constituents theref are separated in the form of reaooaiis ux condensate, and separately removing and collecting the fractionated vapors.

3. The method of converting relatively high boiling hydrocarbon oils into lower boiling products such as gasoline which comprises heating in a confined stream a substantially completely vaporizable hydrocarbon oil charging stock c'onsisting substantially entirely of a petroleum distillate to substantially completely vaporize the oil and bring the vapors to a high cracking temperature, passing the stream Aof heated oil vapors in'to an enlarged chamber wherein they undergo substantial cracking in the vapor phase by their contained heat, removing in a stream the cracked vapors from said chamber and passing the -stream of vapors directly to and through a scrubbing tower, continuously introducing into said tower a small proportion of the said vaporizabie charging distillate stock supplied to the cracking operation and intimately contacting the saidvapors fiowing through said tower* only with `said completely vaporizable distillate charging stock which is added in volume just suicient to scrub from the said cracked vapors substantially only entrained heavy and tarry products of cracking, passing only liquid products comprising said heavy tarry products from said tower into said enlarged chamber while excluding from said chamber heavy residual stocks from external sources, and introducing them into and intimately contacting them with the aforesaid stream of highly heated oil vapors entering the said enlarged chamber, retaining the said heavy products in said chamber at a cracking temperature until they are substantially completely converted to solid residuum, separately withdrawing the scrubbed vapors from said scrubbing tower and passing them directly to a fractionating operation wherein undesired higher boiling constituents thereof are separated in the form of reilux condensate, withdrawing said condensate and passing it to the said heating and vaporizing operation as charging stock therefor, and separately removing and collecting the iractionated vapors.

4. The method of converting relatively high boiling hydrocarbon oils into lower boiling products such as gasoline which comprises heating in a confined stream a substantially completely vaporizable hydrocarbon oil charging stock consisting substantially entirely of a petroleum distillate to substantially completely vaporize the oil and bringthe vapors to a high cracking temperature of at least 900 F., passing the stream of heated oil vapors into an enlarged chamberv wherein they undergo substantial cracking in the vapor phase by their contained heat, removing in a stream the cracked vapors from said chamber` and passing the stream of vapors directly to and through af scrubbing tower, continuously inl troducing into said tower a small proportion of the said vaporizable charging distillate stock supplied to the cracking operation and intimately contacting the said vapors flowing through said tower only with said completely vaporzable distillate charging stock which is added in volume just suflicient to scrub from the said cracked vapors substantially only entrained heavy and tar ry products of cracking, passing only liquid products comprising said heavy tarry products from said tower into said enlarged chamber while excluding from said chamber heavy residual stocks from external sources, and introducing them into and intimately contacting them with the aforesaid stream of highly heated oil vapors entering the said enlarged chamber, the proportion of the returned heavy products being not above 10% relative to the total material charged to said enlarged chamber,` retaining the said heavy products in said chamber at a cracking temperature until they are substantially completely converted to solid residuum, separately withdrawing the scrubbed vapors from said scrubbing tower and passing them directly to a fractionating operation wherein undesired higher boiling constituents thereof are separated in the form of reflux condensatawithdrawingv said 'condensate and passing it to the 4saicl heating and vaporizing operation 'as charging stock therefor, and separately l a confined stream a substantially completely vaporizable hydrocarbon oil charging stock consisting substantially entirely of a petroleum distillate to substantially completely vaporize the oil and bring the vapors to a high cracking temperature, passing the stream of heated oil vapors into an 1 enlarged chamber wherein they undergo substantial cracking in the vapor phase by theirl ccnthe said vaporizable charg ng distillate stock supv plied to the cracking operation and intimately contacting the said vapors flowing through said tower only with said completely vaporizable distillate charging stock to scrub from the said cracked vapors substantially only entrained heavy and tarry products of cracking, separately withs -drawing the said scrubbed heavy tarry products and introducing them into the stream of highly heated vapors at a point intermediate the said heating operation and the said`enlarged chamber, retaining the said heavy products in said chamber at a cracking temperature until they are subin the form of reflux condensate, and separately i removing and collecting the fractionated vapors.

VANDERVEER VOORHEES.