US1913619A - Process for conversion of hydrocarbon oil into motor and marine fuel - Google Patents

Description

s. SWARTZ 1,913,619

PROCESS FOR CONVERSION OF HYDROCARBON OIL INTO MOTOR AND MARINE FUEL June 13, .1933.

Filed Nov. 7, 1929 Patented June 13, 1933 UNITED STATES PATENT OFFICE STEPHEN SWARTZ, OF LONG BEACH, CALIFORNIA ASSIGNOR 'IO JENKINS PETROLEUI PROCESS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF WISCONSIN I PROCESS FOR CONVERSION OF HYDROCABBON OIL INTO MOTOR AND HABINE FUEL Application filed November My invention relates to the conversion of hydrocarbon oils into light motor fuel and marine fuel oil, and particularly to the conversion of residual petroleum hydrocarbon oils into light motor fuel or gasoline and heavy marine fuel oil of approved market specification.

A primal object of my invention is to simultaneously produce from a heavy petroleum hydrocarbon base a light motor fuel or gasoline, and a heavy marine fuel of approved market specification as an end product, without the formation of excessive loss, either in the shape of permanent gas or undesirable by-products such as coke, carbon, or insoluble complex hydrocarbon polymerides.

In a pending U. S. application, Serial No. 723,144, filed June 30, 1924, a conversion process is described, where a body of rapidly circulatingoil is subjected to cyclic crack ing conditions of heat and'pressure in a still of freely connecting channels, in the presence of a finely divided adsorbent for carblon forming substance, such as lime, uniformly dispersed throughout the cracking oil; Where cracked gasoline is produced and a substantial quantity of the cracking oil is constant- I y or intermittently withdrawn from the still, accompanied by adsorbent and associated carbon products; where such withdrawn oil and adsorbent is separated into vaporous and residual fractions in a zone of less pressure than the cracking zone, where the vaporous fractions are eliminated; and where the residual fractions, including adsorbent and associated carbon products are stagnated in an exterior zone of repose, wherein the adsorbent and its associated carbon products settles out to produce a clear, supernatent residuum or fuel oil.

l/Vhile the above process is generally ap- V plicable to all cracking stocks, the time re quired for settling of lime hydrate and associatcd carbon products from a final residuum or fuel oil dependent upon the nature of the cracking stock, the physical structure and the amount of lime hydrate employed, the temperature of cracking, and the timefact-or of reaction. Where cracking stock is of a 7, 1929. Serial N0. 405,412.

heavy residual nature, containing appreciable quantities of resins and asphalts, the

optimum cracking temperature for maximum production of light motor fuel is often coincident with the pyrogenic formation of additional quantities of highly polymerized resins and asphalts, such formation being accelerated by long exposure to heat influx, and

nation, nor is removable by ordinary filtration means; rendering such fuel 011 un-v salable. I have discovered that the formation of such increased quantities of highly polymerized resins and asphalts can be greatly re duced, and the formation of a relativel nonviscous residuum or fuel oil assured, y admixing the cracking base with a hydrocarbon oil substantially free from resins and as phalts, and subjecting such admixed stock to a higher cracking temperature than the formative temperature for resins and asphalts in unadmixed stock, under a reduced cracking time factor, and in the presence of a limited amount of specially prepared (noncolloidal) lime hydrate; an excess of such hydrate tending to increase the formation of objectionable resin-like and asphaltic bodies. Where lime hydrate is used in a conversion process of the nature immediately above described, or in any cracking process where the final residuum or fuel oil contains lime hydrate and associated carbon decomposition products in suspension, it is a basic object of the invention to initially employ a specially prepared (non-colloidal) hydrate of lime in such quantity, state of physical subdivision and structure, that such lime hydrate and its associated carbon products Will readil settle from the final residuum or fuel oi produced.

A corollary object of the invention is to employ in a conversion process of the nature immediately above described a specially prepared (non-colloidal) hydrate of lime in law of Stokes:

such quantity, state of physical subdivision and structure, that such lime hydrate and associated decomposition products of cracking will be readily filterable from the final residuum or fuel oil produced.

