US2072789A - Hydrocarbon process - Google Patents

Description

29 3937, A. ANsoN HYDROCARBON PROCESSv Filed Jan. 2. 193s INVENToR.

L ARTHUR ANsoN.

BY /n/w?, 'l A TTQRNEYS. I

Patented Mar. 2, 1937 UNrTEu STATES PATENT oFFlcE HYDROCARBON PROCESS y Isaac Arthur Anson, Tulsa, Okla.

Application January 2, 1936, Serial No. 57,295

9 Claims.

'I'his invention relates to an improved method of treating hydrocarbons, particularly petroleum hydrocarbons, and relates specifically to an improved method of effecting a separation of the 5 products of a hydrocarbon conversion process into relatively clean desirable products and relatively dirty or highly carbonaceous products.

In the normal conversion process, the resulting products are separated into clean and dirty l products by vaporization of the products followed by fractionation of the resulting vapors to effect the desired separation. In such a process an appreciable portion of the relatively clean products is at all times left in mixture with the highly carl.' bonaceous residues which are ordinarily removed from the process and disposed 'of as low value material.

It is a principal object of this invention to cleanly separate the highly carbonaceous undef sired products from substantially all of the relatively clean desired products of hydrocarbon conversion processes, in order that at least a.A portion of the aforementioned relatively clean products may be re-treated in the conversion process 25 -without detrimental effect upon the eiiciency thereof.

In order to accomplish the aforementioned principal object of my invention, my invention consists, primarily, in reducing substantially al 30 of the products of a hydrocarbon conversion process to the liquidpl'rase, and while in the liquid phase, separating highly carbonaceous, undesired products from relatively clean desired products. Once the products have been reduced to the liquid 35 phase, the desired separation may be accomplished by any one of a number of means, for example, by stratication, sedimentation, solvent extraction or similar means. These methods of separation may be assisted, if desired, by refrig- 40 eration and the undesired portion of the products may be reduced to the semi-solid or solid condition to effect the desired'separation.

I have found that, by reducing substantially all of the productsl of conversion, including the major 45 portion of the normally gaseous hydrocarbons such as the propane and butane fractions almost always present in such products, to the liquid phase, these liquefied, normally gaseous hydro# carbons together with the lighter, normally liquid 50 hydrocarbons present in the conversion products exert an important influence in the separation of the lighter desired products from the highly carbonaceous, undesired products. These light materials apparently act as a selective solvent for 55 the relatively light intermediate products while exerting very little, if any, solvent eect upon the more highly carbonaceous products. The net result is that the products of a hydrocarbon conversion process may be made self-separating byv the proper utilization of certain portions thereof as will be more fully described hereinafter.

The selective solvent eiect of the light products may be increased by the addition of further quantities of similar products either from extraneous sources or from other points in the same process. Or other type solvent may be injected at proper points in the processto improve the separation or to give varying degrees of selectivity in the separation. Such other solvents are carbon disulde, carbon tetrachloride, chloroform, acetone, nitrobenzene, phenol, cresylic acid or other Wood tar derivatives, furfural, B-B-dichloroethyl-ether and other similar solvents.

After the yhighly carbonaceous materials have been separated, in the liquid phase, from the lighter products, these lighter products may be 'separated by distillation and `fractionation or other means into various desired fractions and, where special solvents are used, the solvents may be separated from the lighter conversion products. The lightest fractions of the conversion products and the special solvents may be re-used in the process.

Other objects of my invention will become apparent from the following detailed description when read in conjunction with the attached drawing which illustrates diagrammatically one form of apparatus for practicing my invention.

