US1886093A - Process for treating hydrocarbon oils - Google Patents

Description

I Nov. 1, 1932- c. J. GREENSTREET 1,386,093

PROCESS FOR TREATING HYDROCARBON OILS Original Filed Aug. 9. 1920 SSheets-Sheet l T? CONUKNSEIT 3mm tiara-:5 J'reenafraez c. .1. GREEN-STREET 1,886,093

PROCESS FOR TREATING HYDROCARBON OILS Original Filed Aug. 9, 1920 5 Sheets-Sheet 2 Swuemtoq 1 Cfiarias J Greensreef Cram/4 @M)? A WM,

Nov. 1, 1932.

E I a 3 0 c. J. GREENQTREET PROCESS FOR TREATING HYDROCARBQN OILS 3 Sheets-She, 3

Original Filed Aug. 9. 1920 MA/WMW Patented Nov. 1, 1932 UNITED STATES CHARLES J. GREENSTREET, 01 NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS,-

PATENT OFFICE TO RAYMOND F; ADAMS, OF NEW YORK, N. Y.

IROCESS FOR TREATING HYDROCARBON OILS Original application filed. August 9, 1920, Serial No. 402,381. Divided and this application filed June 24,

1929. Serial No. 373,364. I v

This invention relates to a process for treating hydrocarbon oils, and more particularly to a process in which heavy hydrocarbons are decomposed or cracked by heat and pressure to lighter hydrocarbons.

In cracking heavy hydrocarbons by the application of heat and pressure to produce lighter hydrocarbons suitable for use as a motor fluid, the yield and quantity 'of the product obtained is governed to a very great extent by the temperatures and pressures employed and the time and manner of heating the oil. For instance, if the oils are subjected to an excessively hightemperature above that necessary to crack the oil, there is a tendency for the oil to decompose largely to carbon and uncondensable gases, and also for the volatile liquid hydrocarbons formed in the treatment to be further decomposed to carbon and gases, especially if the heating is continued for too long a period of time. Accordingly, if the heat treatment of the .oil is not uniform and the oil is locall overheated, or, if portions of the oilstic to, or remain too long in contact with, the heating means, the yield of motor fluid is decreased through the excessive formation of gas and carbon at the overheated places. Moreover, portions of the oil may be scorched or burned, producing impurities in the product which require the use ofexcessive amounts of purifying chemicals, or

which may injure the product so that it cannot be thoroughly purified.

One object of the present invention is to provide a process in which the hydrocarbons to be treated are subjected to a uniform and accurately controlled heat treatment for a definite period of time. i

A further object of the invention is to provide a process in which the manner and length of time of treatment of the oil may be accurately controlled.

A further object'of the invention is to pro s vide a process in which the formation ofscorched and resinous "substances and other I impurities in the lighter'hydrocarbon. prod- P ucts obtained in the process is avoided.

With these and other objects in view, the invention consists in the process described in The various features of the invention are.

illustrated in the accompanying drawings in which:

Fig. 1 is a vertical section, taken on line 11 of Fig. 2, of an oil cracking furnace and control house embodying the preferred form. of an apparatus for carrying on the process;

, Fig. 2 is an elevation partly in section on line 22 of Fig. 1, and partly in a section through the control house of the oil cracking apparatus, and

Fig. 3is plan view partly in section on line 33, of Fig. l.

In the present invention the hydrocarbon oil to be treated is supplied at a regulated rate to a number of uniformly heated cracking coils. Beforeentering the coils, the oil is mixed with steam and passes with "the steam into the heated portion of the coils. The oil is rapidly vaporized upon entering the coils and the mixture of steam and oil vapors is heated to a temperature at which the cracking reaction takes place. Throughout its further passage through the heated coils, the steam and oil mixture is maintained uniformly at this cracking temperature until a substantial portion of the oil is cracked to form a product containing volatile hydrocarbon liquids suitable for use as a motor fluid.- A uniform cracking temperature throughout the length of the coils is obtained by maintaining a furnace for heating at a substantially uniform rate. The steam and cracked vapors leaving the coils are immediately chilled, by direct contact with jets of water, or other suitable fluid, to a temperadensed' in a suitable condenser.

ture -at which thecracking reaction ceases, 'and the chilled vapors are thereafter con- Referring more specifically to the accomplied through an oil supply pipe 10 to a pump 12, and is forced by the pump through a delivery pipe 14, to a distributing header 16,.

anying drawings, oil to be treated is sup}.

