US2161247A - Treating hydrocarbon oil - Google Patents

Description

f June 6, 1939. R. J. DEARBORN TREATING HYDROCARBORN OIL orlginai Filed Aug. 24, 1932 .III

' lhNVENTOR #LLM ATTO RN EY Patented June 6, 1939 TREATIN G HYDROCARBON OIL melma J. Dearborn. summit, N. J., assigner to The Texas Company, New York, N. Y., 'a corporation of Delaware A Continuation of application Serial No. 630,169, August 24, 1932. This application June 12, 1936, Serial No. 84,791

4 Claims;

iThis'invention-pertains to the'production of f motor fuel 4suitable for the operation of internal combustion engines; more particularly it relates to pyrolytically treating a mixture of a heavy oil and lighter hydrocarbona'as, for example,

duced and any substantial splitting-off of carbon or hydrogen is avoided. The products of ldecomposition and reformation are then preferably subjected to two stages of fractionation at reduced pressure, in the first of which al1 comthe light paraflln hydrocarbons, including proyponents heavier than gasoline are separated out 5' pane, butane and straight-run naphtha, with or as liquid, and in the second of which the gasowithout the aid of a catalyst to produce highline components are'eondensed and Separated gradeV motor fuel. A from the lighter components.

km According tothe invention a'heavy residue, re- The heavier products are also fractionated .in 10 1 sulting from ordinary `cracking orcrude reducthe first stage of fractionation into a residual ing operations. and lighter saturated hydrocartarry product, which is withdrawn from the sysbons, such as propane and butane or straighttem, and an intermediate fraction of the nature run naphtha which may be rich in hydrogen, 0f gas Oil, which may be withdrawn fromn inare mixed and then treated under favorable contermedate point in the COIlllnn and returned 16 ditions of temperature Aand pressure to decompreferably t0 the ,heating Coil t0 be mixed with pose and reform the constituents to produce the fresh charg. high-grade motor fuel. In the second stage of fractionation the gaso- Thus the invention contemplates treating a line fraction is subjected to stabilization and mixture, one portion of which is a heavy' oil those products lighter than gasoline are Sepe- 20 rich in carbon and another portion of which is rated into a .lighter and e heavier fl'eton, the a-lighter oil-rich in hydrogen, under such conheavier 0f Which may be returned t0 the heating' ditions that the heavy oil will be decomposed and Coil for mixing With the fresh Charge end relighterI products formed, while at the same time treating, While the .lighter fraction may be rea recombination and partial saturation of the moved from the system. 25 products of decomposition may be eected from '.Ihus it is to be seen that the entire charge. the presence of .the lighter oil rich in .,hydrogen, which consists preferably of a heavy residue and thereby substantially preventing the formation a light charge Stock together with recycled ges of coke and heavy tarry materials. Concurrentoil and lighter hydrocarbons which lare develly the lighter saturated hydrocarbons of the volied .in the Operatin. may be subeetedvfor e 30 mixture are substantially reformed into olenic, limited Itime t0 appropriate heating. and theiearomatic and ring compounds of high anti-knock after the products may be subjeeted t0 a Sumproperties. 'The vprocess therefore enables the 'cient time 0f Seeking in Which e desirable deeconomical production of high anti-knock motor composition and reformation or polymerization fuel from a heavy residue, such as a residualltar of the decomposed and lighter products mayl 35 from cracking operations, which ordinarily is be effected. By this method, at the extremely unsuitable for further cracking to produce gasohigh pressure employed and the limited time of line. 1 At the' same time straight-run gasoline, heating and the longer time of seeking, the heavwhich Vusually requires a separate reforming ier fractions of the charge may be decomposed 40 treatment in order to meet the present-day antiand recombined with the lighter fractions of the 40 knock requirements in gasoline, may be reformed charge, thus forming hydrocarbons lighter than to produce a high anti-knock fuel. f the heavier ones of the charge and heavier than ln a preferred embodiment of the invention, the lighter Ones 0f the Charge, and from Which the mixture of residue and lighter hydrocarbons a desirable gasoline 'fraction may be separated. is preferably passed through a heating coil con- These and other yvarious advantages of the in- 45 taining a catalyst under high pressure, say of 4vention may be better understood by referring the order of 3,000 lbs. per square inch or more to the following description and the accomor less, in which the `temperature is raised to panying-drawing, the single ligure of which illusabout 900 F. to 11001F. Following the heating trates in diagrammatic elevation a preferred form and decomposing treatment, the highly :heated of apparatus suitable for carrying on the oper- 50 products are preferably subjected to4 a time of y ation of the process. soaking in contact; with a catalyst, whereby re- The-main elements of the apparatus consist combination of the products of decomposition is' of a heating coil I, a soaking vessel 2, a fraceifected and hydrocarbon components within the Ationator 3, a condenser 4, a separator 5, and a I boiling range of commercial gasoline are pro- ,fractionator 6.

