US2052148A - Process for the conversion of heavy hydrocarbon oils into lower boiling point hydrocarbon products - Google Patents

Description

- E. A. ocoN 2,052,148 PROCESS FOR THE CONVERSION OF`HEAVY HYDROCARBON OILS L Aug. 25,' 1936.

INTO LOWER BOILING POINT HYDROCARBON PRODUCTS Filed Dec. 27, 1933 2 Sheets-Sheet 1 INVENTOR.

ATTORNEY.

nm S.

E. A. ocoN ERSION OF HEAVY HY'DROCA Aug. 25, 1936'.

. 2,052,148y RBoN oILs 'PROCESS FOR THE CONV i INT0v LOWER BOILING POINT HYDROCARBON PRODUCTS `Filed Dec. 27, 1933 2 Sheets-Sheet 2 ATTORNEY.-

GIO im Glo .o uw o@ 9K9@ o @f A .Law xmmmh, 55.0 n QI@ ola Ole c Patented ug.' 25, 1936 M'ED STATESA Mitsui OFFICE PROCESS FOR THE CONVERSION F HEAVY HYDROCARBON OILS INTO LOWER BOH.- ING POINT HYDBOCARBON PRODUCTS Ernest A. Ocon, New York, N. Y. Application Dece 27, 1933, Serial No. '704,174

The object of the present invention is'to provide an emcient and economical process and apparatus for the production of low boiling point hydrocarbon products from heavy petroleum oils and allied hydrocarbons such as liqueed coal or asphalt, shale; etc.

A further object of my invention is to provide a novel process and apparatus for the coni tinuous treatment of recycling of heavy hydrocarbons under substantially similar conditions as those of the rst cycle orrun.

A characteristic ci the process is the initial subjection of,the charging stock to heat above the boiling point temperature of the least volatile constituent of the charging stock and preferably below its critical cracking point and pref- ,bons,then subjecting the hydrocarbons immediately` up'on reaching or passing their crack, ing temperature to sudden expansion and to re duced heat, from 900 to 1100 F. and pref` erably in the presence of catalytic material and maintaining this condition for a time suilicient to secure a desired hydrogenation and catalytic cracking reaction. V

The vapors are then passed to a mixer tank where they are preferably admixed with superheated steam and subjected to the action of a desulfurizing agent. then are passed to an ex pansion tank where Vthe light vapors are separated from t e heavy residue and sulfur .emulsion and are fractionated. The condensed steam refined gas oil and other condensatea being drawn oi from the bottom of'the bubble tower and continuously sent back into the heatin zone for similar processing as described.

The invention williae described with reference to the accompanying drawings, in'which- Fig. l is a schematic view in elevation of an apparatus adapted for carrying the process into effect.

Fig'. 2 is anA -enlarged' schematic elevation showing a modiiled form of kiln and coil placement.- 7 In the drawingal have shown at I a kiln (et isc-csi -constructed of usual heat insulation material which is divided by wall E into two sections A,

B. -The charging stock is passed by pump 3 to an intermediate reux and charge exchange chamber l where it absorbs heat and is then led to theprimary preheater coil E Within section B of the kiln.

In this specification, suitable dimensions are given. for an apparatus of 1,000 barrels daily capacity, and the primary preheater "coi1 may comprise connected tubes having an aggregate length of about 600 feet Aand of 3% inch internal diameter.

Within section A of the kiln is the primary heatingmlement, as, for example, a burner 8,.

and it is intended that coil 5 receive heat blow the critical cracking point temperature oi' the charging stock, yet above its boiling point, such temperature varying with the character of the charging stock being treated and the charging stock having a general range of 300 to-700 F. under pressure from 60 to 600 pounds per square inch, and generallysubstantially,below 100 pounds per square inch. The heat, pressure', and time oi' treatment in the traverse of the charging stock through the primary preheate'r coil. is suiicient to place the charging stock in condition for instant action by additional heat.. treatment, it, for the most part, com- -prislng thoroughly mixed vapors, representing the various fractions, and entrained unvaporized particles. The charging stock in its said condition is discharged from the primary preheater.v

coil 5 into adischarge pipe 1 leading to the primary Aradiant coil or cracking coil B. However, immediately prior to or after its discharge A into primary cracking coil 8, the charging stock in vapor phase is subjected to a blast of steam superheated to a point preferably at least equal to the temperature of the hydrocarbons, the mixture oi' superheated steam and hydrocarbon va-V por and any entrained liquid being admitted to the lowermost of the'tubes comprising the primary cracking coll 8.

oi about 300 feet with an internal diameter of 3% inches.

