US2407817A - Converting hydrocarbons - Google Patents

Description

Sept 1946.v A. v. DANNER 2,407,17

CONVERTING HYDROCARBONS Filed March 28, 1945 55 \S THBILIZEK) INVENTOR rferwe kfio/mzz A NTOR ATTORNEY Patented Sept. 17, 1946 CONVERTING HYDROCARBONS Arthur V. Danner, Villanova, Pa., assignor to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York Application March 28, 1945, Serial No. 585,349

This invention has to do with processes for the conversion of high boiling hydrocarbons of the nature of gas oil into motor fuel of high antiknock capability, and is particularly concerned with processes of that nature which are carried out in the presence of solid adsorbent materialv While the process here set forth is useful for the production of motor fuels for use in any type of internal combustion engine, it is particularly suitable for the production of fuels for use in high compression ratio motors.

This process is particularly concerned with the joint operation of processes for the production of gasoline together with a relatively high production of olefinic gases and the conversion of such olefinic gases to useful motor fue1 components of high anti-knock capability, and has for its principal object the operation of such processes in cooperation, one with another, whereby a greatly enhanced capability in gasoline manufacture is obtained.

It has as another object theprovision of a unitary process whereby in a two step manner a gasoline is produced, and gaseous products of such reaction are recombined as liquid products of high anti-knock capability as compounds of said gasoline.

As another object'it has the effecting of considerable economies in overall operation by the concurrent practise and pro-per coordination of certain heretofore independent process steps in a manner hereinafter disclosed.

In the cracking of hydrocarbons, certain processes frequently give rise when practised at their optimum conditions for yield of gasoline and anti-knock character of gasoline, to olefine products, normally gaseous or present mainly in the lower boiling portion of the gasoline produced. Among such processes are those wherein a solid catalyst of [clay-like nature is suspended as a slurry in a liquid phase or mixed phase or vapor phase operation, similar in nature to ordinary thermal processing but conducted at a temperature sufficiently elevated to take advantage of the suspended, solid adsorbent. A process of this general type is described in Jenkins Patent No. 2,167,211. The gasoline produced directly from such processes, when freed of olefinic constituents, is of high anti-knock capability, but with the olefines present, is of lower value, of lower susceptibility to anti-knock additives, and has a lesser storage stability. Additionally, if sulfur be present in the gas oil originally cracked, significant amounts of lighter mercaptans and other low boiling sulfur compounds are present in .the

8 Claims. (Cl. 196-52) gasoline so produced, and treatment for the removal of such compounds is necessary. Formerly, in sweetening, these compounds were changed to supposedly innocuous compounds, as disulphides remaining in the oil, but present practise demands the removal of such compounds, since the supposedly innocuous disulphides and other sulfur have been found to have a negative effect.

operability, of quality and. amount of products,

and in terms of economic operation, can be obtained by a proper setup of operative processes, as set forth hereinafter.

In order that my process may be understood readily, reference is now made to the drawing attached to and made a part of this specification, the single figure of which shows one operating setup for the practise of my invention.

In the drawing a cracking stock which may be a gas oil of normal characteristics, with or with out admixed heavy naphtha, is introduced through pump l and pipe 2 to pass through heating coils 3, 4 and 5 in furnace 6 and. is then discharged through pipe 1 under the control, if desired, of a back pressure valve 8 into vapor.separator 9. A solid particle form adsorbent material, as and for a, purpose hereinafter described, having been added to the charged by pipe Hi, the tar separated in vapor separator 9 and leaving through pipe II will contain substantially all of that contact mass material. In many cases to 'prevent entire vaporization of the furnace eflluent in vapor separator 9, it is necessary to introduce a quenching oil, later to be described, through pipe I2. Vapors from vapor separator 9 pass through vapor line 13 to fractionator l4,

there to be separated into a heavier than gaso-,

line portion leaving the fractionator HI through pipe l5 and a gasoline and lighter portion passing overhead through pipe Hi. This gasoline and lighter portion enters fractionator I! and is there separated into a raw gasoline fraction leaving through pipe l8 and a gasfraction high in olefinic content leaving through pipe [9. In the preferred form of operation, this gaseous fraction passing through pipes l9 and 20 may be compressed by compressor 2|. and then passes through pipe 22 and pipe 23 into heating coil 24 in furnace 6 where it is heated to a temperature appropriate for the following step and passes through pipe 25 into a catalytic reactor 26. In th s catalytic reactor 26 the olefine containing discovery that;