which may be insulated to prevent a. loss of f heat.

j The vessel 2 is preferably constructed sowas to withstand internal pressures of the order of 4,000 lbs. per square inch and is insulated to prevent heat loss. The vessel 2 is adapted to contain a catalyst I6, if desired, which may be supported by structural supports and a screen or perforated plate or the catalyst may be supported on horizontal bailles over which the material undergoing treatment may be'passed, or it may be in any other convenient form.

A pipe I1 in which a pressure-reducing valve I8 is situated connects the vessel 2 at its bottom and the fractionator 3 at its lower portion. The fractionator 3 may be of any conventional type, being preferably provided with bailles in the lower portion and bubble trays in the upper portion. A pipe 20 in which a'recirculating pump 2I is situ ated leads from the fractionator 3 at the'points of one or more Aof the trays, which may act as trap trays, to an inlet point of the heating coil I, and a drain line 22 at the bottom of the fractionator serves as a residue draw-off. A cooling coil 25 is preferably provided in the top of the frac- Ationator through which a cooling medium is preferably circulated; although direct introduction of reflux liquid Y may be employed if preferred. f

A pipe 25 connects the top of the fractionator 3 and the condenser 4, preferably of the submerged coil type, which in turn is connected to the sepa- `rator 5 by a pipe 21. The separator has bottom and top outlet pipes 28 and 29 which lead to dif-- ferent levels in the fractionator 5. The pipe 28 is provided with a valve 30 and the pipe 2S with a main valve 3l while it also has a plurality of valved connections 32, 33, and 34 to as many levels in the fractionator.

A pipe 38 may also be provided directly connecting pipe 28 with an intermediate point in the column 5 so that the gasoline vapors may be led directly into the column 5 without previous condensation. Suitable valves are provided in the pipes/25 and 38 so that the alternative methods of operation may be carried out.

f The fractionatory 8 may also be of a conventional type preferably containing batlles in the lower portion and bubble traysin the upper portion. A coil 40 is provided in the bottom of the AfractionatorpS through which steam or another heating medium may be circulated anda valved drain line 4I at the bottom of the fractionator serves as a liquid draw-off for the finished gasoline. A pipe having a valved release connection 41 connects the top of the fractionator 8 with a compressor 48. The compressor 45 dis charges through a connecting pipe 48, into a cooler 49 which is in turn connected to a separator 5I by a pipe 50. The separator has a top va'lved outlet 52 and a bottom valv'ed outlet 53, the latter l of which connects to a. pipe 54 leading back to the upper portion of the fractionator 6. A coil 42 istprovided in the top of the .fractionator through which ammonia or another cooling medium may be circulated as an optional arrangement. A

, effected.

pump 56 takes suction from the pipe 53 through a pipe and discharges through a pipe 51 into the heating coil at a junction of several supply pipes, each of which is preferably provided with a check valve. Aplurality of trap trayconnections 60, 6I, and 62 are provided at the upper portion of the fractionator 6 through lwhich a' pump` 63 may take suction and discharge through the pipe 64 into the pipe 51. At the junction of the pipes 64 and.51 also check valves are preferably provided.

