US2271860A - Treatment of hydrocarbons - Google Patents

Description

Feb. 3, 1942. A. GoLDsBY 'rwmm'umu' oF vHYI R0ARB0NS- Filed Feb. 17, 195s mmJOOU INVENTOR JZ .my/Q,

HIS ATTORNEYS ARM R. GOLDSBY catalyst. In such use as charging stocks, materials which containv normal paraftlns,

Patented Feb.. 1942 UNITED. STATE TREATMENT F HYDROCABBONS Arthur n. Gorusby,

Port Arthur, Tex., assignor,

.by mesne ass1gnments, to The Texas Company,- New York, N. Y., a corporation of Delaware Application February 11, 193s, serial No. 190,941 s claims. (c1. 19e-1o) hydrocarbons and has to do particularly with g' the alkylation of paraffin oleiins. Parain hydrocarbons, particularly isoparaffins, may be alkylated with olens underproper the presence of a suitable conditions and 1n an operation it is customary to hydrocarbons with oleiins and isoparains. In the alkylation reaction the 'isoparains and olens are consumed thereby greatly increasing the proportion of the normal parains in the unreacted materials. In accordance with the present invention, the unreacted products from the alkylation reaction are treated whereby the normal parafdns are isomerized to isoparafilns which may be recycled to' the system or otherwise treated with additional charging stock containing olefins to undergo alkylation. l

The alkylation reaction may be carried out in the presence of a catalyst such as strong sulfuric acid of up to 100% concentration, and'preierably about 94%. Other catalysts may comprise aluminum bromide and aluminum chloride. The temperature may range from -40 to +175 F. and preferably around 'I5 to 100 F. The reaction time may range from ten minutes to two hours and preferably aboutone hour. The ratio of isoparaiiin to olens may range from about -2:1 to 20:1 and good yields may be obtained v with ratios of 3'21 to 5:1. Continuous or batch operation using counter current or concurrent ow may be employed.

The isomerization operation may be carried out in the presence of a catalyst such as aluminum bromide oraluminum chloride, either alone or in the presence of hydrogen chloride. Satisfactory results have been obtained with 5 to 30% of aluminum bromide, preferably 10%. Temperatures up to time of reactionis used ranging from a fraction of an hour to a day or more, and preferably as short temperature. Charging stocks which may be treated according to .the invention may comprise any mixture of isoparains, normal paraiilns 4and oleilns, such as normally gaseous hydrocarbons,

mally gaseous and normally liquid hydrocarbons. Specific products which are contemplated are normally gaseous hydrocarbons, particularly: C; and C4 hydrocarbons, gasoline hydrocarbons, etc. The invention is particularly applicable to the treatment of unsaturated normally gaseous 200 F. may be used. A

. the following Aoleiins from another source of supply. WhenV ratio of isobutane to oleiins.

'vided with a stirrer I3.

desirable to charge a gas hydrocarbons suchas cracking still gases predominating in C4 hydrocarbons or C. and C: hydrocarbons. Mixtures consisting essentially of or comprising isobutane, normal butane and butenes may advantageouslyA be treated.

The invention will be further understood from description of the invention read in connection with the accompanying drawing, showing diagrammatically one form of apparatus for carrying out the process or the invention,

Referring to the drawing, a charging stock comprising a mixture of isoparaiiins, normal parafiins and olens is charged through the line I by pump 2 to the reaction chamber 3.' While only one line is shownfor charging the hydrocarbons, it is to charging .stocks may mixture of isoparaflins and normal paraftins may be'charged from one source of supply and the recycling gases containing isobutane, it may be tent along with the normal paraiiins to thereby regulate the olefins charged to obtain the proper The catalyst, such as 94% sulfuric acid, is charged through the line 5 by the pump 6 also to the reaction chamber 3. The reaction chamber is provided with a stirrer 8 for intimately mixing the catalyst and hydrocarbons. It is desirable that as intimate contact as possible be obtained and a high speed stirrer may be used, although-other methods of eicient contact may be employed. The mixture is transferred through the line 9 controlled by valve l0 to a second reaction chamber I2 pro- While two reaction chambers are shown, it is to be understood that any number may be used to obtain the desiredreaction. The products from reaction chamber I2 are transferred through the line l5 controlled normally liquid hydrocarbons or mixtures of nor'- Y tain super-atmospheric pressures,

