US1937759A

US1937759A - Art of refining

Info

Publication number: US1937759A
Application number: US648763A
Authority: US
Inventors: Eugene C Herthel
Original assignee: Sinclair Refining Co
Current assignee: Sinclair Refining Co
Priority date: 1932-12-24
Filing date: 1932-12-24
Publication date: 1933-12-05
Anticipated expiration: 1950-12-05

Description

Dec. 5, 1933. E. c. HERTHEL 1,937,759

ART 0F REFINING Filed Dec. 24. 1952 2 Sheets-Sheet 1 INVENTOR Faye/7e C flerf ie/ ATTORNEY 5 Dec. 5, 1933. Q HERTHEL 1,937,759

'ART OF REFINING INVENTOR Faye/76 C Her ffie/ ATTORNEYS Patented Dec. 5 1933 PATENT OFFICE ART or REFINING Eugene C. Herthel, Flossmoor, 111., assignor to Sinclair Refining Company, New York, N. Y., a

corporation of Maine Application December 24, 1932 Serial No. 648,763

5 Claims.

This invention relates to improvements in the manufacture of gasoline by cracking higher boiling hydrocarbon oils, such as gas oil, at temperatures exceeding 900 F. to produce cracked gasoline of high anti-knock value.

The severe cracking temperatures utilized .to produce gasoline of high anti-knock value, temperatures exceeding 900 F. for example, tend to produce gasoline fractions including lower boiling constituents, lower boiling within the range of the gasoline fraction, in high concentration, the production of such low boiling gasoline constituents accompanying, within limits, the production of even lower boiling constituents incondensible at ordinary atmospheric temperatures and pressure. These severe cracking temperatures also tend to produce unstable hydrocarbon constituents which, although initially within the boiling range of gasoline, tend to polymerize to form higher boiling polymers, gums for example. Such gasolines require stabilization both physically and chemically. This invention combines a physical stabilization and a chemical stabilization in a particularly advantageous manner.

According to the present invention, the raw cracked gasoline fraction, produced by cracking at temperatures exceeding 900 F., is separated into two liquid fractions, one containing those constituents higher boiling than butane and the other containing butane and lower boiling constituents. The higher boiling separated fraction is contacted with an adsorptive catalyst, fullers earth or similar clays for example, at an elevated temperature, upwards of about, 350 F. and below the critical temperature of the separated fraction, under a pressure sufficient to maintain the separated fraction substantially in liquid phase, and a gasoline'fraction' free from constituents higher boiling than suitable as components of the gasoline product is distilled from this contacted fraction. Propane andlower boiling constituents are separated from the lower stantial proportion of higher boiling constitu ents. Polymers produced by the oil-catalyst con- -tact will form at least a part of this necessary higher boiling fraction, but it is usually advantageous to have present a somewhat larger proportion of higher boiling components. Such additional higher boiling components may be supplied as part of the fraction subjected to contact with the adsorptive catalyst or as an extraneous fraction added subsequent to the oil-catalyst contact. In the latter case, the added extrane ous fraction should be free from unstable constituents. Such an extraneous fraction may be added prior to the oil-catalyst contact, and this part of the combined operation of the invention can thus be carried out in the manner described in Letters Patent Number 1,823,175, granted to Sinclair Refining Company September 15, 1931, on an application of James G. Stafiord. This contact with an-adsorptive cata- 7. lyst may be supplemented, and particularly where carried out at temperatures below about 385 F. is with advantage supplemented, by a mild sulphuric acid treatment. A relatively mild sulphuric acid treatment is usually sufilcient in 39 this connection. By carrying out the oil-catalyst contact at higher temperatures, however, upwards of about 385 F., such sulphuric acid treatment can usually be omitted. When the higher boiling initially separated liquid fraction is contacted with the adsorptive catalyst at temperatures in the higher range, the heat imparted to the oil in this connection is with advantage utilized in effecting distillation of the gasoline frac' tion from the contacted fraction, by reducing the pressure on the contacted fraction while at maintained elevated temperature.

