US2189191A - Method and apparatus for processing crude petroleum - Google Patents

Description

2 sheets-sheet 1 DAVID Gv.. BRANDT ,4 TTORNE Y D. G. BRANDT Feb. 6, 1940.

METHOD AND APPARATUS FOR PROCESSING CRUDE PETROLEUM Original Filed April 14, 1934 D. G. BRANDT Feb. 6, 1940.

METHOD'AN'D APPARATUS EoR PROCESSING CRUDE PETROLEUM l Original Filed April 14, 1934 2 Sheets-Sheet 2 IN VEN TOR. AVID G. BRANDT ATTORNEY.

Patented Feb. `6, 1940 UNITED STATES PATENT OFFICE METHOD AND APPARATUS-FOR PROCESS- ING CRUDE `PETROLEUM Davia G. Brandt, westnela, N. J., assignor to" Power Patents Company, Hillside, N.,J., a co1'- poration of Maine Application April 14, 1934, `Serial No. 720,539 n Renewed August 6, 1938- is claims. (o1. 19e-49) This invention relates to a method and apparatus for processing crude oil including the cracking of certain, fractions thereof.

In large refineries .in which a number of cracking and distilling units are operated at a time,it is usually convenient `to handle all fractions of crude oil without material difficulty. lin` small plants however, it is diilicult and `at times `impossible to operate effectively and efficiently be-` cause the elements of the plant are not suficiently coordinated `to process allfractions of the crude.

The primary object of the present invention` is therefore to provide a method and apparatus adapted to handle crude oil in such a way as to make use of all fractions of the oil includingthe cracking of certain fractions to produce an antiknock gasoline.

Other objects and advantages of the invention will be apparent from the following detailed description taken in connection'with the accompanying drawings in which:

Figure 1 is a diagrammatlc flow sheet of an apparatus assembled in accordance with the features of the present invention, and particularly adapted to carry out the process of the invention.

Fig. 2 is an enlarged diagrammatic flow' sheet l line 2 and forced by means of a pump 4 throughl line 6 and preheating coil 8 mounted in crude oil tower 10.1 The oilv in passingthrough the coil 8 is heated to a temperature of about 500 and then conducted through aline l2 and heat exchanger I4 in which the oil is raised to a'temperature of about 550 F. The oil from heat exchanger i4 is passed through a line i6 onto one of the lower trays in the crude oil-tower Eil Where substantial portions of theoil are vaporized. The vapors separated in tower lll are fractionated by passing upwardly therethrough in heat exchange with the oil conducted through coil 8 and in heat exchange with condensate flowing down over the trays in the tower. VThe temperature in the upper part of the -tower is so controlled that `light gasoline is taken overhead `as vapors through a line I8, condensed in a condenser 20, and collected in a 55 receiver 22. A portion of this light gasoline may be' withdrawn from receiver 22 and returned by means of a pump 24 land line 26 onto theupper tray in -the column IU. The amount of light gasoline returned to` the` tower I0 for fractionation `control may be automatically varied bymeansof ,-5

a thermostatically controlled Valve inthe line 26 as shown. Excess gasoline in receiver 22 may be conducted to storage through a Valved pipe 28.

The fractionation in tower i0 which is `conducted ata relatively low superatmospheric pres- 10 sure or ata partial vacuum alsoproduces other l Vfractions: of the crude oil such as a heavy gasoline or naphtha, kerosene and furnace oil. The naphtha fraction may be withdrawn from the upper partof the tower lthrough a valved line 30 into k.115 Ia stripping chamber 32 Where the light ends-are removed as vapors by stripping Withsteam and conducted backinto tower l0 through a line 34.

The stripped naphtha is Withdrawn through a line 36 and passed through a cooler 38and`then into a naphtha storage tank 40. AThe kerosene fraction may be Withdrawn through any of the valved branch lines 42 vintoa stripping section 44 f in which it is treated in substantially the same manner as the naphtha referred to above; The 2 stripped kerosene vis `Withdrawn from the lower -part of the section 44 through a cooler `46. Furnace oil fractions vproduced in the towerl Ill may Vbe withdrawn through any of the Valved branch lines 48 into a'stripping section 50 operated in ,30

.the same manneras the sections 44 and 32. The furnace oil substantially free of lighter fractions fis withdrawn from section 50 through a cooler 52. The stripping in the sections 32, 44 and 50 maybe accomplished by means of steam or other suitable gas introduced through steam linesV 54.