Referring to the drawing, hydrocarbon fluid,

such as crude oil or any of its fractions, which it is desired to convert to other hydrocarbons as by cracking or polymerization, is drawn through a i pipe I and a valve 2 by a pump 3 which discharges the fluid through a coil 4 mounted in a furnace 5 and thence through a pipe 6 and a valve 'l 40 through a heat exchanger 8 into a separating chamber 9. In passing through the coil 4 the fluid ls heated to any desired conversion tem' perature by heat released in the furnace 5 and the fluid is maintained in coil 4 under any de- 45 sired pressure which may be regulated by suitable manipulation of valve 1. In passing through the heat exchanger 8 the products produced from conversion of the hydrocarbon fluid in coil 4 are cooled by heat exchange with cooler uids, obtained as will later be described. If insuiiicient cooling is obtained in this manner to reduce substantially all of the products of conversion to the liquid phase, additional cooling may be effected by introducing a cooling medium into the products passing through pipe 6. This coolingmedum may be introduced through a pipe iii in which is mounted a valve I i and may consist of other hydrocarbon uids thanthat undergoing n .5 conversion or may consist of fluids having the desired solvent or separatory elect upon the conversion products as will bemore fully described hereinafter. Still further cooling of the products of conversion may be effected in separating chamber 9 by passing cooling or refrigerating :fluid through a coil I2 mounted Within separating chamber 9. Additional cooling and/or solvent fluid may be introduced directly into the products in separating chamber 9 via a pipe I3 and a valve M- which leads into separating chamber 9. By any one, or all, or by any combination of the above described means, the products of conversion will 30 phaltenes and free carbon in suspension in they .liquid phase materials. Generally the gasoline, `kerosene and gas oil are the desired products, either as nal products or as recycle material for the process. This is particularly true of the gas oil fraction. It is also particularly desirable, when using the gas oil as recycle stock, that such gas oil be' as completely free as possible of any of the more highly carbonaceous materials such as the asphalts, asphaltenes and free carbon as these f 40 materials are highly detrimental to the smooth and continuous operation of the process when they are present in the charge or recycle stock in even very small amounts. It is therefore `of paramount importance that these materials be elim- 45 inated as completely as possible from the recycle gas oil'as well as from the other light products of the process.A As mentioned above, in the ordinary conversion process, these undesirable materials are usually eliminated by dis- 50 tillation and fractionation of the conversion products, all ofthe desired materials being separated 'from undesired materials by vaporizationleaving the undesired materials as liquid condensation products in the fractionation system. With this 55 method of procedureit is practically impossible to effect a complete separation such that substantially none of the desired material will remainin mixture with the undesired products. In fact, there is usually a veryd appreciable quantity 60 of desirable gas oil left inmixture with the unu desired products with a consequent lossof yiel from the original charge.

IY have found that, by reducing substantially' 70 products such as the lger'osene andga's oil dissolve in the propane-butane-gasoline mixture while the undesired, ,highly carbonaceous 'asphalts, asphaltenes and free carbon remain al-v most completely undissolved and may then be sep- 75 arated by sedimentation or stratication from the mixture of the other products of conversionl Such separation will take place in separating chamber 9 when all of the products of conversion have been reduced to the liquid phase in the manner above described. The highly carbonaceous materials may then be drawn from sep arating chamber 9 through a pipe I5 and valve I6 and may be disposed of in any desired manner.

To improve the degree of separation obtained in separating chamber 9, or toheighten the selectivity of thelighter materials so as to more thoroughlyexclude the highly carbonaceous. materials, I may add further quantities of the various solvents listed abovev to the mixture of products entering separating chamber 9. In some cases it may only be necessary to supply more of the butane-propane and/or gasoline fractions to the mixture of products and thus increase the conf centration of these materials in the mixture to effect the desired degree of separation. In other cases it may be necessary to add other solvents. For example, carbon disulphide will. ordinarily dissolve all of the products completely except the free carbon and some of this material may be added to the mixture to precipitate only the free carbon, leaving the asphalts and asphaltenes in the mixture. This type of separation may be desirablewhen no recyclingof intermediate stocks is contemplated and it is desired to recover a maximumamount of liquid products which are uncontaminated with free carbon.

Carbon tetrachloride may be used when it is desired to exclude only the asphaltenes and free carbon from the mixture of conversion products, as these materials are ordinarily insoluble in this particular solvent and when this particular type separation is elfected the intermediate fractions may be sufciently clean to serve as excellent recycle stock. Similarly, the various other solvents may be utilized to given any desired deL- gree of separation of the conversion products. All of these various solvents may be introduced into the mixture of 'conversion products, either by way of pipe Il) or by way of pipe I3, as may be desired.

When the proper degree oi?- separation has been effected in separating chamber 9, the undesired 'portion will be withdrawn from separating chamf ber 9 through pipe I 5 and valve I6 and the mixture of desired products with or without special solvents depending yupon whether or not such special solvents have been used, will be withdrawn from the upper portion of separating chamber 9 through a pipe- Il and a valve I8 by a pump I9, mounted in pipe II,` Vwhich will discharge this mixture' via vpipe II through heat exchanger 8 where this relatively cool mixture will serve to at least partially cool the products of conversion and will in turn be heated by the products of conversion passing through heat exchanger 8. lThe heated mixture Awill then pass from heat exchanger 8 through a pipe 20 into a fractionator 2 I, Vwhere this mixture may be separated by fractionationvinto any desired number of products. The heat required for this fractionation operation`may be supplied, wholly or'in part, 'from that obtained in heat exchanger 8 or if such heat is\insufiicient for'this ypurpose additional heat may be obtained by circulating a heating fluid through a coil 2,2 mounted in the lower portion of fractionator 2l.