Several important advantages are secured by the practice of this invention. The combined op eration includes a particularly advantageous chemical stabilization of the higher boiling components of the final gasoline product. The emciency of thischemical stabilization, the contact refining operation, is improved, and the capacity of any particular apparatus in which it is carried out is increased, by reducing the proportion of the final gasoline product subjected to the oilcatalyst contact. This reduction in the proportion of the final gasoline product subjected to the contact refining is, moreover, accomplished,

in the combined operation of the invention, as a part of the physical stabilization but without complication of that part of the operation. The elimination of the lower boiling gasoline components from the traction contacted with the adsorptive catalyst not only reduces the burden on the contact-refining" part of the operation but also enables the separate chemical stabilization of this lower boiling part of the final gasoline product in a particularly advantageous manner, namely by treatment with caustic alkali. An improved realization of the advantages of the physical stabilization and the chemical stabilization, in separate treatments of two distinct fractions, is further accomplished by the particular manner in which they are combined in the process of the present invention. 7

The invention will be further described in connection with the accompanying drawings. In the accompanying drawings, Fig. 1 represents, diagrammatically and conventionally, one form of apparatus adapted for carrying out the invention, more particularly with temperatures in the lower range of oil-catalyst contact temperatures, and Fig. 2 represents, diagrammatically and conventionally, another form of apparatus adapted for carrying out the invention, more particularly with temperatures in the higher range of oil-catalyst contact temperatures.

This invention is useful in conjunction with cracking processes generally in whichcracking is effected at temperatures exceeding 500 F.

Since the particular type of such cracking operations is not essential to characterization of this invention, and since such cracking operations are in themselves Well known, the drawings include no illustration of cracking-apparatus. The raw cracked gasoline or raw cracked gasolinecontaining fraction is delivered from the cracking apparatus to the tank 3 or the tank 103, in Figs. 1 and 2 respectively, in the apparatus illustrated in the drawings.

Referring more particularly to Fig. l, the raw cracked gasoline fraction is pumped from the tank 3, by means of pump 4, through a heat exchanger 5 into a fractionating tower 6 in which it is separated into two fractions, one containing those constituents higher boiling than butane and the other containing butane and lower boiling constituents. Fractionating towers so employed are commonly designated debutanizers. The operation of the fractionating tower 6 is controlled by the regulated circulation of a heating medium through the re-boiler 7 and the regulated circulation of a cooling medium through the reflux condenser 8. The heat required in this fractionating operation is supplied either through the reboiler 7 or in part through the re-boiler '7 and in part through the heat exchanger 5. The higher boiling fraction is discharged as a liquid from the re-boiler 7 through connection 9. The vapor mixture escaping from the reflux condenser 8 is subjected to condensation in the condenser 10, the condensate and uncondensed vapors and gases are separated in the receiver 11, the uncondensed vapors and gases are discharged through connection 12 and the condensate is discharged as a liquid through connection 13 to tank 14. The fractionating tower 6 is, for example, operated under a pressure approximating 100-150 pounds per square inch. Under these conditions the liquid fraction discharged from the re-boiler 7 through connection 9 is usually discharged at a temperature upwards of about 350 F. The higher boiling liquid fraction discharged through connection 9 is supplied to the contact vessel 15 at the elevated temperature at which it is discharged from the reboiler 'l. 350-385 F., for example, and under a maintained pressure, upwards of 100 pounds per square inch for example. In the contact vessel 15 this higher boiling fraction is contacted with an adsorptive catalyst, fullers earth or similar clays, at this elevated temperature and under a pressure sufficient to maintain this fraction substantially in liquid phase. The contacted fraction is discharged from the contact vessel 15 through cooler 16 into the tank 17, the pressure on the contacted fraction being reduced approximately to atmospheric pressure as it passes from the cooler 16 into the tank 17. i The contacted fraction is pumped from the tank 17 by means 01' pump 18 through the treating vessels 19 in which it is subjected to treatment with sulphuric acid in a manner conventional except for the use of relatively small proportions of sulphuric acid, one pound of 66 B. sulphuric acid per barrel as compared to live to eight pounds of such acid per barrel for example, and thence into tank 20. The contacted and acid-treated fraction is pumped from the tank 20 by means of pump 21 through the heater 22 into the fractionating tower 23 in which a gasoline fraction free from constituents higher boiling than suitable as components of the gasoline product is separated from higher boiling components of the contacted and acid-treated fraction and any extraneous fraction added to assist in the fractionation. Such an extraneous fraction, supplied through connection 24, may be admixed with the fraction entering the treating vessels 19 from the tank 17 or may be introduced into the tank 20in amount suflicient to provide a higher boiling fraction to be separated in rrac= tionating tower 23 as a condensate approximating, for example, 10% of the lower boiling fraction separated as a vapor mixture. The fractionating tower 23 is controlled by regulated circulation 01 a cooling medium through the reflux condenser 25. The fractionating tower 23 is, for example, operated under approximately atmospheric pressure, although by provision of appropriate conventional apparatus it may be operated under subatmospheric pressure. Considered alone, the operation of the heater 22 and the fractionating tower 23 corresponds to the conventional re-rimning or redistillation of treated gasoline, and is carried out in the conventional manner except in that in the combined operation of this invention the lower boiling part of the gasoline is not included in the re-run" stock. The higher boil- I ing fraction separated in the fractionating tower 23 is discharged through cooler 26. This fraction, for example, maybe supplied to a cracking operation, the cracking operation producing the raw cracked gasoline fraction delivered to tank 3. The vapor mixture escaping from the reflux condenser 25 is subjected to condensation in the condenser 27, and the condensate is discharged as a liquid through connection 28 to tank 29. The lower boiling fraction separated in the fractionating tower 6 is pumped from the tank 14 by means of pump 30 through a heat exchanger 31 into a fractionating tower 32 in which propane and lower boiling constituents are separated as a gas mixture from the remaining higher boiling constituents of the fraction. Fractionating towers so cmployed are commonly designated stabilizers..

