US1967269A - Process of treating hydrocarbons - Google Patents

Description

July 24, 1934. H. 'M. SMITH Er AL 1,957,269

PROCESS OF TREATING HYDROCARBONS I Filed Aug. 19. 1932 'INVENTORS WWW mm flwa m @WEQQ- ATTORNEY Patented July 24, 1934 UNITED STATES 1,967,269 PROCESS OF TREATING HYDROCARBONS" Harold M. Smith, Peter Grandone, and Harry T.

Rail, Bartlesville, Okla.

Application August 19, 1932, Serial No. 629,734 21 Claims. (01. 196-10) (Granted under the act of amended April 30, 1928;

This invention described herein may be manufactured and used by or for the Government for Goyernmentalpurposes, without the payment to us of any royalty thereon,

This invention relates to improvements in processes for the thermal-decomposition of gaseous hydrocarbons such as occur in natural gas and the like. a

One object of this invention is to provide an industrially feasible process for converting gaseous paraflin hydrocarbons, typified by methane, ethane, butane, propane and isobutane, either collectively or separately into products valuable as .component motor fuels, solvents and organic intermediates.

Another object of this invention is to provide a process by which the large volume of'unsaturated-aliphatic gases such as ethylene, propyleneand acetylene heretofore to a large extent wasted in the thermal-decomposition of nat-' ural gases is almost completely converted to light oils and tars.

Another object of this invention is to provide a process wherein not only the amount of poly.-

merization but also its course is restricted so that the ratio of carbon to hydrogen in the compounds comprising the tars' islimited to a ratio of 1.4 or less.

Another object of this invention resides in the provision of a process wherein the gaseous hydrocarbons in the hydrogenizing chamber are subjected to such conditions that only hydrogenated derivatives of the hydrocarbons are formed. g

Another object of this invention resides in the provisionof a method for the thermal-decomposition of gaseous paraflin hydrocarbons wherein the polynuclear compounds are split up and hydrogenated to formhydrocarbons with. only one aromatic or benzene ring.

Another object of this invention is to provide a process by means ojf which gaseous hydrocarbon= or two or more. iiarbon atoms are separated andlzused to enrichthe raw intake gas, either immediately previous to or after cracking.

With the foregoing objects outlined and with other objects in view, which will appear as the description proceeds, this invention consists in the novel features to be hereinafter described in detail and moreparticularly pointed out in the appended claims. I A

= Briefly stated, this invention consists in treating gaseous paraflin hydrocarbons typified by methane, ethane, butane, propane and isolTutane with a diluent in the nature or an inert gas such March 3, 1883, as 3700., G. 757) as nitrogen, heating said gases under pressure to a temperature just sufficient to break the carbon-to-carbon or carbonhydrog'en bonds and with a sufiicient velocity of the gas stream so that no secondary reactions occur in the reaction tube, directing the gaseous mixture immediately into an unheated polymerizing chamber, passing the The early development of new oil fields is usually accompanied by large quantities of natural gas and consequently the coincident production of this gas, rich in commercially valuable compounds, will continue as long as present day production methods are resorted to. At the present time vast quantities of this gas are wasted by being blown into the air.

Research workers have accomplished a great deal in their efforts to overcome this loss by developing processes for converting the gaseous constituents of the natural gas into commercially valuable substances such fuel, wash oil, solvents and the like, but up to the present time their objective has not been fully realized. This failure may be partially attributable to a lack of full regard for such factors is temperature, gas velocity, effect of pre-heating, size, heat conductivity and composition of the reaction tube, temperature effects on the cracking gas, and type streamline or turbulent, vailing methods for the,

of flow, that is to say, all of which, in-the pretreatment of natural gas,

as anti-knock motor unquestionably contribute to the production of undesirable hydrocarbons, usually classified as tars and the waste of large volumes ofunsaturated aliphatic gases, such as ethylene, propylene and acetylene. a

It is therefore the aim and purpose of this invention to provide a simple, inexpensive process which will overcome these defects, afford a more diversified utilization of hydrocarbon gases, especially natural gas, and effect a commercially practical process which will oil yield.