In the form of apparatus illustrated in the drawing, the fractionationV contemplated in fractionator 2I is one in which the mixture to l be fractionated contains no special or extraneous solvent. The solvent in this case being the propane-butane-gasoline product of the process, the concentration of which in the total mixture, has been increased by recycling some of the recovered butane-propane and gasoline fractions. The conversion products entering fractionator 2| and heated in the manner above described will partially vaporize and the vapors will flow upwards in fractionator 2| and will be subjected to the usual type of reflux fractionation whereby the relatively heavy gas oil fraction which is to be recycled to the conversion step of the process is condensed within the fractionator 2| by the action of the reux liquid supplied in the upper portion of fractionator 2| in a manner to be later described and will flow to the lower portion of the fractionator from which it will be withdrawn through a pipe 23 and a valve 24 by a pump 25 which will pump this recycle gas oil through a pipe 26 and valve 2'| into pipe where it will mix with the original charge and thus be recycled through the conversion step of the process. In the same reflux fractionation operation -the gasoline fraction will be condensed within fractionator 2| at an intermediate point therein by the action of the reflux liquid and will be withdrawn from fractionator 2| through a pipe 28 and a valve 29 and delivered to storage which is not shown in the drawing. A portion of the gasoline fraction may, if desired, be returned to 4the mixture of conversion products for increasing the concentration of this material in the mixture for the purposes above described. I n this case a portion of the gasoline will be withdrawn from pipe 28 through a pipe 30 and a valve3| by a pump 32 which will discharge this material into pipe Ill which will then convey the gasoline into pipe 6 where it will be commingled with the products of conversion passing therethrough to serve both as cooling uid and to increase the concentration of gasoline in the mixture of conversion products to produce a higher degree of separation in separating chamber 9.. g

I'he remaining portion of the products of conversion, comprising largely the propane-butane fraction thereof, will remain in the vapor state in the fractionator 2| and will pass therefrom through a pipe 33 and a valve 34, thence through a reflux condenser 35 wherein these vapors will be, in large proportion, condensed and the resulting condensate, consisting principally of propane-butane, and uncondensed vapors, consisting of xed gases, will flow from condenser 35 into a receiver-separator 36. The xed gases will separate from the liquefied propane-butane .in receiver-separator 36 and will be discharged therefrom through a pipe 31 and valve 38 to any desired disposal means which is not shownin the drawing, The liqueed propane-butane fraction will collect in the lower portion of receiver-separator 36 and a portion thereof 'will be withdrawn therefrom through a pipe39 and a valve 40 and will be returned to the upper portion of fractionator 2| to serve as the previously mentioned reflux liquid. If desired, another portion of the propane-butane fraction may be withdrawn from receiver-separator 36 through a pipe 4| and valve 42 by a pump 43 which will pump this material into pipe lll to be used both as cooling fluid for the products of conversion passing through pipe 6 and for increasing -the concentration of this fraction in the products of conversion for'the purpose previously described. The remainder of the propane-butane fraction, y if any, may be withdrawn from receiver separator 36 through a pipe 44 and a valve 45 to storage or other disposal means not shown in the drawing. l

The temperatures employed in the coll 4 will, of course, vary with the type of conversion process and with the type of charge used. Similarly, due

to the variability of the charge and type of products desired and the degree of separation to be effected, no set temperature can be given to be employed in separating chamber 9. The particular special solvent employed will also be an important determining factor as to the particular temperature to be used at this point in the process. In some cases it may be desirable to reduce Vthe temperature below atmospheric temperatures in order to reduce the more highly carbonaceous materials to the semi-solid or solid state, depending upon some particular one or more of the solvents to retain the desired materials in the liquid phase. In other cases some temperature above atmospheric may be desirable to effect the particular separation to be desired. The temperatures employed in fractionator 2| will, of course, be those required to effect the desired fractionation therein.

The pressure employed in effecting the conversion of any particular charge will vary with the charge and the type products desired. The pressure utilized in separating chamber 9 will also be subject to variation depending upon the particular conditions of any operation. In general,

when the propane-butane fraction is to be liquefied, the particular pressure used will be that found necessary to effect the proper degree o f liquefaction of this particular fraction. The pressure in separating chamber 9 will ordinarily be regulated by suitable manipulation of valve I8. The pressure in separating chamber 9 may, in some cases, be maintained suiciently above that in fractionator 2| that the use of pump I9 may be dispensed with and the liquid mixture discharged directly 4from the upper portion of separating-chamberQ through heat exchanger 8 into fractionator 2|. The pressure in fractionator 2| will also be variable and will depend upon the type fractionation desired and upon whether or not all or part of the propane-lontane fraction is to be condensed. The particular pressure used in fractionator 2| will be regulated by the proper manipulation of either valve 34 or valve 38.

