US2022221A - Polymerization of olefines - Google Patents

Description

F, w. SULLIVAN, JR

POLYMERIZATION 0F OLEFINES 2 Sheets-Sheet 1 Filed Nov 25', 1931 pomtEr' ower.

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v Comprewor Inyemor Frederiokw @ullivcmJr 55 mg i KBWAVLH.

yatentecl Nov. 26,; 1935 POLYMERIZATION F OLEFINES Frederick W. Sullivan, Jr., Hammond, Ind., assigner to Standard Oil Company, Chicago, IlL,

a corporation of Indiana Application November 25, 1931, Serial No. 577,221

1 Claims. (or 196-66) This invention relates to improvements in the art of cracking oils. increase the yield of gasoline by effective re-use in the cracking system of certain of the gases produced in the system. Broadly speaking, this is accomplished by the separation of olefinic or unsaturated gases produced in the normal cracking reactions and returning said oleflnic gases to the heating and reaction section of the cracking system.

It is, of course, old to crack high boiling oils in the presence of hydrocarbon gases. Numerous proposals have' been made to carry out such operations in the presence of natural gas or in the presence of fixed gases recycled from the system itself. In some cases the purpose of such addition of gases has been purely mechanical, i. e., to improve agitation, circulation, or heating conditions within the cracking system. In numerous of such processes it has been further claimed that the added gases exerted a mass-actioneffect and thus tended to repress the formation of fixed gases by the cracking reactions. In some cases it has been further claimed that the added gases actually reacted with the oil under treatment, or. products thereof, with consequent ,enhancement of the yield and quality of low boiling products. I

I have investigated the possibility of such processesand ha'vefound that no increased yield or improvement of product can be obtained by said means. In the early and inefiicient forms of oil cracking apparatus, such as are no longer used, some improvement of physical conditions might be obtained by such circulationof gases, but no such improvement can be noted in cracking systems now in use. I have been unable to obtain any evidence of important or useful chemical reactions entered into by said gases under cracking conditions.

I have, however, discovered that this is due to.

My improved process may be briefly described. I 'I take gases from a crackingv system, compress said gases and contact them with a suitable scrub bing oil whereby methane and hydrogen remain undissolvcd while highe 'hydrocarbonsand predcminately higher unsaturated hydrocarbons, are dissolved in the oil. The rich oil is then stripped Icy-heating with or without" direct contact with steam, and theevolved gases are condensed by cooling under elevated pressure. These gases are Its particular object is to returned to the heating and reaction section of the cracking system, with or-without a high temperature treatment to still further increase their olefin content, or said condensed gasesmay be further separated in a reboiler wherein a butanecracked prior to separating and recycling desired fractions thereof.

Referring to Figure 1, charging stock, which may be suitably preheated by heat interchange, is introduced through pipe ll into the heater'lZ where it is raised to cracking temperatures (800-1000 F.) and is passed through transfer line 13 to soaking drum I4 (which is held at a pressure of 100-1000 lbs/sq. in. or thereabouts) whence, after conversion, it passes through valved line [5 to evaporator tower I6. Tar is eliminated at valved draw-oil l1 and the overhead from tower l6 passes by valved pipe l8 to bubble tower l9, from the lower part of which recycle stock is eliminated through valved draw-01f 20 and is returned for further cracking. Gases and uncondensed vapors from tower I!) pass through line 2| to cooler 22 and thence-through line 23 to high pressure separator 24.

"Dry gas is eliminated from separator 24 by line 26 while the liquid products pass through valved line 25 to low pressure separator 21.