Coming now to a. more detailed discussion of the application of the process under consideration, the gaseous mixture to be processed, which may be natural gas, pressure still gases, oil gases, etc., preliminary to its passage to the cracking materially increase light gen. Experiments have shown that .dilution with nitrogen up, to 20 or 25 percent does not effect the desired yields of unsaturated hydrocarbon for light oils, but does decrease the amount and improve the character-of the tar formed, thus nitrogen as a diluent has a two-fold effect in that it serves not only to restrict the amount of polymerization but also the course of said polymerization so that the ratio of carbon to hydrogen in the compounds comprising tar is much smaller. The carbon to hydrogen ratio being about 1.4 or less.

After dilution with nitrogen the raw gaseous mixture is directed to a reaction tube where the incoming gases diluted with nitrogen are heated as rapidly as possible to a temperature sufficient to crack the hydrocarbon molecules and form fragments or free radicals- This is best carried out at temperatures ranging between 700 and 1200 C. and with the gases flowing through the reaction tube with sufficient velocity and turbulence to avoid formation of light oils. Experiments have shown that with a gas of the following composition, methane 65.8%, ethane 3.7%, propane 1.9%, butane 1.0%, pentane and higher 0.4%, nitrogen and inerts 27.2%, the relation between temperature and contact time for the maximum production of unsaturated hydrocarbons is approximately given by the following equation:

L0g1uT=3.016 4=-.0484- 0 where T is the temperature in degrees centigrade and 0 is the contact time in seconds. That contact time is of course inversely proportional to the rate of gas flow or velocity. Thisequation holds very well at atmospheric pressure, and experiments at pressures of six atmospheres do not indicate much deviation. It is obvious that every gas whose composition differs much from the example given will require a different equation, but the relation indicates very well the dependence of results upon the regulation of the gas velocity and temperature. The necessity for exact control of the gas velocity is also well illustrated by the following table showing the per cent ethylene obtained from the same gas mentioned above at 900 C. and atmospheric pressure, when the contact times are changed:

A similar relation will obtain under pressure, but, due to the reversibility of the reaction whereby ethylene is formed, higher temperatures are necessary to attain the same equilibrium point.

During this step the nitrogen diluent assists in preventing the start of secondary reactions in the hot tube.

At this point it might be well to state that as a cracking tube, any alloy or refractory material or combination of these which can be used at high temperatures and pressures up to 100 pounds per square inch may be employed, provided that a large surface of iron or nickel is avoided. The reaction tube may be heated externally by electricity or by any other suitable means, but pref- 1,967,269 tube is diluted with an inert gas preferably nitroerably bythe residue gas from the process. The hot gases now in a state of disintegrationare next directed'into a thermally insulated polymerizing chamber, preferably of the same material as the cracking tube, but of such dimensional 8 relation to the cracking tube that the velocity of the gas stream is materially decreased. During this polymerization stage ofthe process, adequate and efiicient heat control is very essential due to the exothermic character of the reaction, in order that the polymerization may be held within definite limits. This control is obtained by employing the available heat of the incoming gases, the exothermic heat of the polymerizing reactions, and the cooling effect of the raw gases which for this purpose may be by-passed from the source of supply through the polymerization chamber. These factors will serve to maintain the heat equilibrium desired, preferably between 500 and 700 C.

The nitrogen diluent is particularly advantageous in this part of the process by providing heat by convection, for the reaction and by its favorable action in restricting the polymerization reaction to the formation of light oils and tars of low carbon hydrogen ratio. Catalysts favorable to polymerization, such as active silica or active carbon, with or without deposited metals, may be employed during this polymerization stage but their use is not necessary.

As the next step to the process, the entire gaseous mixture, as it leaves the polymerizing chamber with all the light oil and tar in vapor state, is led over a series of hydrogenating catalysts suitably located in a hydrogenating chamber. This catalyst may consist of nickel, cobalt, mixtures of these metals with each other, or with metals such as molybdenum, chromium, mercury and thorium, and it may be mounted on either a support such as granular pumice, silica gel or active charcoal, or mixed with a material such as ground pumice unsupported. Experimental work has shown that catalysts of the type mentioned will bring about the desired reactions, but it is to be understood that the process is not to be restricted to this particular catalyst. To provide the requisite temperature conditions it is desirable to mount the hydrogenating chamber in a compartment formed in the flue of the furnace,

, so that when desirable the heated. fluegases may 125.

be by-passed through the compartment. By utilizing the hydrogen previously evolved in the formation of light oil or tar, several different reactions may take place, depending upon the velocity of the gas stream, the temperature, the catalyst chosen and its concentration, all of. which are determining factors in the extent of splitting and amount of hydrogenation.