The operation of the fractionating tower 32 is controlledby the regulated circulation of a heater 31. The separated gas mixture is discharged through connection 34. The separated liquid fraction is discharged through cooler and through the treating vessel 36 in which it is subjected to treatmentv with an aqueous solution of caustic alkali'in the conventional manner to tank 37. The fractionating tower 32 is, for example, operated under a pressure approximating 150-300 pounds per square inch. The fractions accumulating in the tanks 29 and 37, jointly stabilized physically and separately stabilized chemically, are combined and, by means of pump 38, are forced as 'a mixture constituting a full boiling range gasoline productthrough the treating vessels 39 in which the mixture is subjected to-the The final is discharged through connecconventional sweetening operation. gasoline product tion 40. i

Referring more particularly to Fig. 2, the raw cracked gasoline fraction is pumped from the tank 103', by means of pump 104, through a heat exchanger 105 into a fractionating tower 106 in which it is separated into two fractions, one con-' taining those constituents higher boiling than butane and the other containing butane and lower boiling constituents Some pentanes may be separated with'the butane and lower boiling constituents to ,insure complete separation of butane. The operation of the fractionating tower 106 is controlled by the regulated circulation of a heating medium through the re-boiler 107 and the regulated circulation of a cooling medium through the'reflux condenser 108. The heat required in this fractionating operation is supplied either through the re-boiler 107 or in part through the re-boilei; 107, and in part through the heat exchanger 105. The higher boiling fraction is discharged as a liquid from the re-boiler 107 through connection 109. The vapor mixture escaping from the reflux condenser 108 is subjected to condensation in the condenser 110, the condensateand uncondensed vapors and gases are separated in the receiver 111, the uncondensed vapors and gases are discharged through connection 112 and the condensate is discharged as a liquid through connection 113 to tank 114. .The fractionating tower 106 is, for example, operated under a pressure approximating 100-150 pounds per square inch. Under these conditions a liquid fraction discharged from'the reboiler 107 through connection 109 is usually discharged at a temperature upwards of about 350 F. The higher boiling liquid fraction discharged through connection 109 is pumped, by means of pump 141, through the heater 122 and through the contact vessel 115 into the fractionating tower 123. In the heater 122 this fraction is heated, for example, to a temperature of 385-450 F. under a pressure sufficient to maintain this fraction substantially in liquid phase, a pressure approximating 250 pounds per square inch for example. In the contact vessel 115 this fraction is contacted, under a maintained pressure, with an adsorptive catalyst, fulle'r's earth or similar clays, at the elevated temperature at which it is discharged from the heater 122. The contacted fraction is discharged into the fractionating tower 123 through a valve line product is separated from higher boiling fraction to be separated in fractionating tower 123 asa condensate approximating, for example, 10% of the lower boiling fraction separated as a vapor mixture. The fractionating tower 123 is controlled by regulated circulation of a cooling medium through the reflux condenser 125. The fractionating tower 123 is, for example, operated under approximately atmospheric pressure, although by provision of appropriate conventional apparatus it may be operated under subatmospheric pressure. The higher boiling fraction separated in the fractionating tower 123 is discharged through cooler 126. This fraction, for example, may be supplied to a cracking operation, the cracking operation producing the raw cracked gasoline fraction delivered to tank 103. The vapor mixture escaping from the reflux condenser 125 is subjected to condensation in the condenser 127, and the condensate is discharged as a liquid through connection 128 to tank 129. The lower boiling fraction separated in the fractionating tower 106 is pumped from the tank'114 by means of pump 130 through a heat exchanger 131 into a fractionating tower 132 in which propane and lower boiling constituents are separated as a gas mixture from the remaining higher boiling constituents of the fraction. The operation of the fractionating tower 132 is controlled by the regulated circulation of a heating mediumthrough there-boiler 114 and the regulated circulation of a cooling medium through the reflux condenser 133. The heat required in this fractionating operation is supplied either through the re-boiler 144 or in part through the re-boiler 144 and in part through the heat exchanger 131. The separated gas mixture is discharged through connection 134. The separated liquid fraction is discharged through cooler 135 and through the treating vessel 136 in which it is subjected to treatment with an aqueous solution of caustic alkali in the conventional manner to tank 137. The fractionating tower 132 is, for example, operated under a pressure approximating -300 pounds per square inch. The fractions accumulating in the tanks 129 and 137, jointly stabilized physically and separately stabilized chemically, are combined and, by means of pump 138, are forced as a mixture constituting a full boiling range gasoline product through the treating vessels 139 in which the mixture is subjected to the conventional sweetening operation. The final gasoline product is discharged through connection 140. v p