Gasoline is removed by line valved draw-off 21A and wet gas is removed through line 28. The dry gas, containing predominatingly methane plus hydrogen, may be eliminated from the system by valved oil-take 28A, or the dry gas and the wet gas may be further treated separately, but preferably they are further treated together, being mixed in line 29. Pump 29A compresses these gases to a suitable elevated pressure of -300 50 pounds/square inch above atmospheric, following which they are contacted in scrubber 30 with oil or another suitable scrubbing medium introduced under pressure through inlet 3|. Undissolved gams, consisting mainly of hydrogen and'methane but containing varying small amounts of higher hydrocarbons and particularly of higher saturated hydrocarbons, are removed at off-take 32 and suitably consumed for fuel. The absorber oil charged with dissolved gases'passes through line 60.

33, wherein suitable pumping means (not shown) may be inserted if desired, to stripping still 34v wherein it is heated by indirect means and wherescrubber inlet 3|. The evolved gases-which are at high pressure and elevated temperature pass through line 35, and valve 36 to cooler 31 wherein they are condensed. If direct stripping steam were used in 34 a water separator must be inserted at this point. The liquefied hydrocarbons pass through line 38 to'reboiler 39 wherein suitable heating and fractionating means are provided. Gases lower than butane-butylene are evolved and removed through line 40 while butane-butylene is removed as liquid through line 4| and valve 42. If it is not desired to separate all butane-butylene for addition to the gasoline, a part of this fraction may be bypassed through line 43 and valve 43a, and returned to the system through line 40. If, on the other hand, it is desired to return all of the butane-butylene fraction to the system, the cooler 31 and reboiler 39 may be cut out of the system by opening valve 44 in line 45 and closing valves 46, 36 and 43a in lines 40, 35 and 43 respectively.

Regardless of which of these latter modifica-' tions or procedure is used, the recycled gases in line 40 are compressed by compressor 46A to a suitable pressure for reintroduction into the heating and reaction section of the cracking system. If valve 41 in line 40 be opened and valve 48 in line 49 be closed, these compressed gases will be reintroduced directly into the intake of heater l2. On the other hand, under certain conditions it may be desired to heat these gases in order to further increase their olefine content. In this case valve 41 is closed and 48 is opened so that the compressed gases pass through heater 50 wherein they are subjected to temperatures in the vicinity of 1500 F. The cracked gases from heater 50 may be passed through line 5| and valve 52 in line 53 into the transfer line I3 leading to the soaking drum I4. On the other hand, by

closing valve 52 and opening valve 54 in line 55 propylene-propane. is not to be returned to the oil cracking system it may be eliminated through valved line 58. It will be evident that the particular form and arrangement of apparatus used in'the separation and fractionation of the cracked gases may vary considerably and in fact that entirely different types of apparatus might be used, including the use of somewhat higher pressures with resultant complete or partial liquefaction without use of solvents.

Figure 2 is a diagrammatic representation of the arrangement of apparatus if the gases from the cracking system are to be recracked at higher temperatures prior to the separation step wherein methane and hydrogen are eliminated and desired fractions are recycled to the cracking system. The system is the same as that shown in Figure 1, except that heater 50 and its accessory are connections, etc. 41-55 (both inclusive) omittedand an equivalent heater 5!! is inserted in the system mid to the scrubber 30. Gases from the crackihg system are introduced into heater 59 through line 60 which is connected with gas lines 26 and 28 from the separators of the cracking system. Lines 6| and 62 by-pass the heater and connect with line 29, so that by suitable adjust- I ment of the valves shown in lines 26, 28, BI and 62 the dry gas and the wet gas may both be passed through heater 59 or either one may be by-passed around the heater. Following the heater is a cooler 63 from which the cracked gases are del. livered thru pipe 29 to pump 29a and into scrubber 30. The arrangement of the system following scrubber 30 is unchanged and all of the previously described modifications of the operation thereof are possible. The gases in heater 59 will ordi- 1| narily be subjected to temperatures of 1400 to 1600 F. for a period of ten seconds or less, whereby the total amount of olefins present may be increased.

Whether or not my improved process is operated in accordance with the modifications of Figure 1 or Figure 2 will depend largely on the operating conditions and charging stock used in the cracking system, or in other words, on the olefine content of the gas from said system.