For instance, at temperatures 100-300 C., most of the products in the hydrogenating chamber form hydrogenated derivatives. The tars which are ordinarily rather dark and viscous liquids are converted to hydogenated polynuclear compounds with boiling points below 300 C. Naphthalene forms either tetraor deca-hydro-napthalene, depending on conditions; benzene is converted into cyclohexane; ethylene to ethane; and similarly all of the other hydrocarbons add more or less hydrogen. These reactions are exothermic and excess heat is removed by preheating all or a part of the input gas through a closed coil or other appropriate means.

At temperatures 300 to 600 C;, destructive hydrogenation of the tarsoccur. This may betypifled by the reaction of, naphthalene, one of the major constituents of'thetar, which reacts as follows:

heat, all or a part of the input gas maybe pre heated. Thus the total'yield of light oil of a single nuclear structure is app'oximately doubled, since, under the best COIldiL. lS, somewhat less tar than light oil is originally formed. A considerable portion of hydrogen is removed from theresidue gases, thus enhancing their heating alue.

The, whole of. the gaseous mixture, consisting of fixed gases and vapors, is next passed into a scrubbing tower or other device so operated that a all of the polymerized liquids and gaseous compounds with more than one carbon atom are removed. Tetrahydronaphthalene, one of the products which may be produced by the low temperature hydrogenation, can be advantageously .employed as a wash oil. The residue gases consisting of methane, hydrogen and nitrogen, may

be used in several ways' but preferably by providing heat for the cracking reaction. The entire process from the initial heating .to the absorption of the light products should be carried out within a pressure range of 30-100 pounds. The final step in the process is carried out by reducing the pressure to atmospheric and heatingthe absorbing agent whereby the volatile light oils, or mixtures of aromatic hydrocarbons, are recovered and the gaseous hydrocarbons of two or more carbon atoms are collected and returned to enrich the intake gas at the cracking furnace. In the manner of carrying out the process where such products as tetrahydronaphthalene are formed, they will not be recovered with the volatile oils, but will accumulate with the wash liquid, and as that increases in amount, portions of it may be heated sufiicientlyto distill'off the desired product. Manifestly various forms of apparatus may be employed to carry out the several steps of this invention but for the purpose of the present disclosure. reference will be made to the embodiment diagrammatically shown in the single figure of the accompanying drawing.

Referring more particularly to the drawing, the single figure diagrammatically shows partially in elevation, partially in section, an operative assembly of the several components of one form of apparatus which has been successfully resorted to for the purpose of carrying into effect the principles of this invention.

Assuming the intake A connected to a source of hydrocarbon gas and intake B to the source of a diluent such as nitrogen, after the proper valve of the valve group C has been adjusted to mix the diluent with the hydrocarbon gas, the mixture flows through the line (5) into the upper end of reaction tube (6). Descending the branches of this tube the gases leave its lower end andentering line (6') flow into the upper end of the polymerization chamber (10). During its passage through. the reaction tube (6) the gaseous-mixture is subjected to a temperature ranging between 700 to 1200 C. The polymerization chamber (10) into which the gases flow after leaving reaction tube (6) is internally baflied and centrally positioned in an unheated insulated reaction vessel (11). As .the gases traverse the polymerization chamber (10) following the irregular course prescribed by the baflies, they are heated to a temperature of 500 to 700 C. Temperature control of the polymerization chamber is secured by by-passing a part or all of the input gases irom the intakes A, B, through the line (12) into the bottom of reaction chamber (11), through this chamber and around the polymerization chamber (10) and then through upper end of chamber (11), line (12) back to line (5).

This flow of the input gases around the poly merizing chamber is regulated by means or thermo-electric devices (not shown). By-pass- ,ing' the gases in this manner not only maintains the proper temperature within the polymerization chamber but also enables preheating of the input gases when the occasion demands.