The temperature within section A o! the kiln is above the critical cracking temperature of the hydrocarbon vapors within the primary cracking coil 8 and therefore the temperature may be from'1400 to 2000 1".. normally 1600 to 1700*' F., under the heretofore stated pressure range which The primary cracking coil 8 may compriseinterconnected tubes having an aggregate lengthV oi! catalytic material, and/or tubes which contain catalytic material. I prefer that the said two tubes be constructed of palladium-molybdenum-chromium-nickel alloy or other recognized catalytic alloy to accelerate cracking.

The cracking coil 8 is so proportionedand heated that the hydrocarbons are rapidly broken down or cracked in the presence of superheated steam, which is partly decomposed under the iniiuence of the cracking reactions, causing what appears to be carbon oxidation reactions from the liberated oxygen and carbon released during the cracking and absorption of some hydrogen by the hydrocarbons in their re-formatlons. The catalytic tubes accelerate the cracking reactions and, in effect, the cracking reactions need not be completed at the time the vapors are discharged from the primary cracking coil 8.

The cracked hydrocarbons are passed from primary cracking coil 8 to a primary hydrogenation reaction coil 9 which may comprise connected tubes having an aggregate length of 600 feet with an internal diameter of 51/2 inches, and located at the upper part of kiln connection section B.

When an apparatus such as illustrated in the drawings is employed, it will be desirable to shield the uppermost tubes of `the convection sections,

as by superposed tubes communicating with and forming a part of the primary and/or secondary coils, which will be understood by those skilled in the art.

It is desired that the primary hydrogenation reaction coilbe subjected to a temperature from 900 to,1200 F., normally 1050 F., and that the tubes, at the discharge end oi' the coil, as, for example, the four tubes shown in the drawings, be constructed of catalytic material such as chromium-nickel-iron, or contain a recognized hydrogenation catalytic material. ThusI in the primary hydrogenation reaction coil, the hydrocar-v bons, in the presence of catalytic material and under reduced pressure and temperature, are permitted to complete their reactions and reformations sufficiently to secure desired hydrogenation and catalytic reactions.

'I'he hydrocarbons are discharged from the primary reaction coil through pipe III to a mixing tank II which may be 10 to 30 feet in length and l0 to 20 inches diameter. Within the mixing tank may be disposed a suitab1edesulfurizing catalyzer indicated at I2, and steam may be led to the mixing tank through pipe I8. The mixing tank discharges into separator tank I4. In the mixing and expansion tanks further desulfurizing reactions may be eected in the presence of suitable desulfurizing chemical materials such as alcoholic solution of lead, acetate or sodium plumbite, or the catalyzer may be of tungsten-molybdenum-iron. The function of the mixing and separator tanks is to remove the sulfur, incidentally further nal reactions of the hydrocarbons, and to separate the heavy residues, the lighter vapors being led through pipe Ilm to a fractionating column such as bubble tower I5, the sulfur emulsions and heavy residues passing through pipe |61: to sludge tank I6 and .the condensed synthetic crude or gas oil passing through pipe I1 for further treatment as hereinafter explained.

To aid the separation of the light vapors and facilitate clear-cut fractionation, i'resh oil may be the kiln, as later to be explained. The gasoline may be led off from separator tank 20 by means 10 of pipe 22. Water may be drained from separator tank 20 by means of pipe 23 for re-use in the system, if desired. The steam refining condensate of the bubble tower may be lec. through pipe 24 to a hot supply tank 25 for recycling, tank 25 discharging into pipe 26 communicating with pump 2l which forces oil through pipe 28 leading to secondary preheater 29 within the kiln section B.

Means may be employed for revaporizing withinthe bubbley towerso as to act primarily upon the heaviest condensates therein. For this purpose, I have shown a steam inlet pipe 291: for superheated steam which will be discharged upwardly near the base of the bubble tower, and the steam may be superheated to a point where it will serve to bring or reform some of the said condensates up to the gasoline point. If desired, all or part of the steam refined condensates may be discharged from the base of the bubble tower through pipe 30 leading to pump l3i which will pass condensates to a fuel oil container. A condenser 32 may be interposed between the container and the pump, if desired. Part of the condensate led from the hot supply tank may pass to a pump 21a: which will discharge vupwardly through pipe 33' into the intermediate reflux and charge exchanger 4, and thence through pipe 34 back into the bubble tower where it will be subjected to the action of the steam. All or part of the steam refined condensates at the base of the bubble tower may be by-passed from pipe 30 by pipe 86 to the pipe line 28 leading to the secondary-preheater coil 28.

