US1869681A - Method for the froduction of normally liquid hydrocarbons from gastcus or lower boiling hydrocarbon matebials - Google Patents

Description

Aug. 2, 1932. K, FRQUCH 1,869fi8i METHOD FOR THE PRODUCTION OF NORMALLY LIQUID HYDROCARBONS FROM GnsEOUs OR LOWER BOILING HYDROCARBON MATERIALS Filed March 24, 1930 QM {W gwwwtoz more specifically to a process latented Aug; 2, i932 siren PER K. FBQLICH; O12 ELETH, NEW JERSEY, ELSSIGHUR T6 sacraments GE DWEQE? COMEANY, ACQEPQRATIQN @E" DEMWQEE METHOD FOR THE'PRQDUC'IIQN GI? NORMALLY lLIQUm RQGMBQZBYSw FRUEE GarlaEE-QUtil 0E, IEWEE BQILIHG' HYIEEQGARBQN Application filed March at,

The present invention relates to an im= proved method for the production of nor-' mally liquid hydrocarbons from gaseous or lower boiling hydrocarbon materials and for the production of liquid hydrocarbons boiling within the range suitable for commercial gasoline from gaseous or low boiling hydrocarbons. My process will be fully understood from 19 the following description read in conjunction with the drawing which is a semi-diagrammatic side elevation partly in section of the preferred form of the apparatus.

Large quantities of low boiling hydrocarbons such as ethane, propane, butane and the like, occur in natural or refinery gases and at the present time are largely used for fuel, line to the fact that such hydrocarbons are either gaseous or boil at too low temperatures to be included in commercial gasolines. l have discovered a method by which such materials may be converted into higher boiling products admirably suited for use in internal combustion engines and for other uses for which products of the same boiling range, may be used.

My process consists in a series of steps as follows First the conversion of saturatedmae terials such as ethane, propane and butane into olefins, which is accompanied by the liberation of free hydrogen. -The second step comprises removal from this gaseous mixture of the free hydrogen and the third step comprises polymerization of hydrogen-free gas to form normally liquid hydrocarbons suitable for commercial motor fuel. Each of the said steps will be separately described. The first, or cracking step may be carried out in any desired manner, for example; merely by heating to a decomposition temperature say from approximately 600 to 1000 G. either with or without pressure and in the presencev or absence of catalysts, preferably nonferrous tubes or ferrous metal tubes con-; taining 8% of chromium or more. The preferred method, however, is that disclosed in: the co-pending application Serial No. 360,- 000 of the present inventor with B. O. Boeck-, eler hich was filed May 2, 1929. This process comprises dehydrogenation of hydrocarused in.

race, Serial No. ceases. I

bone by the use of certain catalytic agents at temperatures within the approximate range of 450 (C. to 700 C. with or without pres sure. Metallic catalysts have been found satisfactory and the mixture of metallic oxides after reduction with methanol, hydrogen or hydrocarbon vapors or otherwise, are pre ferred although other types of dehydrogenation catalysts may be used. Gatalysts containing zinc and another metal which hasv two or more valences are particularly desirable, such as 30 mol percent zinc, 10 mol per cent of chromium or other proportions of the same elements, or zinc and molybdenum or tungsten, vanadium and the like. The rate of flow of the gases in this process is preterably very rapid, for example; above about two volumes of hydrocarbon vapor per min ute per volume of reaction space and under such conditions it is observed that twc or more atoms of hydrogen are removed from the hydrocarbon molecule with substantially no decomposition of the carbon structure, that is to say,,substantially no hydrocarbons of fewer carbon atoms are produced.

This process may be used on pure hydrocarbons or mixtures oil two or more hydrocarbons and diluent gases including hydrogen, nitrogen, methane or other gases may be used. In this way the highest yield of olefins and consequently the lowest yield of methane which forms as a waste product in the process is obtained.