gases are contacted under reaction conditions of temperature and pressure with a solid particle form adsorbent contact mass to bring about their polymerization into materials largely of gasoline boiling range. Efiluent vapors from reactor 26 pass through pipe 27 and may, by means of valve 28 be introduced into fractionator 4 at the same point as are Vapors from vapor separator 9 or, valve 28 being closed, they may be introduced through pipe 29 to a higher level in fractionator N, there to be fractionated along with the vapors from the original gas oil cracking.

Frequently, and especially in the case where stocks of relatively high sulfur content are originally cracked, in the ga oil cracking step, it is desirable to reduce the sulfur content of the gaseous products prior to their treatment and especially to reduce the amount of hydrogen sulphide and similar readily reactive sulfur compounds which may be present. In this case, with valve 3!! closed, the gases from pipe 26 will be passed through pipe 3| into a scrubber 32 Wherein they may be scrubbed by caustic soda solution or other appropriate alkaline reagent introduced through pipe 33 and leaving through pipe 34. The scrubbed gases in this case will pass from scrubber 32 through pipe 35' and reenter pipe through pipe 36, being disposed of afterward in the usual fashion. In many cases, particularly if a relatively long cut of these gases has been made, it will be desirable to divert these gases through valve 3'! to pass through a partial condenser 33 and into receiver 39 wherein a liquid/vapor separation occurs, the vapor being passed through pipe 43 to compressor 2!, and the liquids being passed by the agency of pump 4| into pipe 23 for treatment in the polymerization reaction.

It is also frequently desirable to utilize the condenser 38 and receiver 39 to effect a rough separation between gases to be treated and a liquid fraction which it is not desired to treat, in which case that liquid may be withdrawn from the. system through pipe 42. In other cases, liquid from receiver 39 maybe passed through pipe 43 to be included with the gasoline withdrawn from the bottom of iractionator H for stabilization and disposal in a manner hereinafter disclosed.

Fractionator ll may also be so operated as to produce a gas out, which overhead gas out passes under system pressure through pipe 19 and pipe 44 and is introduced directly into pipe 23 to pass through the polymerizing step under that system pressure.

Fractionator I! may also be so operated as to produce a. bottoms cut which comprises the heavier portions of the desired gasoline, a side out which comprise lighter portions of gasoline containing olefinic materials emergent from the fractionator through pipe 45 and a gas cut emergent from the fractionator overhead through pipe l9. In this case the overhead gas cut may be handled in any of the Ways hereinbefore set forth and it will be usual to take the side out produced through pipe 4:5 and pass it through pipes 44 and 48, valve 49 being closed, to condenser 38 and receiver 39, after which through the agency o equipment hereinbefore explained, both the side cut of light gasoline and the over head out of gases may be combined and assed through pipe 23, heating coil 24 and the polymerization reactor 26.

It will be noted that a pipe 53 is provided in order that liquid from pipe 23 may be utilized,

if desired, as wet reflux for control of the top temperature of fractionating tower l1. It will also be noted that a pump 5| and pipe 52 are provided so that liquid product from the bottom of fractionator I! may be utilized as wet reflux for control of the temperature at the top of fractionator Hi.

In case fractionator I1 is utilized to cut simply between a raw gasoline and an overhead vapor cut, the raw gasoline emergent from fractionator I! through pipe is is diverted through pipe 53, valve 54 being closed, to enter stabilizer 55 wherein the gasoline is stabilized to a desired vapor pressure which may be, if desired, a relatively low vapor pressure for more complete removal of olefinic materials, to later be raised by addition of light materials from another source.

Stabilized gasoline departing through pipe 55 is removed from the system as gasoline product at the lower extremity of pip it in the flow sheet shown. Overhead stabilizer gases leaving the stabilizer through pipe 51 are cooled, condensed and collected in the customary setup of cooler 58, condenser 59 andreceivei' 60, thereafter to be forwarded by pump 6| through pipe 62 to pipe 23 to be treated in the polymerization reaction, a portion being diverted through pipe 63 forthe control of the stabilizer.