The secondary preheater coil may receive a 45 charge from the following sources; (a) from the hot supply tank; (b) from the heavy condensates from the base of the bubble tower; (c) fresh oil from any desired source. The secondary preheater coil thus is primarily intended for recycling condensates remaining from the first cycle above described. The secondary preheater coil discharges into a secondary radiant coil or secondary cracking coil 38 within section A of the kiln. The secondary preheater coil may consist of connected tubesaggregating 600 feet with an internal diameter of 31/2 inches, and the cracking coil 36 may comprise connected tubes aggregating 30o feet with an internal diameter of 31/2 inches. 4,

From the secondary cracking coil 36 the hydrocarbons are passed to the secondary hydrogenation reaction coil 31 in Section B which may comprise connected tubes aggregating 600 feet and of 51/2 inches internal diameter, the uppermost tubes of which are formed of catalytic material, being similar to tubes 9 in construction, vor contain catalytic material. The action of the secondary hydrogenatlon reaction coil is the same as that heretofore described with regard to the primary hydrogenation reaction coil. The secondary hydrogenation reaction coil discharges through pipe 38 into ,the mixing tank and thus meets therein the vaporsfrom the primary hydrogenation reaction coil 9. v

The steam employed in the process may be superheated4 by a coil oi suitable length and internal diameter within kiln l and indicated at tu. Adjacent the steam heated coil is a metal alloy gas-conversion coil tu oi sumcient length to insure nxing of the gas as it passes through theI end thereof discharging into the secondary preheater coil, the steam also passing through a branch pipe time communicating with the charging stock supply pipe is: leading to the primary preheater coil d. The steam appears to iorm a thin film oi black iron oxide on the walls oi the tubes preventing the deposit oi carbon.

In the process, the charging stock prior to its passage into the primary cracking coil t has been brought to a temperature approximating, 'While generally yet below, cracking temperature, and

` the crackling is immediately instituted Within the primary cracking coil and proceeds to the point Where the action of catalytic material may be had with 'greatest emciency, the vapors beingl imrnediatcly discharged into a hydrogenation reaction coil where they are expanded and somewhat reduced in temperature and caused to iolloW a lengthy path with unchanged conditions as to heat until the point is reached Where the hydrogenatlon and cracking reactions are substantially completed and desuliurization and separation may properly take place, the heavier con densates being carried back into separate preheating, cracking and reaction coils in the same heating zones as the initial and primary corresponding elements. Il desired, a proportion oi fresh `oil may be carried vwith the heavy condensates into the recycling elements, as, tor ekample, by a controlled branch pipe tra: leading .trom charging stock pipe is to secondary charging pipe it.

The increase of low boiling point motor fuel in this process in contrast with previously employed cracking methods does not afiect the required end point oi the fuel, and the hnished product requires no further treatment. 'The high antiknock characteristic of the motor iuel is the result of the hydrogenation and catalytic reactions of the process itseli, and the value ol the product for blending is similar to benzol.

The condensed steam rened heavier fractions condensed during the first run oi' the process is fuel oil of Diesel oil type which has distinctive characteristics of its own. It is lnot heavy and sticky, is of low viscosity, has more B.' t. u. value per gallon, above l Baum', and can be-used directly as a fuel without further treatment'and can, of coursefbe altered to suit' a specification required by a -user oi a particular grade. v Petroleum oils when subjected to high tem- 'perature with absence ot substantiall pressure,

follow the gas laws and the amount of cracking depends upon the time the oil is subjected to heat. The yield ci gasoline and gas depends on the time the oil is subjected to the cracking temperature and to the pressure applied. Q70

4greatest percentage of the desired products. "Hydrogen or hydrogen-containing gases may be inlooted into the preheater or' cracking coils, or either, il desired.