A.The unvaporized constituents ofthecrude oil vaporize all constituents of the crude except the fuel oil residua, The materials heated in coil 64 yare conducted .through a transfer 1inef68 into a vapor-liquid separator 1D in which the fuel oil residue is separated as liquid from vapors .pro-

`duced by the heating in coils 64.` The unvaporized residue collectedy in separator 10 is withdrawn through a valved line 12 at a reduced pressure into lay`conce'ntiator 14 where portions `of the 55 lighter constituents of the fuel oil are vaporized under reduced pressure.

The vapors separated in the separator l0, comprising substantially the gas-oil fraction of the crude oil, are conducted through a line 16 and a series of radiant heating coils 'I8 mounted in furnace 66. The vapors passing through these coils are subjected to very high temperature o f from 950 to 1025 F., so that a very substantial cracking is effected. The highly heated products from the coils 18 are 'conducted through a transfer line into a combined reaction and 4quenching chamber 82 through the upper portion of which the vapors pass at a substantially reduced velocity and undergo a 'time cracking reaction. As the vapors advance downwardly through the chamber 824 they vpass through a lfunnel section 84 and are simultaneously'sprayed with relatively heavy oil discharged from spray nozzles 88. In this operation the vapors are -suddenly reduced in temperature to a point below that at which substantial cracking takes place, so that there is Ano substantial formation of coke. The liquid oil constituents collectedgin the lower part of chamber 82 are conducted at a reduced pressure through lines 88 and 12 into the concentrator 14.

The vapors produced in the concentrator '|4 areconducted through a vapor line 9|) and a series of condensing and cooling elements 92, 94 and 9S, and vthen-into a storage tank 98. The relatively heavy oil collecting in the storage tank 98 is withdrawn by means of a pump |08 and yforced through a line |92 and a connecting line A|04 into thevspray nozzles 86 in chamber 82, vwhere the oil is used for quenching the high temperature vapors referred to above.

The cooling eected in the lower part of chamber 82 may be carried out to the extent of cooling the vapors down to a temperature of from 600 to 700 F. The vapors remaining uncondensed in the chamber 82 are conducted through a vapor line linto the lower portion of a fractionating tower |88, wherein the vapors are cooledby passing upwardly through zones of -lower 'temperature in contact with condensate flowing downwardly therethrough. The cooling and condensation in tower |88 is so controlled that the pressure distillate fraction of the vapors is removed through a vapor line ||0 and conducted through a series of heat exchange coolers 1| I2 mounted in a stabilizer tower ||4 and then into a series of condensers IIB. The condensed pressure distillate product and uncondensed gases resulting from the cracking operation are passed together through a line ||8 into a receiver |20 Where the gases are separated from the liquid pressure distillate. The pressure distillate condensate collected in receiver =|20 contains certain amounts of absorbed gases which make the product unstable and therefore unsuitable as a marketable gasoline. It is therefore conducted VVthrough a float valve controlled pipe |22, a heat exchange coil in the upper condenser H6, and then into the upper midportion of the stabilizer tower H4'.

The stabilizer tower ||4 is divided into two sections which are supplied Awith heat from the coils ||2 or other suitable heating means. The pressure distillate introduced by the line I 22 into the upper part of the tower ||4 is rectied under conditions adapted to remove the low Aboiling point constituents such as the propane and part ofthe butane,; which are conducted n pane and butane.

receiver |28. Gas remaining uncondensed is removed from receiver |28 through an automatic pressure regulated relief line |38. Portions of the condensate collected in receiver |28 may be passed through a line |32 into the upper part of tower ||4 to aid in controlling the outlet temperature therein. The excess condensate from receiver |28 may be withdrawn through a valved line |34. The unvaporized gasoline constituents collected in the upper part of tower ||4 are withdrawn through a valved line I 36 into .the lower section where they are subjected to a higher temperature suicient to vaporize the light gasoline constituents. These light gasoline constituents are removed through a pressure controlled vapor line |38 and passed through a condenser :|42 which discharges into a receiver |42. The excess of light gasoline collected in receiver |42 may be withdrawn to storage through a float valve controlled line |43. A portion ofthe 'light gasoline condensate collected in receiver |42 is withdrawn through a line |44 and forced by means of a pump through lines |46 which discharge into the two sections of tower H4. The condensate introduced into the tower II 4 through lines |46 is used to aid in controlling the fractionation therein.