From the distribution header 16, the oil is distributed to a number of pipes 18, corresponding in number to the coils in which the oil is to be heated. The pressure and rate of supply of the oil through each of the pipes 18, are measured by means of pressure gauges 19 and oil meters 20, and the rate of supply of the oil is regulated and kept constant by means of valves 22, in the pipes 18. The oil passes from the meters 20, through pipes 2% to mixing nozzles 26, in which it is mixed with steam before entering the cracking coils. Steam for mixing with the oil in the mixing nozzles 26 is supplied from a steam header 30 through a number of supply pipes 32. The rate of supply of steam is controlled by means of valves 34 in the pipes 32, and the pressure is measured by means of a pressure gauge 36. Satisfactory results are obtained when the ressure in the steam header is approximate y 125 pounds per square inch, and the pressure of the oil approximately 110 pounds per square inch. The quantity of steam supplied should, under these conditions, be approximately fifteen per cent of the quantity of oil supplied.

From the mixlng nozzles 26, the mixture of steam and oil passes through connecting pipes 38 to the inlet ends of a number of heatmg or cracking coils of seamless steel tubing sus ended in a furnace 42.. Wrought iron tu ing may be used in place of steel tubin but in this case the seams of the tubing s ould be welded together electrically, or fused together by means of a thermite mixture or blow pipe or other means by which a. substantially uniform, homogeneous structure is obtained throughout all portions of the wall of the tube. A properly constructed wrought iron tube of this type may be used without danger of the seams of the tube opening and appears to have the advantage that the wrought iron tends to increase the quantity of oil which may be cracked in a coil of a given length. Upon entering the furnace the oil is vaporized and the steam and oil va ors are raised to a temperature at which t e heavy hydrocarbons of the oil break down or crack to form a substantial drocarbons. It is very desirable to have the oil pass through the coils at a very high rate of speed since this, together with the steam, serves to prevent any carbon or tarry matters from settling out of the flowing fluids and from sticking to the sides of the heating coil. Very good results are obtained in cracking gas oil, for instance, when a pipe of two inches in diameter and four hundred feet in length is employed, and when the oil dinarily maintained slightly below 1100 F After the oil has been heated and maintamed at the proper cracking temperature for a length of time sufficient to form the desired products, it is immediately removed from the coil and chilled to check the further rapid cracking of the hydrocarbons. For this purpose the steam and oil vapors from the coils 40 pass through short connecting pipes 44 into cooling drums 45, one drum being provided for each coil. \Vatcr or other suitable cooling liquid is injected into the drums 45 through supply ipes 46, and comes nto direct contact with t 1e hot cracked vapors. The wateris thereupon rapidly vaporized, absorbing a large amount of heat from the cracked vapors, and chills the vapors to a temperature at which further cracking of the vapors does not take place to an appreciable extent.

A hydrocarbon distillate may be used as a chilling liquid if it is substantially free from heavy tarry materials and upon vaporizing chills the hot vapors to the desired temperatures. When a distillate to be cracked contains a. quantity of light hydrocarbons it is advantageous to use such distillate asa cooling liquid, thereby removing the light vagors from the distillate before passing the istillate through the cracking coils. When using a. hydrocarbon liquid or distillate, however,'a larger quantity is required than when water is used. The amount used should be sufficient to reduce the temperature of the vapors to a point at which, a substantial cracking of the distillate does not take place. The distillate may be admitted to the inlet pipe 46 through a branch pipe 47 Fig. 1, leading from a distillate storage tank or other source of supply.

In the normal operation of the process there is no accumulation of liquid in the cooling drums, the water being completely vaporized, and any heavy oils cooled below their boiling points being carried out of the drums. From the cooling drums the steam and vapors pass through outlet pipes 48 to a collecting header 50 into which the vapors from all of the drums are delivered. From the header 50 the vapors pass through an outlet ipe 51 and a pressure release valve 52 to con ensers.

The heating coils 40 are heated in the furnace 42 to a. substantially uniform temperature throughout their entire length by a substantially uniformcombustion offuel in the lower part of the furnace and a uniform distribution of the heat of combustion throughout the portion of the furnace in which the coils are suspended. To this end a supply of coal or other fuel is fed from a feeding hopper 54to a traveling chain grate 56 exten i 11 through a combustion chamber 58 below .the coils 40 in the furnace 42. The coal is uniformly distributed oh the chain grate 56 by means of a regulating gate 60 or other suitable distributing means at the feed end of the grate. The grate 56 ispositioned a sufficient distance below the coils 40 to permit the complete combustion of the coal and of gases produced during combustion before the products of combustion come into contact with the coils.