In describing the fractionation which takes place in fractionator 2| I have shown a separation of the relatively clean products of conversion into recycle gas oil, gasoline and propane-butane fractions. It will be understood however, that other fractions may also be separated. For example, I may separate a fraction intermediate between the gas oil and gasoline fractions or Imay fractionate so that all of the gasoline will leave fractionator 2| as a vapor together with the vaporous propane-butane fraction and then condense in condenser 35 most of the gasoline and leave the propane-butano fraction irithe vapor state to be discharged from receiver-separator 36 with the xed gases.

In the event that I may employ solvents other than the hydrocarbon materials produced inthe process, it may be necessary to supply additional fractionating equipment to effectively recover such solvents from the conversion products. Such equipment and its proper place in my process will be evident to those skilled in the art.

In the above detailed description of one form of my invention I have disclosed a process in which the reduction of the conversion products to the liquid phase is effected more or less en masse. However, I may find it advantageous to reduce the products to the liquid phase in a series of steps whereby a series of liquid fractions heaviest only of the fractions and eliminate certain of the intermediate fractions from the separating steps of the process.

Other advantages of my invention will be apparent to those skilled in the art and while I have described one formof my invention in considerable detail, I do not intend to be strictly lmited thereto, but desire to claim all modifications and variations thereof which come within the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

l. In a hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products' of the conversion to the liquid phase including a substantial portion of the normally gaseous products of said conversion, separating and removing from the system highly carbonaceous products from relatively clean products while in the liquid phase, and withdrawing in the liquid state the mixture of clean productsand said normally gaseous products for subsequent fractionation and separation.

2. In a hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the conversion to the liquid phase including a substantial portion of the normally gaseous products of said conversion,

separation.

n 3. In a hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the 'conversion'to the liquid phase including a substantial portion of the normally gaseous products of said conversion, increasing the concentration of some of said products in the total mixture by adding thereto additional quantities of like products, separating and removing from the system highly carbonaceous products from relatively clean products while in the liquid phase, andwithdrawing in the liquid state the mixture of clean products, saidA normally gaseous products and said added products for subsequent fractionation and separation. v x

4. In a hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the conversion to the liquid phase including a substantial portion of the normally gaseous products of said conversion. adding normally gaseous hydrocarbons to said products,'separatingland removing from the system highly carbonaceous products from relatively clean products while in the liquid phase,

withdrawing in the liquid state the mixture of clean products, said normally gaseous products and said added hydrocarbons, separating said mixture .into fractions one of which contains said normally gaseous hydrocarbons, and returning said fraction containing said normally gaseous hydrocarbons to said conversion products in the said liquid phase.

5. Infa hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the conversion to the liquid 'phase including a substantial portion of -the normally gaseous products of said conver- 6. In a hydrocarbon conversion process, the

improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the conversion to thel liquid phase including a substantial portion of the normally gaseous products of said conversion, adding a selective solvent to said products, separating and removing from theY system highly carbonaceous products fromrelatively clean products while in the liquid phase, withdrawing in the liquid state the mixture of clean products, said normally gaseous products and selective solvent for subsequent fractionation and separation, and returning a portion of said mixture to the said conversion zone.

7. In a hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the conversion to the liquid phase including a substantial portion of the normally gaseous products of said conversion, adding a selective solvent to said products, separating and removing from the system highly carbonaceous products from relatively clean products while in the liquid phase, withdrawing in the liquid state the mixture of clean products, said normally gaseous products and selective solvent, separating said mixture into lighter and heavier fractions, returning some of said lighter fractially all the products'of the conversion to the l liquid phase including a substantial portion of the normally gaseous products of said conversion, y

adding a selective solvent to said products, separating and removing from the system highly carbonaceous products from relatively clean products while in the liquid phase, withdrawing in the liquid state the mixture of clean products, said normally gaseous products and selective solvent, separating the said mixture into a normally gaseous fraction, gasoline and a relatively heavy fraction, removing said gasoline from the process. returning said relatively heavy fraction to the said conversion zone, and returning said normally gaseous fraction to the products being reduced to the liquid phase.

9. In a hydrocarbon conversion process, the improvement which comprises converting hydrocarbons in a conversion zone, reducing substantially all the products of the conversion to the liquid phase including a substantial portion of the normally gaseous products of said conversion, adding a selective solvent to said products,

separating and removing from the system highlyA gaseous fraction, gasoline and a relatively heavy fraction, returning said relatively heavy fraction to the said conversion zone, removing a portion of said gasoline from the process, and returning the remainder of said gasoline and said normally 5 gaseous fraction to the products being reduced to the liquid phase.

ISAAC ARTHUR ANSON.

DISCLAIMER 2,072,789.Isaac Arthur Anson, Tulsa, Okla. HYDROCARBON PROCESS. Patent dated March 2, 1937. Disclaimer led November 26, 1937, by the assignee, Standard Oil Company. Hereby enters this disclaimer to claim 1 in said speccation.

[Oical Gazette December 14, 1987.]

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