The cracked gases having been polymerized by their passage through the polymerization chamber (10), enter line (14) and passing through this line flow into the upper end of the hydrogenating chamber (15). Hydrogenating chamber (15) is located in a walled compartment D formed in the upper part of furnace E. A pair of flue valves (19) and (20) permit the flue gases to be bypassed through compartment D for the purpose of controlling temperature conditions in the hydrogenating chamber as'will be understood without further discussion. These valves are adapted to be operated by thermo-electric devices (not shown). The gases entering the hydrogenating chamber (15) flow through said chamber over catalysts (16). At this point several reactions take place depending upon temperature conditions, the gas stream velocity, nature of the catalyst and its concentration, all of which'are, as previously stated, determining factors in the extent of splitting and the amount of hydrogenation. 7

Leaving the hydrogenating chamber (15) the gases entei line (21) and flow into the upper end of heat exchanger (22). After being suitably cooled by their passage through the heat exchanger, the gases enter line (23) and flowing through the latter are directed into the lower end of pressure scrubbing tower (24). into which-wash oil is sprayed from the nozzle (25). This nozzle is mounted in the upper end of the tower, and connectedto a source of wash oil supply in a manner hereinafter to be described. The wash oil sprayed into the scrubbing tower absorbs the liquid hydrocarbons and also gaseous hydrocarbons having two or more carbon atoms. The methane hydrogen and other fixed gases collecting in the upper end of the scrubbing tower enter line (26) through which they are directed into lines (26), (27') and thence to burners (8) and (8').

Coming now to the final stage of this process the enrichedabsorbent in the bottom of scrubbing tower (24) is'directed via line (27 .to coil (22') in heat exchanger (22) wherein it is heated by the incoming gases from line (21). Leaving the coil (22') it is directed via line (28') into heating coil (28) located in the base of the furnace and thence through line 30 into evaporating chamber (31) 3 The denuded wash oil collecting in the bottom the upper end of evaporating chamber (31) and directed into condenser (33) via line (32). The

lower end of the condenser (33) connects with separator (35). The volatile light oils or mixtures of aromatic hydrocarbons collect in the separator (35) while the hydrocarbon gases having two or more carbon atoms arerecycled through line (36), pump (37), line (38), and valves (39) and (40) to reaction tube (6) and/or polymerizing chamber (10) depending upon the exigencies of the situation.

The air for combustion in the burners is introduced through theinlet valve (47), recuperator (48), line (49), valve (50), and line (27). Valve (51) provides for by-passing the methane and fixed gases from the top of the scrubbing tower (24) to any desired place. The valve (52) furnished another intake for extra fuel when the latter becomes necessary.

In conclusion, it is evident this invention by converting the undesirable tars into useful products and utilizing valuable constituents of the gases which in similar processes have been wasted, greatly improves the light oil yield and materially widens the market for natural gas products/ Having described our invention, what we claim as new and wish to secure by Letters Patent is:

1. A process for. the thermal decomposition of gaseous paraflin hydrocarbons consisting in heating the gases under pressure to a temperature just suflicient to crack the hydrocarbons and form fragments or free radicals, regulating the velocity and turbulence of the gas stream during this thermal treatment to prevent secondary reactions, directing the heated gases into a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature and then extracting the liquid products formed.

2. A process for the thermal decomposition of gaseous parafiin hydrocarbons consisting in rapidly heating the gases under pressure to a temperature just suihcient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this treatment so as to prevent secondary reactions, directing the heated gases into a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tars while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature, reducing the gas pressure to atmospheric and then extracting the liquid products formed.

3. A process for the thermal decomposition of gaseous paraffin hydrocarbons consisting in heating the gases under pressure to a temperature sufficient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this thermal treatment so as to prevent secondary reactions, directing the heated gases to a polymerizing chamber and materially reducing the velocity of gaseous flow, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar still in vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature, reducing the pressure of the gases to atmospheric and extracting the liquid products formed.

4. A process for the thermal decomposition of gaseous parafiin hydrocarbons consisting in heating the gases under pressure to a temperature sufficient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this heating period to prevent secondary reactions, directing the heated gases into a polymerizing chamber where their flow is materially reduced, limiting the polymerization reaction to a temperature between 500-700 C., passing the light oils and tar still in a vapor state over a hydrogenating catalyst at a predetermined temperature and then removing the liquid products formed. 3

5. A process for the thermal decomposition of gaseous paraflin hydrocarbons consisting in heating the gases under pressure to a temperature between 700-1200 C., which is just sufficient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this thermal treatment so as to prevent secondary reactions, directing the heated gases to a polymerizing chamber, the dimensions of which are such as to materially reduce the gas flow, limiting the polymerization reaction to a definite temperature range, passing the light oils and tar still in a vapor state over a hydrogenating catalyst at a predetermined temperature and then removing the liquid products formed.