Since the fresh fuel ordinarily has a longer flame than the partly coked and partly burned fuel, particularly when bituminous or soft coal is used, the grate 56 is inclined upwardly toward its discharge end to give a longer path to the long flame portions of the fuel. The exact dimensions of the furnace will, of course, vary with difierent operating conditions and different types of fuel, but with ordinary coal a distance of from six to seven'feet from the bed of coal to the bottom of the coils has been found satisfactory.

By thus completing combustion before the hot gases are brought into contact with the heating coils, local overheating of the COllS due to irregularities in'the combustion of the fuel is avoided and the hot products of combustion are brought to a uniform high temperature before coming in contact with the coils. The tendency towards the formation of deposits of soot on the heating coils is also lessened by this method of heating. The hot products of combustion formed in the combustion chamber 58 pass upwardly through a heating chamber 62 inwhi'ch the coils 40 are suspended and leave the heating chamber through a number-of openings 64 connecting the chambers 62 with an exhaust flue 66.

The air for supporting combustion is supplied to the grate'in such a manner as to maintain a substantially constant temperature throughout the products of combustion flowing upwardly past the cracking coils. To

this end the air for supporting combustion is forced by means of a fan 68, Figs. 1 and 2,to a wind box or air supply conduit 7 0,,ex-

' tending through the furnace at one side of,

' and a little below, the upper part of the chainv grate. From the wind box air, -is supplied through a number of openings 7 2, lead ing from the 'wind box to a number of airdistributing troughs 74 extending across the furnace adj acent each other and opening upwardly under the upper part of the grate 56. The amount of air supplied to each off-the distributing troughs 74 is controlled by means of'a damper 76 partlyqclosing the burner 79 near the discharge end to. maintain a constant temperature if the coal tends to burn out before reaching the discharge end of the grate.

The temperature of the hot products of combustion entering the heating chamber 62 is measured by a number of pyrometers 80 of the thermo electric couple, or other suitable type, positioned in the lower part of the heating chamber 62. The pyrometers 80 are connected by means of connecting wires 82 to a switch board-84 and galvanometer 86 positioned in a control house 88, Fig. 1. Each of the pyrometers 80 may be separately connected with the galvanometer through switches 90 on the switch board 84, Fig. 2, and the temperature at any portion of the furnace may be determined in this manner.

The temperature of the hot products of combustion in the upper part of the heating chamber 62 is measured by means of a number of pyrometers 92 spaced at intervals throughout the length of the furnace and connected by wires 94 to the switch board 84 and galvanometer 86. By means of this pyromet'er arrangement an accurate measurement of the temperature throughout the furnacev may be obtained at all times and the air supply to the fuel in the combustion chamber 58 may-be adjusted in connection with these measurements to obtain the proper temperature condition in the furnace.

The maintenance of the proper temperaturedistribution in the furnace is controlled by means of a-numberof dampers 96 controlling the outlet openings 64 and adjustable by meansof supporting rods 98 extending through the roof of the furnace. By means of damper controls, the volume of hot products Ofcombustion passing through any part of the furnace and the distribution of the. combustion gases may be controlled to regulate the temperatures throughout the heating chamber 62. z i

In cracking a gas oil at a: temperature somewhat below 1100 F. for instance, the tem perature of lower part of the heating chamthe temperature in the upper part of the'furf st nace surrounding the cracking portion of the coils and adjacent the outlet-openings 64 is slightly lower. The above temperatures f which are, of course, merely iven by way of example, areordinarily obtained after the I process has been operated for some time and conditions within the furnace have been stabilized.

An accurate measure of the temperature of 105. The determined temperature of the ases leaving the heating coil is maintained y adjusting the supply of steam and oil by means of the valves 22 and 34 respectivel until the proper temperature is obtaine 95 The length of coil '40 will have been adjusted so that when the temperatures of the furnace and of the cracked vapors are maintained at the )roper points, the oil is subjected to the cracking conditions for a length of time sufiicient to transform a determined portion of the heavy oils into light hydrocarbons suitable for use as gasoline or motor fluid. The

temperatures maintained in the cooling drums 45 are alsojmeasured by means of pyrometers 106 and are regulated by controlling the supply of water or other liquid injected. A portion of the cracked products may be withdrawn from the pipes 44 through test cocks 107 adjacent the header 46 and an accurate control of the process thereby maintained.

-The pressure in the pipe 51 is also determined by means of a pressure gauge 108connectcd to the pipe through a connecting pipe 110. The pressure in the treating apparatus is controlled from the control house by means of a valve spindle 112 connected to the valve 52 so that the pressure may be regulated in connection with the pressure gauge 108. The

pressure at the outlet end of the coils may be adjusted to the type of oil being treated and other conditions of operation, but is ordinarily somewhat less than 100 pounds per square inch.