Animportant object of the invention is the production of light motor fuel, and heavy marine fuel of marketable specification, from a heavy residual hydrocarbon containing appreciable quantities of resin-like and asphaltic bodies, wherein such residual hydrocarbon, admixed with a hydrocarbon oil of substantially non-resinous and non-asphaltic content, is subjected to an optimum cracking temperature higher than the optimum cracking temperature of such unadmixed residual hydrocarbon and inhibitive of formation of additional quantities of highly polymerized resins and asphalts; conducting such conversion in the presence of a uniformly distributed, limited quantity of specially prepared (non-colloidal) hydrate of lime, to produce a final relatively non-viscous residuum or fuel oil, from which such lime hydrate and its associated carbon decomposition products will readily separate upon stagnation, or can be removed by filtration. Where ordinarily prepared (colloidal) lime hydrate however, is contacted with a cracking residuum of the nature described, liquid carbon forming substance (highly polymerized hydrocarbons) is not only adsorbed, but'the fissures and cracks absorb sufficient liquid hydrocarbons to lower the specific gravity of the larger particles of lime hydrate; while the colloidal, oil-saturated particles group themselves 1nto larger aggregates of round outline through the force of cohesion; the groups uniting to form swollen final jelly-like aggregates of a specific gravity in many instances substantially equal to, and in other cases appreciably less, than the enveloping medium; causing settling to be indefinitely prolonged or fail entirely.

I achieve a ready separation of lime hydrate and associated carbon products from a final residuum or fuel oil of the nature previously described, by initially employing a lime hydrate generally prepared according to the'method described in U. S. Patent 1,580,710 and subsequently refined as hereafter described, wherein such lime hydrate consists of substantially fissure free, noncolloidal, limited-sized particles, which when contacted with a cracking residuum tend to form without appreciable volumetric change, a non-jelly-like aggregate of hydrate and associated decomposition products of cracking,

of a specific gravity usually heavier than the enveloping residuum medium; the rate of settling being determined by the well known in which V is the rate of settling; 1' the radius of an agglomerate particle, 8 its specific gravity, 8 the specific gravity of the medium, 9 the constant for gravity and n the internal friction of the medium. Where such rate of settling is below a commercial optimum, I

have found that owing to the absence of a jelly-like quality in the agglomerate, that the latter can be readily separated from its enveloping medium by filtration without formation of the usual gummy deposit so inhibitive to successful operation.

For practical purposes, I employ a lime hydrate of such a degree of fineness that substantially 100% will pass through a 100 mesh to the inch sieve, but substantially not more than 50%, nor less than 25%, will pass through a 325 mesh to the inch sieve; the exact percentages and sieve meshes not being so important as obtaining a non-colloidal aggregate, comprising large and small part cles in such ratio and of such size, as to respectively ensure permeability to liquid flow through such aggregate, and optimum associative action towards carbon forming substances.

It is'preferable to employ a lime hydrate which has been previously prepared from quick lime by slacking in a substantial excess of water thus producing particle" of lime hydrate which are substantially fissure free.

I preferably employ lime hydrate of the characteristics immediately above described in the ratio of 0.500.75 pounds to the barrel of charging stock processed, and although the optimum quantity of such hydrate may vary with the resinous and asphaltic content of the charging stock, temperature and rate of cracking, I avoid any excess formative of of the nature above described, either in method of application or in quantity employed, to any one cracking process, a preferred method andmeans of application is subsequently described in order that my invention may be better understood by those familiar with the art; reference being made to the accompanying diagrammatic drawing, where the figure represents a cracking assembly of well known type, in which'l designates a cracking still comprising a closed, upper horizontal drum 2 superimposed over and freely connecting to a tube bank 3, by means of sluiceways 4 and 5, and cross drums refining means.

6 and 7, into which the tube bank is expanded.