By the aforedescribed process I reintroduce into the cracking system only the hydrocarbon gases having two, three or four carbon atoms in their molecule, and predominately only the unsaturated hydrocarbons in this range. By eliminating the hydrogen and methane which are ordinarily present in large volume in gases from cracking systems and by eliminating to as large an extent as possible all saturated hydrocarbons, I eliminate the diluent and retarding effect which the latter customarily exerts upon the polymerization of the unsaturated constituents and obtain markedly increased yields of gasoline.

While the foregoing is a full and complete description of my invention it is understood that I am not limited therein except as defined in the claims as follows.

I claim:

1. A method of converting hydrocarbon oils into gasoline-like products which comprises flow- 45 ing a stream of oil through an elongated passageway while maintaining the oil under a high superatmospheric pressure, cracking the stream of oil during its flow through said passageway, in the presence of recycled unsaturated normally gaseous hydrocarbons formed in the process and from which substantial amounts of hydrogen and methane have been removed, to produce products including gasoline-like products and a mixture of light normally gaseous hydrocarbon products comprising hydrogen, methane and heavier normally, gaseous unsaturated hydrocarbons,

passing the stream of reaction products from said passageway to a separating zone wherein heavy tarry residues are separated in liquid form and lighter products are separated in vapor form, collecting said tarry residues without returning any of them to the oil undergoing cracking, separate ly withdrawing vapors from said separating zone and fractionating them to separate therefrom as separate fractions desired gasoline-like products and a mixture of light normally gaseous hydrocarbon products comprising hydrogen, methane and heavier unsaturated normally gaseous hydrocarbons, fractionating the said mixture of normally gaseous hydrocarbon products to separate hydrogen and methane constituents therefrom and discharging such separated constituents from the system, thereby forming a normally gaseous mixture of materially increased concentration of unsaturated hydrocarbons, introducing as the aforedescribed recycledgaseous hydrocarbons at least a portion of the resulting concentrated heavier normally gaseous hydrocarbons into the first mentioned stream of oil and subjecting the unsaturated constituents of said gaseous hydrocarbons to a polymerization reaction for the first time subsequent to said concentrating operation to form normally liquid gasoline-like products. in the presence of the oil stream undergoing cracking into gasoline-like products, with the result that a marked increase in gasoline-like products is effected in the process and there is produced a gasoline product having relatively high anti-knock properties.

2. The method of converting hydrocarbon oils into gasoline-like products which comprises heating a flowing stream of oil during its flow through an elongated passageway to a cracking temperature while maintaining it under a high superatmcspheric pressure, maintaining the oil stream at said temperature and under said pressure until the desired conversion into gasoline-like products is eifected, thereafter passing the stream of reaction products from said passageway to a separating zone wherein heavy tarry residues are separated in liquid form and lighterproducts are separated in vapor form, collecting said tarry residues without returning any of them to the oil stream undergoing cracking, separately withdrawing vapors from said separating zone and fractionating them to separate therefrom as separate fractions desired gasoline-like products and a mixture of light normally gaseous hydrocarbon products comprising hydrogen, methane and heavier unsaturated normally gaseous hydrocarbons, fractionating the said mixture of normally gaseous hydrocarbon products to separate hydrogen and methane constituents therefrom and discharging such separated constituents from the system, thereby forming a normally gaseous mixture of materially increased concentration of unsaturated hydrocarbons and directlyintroducing at least a portion of the said concentrated heavier normally gaseous mixture into the said elongated I passageway to admix with the oil therein subjected to cracking and be subjected to thermal conversion for the first time following said concentrating operation,- whereby the unsaturated constituents of said gaseous hydrocarbons undergo a polymerization reaction to form normally liquid gasoline-like products in the presence of the oil stream undergoing cracking into gasoline-like products, with the result that a marked increase in gasoline-like products is effected in the proeess and there is produced a gasoline product having relatively high anti-knock pr perties.