The heavy gasoline constituents gravitating to the lower part of tower I|4 are removed through a float valve controlled line |48, passed through a cooler |58 and then into a treating unit shown generally at |52. The treating unit |52 may comprise any of the usual forms of apparatus such as an acid mixing device and agitator, a caustic washing device and any other equipment desired for rening the finished gasoline. The light gasoline discharged through the line |43 may also be rened in any desired manner. The vapor fractions condensed in the towers vHi8 and H4 are preferably condensed at -superatmospheric pressures of from to 250 pounds per square inch,the pressure being derived from that in chambers l0 and 82. This is particularly advantageous in tower ||4 because the high pressure will aid in the condensation of lower boiling constituents such as pro- Furthermore the condensation of the pressure distillate constituents under high pressure in condensers H6 leaves a relatively dry gas which is separated in receiver |28 and removed through a pressure controlled discharge line 2|.

In order to adequately fractionate the vapors in tower |88, the crude oil charging stock for the process may be divided into two parts, one

part of which is introduced into the system through the line 2 referred to above, while the valve controlled line |60 and line I6 into the lower part of tower I0 where the crude oil is vaporized in the manner described above. The relative proportion of the charging stock introduced through the lines 2 and |54 may be regulated in accordance with the cooling required in the towers l0 and |08. Distillate from the line |82 may also be introduced into tower |88 'through a branch line |05.

The reux condensate produced in the tower |08 is withdrawn therefrom through a line |62 Whiclfi may include a: coil heating section in the lower part of tower I0 arranged so that the heat of the reflux condensate may be used for heating the bottoms from the crude oil discharged into the tower I0. If an increase in kerosene or furnace oil is desired over that normally occurring in the crude oil, al1 or any part of the reflux condensate in the line E62 may be introduced into tower I0 by lines |63, |60 and I6. In this case the higher boiling constituents will be withdrawn with the crude bottoms through line 56. The reflux condensate flowing through the line |62 and not introduced into tower I0 is forced by means of `a pump |64 into the line 62 in which the reflux is mingled with the crude oil bottoms conducted tothe coil 64. The heating of the reflux condensate along with the crude oil bottoms in coil 64 may result in a certain amount of cracking to gasoline as well as vaporization of the reflux condensate in the separator `10. As pointed out above, the vapors removedfrom the separator 10 are cracked at high temperature in coils 18.

The cracked gasoline treated in the chemical treating unit |52 necessarily contains certain heavy ends which must be removed in order to make a marketable product. Therefore the treated gasoline is withdrawn from the treating unit through a line |66, preheated in heat exchanger 94 and conducted into the mid-portion of a rerun tower |68. Y `The additional heat necessary in thetower |68 issupplied from 'thev hot vapors passedthrough coil `92 and steam may beusedwif necessary to more completely strip the bottoms.` The desired gasoline product is completely vaporized in this tower and passed through a vapor line |10, condenser |12, and into a receiver |14. The finished gasoline may be withdrawn to storage lthrough a valved line |16lwhile a portion of the finished gasoline may be used in the upper part of tower |68 to control the temperature by passing the same through a line |18 containing a thermostatically controlled valve by which the amount of gasoline introduced into. the top of tower |68 is controlled from the outlet temperature of the vapors therein. The heavy ends of the pressure distillates which remain unvaporized in tower |68 are withdrawn through a float valve control line |80, passed through a cooler |82 and conducted into storage tank 40. s i