Owing to the high temperatures maintained in the furnace, the heating coils 46 may gradually deteriorate after a long continued peri-' 0d of use, and may burn through or burst under the pressure of the stream of steam and oil. When this occurs, or when it is believed that any coil has been weakened suflicientl to justify its removal and replacement, it is drawn upwardly out of the furnace by means of a traveling hoist. To permit the easy removal and replacement of the coils, the coils are ,connected to the inlet and outlet pipes 38- end 44 respectively by means of flan e unions 114 end 116 connectin the coils to t e pipes 38 and 44 respective y. When the ange unions are disconnected the coil may be lifted directly out of the furnace b lifting the supporting means for the coil. This supporting device comprises an I-beam 117 supported a short distance above the furnace on transverse E-beams 118 and 120 at the front and rear of the furnace respectively. The coils are supported from the I-beam 117 by means of a number of hangers 121, which encircle the I-beam and extend downwardly around the individual heating coils. Another set of hangers 122 also extend downwardly from the I-beam 117 and engage rods 124 extending the length of the furnace. Upon each rod there is strung a series of fire resistant blocks 126. There is one rod 124 for each set of coils 40 and the series of blocks 126 are of such awidth that when all of the coils and suspending means are in lace the blocks form a continuous roof or the furnace. When the flange unions 114 and 116 are disconnected and a coil is to be removed from the'furnace, the supporting I-beam 117 is lifted by means of hooks 128 supported from pulley 136 and with the I-beam 117 a corresponding section of roof blocks 126 and a coil 40 is lifted upwardly out of the furnace.

The coil and its supporting beam and corresponding roof section are then moved toone side of the furnace by means of a trolley 132, which supports the pulley 130 and which is itself supported by asuperstructure 134, which extends outwardly to one side of the furnace. To prevent the rapid deterioration of the supporting hangers 120, a narrow arch 136 is constructed beneath each set of han ers and protects the bottom of the hanger rom direct radiation from the fuel bed on the grate 56. The side of the furnace is also protected from rapid deterioration by direct contact with the glowing fuel by means of a water cooled clinker plate 138 adjacent the grate 56 and extending above it approximatel or a little greater than the depth of the fuel (1.

A small quantity of ash may sift downwardly from the grate 56 into the air distributing trough 74. This ash may be removed by means of a jet of steam admitted through a steam pipe 140 and directed adjacent the bottom of the arches to blow the ashes into a chute 142 extending downwardly into a drip channel 144. The condition of the troughs may be inspected by means of doors 146. 1

Owin to the protective action of the steam preventing any particles of oil or decomposition products from contacting with and sticking to the wall of the heating coil, every portion ofthe oil passes at a uniform rate through the coil and receives the same heat treatment. This action, coupled with the aesaeea uniform heating oi the coil prevents a scorcha very light color, being free from ill smelling compounds or anything which would require that the product be subjected to the usual chemical treatment to remove impurim ties. As a result, a product suitable for use as a motor fluid without further purification is obtained upon fractionally condensing and removing the heavier oils resulting from the reaction and subsequently condensing the l ght vapors. This product may of course be purified in the usual manner to produce a water white product if desired. A considerable saving of the light hydrocarbons is obtained when the product is used directly without a purification treatment and the lightest most volatile portions and other valuable constituents which are usually lost in the agitators are retained and add materially to the value of the product. Owing to the absence of scorching and to the uniform heat treatment, it has been found that when sulphur containing oils are treated by this process, the sulphur in the oil is transformed to hydrogen sulphide or other sulphur compounds which do not contaminate the lighter hydrocarbons produced. The hydrogen sulphide or other sulphur compounds pass off with the waste or residue products and leave a pleasant smelling motor fuel which can be used d rectlywithout further purification.

The motor fluid produced in the present process may be distinguished from the ordinary types of natural or of cracked gasolenes by its pleasant odor, its slight yellow color,

and the presence of substances ordinarily removed by treatment withsulphuric acid and alkali such as light hydrocarbons corresponding to casing head gasoline but produced as a result of cracking and accordingly conhydrocarbons. This motor fluid, therefore, has a greater density within the desired boiling point and correspondingly greater fuel or power value. The heavier fractions of the cracked products may be re-run through the cracking operation to produce additional quantities of light hydrocarbons or may be disposed of as a fuel o l or treated to produce. other products.

While the abovb process'has'fbeen specifically described as utilizing the steam for preventing scorching ofthe oil and diluting the hydrocarbon vapors, it is, of course, obs.

