US1900057A - Process for treating an oil-gas - Google Patents

Description

March 7, 1933.

A. E. HARNSBERGER PROCESS FOR TREATING AN QIL GAS Filed May 8, 1929 v KMR a W mu 6 e w m y a E k a a W u A a mm n 35v QZJQQ ||U LLLLLLLLL mqml .EMEEM .N. Q T Ekmmmq $23000 IL 3 Patented Mar. 7, '1933 I UNITED STATES PATENT OFFICE E. HARNSBERGER, OF CHICAGO, ILLINOIS, ASSIGNOB TO THE ZEURE OII:

COMPANY, OF CHICAGO, ILLINOIS,A CORPORATION OF, OHIO Y "TREISSUED JUN 2 5 1940 AUDLEYL PROCESS FOR TREATING OIIi -G AS Application filed May 8,

This invention relates to the pyrogenesis of hydrocarbons and, with respect to its more specific aspects, the invention has for an object the provision of a system ada ted for the 6 cracking of hydrocarbon gases or the purpose of producing from such gases liquid hydrocarbons having substantia ly the boiling range of gasoline or analogous hydrocarbon motor fuels.

Another object of the invention resides in a system for effecting the molecular'decomposition of hydrocarbons wh rein the charging stock consists of the so-called permanent gas, suchas is commonly made in oil cracking processes.

In the operation of cracking hydrocarbons it is customary to employ a charging stock heavier than gasoline, Such a charging stock, for example, may be a gas-oil fraction 2 having a gravity range between and B. When such a fraction is assed throu h a heated crackin zone and subgected to crac ing reactions, t ree products are obtained, namely, a fuel oil fraction that isheavier 25 than the original charging stock and possessing usually a gravity of between 10 and 12 B.; second, a gasoline or motor fuel, fraction that is lighter than theoriginal char ing stock and which may possess a gravity 0 approximately 56 B.; and, third, 'a so-called permanent gas fraction that is somewhat lighter than the gasoline or motor fuel fraction., The gas fraction is generally produced at a pressure varying from one pound to pounds or higher and, under customary methods of procedure, is compressed to a higher pressure and cooled in order to 'condense out certain valuable liquefiable fractions which fall into the so-called casing 0 head series of gasoline. This condensate normally is very wild or volatile and is therefore stabilized under pressure to reduce somewhatits volatility and then blended with gasoline or other motor fuel fractions.- This operation generally removes the greater part of the isohutane content from the permanent While this method effects a reduction in the quantity of permanent gas produced from a given cracking operation neverthe- 1929. Serial no. 861,447.

less, a very considerable quantity of such gas is formed in relation to the total quantity of condensate obtained from" a particular charging stock as a motor-fuel, and it is therefore an outstanding object ofthe present invention to provide a'system for treating the socalledpermanent gas for the urpose of more effectively securing through ecomposition or polymerization reactions the, total liquefiable content of the hydrocarbons under treatment. I

In accordance with the present invention, permanent gas obtained from acracking operation is passed through a-heating zone in order \to crack or polymerize the gas into two fractions, one a fraction heavier than the gas,

which is partly liquid under ordinary temperatures, and the second a lightgr permanent gas- For instance, if the chargmg materials should comprise a gas having a specific gravity of one, this stock upon cracking will pro-.

duce a condensate having the approximate boiling range of gasoline, and at the same time make a lighter permanent gas having a specific gravity of,-for example, between .55 and .65.

Thus the present invention provides a system for the treatmentof fixed gases, obtained from cracking stills, wherein the fixed gases are passed under pressure through a heating zone. and while in said zone subjected to temperatures sufficiently high to effect molecular reactions which produce a liquefiable fraction and a light gas fraction, the liquefiable fraction being suitable for use as a motor fuel.

For a further understanding of the inven tion reference is'to be had to the following description and the accompanying drawing wherein:

Figure 1 is a view disclosing diagrammatically the apparatus used in carrying out the features of .the present invention, and

Fi ure 2 is a horizontal sectional view 0n the ine 22 of Figure 1.

Referring more particularly to the draw-- ing, a source of oil gas is shown which in this instance consists of a vessel 1 in which is received the so-called fixed or perma 9 the/ tubes 19 the charging stock passes into a the accumulator 5 and the obtain on the gas, and this pressure may vary between 1 and 150 pounds, depending upon the particular kind of cracking system m conjunction with which the present invention is used. This gas is passed by a line 2 to a compressor 3 in which the gas is compressed to a pressure of approximately 175 pounds for square inch. From the outlet Within the stabilizer the more volatile frac-' tions are removed from the liquid condensate, the said volatile or vaporous fractions passing off from the stabilizer by way of a pipe line 8, while the liquid condensate, which accumulates in the bottom of the stabilizer, is removed by way ofa pipe line 9 to a storage vessel. Reflux oil may be introduced into the upper portion of the stabilizer by a branch line 10 connected with the pipe line 6. All of these lines may be provided with suitable valves for governing fluid flow therethrough.