The gas obtained from the first stew of my process comprises a mixture of ole s, unreacted parafinic hydrocarbons, and hydrogen. Removal of the major quantity of the free-hydrogen comprises the second step and this may be accomplished in any desired mannor, for example; by liquefaction and subsequent rectification, or by other physics means, but it is preferably accomplis ed by a process of preferential oxidation which is dis-v closed in the co-pending application Serial No. 438,651, entitled Process for purifying gases filed on March 2t, 1930, by A. White and the presentinventor.

In the operation of the preferential oxidation method the gas is mixed with air or other gases containing free oxygen in substantially equivalent quantities required for complete combustion of the free hydrogen. The mixture is then passed over a catalytic material at a temperature within the range of about 250 to 450 C. with or without pressure. Means are preferably provided for removing the heat caused by the combustion and this may be done by the use of small tubes or by the use of tubes provided with fins or other heat radiating elements, or in the case of larger tubes where relatively large volumes of ases are to be treated, internal cooling wit? steam or other suitable means may be use It has been found that copper shot or copper oxide is the most satisfactory catalytic material, but other materials such as lead, nickel, tin, bismuth or their oxides or equivalent metals whose oxides are readily reducible by hydrogen within the specified temperature range or mixtures of such substances may be used. When the metals are used it is usually preferable to use temperatures in the up r end of the range given, for example from 300 to 450 C. while if the oxides are used lower temperatures such as 200 to 350 C. are more satisfactory. It is of advantage to remove as large a proportion of the free hydrogen as can be readily caused to react without substantial combustion of the olefins and it may be reduced below 5%. in the outlet mixture or even as low as 3% or 1%. It is desirable to purify the gases of sulphur compounds prior to the partial oxidationstep since sulphurous impurities tend to poison the referential oxidation catalyst. The uri cation step may be carried out prior to t e cracking step or after the cracking step and may be accom lished either by a soda wash or by e uiva ent means.

The third or polymerization step may be carried out under atmospheric pressure or at higher pressures, for example; above 100 pounds per square inch, but preferably in the range from 300 to 1000 pounds per square inch. The temperature may vary considerably within the approximate limits of 500 to 900 C. and it has been found that with higher pressure it is generally desirable to use somewhat lower temperatures. The time of reaction may vary widely, for example, from less than 1 minute at higher temperatures to 25 or 30 minutes or longer at lower temperatures and contact materials may be used, preferably of a metallic character having a high heat conductivity in order to maintain uniform temperatures throughout the reaction.

chamber.

Using the present process, comprising the three steps described above, yields of 1 to 5 gallons of liquid products may be obtained per thousand cubic feet of propane or gases comprising, ethane, propane and butane. One half or more of the distillate isgenerally sufliciently low boiling for commercial gaso- The gases are then passed either through a desulfurizer 5 or through a by-pass line 6 to the hydrogen remover 7 to which air is admitted by means of compressor or blower 8 and manifold'9 while steam may be admitted through line 10. From the hydrogen remover the gases either pass through cooler 11 or through by-pass line 12 and, after compression by compressor 13 and passage through heat exchanger 14, they come into the polymerizing chamber 15 which is followed by heat exchan er 14, condenser 16 and liquid receiver 1 The final liquid products are removed through line 18 and the gases through line 19.

As an example of the operation of my process propane is passed through a tube of copper or other metal such as chrome steel or ceramic material heated to a temperature of about 800 C. The outgoing gas has the following composition:

Per cent 0 H 18 OH 37 oH.+o .H. 45

The gas is now compressed to a pressure of 600 pounds per square inch and passed through a chamber held at a temperature of 525C. at a rate so as to give a reaction time of about 30 minutes. About 61% of the olefins react and a yield of- 4.56 gallons of liquid material is obtained from 1000 cubic feet of the inlet propane. About 4.26 gallons or over 90% of the total product boils within the range from 30 to 225 C. and has a bromine number of 110. The material is light in color and after finishing in the ordinary nfethods well known in the petroleum industry is admirably suited for use in internal combustion engines, being equivalent in anti-detonation value to a naphtha from an ordinary sweet crude, such as Mid Conti- Per cent -nent crude, towhich 80% of benzol has been added.

converting the paraifins to olefins The entire series of steps may be carried out at atmospheric or higher pressures, say 100 pounds per square inch or if desired, one or more stepsqnay be at low the other or others are accomplished at higher pressure. It is particularly desirable to conduct the cracking steps at atmospheric pressure or below 100 pounds, scrub with alkali to remove sulphur, remove free hydrogen at the same pressure and subsequently polymerize at pressures above 100 pounds.