In the operation of the process, the pump IU may delivera heavy residual charge stock, such as residue from cracking operations or from crude petroleum reducing operations, from a source not shown, into the upper section of the heater'I where it is preheated to a predetermined temperature, which may be suiicient to break the viscosity somewhat. Ordinarily, this temperature may be of the order of '750 F. The pump I I may deliver a light charge stock, such as propane and butane or straight-run naphtha, from a source not shown, into the heater coil I at a lower point commingling it with the preheated heavy portion of the charge which is being passed therethrough. At the point of the light chargeiinlet to the coil a recycle gas oil and, if desired; gaseous hydrocarbons developed in the operation of the process may also be introduced. The combined charge stocks are then preferably further heated in the heater I to a temperature'of about 900 F. to 1100 F. under a pressure of 3,000 lbs. per square inch or more or less.

It may be preferable to employ a catalyst, such as a metallic oxide or carbide, in the latter portion of the heating coil where the reaction is The highly heated material from the heater is preferably delivered into the upper portion of the soaking chamber 2 andpassed through a bed of finie, aromatic and ring compounds toV produce valuable anti-knock material -within the boiling range of gasoline.

It will be understood that the process may be operated if desired without the use of a catalyst.

Upon discharging the material, from the bottom of the soaking chamber, the pressure is dropped vto about 100 lbs.per squareinch ormore or less thereon and the 'products `are delivered into the fractionator 3 in which fractionation is carried on. 'Here the resulting heavier tarry products are deposited in the bottom of the fractionator and are regulatably withdrawn, while the vaporous products are moved upwardly through a series of ballles or trays. The heavier portions of the vapor, that is, substantially allthose constituents boiling above the gasoline fraction, are

condensed and trapped off as an intermediatecut for returning to the heating coil I for further treatment while the remaining gasoline com- .,-ponents and lighter are withdrawn overhead.

The condensate which is trapped oil.' and returned to the coil is preferably of. the nature of a clean l means suchasthe-coil 2l l the system, while sas `oil and does not contain a substantial amount of tarry constituents, In order to eifect proper reuxing in the fractimator, it may be preferable to provide cooling in the upper portion of the fractionator, which may be done by indirect through which water or any desirable *l l The vaporo'us products 'withdrawn overhead from the fractionator I are passedthrough the condenser AI 'and the resulting liquid and gaseous products may be delivered to the separator l.

The liquid 'portion separated out in the separator B will usually contain some so-called wild gases. while'the gaseous portion will usually contain some liqueuable fractions which may be separated out and recombined with the liquid portion to produce commercial gasoline. Accordingly, these fractions are both conducted to the fractionator 6 forI fractionation but are preferably introduced thereto at different levels. l In this fractionator, the liquid portion issubjected to reboiling in the bottom thereof and the vapors so produced are moved upwardly through the column to be combined with the gaseous portion delivered thereto from the separator 5 and the combined.v vaporous and gaseous products are subjected to a reiluxing action to effect the complete separation of the gasoline portion and ,those products boiling below the gasoline range. 'Ihe gasoline fraction may be withdrawn from the bottom of the fractionator and disposed of according to any preferred method of treatment.