, The still is to be considered as erected over a conventional heating means and provided with the usual accessories, such as safety valves, pressure and liquid level gauges, thermometers, pyrometers and the like (not shown) Circulation of the still contents is effected by the propeller 8, located in the sluice-wa 5, mounted on shaft 9 passing throu h stu ng box 10, and driven by any suita le means, such as an electric motor'11. The vapor. line 12 serves to conduct the cracked vapors produced to the baflie tower 13, reflux from thelatter returning to the drum 2-through the reflux line 14; the desired pressure on the baffle tower and still being maintained by adjustment of the valve 15, on the secondary vapor line 16, whichserves to conduct crude gasoline or motor fuel vapor from thebaflle tower to a bubble tower (not shown) or other Charging of the system is effected by the continuous acting high pressure pumps 17 and 18, of well-known type, the former taking suction by line 19, fromany suitable source of cracking stock supply (not shown), and

discharging through line 20, past check valve 21, into the baffle tower 13; the pump 18 serving to introduce lime hydrate uniformly admixed with charging stock, taking suction from the mixing tank 22 through suctionline 23, and discharging by branch line 24 into the main charging line 20. Tank 22 is provided with an agitating device of conventional means such as a revolving paddle (not shown), for maintaining the hydrate of lime in a uniformly suspended condition in thecharging stock carrier. Release of cracking stock from the still, Including lime hydrate and associated carbon products, is effected through line 25, discharging from cross drum 6 to the low pressure vapor separator 26, with rate of discharge thereto controlled by valve 27; line 28 serving to carry away vapor from such separator to any conventional type of condenser (not shown), from whence the condensate may be returned to the system as charging stock. Line 29 serves as a flow line for liquid residuum, including lime hydrate and associated carbon products, to the fuel oil settlers 30 and 30, with flow thereto con trolled by valves 31 and 31 respectively. The settlers may be of any desired number or size, two usually amply sufficing, where each is of sufiicient capacity to hold a 24 hour run of fuel oil; such settlers being preferably of conventional cylindrical cone ottom construction, insulated to conserve I heat.

The cone bottoms terminate in the discharge lines 32 and 32', provided with drawoif valves 33 and 33'. The discharge lines 32 and 32' are cross connected to the flow line 34 and suction line 35, leading to the settled fuel oil tank 36 and high pressure pump 37, respectively. ,Selective control of discharge from one or both settlers to tank 36,

or pump 37, is afforded by proper .manipu- 1 latlon of valves 38, 38', 39 and 39, in a manner apparent to one skilled in the art. The

pump 37 serves to conduct (partially settled fuel oil, or oil carrying se mentary material,.- through the discharge line 4:0 to the conventional filter press 41; or the latter may be replaced by other suitable filtration means, the filtrate being recovered in either case in the usual manner, as sediment free fuel oil and the press cake rejected as waste material.

As a typical example of actual practice of my invention it may be assumed that still 1 is under cracking conditions of heat (785 F.) and pressure (130 pounds) with attendant constant forced circulation, and that the following operations and respec tive hourly quantitles are continuously maintained; i.\e., charging of system with admixed reduced crude and recycle stock (substantially resin and asphalt free) to produce a composite 25 A. P. I. gravity stock, barrels; introduction of previously described specially prepared hydrate of lime, 55 pounds, release of crude gasoline or crude motor fuel, 31 barrels; and withdrawal of reacting still contents, including lime hydrate with associated carbon and carbon decomposition products, 50 barrels and 55 pounds, respectively.

Still referring to hourly quantities, it may be further assumed that the 50 barrels of the withdrawn reacting still'contents separates in the low pressure vapor separator, under the substantially atmospheric pressure there maintaining, into 28 barrels of recycle vapor and 22 barrels of 1012 A. P. I. gravity residiuum or fuel oil, the latter containing the 55 pounds of lime hydrate and associated carbon and carbon products in suspension. The recycle vapor is eliminated through line 28, and the mixture of fuel oil and lime hydrate with its associated carbon products flows through line 29 to the fuel oil settlers 30 and 30', as controlled by valves 31 and secon s orreater at 122 -F., the separa tion of" special y prepared lime hydrate and associated carbon products may be so retarded that it becomes expedient to filter the partially settled mixture after a certain amount of sediment has settled and been withdrawn, or in other cases it may be advantageous to introduce the settled out material direct to the filter press and recover the supernatent'oil as substantially sediment free fuel. Even in extreme cases, I find that approximatel 75% of the original sediment content of a uel oil which may initially run as high as 12%, settles out in the fuel oil settler within 24 hours, producing a partialsettled, easily filterable fuel of say 3.0%

.S. extraction.