The 'gas, which is released from the to s of stabilizer is conducted by way of a pipe line 11 to a heating and cracking coil 12 located, in this instance, above the bridge wall 13 of a furnace 14. This furnace is formed to include the customary setting which is divided internally by the bridge wall 13 into combustion and tube chambers 15 and 16frespectively. burner 17 is located in the bottom of the combustion chamber 15 and preferably a similar burner 18 is located in the to of the furnace to more effectivelyheat, i necessary, the coil 12. 'This cracking coil preferably consists of approximately five lengths of chrome-nickel tubing, which alloy possesses characteristics that will enable the tubing to operate indefinitely at the operating pressure employed up to tube wall temperatures of 1500 F. I

Also arranged in the furnace are tubes 19 through which the original charging stock is passed. While traveling throug 19 in vaporous form the chargmg stock is preferably heated to a temperature varying between 1000 F. and 1250 F. and thereby subjected to molecular decomposition. From fractionating' column 20, the liquid condensate beingf'removed from the b ttom of the column 20 by way of the outlet 21, while the vaporous fraction passes overhead and thence through a condenser 22 and finally to a' gas separator 23, the liquids being removed from the bottom of the separator while the gases pass firom the'top of the separator through apipeline 24 to the vessel 1. This permits the gases developed by the cracking reach the tubes tions which take place in the tubes 19 to be employed as a charging stock for the coil 12.

At the end of the first pass of tubes comprising the coil 12, I may introduce a small amount of steam into the gas cracking coil, as indicated at 25. At this point the temperature of the gas passing through the coil 12 will be above the condensing temperature of the steam within the pressure range specified. Steam need not be supplied to the coil 12 continuously but may be introduced periodically in order to remove coke deposits within the tubes 12. It is also possible to introduce steam and a small amount of air into the coil 12 to burn out carbon deposits. At such times the exit of the coil 12 is piped to a safe point in the atmosphere by means of the pipe lines and valves disclosed. Also, one or moreof the tubes comprising the coil 12 may contain cores of catalytic materials, such as iron oxide or nickel.

The'gases passing through the coil 12 are usually heated to a temperature of approximately 1300 to 1400 F., but these values may be varied somewhat in order to secure desired results. Following passage through the cracking zone formed by the coil 12 the vapors are then conducted by means of the pipe line 26 to an arrester 27 wherein the temperature of the vapors is suddenly reduced to below 600 F. by means of a cooling fluid, such as water or oil or gas introduced in spray or finely divided form into the 'arrester and into intimate contact with the heated vapors by means of a pipeline 28 provided with nozzles A 29. The nozzles 29 spray-the cold oil or other cooling liquid into intimate physical contact with the heated oil vapor obtained from the cracking coil 12, shock-chilling said vapors to arrest further cracking reactions. Control of the time of the reaction can be obtained by introducing the fluid at any one of several points within the arrester by the manipulation of the valves 30 governing the flow of the cooling fluid to the nozzles 29. Final cooling may be provided by an ordinary cooling coil 31 using water or, in certain instances, the cooling coil 31 may be resorted to for effecting completely the arresting of the conversion reactions of the vapors discharged from the coil12, along with final cooling to atmospheric temperature.

The liquid and gas are then introduced into a stabilizing column or fractionating tower '32 at any convenient point, and the condensate rectified to proper specifications and drained from the bottom of the tower through a line 33, whence it is conducted to a storage tank 34 as a motor fuel condensate. In the bottom '1 cated a cooling coil 36, using cold water or some other cooling medium for the purpose ofcontrolling the outlet temperature of the I preferably this which latter, in many cases,

gases or vapors issuing from the top of the stabilizer. Pressure on the entire system is controlled by a back pressure regulator 37' located in the outlet 38 of the stabilizer, an

' 10 utilization as-a fuel, or may be conducted to other suitable points of storage. The fluid reboiled by the coil 35 may be cooled by a cooler 40, gassed through a separator 41 and then led y way of a line 42 to storage.