, vious that other agents having similar characteris'tics and properties could be substituted for steam for producing equivalent results in the final product.

This application is a division of my prior application Serial No. 402,381, filed August 9,

taining an amount of unsaturated orolefinev ll claim:

1. The method of treating heavy hydrocarbon oils for the production of light hydrocarbons suitable for use for motor fuel, which comprises forcing the 'oil rapidly through a long heatingconduit and heating the oil therein to atemperatu-re around 1100 F. or higher to efiect conversion of a substantial portion of the oil into lighter hydrocarbons suitable for use as motor fuel, immediately 35 cooling thecracked products to a temperature at which cracking ceases by direct contact with hydrocarbon oil containing light hydrocarbons to effect vaporization thereof simultaneously With the cooling of the cracked product and further cooling the vapors of the light hydrocarbons formed by the cracking reaction and vapors of the light hydrocarbons liberated from the cooling medium to condense them, v

2. The method of removing low boiling constituents from heavy hydrocarbon oils before subjecti the oilsto cracking,which comprises crac ing oil by bausing'it to'flow rapidly through a longheating conduit and heating the same therein to a temperature around 1100 F. to efiect conversion of a substantial portion of heavy hydrocarbons into lighter hydrocarbons suitable for use as motor fuel and immediately bringing the resulting cracked product into direct and intimate contact with the hydrocarbon oil from which the light constituents are to be removed to elfect rapid cooling oi the cracked product below the temperature at Which the 109 cracking reaction ceases and further cooling vapors resulting from the preceding cracking and cooling operations to condenseadmixed constituents from the cracking operation and from the preheating and distillation of the oil which is to be subjected to cracking. 3. The method of treating heavy hydrocarbon oils to produce light hydrocarbons suitable for use as motor fuel which coml -f0 prises subjecting; the heavy hydrocarbon oil to vaporization andvapor phase-cracking bycausing it. to flow through a long heating conduit and heating-it therein to a temperature at which rapid cracking-of the oil takes place until a substantial portion of the oil is cracked to form products suitable formotor fuel, rcgulatingthe cracking operation to substantially prevent carbon deposit in the heating conduit and immediately chilling the cracked vapors by bringing them into direct and intimate contact with liquid hydrocarbon oils in proportionssuchthat a considerable part of the liquid hydrocarbon is vaporized while the cracked product is rapidly cooled to a temperature at which the cracking reaction ceases, and subjecting the resulting admixed vapors from the cracking o eration and from the vaporization of the liquid oil to cooling to condenses. mixed oil product therefrom.

4. The'method of treating heavy hydrocarbon oils to roduce light hydrocarbons therefrom suita ble for use asmotor fuel which comprises passing the oil rapidly through a long heating conduit and heating the oil therein to a temperature around 1100 F. or higher to efiect conversion of a substantial portion of the heavy oil into a product suitable for motor fuel without substantial formation and deposit of carbon in the'heating conduit, and immediately chilling the cracked product to a temperature at which the cracking reaction ceases by bringing into direct and intimate contact therewith a liquid hydrocarbon in proportions to effect distillation of a large part of the hydrocarbon, and cooling admixed distillate vaporsand vapors resulting from the cracking operation to separate a composite condensate therefrom.

5. The method of treating heavy hydrocarbon oils to produce light hydrocarbons suithydrocarbons able for use as motor fuel which comprises subjecting the oil to cracking by causing the same to flow rapidly through a long heat- 7 ing conduit and heating the same therein to a temperature around 1100 F. or higher until a substantial portion of the oil is converted into light constituents suitable for use as motor fuel, avoiding prolonged heating and overheating of the cracked product and any substantial carbon deposit in the heating conduit and immediately chilling the cracked products leaving the heating conduit by direct contact with hydrocarbon'oil to a temperature at which the cracking reaction ceases.

6. The method of cracking heavy hydrocarbon oils to produce light-hydrocarbon suitable for use asmotor fuel which comprises causing the oil to flow rapidly through a heating conduit and heating the oil therein to a high cracking temperature to effect rapid cracking of a substantial portion of the heavy oil to produce light oil suitable for use as r motor fuel, and immediately chilling the cracked products to a temperature below that atwhichthe cracking reaction ceasesbybringing the same into direct and intimate contact with oil to be cracked and which contains light hydrocarbons, thereby removing the light hydrocarbons from the oil to be cracked and condensing the same in admixture with light generated during the cracking operation.

In testimony whereof I afiix my signature.

CHARLES J. GREENSTREET.

1,ese,oes

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