by valve I6 to a separator I8. In the separator I8 a separation is allowed to take place between the catalyst and the oil. When using sulfuric acid, the acid will drop arator and may be recycled through the line 20 by the pump 2| to the line 5, thence into the reaction chamber 3. The oil collecting in the top oi the separator l0 is conducted through the line 23 controlledby valve 24 to the still 25.

In the treatment of normally gaseous hydrocarbons particularly, it is customary to mainfor example 50 to pounds or more, suillcient to keep the materials in the liquid phase. The pressure be understoodl that one or more- I be used; for example a high in olen conf to the bottom of the sepmay be reduced by means of the valve 24 whereby a separation between the unreacted normally gaseous'hydrocarbons andthe alkylation products which are normally liquid, may be effected in the stabilizer 25. If necessary, heat may be applied to the stabilizer, for example by means of the heating coil 26 in the lower portion thereof.- The alkylation products are withdrawn from the lower portion of the stabilizer 25, through the line 2l. The unreacted normally gaseous hydrocarbons are conducted throughthe vapor line 29 to fractionator 28, wherein separation is madebetween normal butane and isobutane. The isobutane and any lighter hydrocarbons are taken overhead from fractionator 28l through vapor line I9, compressed by compressor 22, cooled in the cooler 30 and the condensate collected in accumulator 3l. Any light gases, such as C1 and C2 hydrocarbons, may be removed through gas release line 32. The isobutane is withdrawn from the accumulator through line 33 and returned to the reactor 3- The normal cbutane collecting in the bottom of the fractionator 28` is transferred through the line 34 by the pump 35 to an isomerization or reaction chamber 36 which is provided with a stirrer 31 and a line 38 for the addition of a catalyst which may be aluminum bromide in the form ,of a hydrocarbon compound. The isomerization chamber 36 is usually of such size or a suilcient number of chambers used, whereby ltime and contact are provided for effecting the desired amount of isomerizatio'n which may be, for example, on the order of 50% conversionrof paraiilns to isoparailins. The reaction products are transferred through Ithe line 4| by pump 4 2 to a separation or settling chamber 44, wherein the catalyst is separated by settling or distillation of the hydrocarbons therefrom, andmay be withdrawn from the lower portion thereof, through the -line 45. The hydrocarbons are conducted through the line 46 to astill or fractionator 48 provided with heating means, such as coil 49, in the lower portion thereof. In the still 48 the hydrocarbons are fractionated to separate a fraction comprising the isoparalns, such as isobutane, which is withdrawn from the intermediate point of the fractionator to a reboiler 50, through the line 5|. Ihe reboiler 50 is provided Witha vapor line 52 for returning vapors to the still and a liquid line 53 for withdrawing the desired fraction. The higher and lower boiling point materials may be withdrawn from the lower portion andthe upper portion of the fractionator through the lines 55 and 56 respectively. The fraction withdrawn through the line 53 from the reboiler n50 is recycled by the pump 54 to the charge line. l leading to the reaction chamber 3. A'

As an example of the operation of the invention, a C4 hydrocarbon fraction comprising about olens, 30% isobutane and 40% normal butane, was treated-with about an equal amount by volume of 94% sulfuric acid operating ina continuous manner. A total yield of alkylation products comprising normally liquid hydrocarbons with end point around 600 F. of about 140%' based on the olens charged was obtained, of which about 100% based on olens charged were within the motor fuel boiling range having an end point belowr400 F. The unreactednormally gaseous hydrocarbons, relatively rich in normal butane were subjected to isomerization by the treatment with about 10% aluminum bromide at' room temperatures for approximately 40 hours.v

The reaction products contain approximately 50% isobutane along with a small proportion o1' lower and higher boiling hydrocarbons. 'Ihe products were fractionated to obtain a. fraction containing in excess of 50% of isobutane which was recycled to the alkylation operation. By operating in this manner, a total yield of liquid alkylation products of about 175% based on the olens charged was obtained, with a yield of motor fuel products having end point below 400 F. equal to about 160% of the olens charged. and having a high antiknock value.