My invention is not to be limited by any theory of the mechanism of the reactions nor to anyspecific example which may have been given for purpose of illustration, but only by the following claims in which I wish to claim all novelty inherent in my invention.

I claim:

1. An improved process for producing valuable higher boiling hydrocarbons from lower boiling saturated hydrocarbons of more than one carbon atom, which comprises the steps of converting such saturated hydrocarbons into unsaturates, removing the major quantity of'free hydrogen and polymeriz ng the olefins to form higher boiling hydrocarbons.

2. An improved process for converting low molecular paraffinic hydrocarbons containing more than one carbon atom into higher molecular Weight hydrocarbons comprising and free hydrogen by the action of heat, removing the major quantity of free hydrogen by partial combustion and polymerizing the olefin product in absence of substantial quantities of free hydrogen.

3. An improved process for obtaining normally liquid hydrocarbons from gaseous hydrocarbons heavier than methane comprising the steps of converting a substantial part of the gaseous paraffins into olefins and hydrogen by application of heat at a decomposltion temperature, removing the major quantity of free hydrogen by partial combustion in the presence of a suitable catalytic agent and polymerizing the olefins in absence 0 substantial quantities of hydrogen.

4. Process according to claim 3 in which the paraflinsare converted into olefins by passage, at a temperature in excess of about 450 C. over a suitable dehydrogenation catalyst.

5. Process according to claim 3 in which the paraflins by passage at a temperature between 450 and 700 C. over reduced metal oxides.

6. Process according to claim 3 in which the mixture comprising olefins and hydrogen is 'mixedwith a gas containing free oxygen and passed over a catalyst containing a metal whose oxide is readily reducible by hydrogen while at a temperature from 200 to 350 pressure, while are converted largely to olefins whereby the hydrogen of free 9. Process according to claim 3 in which the olefin mixture is heated so as to leave not j more than 5% offree hydrogen and the resultin mixture is polymerized at temperatures rom 500 to 990 C.

10. Process according to claim 3 in which the gas containing less than 3% of free hy- .drogen is polymerized under pressure at temperatures from 500 to 900 C. in a zone of substantially uniform temperatures.

11.. Process according to claim 3 in which the gas containing not more than 3% of free hydrogen is polymerized under pressure in excess of 300 pounds per square inch.

12. Process according to claim 3 in which the olefin containing gas substantially free of hydrogen is polymerized by digestion under pressure in excess of 300 pounds per square inch for a period varying inversely with temperature.

13. An improved process for obtaining valuable, hydrocarbon liquids suitable for motor fuel from hydrocarbon gases rich in a constituent heavier than methane comprising partially dehydrogenating the gases by heat at temperature above 450 C. removing major quantity of free hydrogen by par-1 f under'pressure above 300 pounds per square inch andcooling and condensing normally liquid constituents.

PER K. FROLICH.

,DISOLAIMER v 1,869,681. Per K. Froli ch, Elizabeth, N. J. METHOD non 'rnn Pn'oimc'rroN or I 'NORMALLY LIQUID -HYDROCARBONS FROM GAsEOUs 0R LOWER BOILING HXDROCARBON MATERIALS. Patent dated August 2, 1932. Disclaimer filed March 6, 1935, by the Assignee, Standard Oil Development Company.

v Hereby enters this disclaimer to that partof the claims in said specification which is in the following words, to wit: v v

1. An improved process for produclng valuable'hlgher boihng hydrocarbons from c .lower boiling saturated hydrocarbons of more than one carbon atom, which comprises -the steps of converting such saturated hydrocarbons into;unsaturates, removing the ma'or quantity of free hydrogen and polymerizing the olefines to form higher boilinghy carbons? [Qficial Gazette April 2, 1.935;]

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