The lighter products whichilnd their way to the upper portion of the tower may| consist largely of oleflns boiling below gasoline, the heavier por` tion of whichv ma'y be suitable for further treatment in the process for-combining with the residual` and gas oil portion ofthe charge. Accordingl'y, a further separation is eil'ected in a compressing.. cooling and expanding stage which opcrates in commotion with the upper portion of the fractionator i in which the lighter portion or dry gas may beseparated out and withdrawn from the heavier portion may be recycled to the heater I and commingled with the other constituents forming the charge stock for i further treatment. In order` to eifect this separation, it may be preferable to withdraw gas continuously from the top of the fractionator l which will condense the heavier portion and permit separation of theiliquid and gaseous portions in the separator Il and the ready release of that remaining uncondensed. The cooled condensate, or such portion as may be required, ma'y be conducted through the pipe Il and expanded into the upper portion of the fractionator I to serve as a cooling medium. In case it is desirable, ammo or other cooling agent 'Y may be circulated through the coil I! in lieu of eooung medium maybe Alarge yield of high-grade motor fuel narily,theremaybeasmallsurplusoithecom pressed cooled condensate continuously collecting in the separator Ii which may be relieved by the pump Il `taking suction thereupon through the pipe Il and the outlet line Il. This cooled condensate is preferably discharged into the pipe Il to be commingled with the liquid removed from the upper trays in the fractionator I, and is con'- ducted to the entrance point of the lighter portion of the fresh charge into the coil I. Thus, according to the invention, a relatively may be produced from a combined charge stock consisting essentially of a heavy residue usually having a high content of unsaturates and light paraflinic hydrocarbons, including straight-run gasoline.

This is a continuation of my application Serial No. 630,169, filed August 24, 1932.

Obviously many modifications and variations ot the invention, as hereinbefore set forth, may belmade without departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims. I claim: l l. The method of producing a. high anti-knock gasoline that comprises passing a heavy hydrocarbon oil through a heating zone,l admixing lighter hydrocarbon oil and already formed normally gaseous hydrocarbons, thereafter 'commingling said mixture, without heating thereof, with said heavy hydrocarbon oil, subjecting said commingled hydrocarbons inl a. heating zone to elevated temperature while under a relatively high pressure to effect conversion ofthe hydrocarbons into gasoline of high anti-knock value, separating said gasoline and normally gaseous hydrocarbons from the conversion products. fur-v ther separating the normally gaseous hydrocarbons into heavy and light portions, and returning at least a part of the heavy portion for subjection to said elevated temperature and high pressure.

2. The method of producing a high anti-knock gasoline that comprises passing a heavy hydrocarbon oil through a. heating zone, combining with the heated oil normally gaseous hydrocarbons and a lighter hydrocarbon oil, subjecting said combined hydrocarbons in a heating zone to elevated temperature while under a relatively high pressure to eile'ct conversion of the hydrocarbons into gasoline of high anti-knock value, separating said gasoline and normally gaseous hydrocarbons from the conversion products, f urther separating the normally gaseous hydrocarbons into heavy and light portions, and return ing at least a part of the heavy portion for subjection to said elevated temperature and high pressure.

3. 'I'he method in accordance with claim 1 wherein the conversion of the combined hydrocarbons is effected in the presence of a catalyst 4capable of promoting said conversion.

4. The method of producing a high anti-knock gasoline that comprises passing through a heat-A ing zone a heavy residual oil of the nature of a reduced crude` petroleum or tarry residue derived from the cracking of highboiling oils into lower boiling ones and being relatively rich in carbon in its hydrocarbon content to thereby fraise said heavy residual oil to a low' cracking temperature of the order of v750" F., combining with the heated heavy residual oil normally gaseous hydrocarbons and a gasoline stock relatively rich in hydrogen in its hydrocarbon content and having relatively low anti-knock value and passing the combined oils through a heating zone wherein the oilsare heated to a temperature of 'the order of 900 CFK-1100?y F., directing the heated of the decomposition and'subjecting the resultant products of reaction to fractionation to separate a gasoline of high anti-knock value from heavier hydrocarbons and lighter normally gaseous hydrocarbons, cooling the normally gaseous hydrocarbons to liquefy heavier constituents thereof and returning liqueed hydrocarbons thus obtained for combining with the hydrocarbon oils as aforesaid.

RICHARD J. DEARBORN. 10

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