that the present invention provides a system for cracking or treatin converter gas for the purpose of obtaining rom such gas or other pressure-cracking operation a maximum quantity of its liquefiable constituents. I am aware of the factthat it is customary to compress converted ases of this type to .secure as far as possib e the liquid content, but it will be observed that the present invention oes beyond this customary step by passing t e gases, which remain after compression, to a highly heated cracking still, whereby such gases are subjected to violent vmolecu ar reactions to produce chemically (either cracking or polymerization) liquefiable compounds suitable as motor fuels. The invention has particular application to vapor phase methods ofcracking oils, in which sysxed gas are -liber-" ated. Through the employment of the prestems large quantities of ent invention a ver large percentage of this fixed gas is trans erred into liquid hydrocarbons which have amuch hi her commercial value than the gaseous are used merely 'for fuel purposes at the refinery.

The stabilizer 7 may be provided with reboiling and refluxing coils to correspond with those provided in the second" stabilizing column 32. Preferably, a sediment trap is disposed in the pipe line between the conversion arrester 27 and the cooling coil 31 to act as a tra for the collection of sediment, such as car on or coke formed in the cooling of the converted oils. .The cooling fluid used in the arrester may be in the form of-a cool gas obtained from any suitable source, xrather than a liquid, the gaseous cooling medium being utilized in some instances for the purpose of reducingcarbon formation.

.What is claimed is:

1. The method pf converting hydrocarbons, which consists in assing Va orized hydrocarbons of high boihng range t rougha heated converting zone possessing relativelyhigh and low temperature regions, heating said hydrocarbons during their passage through said zone to desired converting temperatures to effect molecular decomposition of such hydrocarbons while in the vapor regulator is set to maintaina pressure of approximately 150 pounds per.

to produce therefrom reaction In view of the fore oing it will be seenydrocarbons,

phase and at temperatures of the order of 1000 F. into hydrocarbons oflower boilingthe lighter 4 gases to converting temperatures requisite roducts consisting of compounds of higher oiling range than said gases and accompanying quantities of lighter gases, separating said lighter gases from the high boiling compounds, and separately collecting and condensing the high boilingcompounds.

range hydrocarbons in a vaporized state througha heated converting zone possessing 2. The method of converting hydrocarrelatively high and low temperature regions,

heating said vaporized hydr ocarbons during their passage through said zone to a converting temperature of the order of 1000 F., re-

moving the convertedhydrocarbons from said zone and" separating the high and low boiling fractions thereof, separating from the hydrocarbons comprising said lighter fractions the incondensible gases formed in the converting zone, returning a portion, at least, of said gases for passage through the high temperature region only of said converting zone without commingling said gases with the higher boiling hydrocarbons passing through said zone and under increased pressure, whereby to subject said gases to converting temperatures of the order of 1300 F. and pressures of the order of 150 pounds per square inch to produce therefrom reaction products consisting of compounds ofhigher boiling range than said gases and accompanying quantities of lighter gases, separating said lighter gases from the high boiling compounds, and separately collect-in and condensing the high boiling compoun s.

3. The method as specified in claim 1 in connection with the step of introducing super-heated steam into the gases passing through the high temperature region of the converting zone.

4. The method as specified in claim 1 in connection with the step of shock chilling the products formed by the passage of the ases converting zone to sharply arrest conversion reactions in said products immediately upon their discharge from saidzone. Y g

5. The method as defined in claim 2 in combination with the step of maintaining the gases during their passage through the high temperature region of the converting zone in contact with a metallic catalyst.

' 6. The method of converting hydrocar bons,' which consists in passing "a confined moving stream of high boiling range hydrocarbons through a heated converting zone, 5 heating said zone to produce therein relatively high andlow temperature regions, controlling the application of heat to the hydrocarbons during their passage through said zone to raise the same to converting temperatures 0 varying between 1000 F. and 1200 F. while said hydrocarbons are maintained in a vaporized" condition, removing the converted hydrocarbons from said zone and condensing the lighter compounds thereof to remove from said compounds incondensible gases formed in the convertin zone, returning a portion,'at least, of sai gases for passage through the high temperature region only of the aforesaid converting zone without commingling said gases with the high boilin hydrocarbons initially passing through said zone, heating said gases during their passage through the high temperature region of the converting zone to converting temperatures of the order of approximately 1300 to 1400 F. while maintaining the gases under a pressure of several atmospheres, whereby to produce from said gases hydrocarbon coinpounds having substantially the boiling range of ordinary.v gasoline, and separatel collecting andicondensing the said latter hig boiling compounds.

In testimony whereof liafix my signature.

AUDLEY E. HARNSBE RGER.

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