To produce fuel. oil, a portion or all ofthe steam reined hydrocarbon oil'is drawn off at the bottom ci the iractionating tower and its gravity controlled by means oi superheated steam and oil rehux led into the tower.

in Fig. 2 ci the drawings, l have shown a modidcation of the apparatus in that the primary preheater and reaction coils are in a zone vsepcrate trom the zoneV in which the secondary preheater and reaction coils are located. However, the operation and edect oi the arrangement is the same as that shown in the preceding dgure and hence the same numerals are employed to designate the elements shown in Fig.

l. ln Fig. 2, the kiln is constructed with primary and secondary heating zones C, Cx, which are separated by o. Wall 2m, the primary preheater and reaction coils being located, respectively in said sones C, Cac. Outdrait may be provided at or toward the base of each zone, as indicatedby the dotted lines a, Figs. l and 2. Should, alter a long period oi time, the catalytic tubes ci the coil of either section become inactive or oi'reduced inactivity, heat may be discontinued in the corresponding zone and the hou' through the coils oi the zone likewise discontinued, lor reactivation or replacement oi said catalytic tubes or other changes within the acne, While the operations Within the second cone may continue unadected. Also, should it be desired to employ zone Cac for the primary purpose oi producing lined gas, the heat therein may be increased to the desired point without adecting the thermal condition oi zone C. A -further advantage is that the thermal effects of the two zones may be varied as desired in the action upon the hydrocarbon material for specifically desired edects. vAlso, by controlling valves V and Va: located, ior example, one in the primary discharge line and the second in the secondary discharge line, the pressures within the tubes of the privmary and secondary elements may be varied to correspondingly vary the treatment oi theV hydrocarbons passed through vsaid tubes.

iin additional and importantadvantage ci the structure shown in Fig. 2, is that it enables the operation ol my'process as adapted ior the production oi saturated and unsaturated hydrocarbons ol low boiling point from a given charging stock or diderent charging stocks suitable, as to their cracked products, i'or blending.

It is now recognized that pressure largely com trols theproduction of saturated hydrocarbon cracked products, as shown by the fact that under low or moderate pressure, as in. vapor phase cracking, the relative proportion of unsaturates, as compared with high pressure cracking operation, is substantially increased. It is generally desirable to blend a saturted motor iuel product with a motor fuel of high unsat- Y urated content in order'to secure an antl-knock" `c haracteristic by the blend, and for other reasons recognized inthe art. Thus, by running a charging stock through the coils of the heating chambers C, Ca: of Fig. 2, or through the two independent series oi' coils oi chambers A and B of Fig. l, under substantially different conditions of pressure, the product from one coil series maym be largely saturated by heat reactions under the inuence of high pressure, whilst the cracked vapors from the second coil series will be of high unsaturated characteristic. Inasmuch as the rblending is eiected under ideal conditions,

through the mixing of the vaporsand the condensation of the mixed vapors into a stable blend not only may the desired blend be-obtained most economically, but emciency and stability o! the blend will be obtained.

Features of my process and apparatus, compared with standard cracking methods are as follows:

(a) Hydrogenation and without formation of carbon.

(b) High yield of gasoline, 'I0 to 85% of (7G-80) octane number.

(c) Large capacity and yield in proportion to size and cost of the unit.

(d) Greatest absorption of heat with less consumption of iuel in proportion to capacity and yield.

(e) Less cost of maintenance, labor and production.

(f) Flexibility to control'the percentage ci a given product such as gascline,` fuel oil or nxed illuminating oil gas.

Although in the description ci my process and I stated that the vapors of the hydrogenatiou and catalytic cre-citing coils of the two sections discharge simultaneously and are mixed into the miser container, if desired, l can use a seperate ruiner for each section of coils.

it is to be understood that the apparatus shown lgs is schematic and may be substantially rncclined without deviating from the scope o my invention.

The gas conversion coil, disposed in the uppermost part section C1: in Fig. 2, may be used as a su euientsry steam superheater when the unit is *narily operated for the production of rnotor fuel.

it is be understood that the tubes may be disposed horizontally, vertically or spirally, and that their size as well as the tanks, etc., will depend on the capacity of the unit.

Earring described my invention, what I claim and desire to secure by Letters Patent, is as 1cllowsl. in the conversion ci' high boiling point hydrocarbons into lower boiling point products which comprises passing c. stream of high boilpcirlt hydrocarbons substantially in the vapor phase and under superatmospheric pressure through a prilnary conversion coil in less than thirty seconds, rapidly heal-.ing the vapors to above their critical vapor phase cracking temperature by heat conduction through the coil to the vapors and by injection of steam super-heatcatalytic cracking f ed to above the temperature oi the vapors at the point oi injection of the steam, expanding the stream or vapors from the primary coil into a lower pressure sone in which heat is conducted to the vapors but in -less degree than in the primary coil, so as to maintain s, temperature of between 900 and i200 F., and maintaining the vapors in the lower pressure rione for a period of time longer than they were maintained in the primary conversion zone.