3. The method of converting hydrocarbon oil's into gasoline-like products which comprises heating a flowing stream of oil during its flow through an elongated passageway to a cracking temperature while maintaining it under a. high superatmospheric pressure, maintaining the .oil stream at said temperature and under said pressure until the desired conversion into gasolinelike products is effected, thereafter passing the stream of reaction products from said passageway to a separating zone wherein heavy tarry residues are separated in liquid form and lighter products are separated in vapor form, collecting said tarry residues without returning any of them to the oil stream undergoing cracking, separately withdrawing vapors from said separating zone and fractionating them to separate therefrom as separate fractions desired gasoline-like products,

and discharging such separated constituents from the system thereby forming a normally gaseous 0 mixture of materially increased concentration of unsaturated hydrocarbons, returning reflux condensate from the aforesaid fractionating operation to said elongated passage for further cracking therein, and directly introducing at least 15 a portion of the said concentrated heavier normally gaseous mixture into the said'elongated passageway to admix with the oil therein subjected to cracking and be subjected to thermal conversion for the first time following said con- 20 centrating operation, whereby the unsaturated constituents of said gaseous hydrocarbons undergo a polymerization reaction to form normally liquid gasoline-like products in the presence of the oil stream undergoing cracking into gaso- 2; line-like products, with the result that a marked increase in gasoline-like productsis efiected in the process and there is produced a' gasoline product having relatively high anti-knock properties. I 3) 4. The method of converting hydrocarbon oils into gasoline-like products which comprises heating a flowing stream of oil during its flow through an elongated passageway to a cracking are separated in vapor form, collecting said tarry 45 residues without returning any of them to the oil stream undergoing cracking, separately withdrawing vapors from said separating zone and fractionating them to separate therefrom as separate fractions desired gasoline-like products and a mixture of light normally gaseous hydrocarbon products comprising hydrogen, methane and heavier unsaturated normally gaseous hydrocarbons, fractionating the said mixture of normally gaseous hydrocarbon products to separate hydrogen and methane constituents therefrom and discharging such separated constituents from the system, thereby forming a normally gaseous mixture of materially increased concentration of unsaturated hydrocarbons, and directly introducing at least a portion of the said concentrated heavier normally gaseous mixture into the'said elongated passageway to admix with the oil therein subjected to cracking and be subjected to thermal conversion for the first time following '65 said concentrating operation, whereby the unsaturated constituents of said gaseous 'hydro-. carbons undergo a polymerization reaction to form normally liquid gasoline-like products in the presence of the oil stream undergoing cracking into gasoline-like products, with the result that a marked increase in'gasoline-like products is effected in the process and there is produced a gasoline product having relatively high antiknock properties.

, atmospheric pressure, maintaining the oil stream an elongated passageway to a cracking temperature, while maintaining it under a high superat said temperature and under said pressure until' the desired conversion into gasoline-like products is effected, thereafter passing the stream of reaction products from said passageway to a separating zone wherein heavy tarry residues are separated in liquid form and lighter products are separated in vapor form,,collectin g said tarry residues without returning any of them to the oil stream undergoing cracking, separately withdrawing vapors from said separating zone and fractionating them to separate therefrom as separate fractions desired gasoline-like products and a mixture of light normally gaseous hydrocarbon products, subjecting at least a portion of said normally gaseous hydrocarbon products to thermal treatment to crack unsaturated constituents thereof into normally gaseous olefines, fractionating the resulting converted gases to separate hydrogen and methane constituents therefrom and discharging such separated constituents from the system, thereby forming a normally gaseous mixture of materially increased concentration of unsaturated hydrocarbons, and directly introducing at least a portion of the said concentrated heavier normally gaseous mixture into the said elongated passageway to admix with the oil therein subjected to cracking and be subjected to thermal conversion for the first time following said concentrating operation, whereby the unsaturated constituents of said gaseous hydrocarbons undergo a polymerization reaction to form normally liquid gasoline-like products in .the presence of the oil stream undergoing cracking into gasoline-like products, with the result that a marked increase in gasoline-like products is effected in the process and thereis produced a gasoline product having relatively high antiknock properties.