6. A process for the thermal decomposition of gaseous paraffin hydrocarbons, consisting in heating gases under pressure to a temperature within the temperature range of "700-1200" 0., which is Q; just sufficient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream to prevent secondary reactions, directing the heated gases into the polymerizing chamber, the dimensions of which are such as to materially reduce the gas flow, limiting polymerization reaction to a temperature between 500-700 C., passing the light oils and tar still in' a vapor state over a hydrogenating catalyst at a predetermined temperature and then removing the liquid products formed.

'7. A process for the thermal decomposition of gaseous parafiin hydrocarbons consisting in heating the gases under pressure to a tempera- 125 ture within the temperature range of '700-120 O C., which is just sufiicient to crack the hydrocarbons and form freeradicals, controlling the velocity and turbulence of the gas stream to prevent secondary reactions, directing the heated 130 gases into a polymerizing chamber, whose dimensions are such as to materially decrease the gas flow, limiting the polymerization reaction to a temperature between SOD-700 C., passing the light oils and tar still in a vapor state over a 35 hydrogenating catalyst at a temperature bea tween 100-300 C., and then removing the liquid products formed.

8. A process for the thermal decomposition of gaseous paraffin hydrocarbons consisting in heat- 14( ing the gases to be processed to a temperature just sufficient to crack the hydrocarbon and to form fragments or free radicals, restricting the pressureto a range of 1-100 pounds per square inch, directing the gas along an irregular path 145 so as to impart sufficient flow and turbulences to the gas'stream during this stage of the process to prevent secondary reactions, directing the heated gases into a polymerizing chamber, whose dimensions are such as to materially reduce the 150 to a definite temperature range, passing the light oils and tar still in a vapor state over a hydrogenating catalyst at a predetermined temperature and then removing. the liquid products formed.

9. A process for the thermal decomposition of gaseous paraflin hydrocarbons consisting in heating the gases under pressure to a temperature between 700-1200 0., which is just suflicient to crack .the hydrocarbons and form free radicals, controlling the velocity and turbulence of the gas stream to prevent secondary reactions, directing the heated gases into a polymerizing chamber, whose dimensions are such as to materially decrease the gas flow, limiting the polymerization reaction to a temperature between 500-700 0., passing the light oils and tar still in vapor state over a hydrogenating catalyst at a temperature between BOO-600 0., and then removing the liquid products formed.

10. A process for the thermal decomposition of gaseous ,paraflin hydrocarbons consisting in diluting the gas to be treated with an inert gas, heating this mixture under pressure to a temperature just-sufficient to crack the hydrocarbons and form fragments or free radicals, the velocity and turbulence of the gas stream during this thermal treatment being such as to prevent secondary reactions, directing the heated gases into the polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature and then extracting the liquid products formed.

11. A process for the thermal decomposition of gaseous paraifin hydrocarbons consisting in diluting the raw gas with a diluent in the nature ofan inert gas such as nitrogen, heating the mixture under pressure to a temperature just sufficient to crack the hydrocarbons and form fragments or free radicals; the velocity and turbulence of the gas stream during this stage being such as to prevent secondary reactions, directing the heated gases into a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature and then extracting the liquid products formed.

12. A process for the thermal decomposition of gaseous paraflin hydrocarbons consisting in diluting the raw gas with an inert diluent such as nitrogen, rapidly heating the gases under pressure to a temperature between 700-1200" 0., which is just sufiicient to crack the-hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this stage to prevent secondary reactions, so as to avoid formation of light oils and tar from unsaturated gases, directing the heated gases into a polymerizing chamber, the dimensions of which are such as to materially decrease the rate of gas flow, limitingpolymerization reaction to a deflnite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature and then extracting the liquid products formed.

13. A ,process for the thermal decom osition of gaseous paraflin hydrocarbons consisting in diluting the gases to be processed with an inert diluent such as nitrogen, heating the gases under.

pressure to a temperature between 700-1200 0., which is just sufficient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this thermal treatment so as to prevent secondary reactions, directing the hot gasesnow in a state of disintegration to a polymerizing chamber, the dimensions of which are such as to efiect a material reduction in the rate of gas flow, limiting the polymerization reaction to a temperature between 500-700 0., removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature and then extracting the liquid products formed.