The storagetank 40 is used to accumulate the pressure distillate bottoms and the straight run naphtha or heavy` gasoline removed from tower l0. This material may be coverted into an antiknock motor fuel by cracking under suitable high temperature and pressure. This is accomplished by conducting the relatively light oil from tank 40 through a line |84 and forcing it by means of a pump |86 either through a valved line |88v directly into the coils 18 mounted in furnace 66 or through a branch line |90 into the coils 64. 'The material from tank 4o may be passed through both of mev lines |88 and |90 so that separate portions are heated in the two coils 64 and 18.r It isapparent however that the lowboiling material passed through the coils 64 will be vaporized and separated in chamber 10 and the vapors eventually conducted tothe heating coil 18. Therefore any of the light material passed through the coil 64 will also pass through thecoil 18 to be cracked in vapor phase. The relatively low boiling `stock withdrawn from tank 40 is effectively utilized in the process for balancing the heatjabsrbedin the "respective coils 64 and 18 and for controlling l 'the temperature in these coils. For example, it

furnace 66, and with a given supply of crude oil bottoms from tower |0 and reflux condensate' from tower |08, that the temperature in coil 64 is too high.y The supply of a regulated amount of naphtha stockthrough the line |90 to the'coils 64 will reduce this temperature to the desired point because this low boiling stock will be completely vaporized. The same conditions may be assumed in connection `with the coil 18, but it is advisable to provide suliicient capacity in the coil 18 toaocominodate a constant supply of stock from the tank 40 either directly through the line `|88 `or indirectly through coils 64 and separator 10.

'Ihelight gasoline removed through the receivers 22 and |42 may be blended with any gasoline material such as that removed from receiver |14.` `If desired tower ||4 may be operated so that propane and lower` constituents are `removed through lineV |24, while the necessary butane is removed through'vapcr line |38 to leave l a stable gasoline. y

The steps outlined in the foregoing description. constitute an effective process for the handling of crude oilincluding all its fractions *and constituents in a comparatively simple manner.` The process includes the cracking `of certain of the constituents of the oil,A to produce an anti-knock gasoline product. The process also includes the production of kerosene, furnace oil and fuel oil. The process and apparatus in fact constitute a complete unit for the handling of crude oil which` recover `a maximum of either of these constituents. kWhere such products are not in demand they may be used as cracking stock by conducting l either or both to tank 40, and conducting all spective coils 18 and'64, and these coils may comprise primary. and secondary cracking zones, de-

pending on the relative proportion of high antiknock gasoline demanded inthe locality.

I-Iaving` thus described `the invention in its preferred form, what is claimed as new is:

1. The process of distilling and cracking min-'l eral oils, which comprises heating crude oil to atemperature sufficient to vaporize substantial portions thereof, fractionating the vapors to separate a lightancl a heavy gasoline, kerosene and furnace oil, further heatingthe unvaporized oil constituents of the crudel oil in a heating coil mountedin a furnace to a temperature suicient to vaporize further portions of the crude oil, separating the vapors from unvaporized oil constituents, and passing the vapors throughasecond heating coil mounted in said furnace wherein the vapors are heated to a high cracking temperature under superatmospheric pressure, intro..

ducing portions of said heavy gasoline into said heating coils and controlling the relative quantities introduced into each` coil to balance `the heat absorbed and temperature attained by the oil constituents passing therethrough, removing unvaporized oil constituents from said separating zone and distilling the same to produce a high boiling distillate therefrom, mingling the resulting distillate with the highly heated and cracked products rfrom said second coil to suddenly reduce the temperature thereof below a cracking temperature whereby deposition of coke is substantially prevented, and fractionating the vapors resulting from the cracking of the oil in said second coil to produce a cracked gasoline product.

2. The process of cracking and distilling petroleum oil which comprises preheating crude oil by indirect heat exchange with cracked vapors from a cracking zone, passing the preheated crude oil into a vapor separating zone, condensing a distillate from the vapors removed from the crude oil and subjecting the same to a highcracking temperature at a superatmospheric pressure in the cracking zone, maintaining the distillate in the cracking Zone fora suiiicient timeto convert a substantial portion thereof into lower boiling point products, suddenlyreducing the temperature of the cracked vapors in a temperature reducing zone following the completing of the cracking reaction whereby substantial deposition of coke is prevented by mixing with the vapors a relatively high boiling point distillate, maintaining the vapors and distillate at a high superatmospheric pressure while reducing the temperature of said vapors, removing the resulting liquid from the temperature reducing zone and subjecting it to distillation at a substantially lower pressure to produce a distillate therefrom, and utilizing the resulting distillate for reducing the temperature of the highly heated vapors in said temperature reducing zone, passing vapors remaining uncondensed in the temperature reducing zone into indirect heat exchange with said crude oil, and separating a motor fuel product from'the cracked vapors.