2. ln the conversion of heavy hydrocarbon oils containing sulfur compounds into refined valuable hydrocarbon products, a dual two-stage treatment which comprises subjecting the initial material to vaporization, subjecting the substantially vaporized material under pressure to vapor-phase substantial conversion, subjecting the products of conversion to successive desulfurizing and fractionation to obtain a purified condensate recycle stock comprising the heavier fractions resulting from said treatment, then separately subjecting said recycle stock in the presence of steam to vapor phase conversion, and to common desulfurizing and fractionation with the vapors of the initial two-stage treatment.

3. In the conversion of high boiling point hydrocarbons into lower boiling products, a dual two-stage conversion process which comprises subjecting a charging stock of the high boiling point hydrocarbons substantially in the vapor phase to a rapid vapor phase cracking treatment under superatmospheric pressure Within the range of 100 to 600 pounds per square inch in the presence of superheated hydrogenous gas, passing the vapors from the vapor phase cracking treatment through a hydrogenating zone l5 maintained under low pressure and with heat input of less amount than in the preceding treatment but with longer reaction time, subjecting the products of the hydrogenation to fractionation, then subjecting a redux condensate to the same steps or cracking and hydrogenation in a separate stream and separately controlled, and subjecting the vapor products of this latter treatment to common fractionation with the products of the hydrogenatlon ci the initial ma.- terial to produce a valuable blended anti--clet-A onating motor fuel.

4. .el process in accordance with claim l, in which the cracked charging Stoch vapor mixture Within the lower pressure zone is subjected under expansion and reduced applied heat to the action of a metal catalyst of the hydrogenation type, and the reflux condensate is mixed with the charging stock, and subjecting the mixture to va porization and two-stage cracking and hydrogenation reactions as described.

5. A process in accordance with claim l; in which hydrogen is passed into the primary conversion coil simultaneously with the steam.

6. En the conversion of heavy hydrocarbon oils containing sulfur compounds :into refined valuable hydrocarbon products, e. dual two-stage and cracked vapor blending process which comprises the subjection of a plurality of Astreams of liquid.

oil charging stocks separately to a progressive heat action in separate heating coils to raise the temperature of the stoclr to above the boiling point of the least volatile constituent and preter-v ably below its cracking temperature and thereby eecting substantial vaporization thereof, sub jecting the plurality of streams of substantially vapor phase charging stock separately, each to a primary stage of rapid cracking action and under superatrnospheric pressure, maintaining the vapor in said condition for a short period of time, the pressure of one stream being varied substantially from the pressure at which the other stream is subjected, and Within the range oi 100 to SCG pounds per square inch, the primary stage of rapid cracking action being effected by the simultaneous absorption of heat applied externally to the coils and by the injection into the oil vapor .of steam superheated to e. temperature substantially above the temperature oil the oil vapor at the point of injection, passing the plurality of streams of oil-steam cracked mixture, each into its respective hydrogenation reaction zone under reduced pressure and heat, the temperature being from 900 to 1200 F., and the period of time that the substantially cracked mixture is subjected to the reduced heat and pressure Within the hydrogenation reaction zones being greater than that of within theprimary stages of rapid cracking and less than one minute, and blending the products of such treatments.

which the highly saturated and highly unsaturated cracked oil vapors leaving the lower pressure zone are blended under expansion, and during the blending process are subjected to the action of a desulfurizing agent selected from materials such as alcoholic solution of lead acetate and sodium plumbite, allowing the vapors to separate from any residue and entrained liquid, subjecting the 'vapors to fractionation, and during fractionation allowing the heavier hydrocarbon vapors to separate from the lighter vapors and condense, mixing said puried heavier condensate with the oil charging stock subjected in the cracking action to the lesser pressure and subjecting the mixture to vaporization and two-stages of cracking and hydrogenation and blending as described.

8. A process in accordance with claim 3, in

which the time and pressure of cracking and hy-` drogenation reactions to which one of the plurality of streams of oil charging stock is subjected is greater than the time and pressure of cracking and hydrogenation reactions at which the other stream is subjected to secure highly saturated cracked oil vapors and highly unsaturated cracked oil vapors that by blending and fractionating will result in the production of a stable; homogeneous and highly anti-knock condensate of motor fuel type.

9. A process in accordance with claim l, in which the oil-steam mixture within the lower pressure zone is subjected under expansion and reduced applied heat to the action of a metal l5 catalyst of the hydrogenation type.

ERNEST A. OCON.

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