14. A process for thethermal decomposition of gaseous paraifin hydrocarbons consisting in diluting the gas or gases to be processed with an inert diluent in the nature of nitrogen, heating the gases under pressure to a temperature between 700-l200 0., which is just sufiicient to crack the hydrocarbons and form fragments or free radicals, controlling the velocity and turbulence of the gas stream during this thermal treatment so as to prevent secondary reactions, directing the heated gases to a polymerizing chamber, the dimensions of which are such as to effect a material reduction in the rate of gasfiow, limiting the polymerization reaction to a temperature between 500-700 0., removing the light oils and tar while still in a vapor state from the polymerizing chamluting the gas or gases to be processed with an inert diluent in the nature of nitrogen, heating the gases under pressure to a temperature between 700-1200 0., which is just sufficient to crack the hydrocarbons and form fragments or radicals, controlling the velocity and turbulence of the gas stream during this thermal treatment soas to prevent secondary reactions, directing the heated gases to' a polymerizing chamber wherein the dimensions of which are such as to effect a material reduction in the rate of gas flow, limiting the polymerization reaction to a temperature between 500-700 0., removing the light oils and tar while still in a vapor state from the polymerizing chamber, and passing them over a hydrogenatlng catalyst at a temperature between 300-600 0., and then removing the liquid products formed.

16. A process for the thermal decomposition of gaseous paraffln hydrocarbons consisting in diluting the gas or gases to be processed with an reduction in the rate 01" gas flow, limiting the polymerization reaction to a temperature between 700-1200 0., removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing it over a hydrogenating catalyst under conditions to form hydrocarbons with only one aromatic or benzene ring and then removing the liquid products formed.

17. A process for the thermal decomposition of gaseous parafiin hydrocarbons consisting in diluting the gases to be processed with an inert diluent in the nature of nitrogen gas, heating the gaseous mixture under pressure to a temperature just sufiicient to crack the hydrocarbons and form fragments or free radicals, regulating the velocity and turbulence of the fiow of the gas stream during this thermal treatment to prevent secondary reactions, directing the hot gases now in a state of disintegration into a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating. catalyst at a predetermined temperature, the concentration of the catalyst being varied depending upon the amount of hydrogenation desired, and then extracting the liquid products formed. p

18. A process for the thermal decomposition of gaseous paraflinhydrocarbdns consisting in diluting the gas to be processed with an inert diluent in the nature of nitrogen gas, heating this gaseous mixture under pressure to a temperature just sufiicient to crack the hydrocarbons and form fragments or free radicals, regulating the velocity and turbulence of the gas stream during this thermal treatment to prevent secondary reactions, directing the hot disintegrated gases into a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst, maintaining the hydrogenating temperature within definite limits to form only hydrogenated derivatives and then extracting the liquid products formed. a

19. A process for the thermal decomposition of gaseous paraflln hydrocarbons consisting in diluting the gas or gases to be processed with an inert diluent such as nitrogen gas, heating this mixture under pressure to a temperature just sufiicient to crack the hydrocarbons and form fragments or free radicals, regulating the velocity and turbulence of the gas stream to prevent secondary reactions, directing the heated gas to a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar from the polymerizing chamber while still in a vapor state andlpassing'them over a hydrogenating catalyst at a pre-= determined temperature, extracting the liquid products formed and returning the hydrocarbons of two or more carbon atoms to the intake gas for enrichment purposes.

' 20. A process for the thermal decomposition of gaseous parafiin hydrocarbons consisting in diluting the gases to be processed with an inert diluent in the nature of nitrogen gas, heating the gas under pressure to a temperature just surficient to crack the hydrocarbons and form fragments or free radicals, regulating the velocity and turbulence of the gas stream during this thermal treatment to prevent secondary reactions, directing the hot gases in a state of disintegration into a polymerizing chamber, limiting the polymerization reaction to a definite temperature range, removing the light oils and tar while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst at a predetermined temperature, reducing the pressure of the gases to atmospheric and then extracting the liquid products formed.

21. A process for the thermal decomposition of gaseous paraifin hydrocarbons consisting in subjecting the gases under pressure to a temperature just sufficient to crack the hydrocarbons to form fragments or free radicals, regulating the velocity and turbulence of the gas stream during its thermal treatment to prevent secondary reactions, directing the heated gases into a polymerizing chamber, removing the light oils and tars while still in a vapor state from the polymerizing chamber and passing them over a hydrogenating catalyst, and then extracting the liquid products formed.

- HAROLD M. SMITH.

PETER GRANDONE. HARRY T. RAIL.

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