3. An apparatus for the distilling and cracking of petroleum oils comprising a high pressure fractionating tower and a low pressure fractionating tower, means for passing oil charging stock through said towers in indirect heat exchange with vapors therein, means for conducting preheated charging stock from said means into the lower part of the low pressure tower, means for withdrawing a plurality of condensates from said low pressure tower, a heating coil mounted in a furnace, means for passing liquid oil from the lower part of said low pressure tower through said coil, a vapor-liquid separator and a quenching chamber, means for passing oil from said coil into said separator, a second 'heating coil mounted in a furnace, means foripassing vapors from said separator through said second heating coil and then into said quenching chamber, means for introducing a quenching liquid into said chamber, means for conducting vapors from said quenching chamber into the high pressure tower, and means for passing a condensate from the low pressure tower directly into said heating coils.

4. The process of cracking petroleum oil for the production of a gasoline motor fuel product, which comprises subjecting a distillate oil to a high cracking temperature of from 950 to 19.25 F. at a superatmospheric pressure in a cracking zone, maintaining the distillate at a high cracking temperature in the cracking zone for a sufficient time to-convert a substantial proportion thereof into the desired gasoline product, sud- ;denly reducing the temperature of the highly heated cracked products from said cracking zone toa temperature of from 609 to 700 F'. in a temperature reducing zone following the completlon of the cracking reaction by introducing into the highly heated constituents a relatively high boiling point distillate oil whereby substantial deposition of coke from said highly heated products is prevented, maintaining a high superatmospheric pressure on the highly heated constituents and high boilingdistillate during said sudden reduction in temperature, separating vapors from the resulting liquid oil residue following said temperature reduction, removing and fractionating the separated vapors in a fractionating zone to recover the cracked gasoline motor fuel constituents produced in the cracking operation, separately removing .the resulting liquid from the temperature reducing zone and subjecting it to hash distillation at a substantially lower pressure to produce a distillate therefrom, and utilizing the resulting distillate in the temperature reducing zone as a chilling medium' for suddenly reducing the temperature of the highly heated cracked products introduced thereinto.

5. In the process of cracking mineral oils in which a heavy oil stock to be subjected to cracking conditions is passed in a stream through a coil mounted in a pipe still furnace and heated to a temperature suicicnt to vaporize substantial proportions of the oil, passing the thusi heated oil into a separating chamber in which vapors are separatedgfrom unvaporized oil constituents, passing the separated vapors through a secondv heating coil lmounted in a pipe still furnace and heating the vapors therein to a high cracking temperature ata superatmospheric pressure, passing the resulting highly heated products subjected to said cracking temperature into one end ofan enlarged reaction zone and passing the vapors therethrough While maintaining .them at a cracking temperature, dischargingthe conversion products from the opposite end of said chamber and mingling them with a distillate oil in sulcient proportion to suddenly reduce the temperature of' the conversion products following the completion of the desired cracking reactions whereby substantial deposition of coke from the conversion products is prevented, passing the vapors remaining uncondensed by said temperature reducing operation for fractionation to separate out the desired gasoline product, withdrawing unvaporized. oil constituents from said separating chamber into a concentrator and distilling the same therein to product av distillate oil, and utilizing said distillate oil for effecting the sudden reduction inl temperature of the vapors passed through said enlarged reaction zone.