In filter pressin such partially settled fuel oil, I comr'nonIy employ a-temperature of 250300 F., and where resinous compounds are present, I pretreat the fuel oil with naphthenic acid and diatomaceous earth, as is described in my pending application Serial No. 337,167, filed February 2, 1929. To secure eflicient filtration, a sheet of heavy canvas duck or close mesh wire screen is preferably employed as a supporting means for aprecoat consisting of a uniform, thin deposit of diatomaceous earth,

,projected on the supporting means by pumping the requisite quantity of precoat suspended in sediment free oil, such as for example, kerosene.

The specially prepared hydrate of lime with its associated carbon decomposition products, as suspended in low specific gravity fuel oil is of a fluffy nature, rapidly packs when subjected to high pressure to a medium impervious to liquid flow, and it is an important phase of my invention to so regulate the pressure and rate of filtration as to prevent formation of such impervious medium. In studying the mechanism of filtration, I have discovered the precoated supporting means .or filter aid primarily completely removes only resin like compounds, and that the production of clarified fuel occurs through the building up of a cake of sediment on the filter aid, which cake itself becomes the true filter; the larger particles of lime hydrate arching over to form a porous cake, and the finer particles, with which are associated the greater part of free carbon .produced through destructive distillative polymerization of carbon forming substance, gradually depositing within the pores of the cake until permeability to flow is finally lost.

From the above explanation, the. importance of the limit range of the size of the lime particles, and especially the necessity of having a considerable percentage of large particles within such range, becomes at once apparent; such grading permitting the formation of a thicker cake than a hydrate composed of entirely fine particles, which tend to form a rubber like layer on the filter aid, preventive of permeability; my preferred filtration method permitting the production of filtered marine fuel oil of less than 0.25% BS. extraction.

It will be further understood, that apart from the limiting range of specially prepared lime hydrate particles, the invention is not confined to the quantities, temperatures, specific gravities and apparatus disclosed in the foregoing specification, and what I claim as new and desire to protect by Letters Patent is:

1. In an oil cracking process for the production of gasoline and other oils from heavy hydrocarbon oils of an asphaltic nature the method of producing residual oils substantially free from carbon and other objectionable solid materials for use as fuel oil which comprises grading lime hydrate to particles of such size that substantially all of said particles will pass through a 100 mesh to the 1110i! sieve, but substantially not more than fifty percent nor less than twenty-five percent of said particles will pass through a 325 mesh to the inch sieve; adding lime hydrate thus graded to said heavy hydrocarbon oils of an asphaltic nature; subjecting a moving mass of such oils to cracking conditions of temperature and pressure to obtain vaporous products and unvaporized residual oils containing suspended particles of lime and associated carbon readily separable from said unvaporized residual oils by settling; conducting off said vaporous products; separately withdrawing said unvaporized residual oils containing suspended particles of lime and assoclated carbon to a zone of repose and therein settling out said suspended particles of lime and associated carbon from the unvaporized residual oils thus withdrawn leaving clarified residual oils substantially free from carbon and other objectionable solid materials for use as fuel oil.