Returning now to the polymerization reactor 26, we find this reactor to be supplied with a solid particle form catalytic .material' through pipe 64, hopper 65, and appropriate controlled feed leg 66. Spent contact masses from this re actor removed. through controlled drain leg 6! is collected in a hopper 68. It is therein preferably reduced into a slurry through the agency of gas oil supplied by pipe 69 and passes from hopper 68 in slurry form through pipe In to be introducedinto the gas oil cracking reaction.

Turning tothe bottom of fractionator Mjthe heavier than gasoline or recycle gas oil cut collected therein, is drawn upon by pump 10 and passed through pipe H from whence a portion or all may be diverted through pipe 12 to supply the quenching requirements of the operation through pipe [2 and/or the slurry producing requirements of the operation through pipe 69. Also material from pipe Tl may pass through pipe 13 to assist in introduction of the slurry into the gas oil cracking system as well as to serve as recycle therein. It wil'l'be noted that, if desired, all of the recycle stock produced in fractionator It may thus be recycled to the gas oil cracking operation. If it is not desired to recycle all of this material, a portion may be withdrawn from the system through. pipe M. It willalso be noted that a light gas oil fraction may be withdrawn, if desired, from tower It through pipe T5.

The gas oil cracking operation may be conducted in vapor phase, in liquid phase or in mixed phase condition. The process also may be used to crack or vis-break heavier charge stocks. Most usually, the process will be conducted either in vapor phase or in a mixed phase condition bordering upon complete vaporization.

The gas oil cracking will ordinarily be conducted at temperatures in the range of from about 1000 F. to about 1100 F. and at pressures of the order of 400 to 500- p. s. i. gauge or more, in the presence of from about 2 pound to about 10 pounds of contact mass per barrel of total charge to furnace. Sucha process will produce, from normal gas oiI upon a once through basis, from about 20% to about 50% af gasoline of400 F. end point by volume on gas oil consumed in process, together with from about five to about twenty percent of gases, (by weight on charge consumed), which gases are highly olefinic in nature and principally composed of C3 and C4 materials. Such gases, when treated in the polymerization step at temperatures of the order of 500 F. to 1000 F., preferably at about 700" F.- 750 F. in the presence of an alumina-silica catalyst in amounts appropriate for the system, are converted largely into materials of gasoline boiling range. Thus the combined process is found capable of producing from about thirty to about sixty per cent of gasoline of high value from net gas oil consumed in process.

The polymerization operation is shown herein as an operation wherein the catalyst is employed as a downwardly moving bed of contact mass material. The operation at this stage is not restricted to such a process and may be conducted either in this manner or a one wherein the catalyst is suspended by the reactant vapors in a condition of hindered settling. It is also within the contemplation of this invention that a series of fixed bed catalyst chambers might be used alternately, the bed in each chamber being discharged to hopper 68 after use and the reactor chamber being re-filled.

The solid particle form adsorptive catalytic contact mass to be used both in the gas-oil cracking step and in the olefine polymerization step may be any one of a number of forms of metallic oxide catalyst. Most usually the catalyst will be of the nature of an alumina or alumina-silica complex, of natural or synthetic origin, such as fullers earth, various other natural clay-like materials, including acid treated clays, and the like, various synthetic materials, such as those which may be prepared by the gelation of alumina and/or silica, either individually, with mixing, or with coprecipitation. Such alumina and/0r silica complexes may also carry oxides of other metals, as chromia, vanadia, magnesia, manganese, etc., added as by mixture, impregnation, coprecipitation and the like. In normal operation, however, preference is had for the alumina/ silica complexes either natural or synthetic, without added oxides of other metals, since these have the type of catalytic effect desired for the gas-oil cracking, and while they may be neither as selective nor as highly efficient as certain specialized catalytic materials for the olefine polymerization, this process permits their economic use in such proportions as actually to achieve an enhanced production against the use of such catalysts. In general, therefore, the process contemplates the use of any solid, adsorbent polymerization catalyst which is stable under the cracking conditions and hence can serve in both operations of the process.