6. In the cracking of petroleum oils for the production of a gasolinemotor fuel product, the

improvement which comprises subjecting a distillate oil to a high cracking temperature at a superatmospheric pressure while passing in a stream of restricted cross-section through a coil mounted in a pipe still furnace, maintaining the distillate oil at a cracking temperature for a sufficient time to convert a substantial proportion thereof into lower boiling point products suitable for use as a gasoline motor fuel, suddenly reducing the temperature of the cracked oil products ina temperature reducing zone following the completion of the desired cracking reaction whereby' substantial deposition of coke is prevented by mixing a relatively high boiling point distillate with the cracked oil products, maintaining the cracked oil products and high` boiling point distillate at a high superatmospheric pressure in the temperature reducing zone while reducing the temperature of the cracking oil products, withdrawing the resulting liquid oilconstituents from the zone of high pressure in which said sudden temperature reduction is effected and subjecting said liquid oil constituents to distillation at a substantially lower pressure in a concentrator to produce a distillate therefrom, utilizing the resulting distillate for eiecting said sudden temperature reduction, and subjecting the cracked vapor products remaining uncondensed in said temperature reducing zone to a fractionation operation to separate out the desired gasoline motor fuel product. f

'7. In the process of cracking mineral oils in which a heavy oil stock to be subjected to cracking conditions is passed in a stream of restricted cross section and heatedto a temperature sufficient to vaporize a substantial proportion of the oil, passing the thus heated oil into a separating chamber in which vapors are separated from unvaporized oil constituents, passing the separated vapors at a superatmospheric pressure in a stream of restricted cross-section in which the vapors are heated toa high cracking temperature, maintaining the heated vapors at a cracking temperature for a sufficient time to convert a substantial proportion thereof into lower boiling point products suitable for use as a gasoline motor fuel, suddenly reducing the temperature of the highly heated cracked vapors in a temperaturereducing zone following the completion ofthe desired cracking reaction by mixing a relatively cool distillate oil therewith whereby substantial deposition of coke from the conversion products is prevented, passing the vapors remaining uncondensed in said temperature reducing zone for fractionation to separate out the desired gasolineproduct, withdrawing unvaporized oil constituents from said separating chamber and from said temperature reducing zoney and passing them into a concentrator in which they aredistilled at reduced pressure to produce a distillate oil, and utilizing said distillate oil for eiiecting the sudden reduction in temperature of the highly heated vapor conversion products in said temperature reducing zone.

8'. In the cracking of petroleum oils for the production of a gasoline motor fuel product as defined by claim 6 in which the stream of distillate oil is passed from said coil into an enlarged reaction chamber in which the vapors of said oil are maintained at a cracking temperature for a substantial period of time.

9. In the cracking of petroleum oils for the production of a gasoline motor fuel product as defined by claim 6 in which said stream of distillate oil is conducted from said coil into the upper portion of an enlarged vertical reaction chamber and passed downwardly therethrough, passing the conversion products in the lower por- 'operation after they have passed therefrom for said fractionation. i

ll. In the cracking of petroleum oils for the production of a gasoline motor fuel product as defined by claim 6 in which a portion of the distillate produced by the distillation in said concentrator is brought in contact with the cracked vapor products which remain uncondensed in said temperature reducing zone.

l2. In the cracking of petroleum oils for the production of a gasolinernotor fuel product as defined by claim '7 in which a portion of the distillate produced by the distillation in said concentrator is brought in contact with the cracked vapor products which remain uncondensed in said temperature reducing zone. v

13. In the method of controlling the heating of oil constituents subjected to heating operations in two coils mounted in a pipe still furnace, in which a relatively@ heavy oil stock` to be treated is continuously passed through one of coils and heated to a temperature sufcient to vaporize ya substantial proportion of the stock, 'the resulting products discharged into a vaporliquid separating chamber for separation of va pors from unvaporized heavy` oil and the separated vapors continuously passed from the separating chamber through the other of said coils mounted in said furnace and subjected to a cracking temperature therein; the improvement which comprises firing the furnace to supply suiiicient heat and temperature to the coils of said furnace at a substantially constant rate to heat a given quantity of the said oil constituents passing through said coils, separately introducing into each of said heating coils a relatively low boiling point distillate which is substantially lighter than said oil stock and in addition thereto CFI to be heated and vaporized therein with the oil stock and the vapors derived therefrom passing through the coils thereby increasing the vaporization in said one coil and the quantity of vapors to be heated in said other coil, balancing the heat absorbedin the respective coils and controlling the temperature to which the oil constituents` DAVID G. BRANDT.

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