2. In an oil cracking'process for the production of gasoline and other oils from heavy hydrocarbon oils of an alphaltic nature the method of producing residual oils substantially free from carbon and other objectionable solid materials for use as fuel oil which comprises previously preparing lime hydrate to obtain substantially fissure free particles by slaking in a substantil excess of water; grading said lime hydrate to particles of such size that substantially all of saidparticles will pass through a 100 mesh to the inch sieve but substantially not more than fifty percent nor less than twenty-five percent of said particles will pass through a 325 mesh to the inch sieve; adding lime hydrate thus prepared to said heavy hydrocarbon oils of an asphaltic nature; subjecting a moving mass of such oils to cracking conditions of temperature and pressure to obtain vaporous products and unvaporized residual oils containing suspended particles of lime and associated carbon readily separable from said unvaporized residual oils by settling; conmethod of producing residual oils substan-o unvaporized residual oils thus withdrawn.

leaving clarified residual oils substantially free from carbon and other objectionable solid materials for use as fuel oil.

3. In an oil cracking'process for the production of gasoline and other oils from heavy hydrocarbon oils of an asphaltic nature the method of producing residual oils substantially free from carbon and other ob'ectionable solid materials foruse as fuel oi which comprises grading lime hydrateto particles of suc'hsize that substantially all of said particles will pass through a 100 mesh to the inch sieve, but substantially not more than fifty percent nor less than twenty-five percent of said particles will pass through a 325 mesh to the inch sieve; adding a proximately fivetenths toseventy-five-hun redths of a pound of such graded lime h drate to'each barrel ofsaid heavy hydrocar on oils of an asphaltic nature; subjecting a movin mass of such oils to cracking conditions 0 temperature and pressure to obtain vaporous products and unvaporized residual oils containing suspended particles of lime and associated carbon readily separable from said unvaporized residual oils b settling; conducting off said vaporous pro ucts; separately withdrawing said unvaporized residual oils containing suspended particles of lime and associated carbon to a zone of repose and therein settling out said suspended particles of lime and asso-- ciated carbon from the unvaporized residual oils thus withdrawn leaving clarified residual oils substantially free from carbon and other objectionable solid materials for use as fuel oil.

' 4. Inan oil cracking process for the production of gasoline and other oils from heavy hydrocarbon oils of an asphaltic nature the tially free from carbon and other objectionable solid materials for use as fuel oil which com rises previously preparing lime hydrate to obtain substantially fissure free particles by slaking in a substantial excess of water; grading said lime hydrate to particles of such size that substantially all of said particles will pass through a 100 mesh to the inch sieve; but substantially not more than fifty percent nor less than twenty-five percent of said particles will pass through a 325 mesh to the inch sieve; adding approximately fivetenths to seventy-fiVe-hundredths of a pound of lime hydrate thus prepared to each barrel of said heavy hydrocarbon oils of an asphaltic nature; subjecting a movin mass of such oils to cracking conditions 0 temperature and pressure to obtain vaporous products and unvaporized residual oils containing sus ended artlcles of lime and associated carn rea 11y separable from sa1d unvaporized residual oils b settling; conducting off said vaporous pro ucts; separately withdrawing sus ended particles of lime. and associated said unvaporized residual oils containing car on to a zone of repose and therein settling out said suspended particles of lime and associated carbon from the unvaporized residual oils thus withdrawn leaving clarified residual oils substantially freefrom carbon and other objectionable solid. materials for use as fuel oil.

5. Inan oil cracking process for the production of gasoline and other oils from heavyhydrocarbon oils of an asphaltic nature the method of producing residual oils substantially free from carbon and'other objectionable solid materials for use as fuel oil which comprises grading lime hydrate to particles of such size that substantially all of said particles will pass through a 100 mesh to the inch sieve, but substantially not more than fifty percent nor less than twenty-five percent of said particles will pass through a. 325 mesh to the inch sieve; adding lime hydrate thus graded to said heavy hydrocarbon oils of an asphaltic nature; subjecting a moving mass of such oils to cracking conditions of temperature and pressure to obtain vaporous products and unvaporized residual oils containing suspended particles of lime and associated carbon readily separable from said associated carbon from the unvaporized residual oils leaving clarified residual oils substantially free from carbon and other objectionable solid materials for use as fuel oil.

In witness whereof, I hereunto subscribe my name to this application.

STEPHEN SWARTZ.

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