The catalytic contact mass may be utilized either as relatively small particles, such as those used in contact filtration, in the form of granules such as the ordinary particle of fullers earth used in percolation filtration, or in the form of prepared pellets, spheres and the like of relatively small size, such as many of the synthetically prepared catalysts.

Many variation of the invention herein set forth will occur to the man skilled in the art when installing and practising this invention. All such I consider as within the scope of my invention except as limited by the claims hereinafter set forth.

I claim:

1. In a. process for the conversion of hydrocarbons of higher boiling point to motor fuel of high quality the steps which comprise: subjec ing a liquid hydrocarbon to cracking conditions of time, temperature and pressure to convert a substantial portion thereof to gasoline and other portions thereof to olefines, in the presence of a solid, particle-form adsorptive contact mass maintained in suspension in said charge, separating the products of such cracking into vapors and a liquid fraction containing the suspended solid, fractionating the vapors into an olefine containing fraction, a gasoline, and a heavierthan-gasoline fraction, contacting the olefine fraction at reaction conditions of temperature and pressure with a solid particle form adsorptive catalytic contact mass to convert a substantial portion thereof to material of gasoline boiling range, passing the vaporous products of such conversion to common fractionation with the vapors of the first cracking operation, removing contact mass from the olefine conversion stage, and injecting said contact mass into suspension in the hydrocarbon in the first cracking operation.

2. In a process for the conversion of hydrocarbons of higher boiling point to motor fuel of high quality the steps which comprise: subjecting. a liquid hydrocarbon to cracking conditions of time, temperature and pressure to convert a sub: stantial portion thereof to gasoline and other portions thereof to olefines, in the presence of a solid, particle-form adsorptive contact mass maintained in suspension in said charge, separating the products of such cracking into vapors and a liquid fraction containing the, suspended solid, fractionating the vapors into an olefine containing fraction, a gasoline, and aheavierthan-gasoline fraction, removing sulfur from the olefine fraction, contacting the olefine fraction at reaction conditions of temperature and pressure with a solid-particle form adsorptive catalytic contact mass to convert a substantial portion thereof to material of gasoline boiling range, passing the vaporous products of such conversion to common fractionation with the vapors of the first cracking operation, removing contact mass from the olefine conversion stage, and injecting said contact mass into suspension in the hydrocarbon in the first cracking operation.

3. In a process for the conversion of hydrocarbons of higher boiling point to motor fuel of high quality the steps which comprise: subjecting a liquid hydrocarbon to cracking conditions of time, temperature and pressure to convert a substantial portionthereof to gasoline and other portions thereof to olefines, in the presence of a solid, particle-form adsorptive contact mass maintained in suspension in said charge, separating the products of such cracking into 'vapors and a liquid fraction containing the suspended solid, fractionating the vapors into an olefine containing fraction, gasoline, and a heavierthan-gasoline fraction, contacting the olefine fraction at reaction conditions of temperature and pressure with a solid-particle-form adsorptive catalytic contact mass to convert a substantial portion thereof to material of gasoline boiling range, passing the vaporous products of such conversion to common fractionation with the vapors of the first cracking operation, removing contact mass from the olefine conversion stage, admixing said contact mass with at least a portion of the heavier-than-gasoline fraction from said fractionation, and injecting said contact 7 mass into suspension in thehydrocarbon in the first'c'racking operation.

4. Ina process for the conversion of hydrocarbons of higher boiling point to motor fuel of high quality the steps which comprise: subjecting a liquid hydrocarbon to cracking at temperatures between about 1000 F. and about 1100 F. to convert a substantial portion thereof to gasoline and other portions thereof to olefines, in the presence of a solid, particle-form adsorptive contact mass maintained in suspension in said charge, separating the products of such cracking into vapors and a liquid fraction containing the suspended solid, fractionating the vapors into an olefine containing fraction, a. gasoline, and a heavierthan-gascline fraction, contacting the olefine fraction at reaction conditions of temperature and pressure with a solid particle-form adsorptive catalytic contact mass to convert a substantial portion thereof to material of gasoline boiling range, passing the vaporous products of such conversion to common fractionation with the vapors of the first cracking operation, removing contact mass from the olefine conversion stage, and injecting said contact mass into suspension inthe hydrocarbon in the first cracking operation.