.6. The method of converting hydrocarbon oils into gasoline-like products which comprises heating a flowing stream of oil during its flow through an elongated pasageway to a cracking temperature of the order of from about 800 F.

'to as high as 1000 F. while maintaining it under a high superatmospheric pressure of the order of from about 100 to as high as 1000 pounds per square inch, maintaining the oil stream at said temperature and under said pressure until the desired conversion into gasoline-like products is efiected, thereafter passing the stream of reaction products from said passageway to a separating zone wherein heavy tarry residues are separated in liquid form and lighter products are separated in vapor form, collecting said tarry residues without returning any of them to the oil stream undergoing cracking, separately withdrawing vapors from said separating zone and fractionating them to separate therefrom as separate fractions desired gasoline-like products and a mixture of light normally gaseous hydrocarbon products, subjecting at least a portion of said normally gaseous hydrocarbon products to thermal treatment at temperatures of the order of about 1400 F. to about 1600 F. to crack unsaturated constituents thereof intonormally gaseous olefines. fractionating the resulting converted gases to separate hydrogen and methane constituents therefrom and discharging such separated constituents from the system, thereby forming. a normally gaseous mixture of materially increased concentration of unsaturated hydro- 5 carbons, and directly introducing at least a portion of said concentrated heavier normally gaseous mixture into the said elongated passageway to admix with the oil therein subjected to cracking and be subjected to thermal conversion for the first time following said concentrating operation, whereby the unsaturated constituents of said gaseous hydrocarbons undergo a polymerization reaction to form normally liquid gasolinelike products in the presence of the oil stream undergoing cracking into gasoline-like products, with the result that a, marked increase in gasoline-like products is effected in the process and there is produced a gasoline product having relatively high anti-knock properties. '7. A method of converting hydrocarbon oils= into gasoline-like products which comprises flowing a stream of oil through an elongated passageway while maintaining the oil under a high superatmospheric pressure, cracking the stream of oil during its flow through said passageway, in the presence of recycled unsaturated normally gaseous hydrocarbons formed in the process and from'which substantial amounts of hydrogen and methane have been removed, to produce products including gasoline-like products and a mixture of light normally gaseous hydrocarbon products comprising hydrogen, methane and heavier normally gaseous unsaturated hydrocarbons, passing the stream of reaction products from said passageway to a separating zone wherein heavy tarry residuesare separated in liquid form and lighter products are separated in vapor form, collecting said tarry residues without returning any of them to the oil undergoing cracking, separately withdrawing vapors from said separating zone and fractionating, them to separate therefrom as separate fractions desired gasoline-like products and a mixture of light normally gaseous hydrocarbon products comprising hydrogen, methane and heavier unsaturated normally gaseous hydrocarbons, fractionating the said mixture of normally gaseous hydrocarbon products to separate hydrogen and methane constitutents therefrom and dis-. charging such separated constituents from the system thereby forming a normally gaseous mixture of materially increased concentration of unsaturated hydrocarbons and comprising ethylene and propylene and their saturated analogs substantially free from higher or lower boiling materials, introducing as the aforedescribed recycled gaseous hydrocarbons at least a portion of theresulting concentrated heavier, normally gaseous hydrocarbons into the first mentioned 0 stream of oil and subjecting the unsaturated constituents of said gaseous hydrocarbons to a polymerization reaction for the first time subsequent to said concentrating operation to form normally liquid gasoline-like products in the presence of the oil stream undergoing cracking into gasoline-like products, with the result that a marked increase in gasoline-like products is effected in the process and there is produced a gasoline product having relatively high antiknock properties,

FREDERICK W. SULLIVAN, JR.

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