. 'I he process sparticularly advantageous in that it provides a means for utilizing substantially all the materials of an ordinary charging stock comprising isoparailns, normal paraiins and olens. By isomerizing the normal parafns to isoparaiiins, a much higher ultimate yield for a given charging stock is obtained and elimmates the necessity of supplying extraneous lsoparans to the system.

.Obviously many modifications and variations of the invention, as h ereinbefore set forth, may be made Without departing from 4the spirit and scope thereof, and therefore only such limitations should be. imposed as are indicated in the appended claims.

I claim:

1. A process for the manufacture of higher boiling isoparanins useful as motor fuel from low boiling isoparaflins and olens, which comprises subjecting a hydrocarbon fraction containing low boiling isoparailns,`olens and normal parains to alkylating conditions whereby the isoparaflins are condensed with the olefins to form higher boiling normally liquid isoparains, separating the normal parallnsfrom the reaction products,

, isomerizing the normal parains to isoparailins and charging the last mentioned isoparalns to the alkylation operation to increase the ratio of isoparailins to olens in the reaction mixture and' to react with the olens to produce further quantities of higher boiling isoparaiiins.

' 2. A process for the manufacture of high antiknock gasoline hydrocarbons, which comprises subjecting a hydrocarbon fraction containing low boiling isoparaflins,'normally gaseous olens and low boiling normal paraiiins, to the action of an alkylation catalyst whereby the iso are alkylated by the olefins to produce'iso of high antiknock value of gasoline boiling point range, separating said gasoline hydrocarbons, from the reaction products, also separating from the products of reaction normal parailins including normal butane, isomerizing said normal butane to isobutane and charging the isobutane formed by said lisomerization to the alkylation operation.

3. A process for the manufacture of high antiknock normally liquid hydrocarbons from normally gaseous hydrocarbons, which comprises subjecting normally gaseous hydrocarbons including normal and isobutane, and oleilns containing between 2 and 5 carbon atoms, to the action of concentrated'sulfuric acid whereby the isobutane is alkylated by the olens to produce normally liquid isoparamns, separating the normally liquid hydrocarbons from the reaction products, also separating from the reaction pmd-v ucts a fraction rich in normal butane, subject# ing Said fraction to an isomeriaation operation whereby the normal butane is converted to isobutane and charging saidy isobutane from the omerization operation to the alkylation Opera- 4. A process for the manufacture of saturated liquid hydrocarbons of high antiknock value which comprises subjecting normal butane to an isomerization operation whereby normal butane is partially converted in substantial amount to isobutane, treating said isobutane, in mixture with unconverted normal butane, with olens under alkylating conditions whereby the isobutane is condensed `with the olens to form normally liquid isoparafns, maintaining an excess of isobutane in the reaction mix'ture, separating ex., cess isobutane from the reaction products, recycling saidseparated isobutane to the alkylaseparated normal butane to the isomerization operation.

5. A process for the manufacture of antiknock motor fuel hydrocarbons, fwhich comprises reacting isobutane in a hydrocarbon mixture containing isobutane and normal butane with olens in the presence of an alkylating catalyst, while maintaining the isobutane in considerable egcess of the olefins, separating the hydrocarbon reaction products into a normally liquid alkylate and unreacted hydrocarbons containing the excessisobutane and normal butane, Iractionating said unreacted hydrocarbons 'to separate normal butane from isobutane, converting by isomerizing the normal butane to isobutane-in the presence of an somerizing catalyst and charging the Y tion operation, also separating normal butane from the vreaction products and recycling said isobutane formed inthe isomenzation stage to` the alkylation stage.

6. A process according to claim 5 in which the sobutane from the fractionation stage is re' cycled to the alkylation stage.

R. GOLDSBY.

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