' In a process for the conversion of hydrocarbons of higher :boiling point to motor fuel of high quality the steps which comprise: subjecting a liquid hydrocarbon to cracking conditions of time,

temperature and pressure to convert a substantial portion thereof to gasoline and other portions thereof to olefines, in the presence of a solid, pa'rt-icle form adsorptive alumina-silica contact mass maintained in suspension in said charge,

separating the products of such cracking into a vapors and a liquid fraction containing the suspended solid, fractionating the vapors into an olefine containing fraction, a gasoline, and a heaviepthan-gasoline fraction, contacting the olefine fraction at reaction conditions of temperature and pressure with a solid particle-form adsorptive catalytic alumina-silica contact mass to convert a substantial portion thereof to material of-gasoline boiling range, passing the vaporous products of such conversion to common fractionation with'the vapors of the first cracking operation, removing contact mass from the olefine conversion stage, and injecting said contact mass into suspension in the hydrocarbon in the first cracking operation,

6. In a process for the conversion of hydrocarbons of higher boiling point to motor fuel of high quality the steps which comprise: subjecting a liquid hydrocarbon to cracking at temperatures between about 1000 F. and about 1100 F. to convert a substantial portion thereof to gasoline and other portions thereof to olefines, in the presence of a solid, particle-form adsorptive contact mass maintained in suspension in said charge, separating the products of such cracking into vapors and a liquid fraction containing the suspended solid, fractionating the vapors into an olefine containing fraction, a gasoline, and a heavier-than-gasoline fraction, contacting the olefine fraction at reaction conditions of temperature and pressure with a solid-particle-form adsorptive catalytic contact mass to convert 31251119- stantial portion thereof to. material of gasoline boiling" range, passing the vaporous products of such conversion to common fractionation with the vapors of the first cracking operation, removingcontact mass from the olefine conversion stage, admixing said contact mass with at least a portion of the heavier-than-gasoline fraction from said fractionation, andinject-ing saidcon tact mass into suspension in the hydrocarbon in the first cracking operation.

7. In a process for the conversion of hydrocarbons of higher boiling point to motor fuelof high quality the steps which comprise: subjecting a liquid hydrocarbon to cracking conditions of time, temperature and pressure to convert a substan tial portion thereof to gasoline and other por tions thereof to olefines, said cracking being conducted at a pressure sufficient to cause retention of liquid state by at least a portion of said charge and in the presence of a solid, particle-form adsorptive contact mass maintained in suspension in said charge, separating the products of such cracking into vapors and a liquid fraction con'-- taining the suspended solid, fractionating the vapors into an olefine containing fraction, a gasoline, and a heavier-than-gasoline fraction, contacting the olefine'fraction at reaction conditions of temperature and pressure, with a solid; parti ole-form adsorptive catalytic contact mass to con-- vert a swbstantialjportion thereof to material of gasoliine boiling range, passing the vaporous products of such conversion to common. fraction= ation with the vapors of the first cracking opera tion, removing contact mass from the olefine conversion stage, and injecting said contact mass into suspension in the hydrocarbon in .the first, crack ing operation. 1

8. In a process for the conversion of hydrocarbons of higher :boiling point to motor fuel of high quality the steps which comprise: subjecting a liquid hydrocarbon to cracking at temperatures between about 1000 F. and about 1100 F. to convert a substantial portion thereof to gasoline and other portions thereof to olefines, said c'ra'ck ing being conducted at a pressure sufficient to cause retention of liquid state by at least a portion of said chargeand in the presence of a solid,

particle-form adsorptive contact mass maintained insuspension in said charge, separating the prod-" ucts of such cracking into vaprs and a liquid fraction containing the suspended solid, fractionating' the vapors into an olefine containing fraction, a gasoline, and a heavier than-gasoline fraction, contacting the olefine fraction at; reaction conditions of temperature and pressure with a solid-particle-form adsorptive catalytic contact mass to convert a substantial portion thereof to material of gasoline boiling range, passing the vaporous products of such conversion to common fractionation with the vapors of the first cracking operation, removing contact mass from the olefine conversion stage, admixing said contact mass with at least a portion of the heavier-thangasoline fraction from said fractionation, and injectingsaid contact mass into suspension in the hydrocarbon in the first cracking operation.

ARTHUR V. BANNER.

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