The uncondensed vapors and gases'discharged through connection 12, or connection 112, usually contain gasoline constituents which make it appropriate to subject this vapor mixture to conventional recovery operations. The gas mixture escaping through connection 34, or connection 134, is usually substantially free from condensable gasoline constituents.

I claim:

1. In the manufacture of gasoline by cracking higher boiling oils at temperatures exceeding 900 F., the improvement which comprises separating the raw cracked gasoline fraction into two liquid fractions, one containing those constituents higher boiling than butane and the other contain- 150 ing butane and lower boiling constituents, contacting the higher boiling separated fraction with an adsorptive catalyst at an elevated temperature upwards of about 350 F. and below its critical temperature under a pressure sufficient to maintain it substantially in liquid phase, distilling a gasoline fraction free from constituents higher boiling than suitable as components of the gasoline product from the contacted fraction, separating propane and lower boiling constituents from the lower boiling initially separated fraction, treating the higher boiling separated fraction from the last mentioned separation with caustic alkali, and combining the alkali treated fraction and the distilled gasoline fraction.

2. In the manufacture of gasoline by cracking higher boiling oils at temperatures exceeding 900 F., the improvement which comprises separating the raw cracked gasoline fraction into two liquid fractions, one containing those constituents higher boiling than butane and the other containing butane and lower boiling constituents, contacting the higher boiling separated fraction with an adsorptive catalyst at an elevated temperature upwards of about 350 F. and below its critical temperature under a pressure suificient to maintain it substantially in liquid phase, treating the contacted fraction with sulphuric acid, distilling a gasoline fraction free from constituents higher boiling than suitable as components of the gasoline product from the contacted and acid treated fraction, separating propane and lower boiling constituents from the lower boiling initially separated fraction, treating the higher boiling separated fraction from the last mentioned separation with caustic alkali, and combining the alkali treated fraction and the distilled gasoline fraction.

3. In the manufacture of gasoline by cracking higher boiling oils at temperatures exceeding 900 F., the improvement which comprises separating the raw cracked gasoline fraction into two liquid fractions, one containing those constituents higher boiling than butane and the other containing butane and lower boiling constituents, contacting the higher boiling separated fraction with an adsorptive catalyst at an elevated temperature upwards of about 350 F. and below its critical temperature under a pressure sufficient to maintain it substantially in liquid phase, distilling a gasoline fraction free from constituents higher boiling than suitable as components of the gasoline product from a mixture including the contacted fraction and an added fraction including higher boiling constituents, separating propane and lower boiling constituents from the lower boiling initially separated fraction, treating the higher boiling separated fraction from the last mentioned separation with caustic alkali, and combining the alkali treated fraction and the distilled gasoline fraction.

4. In the manufacture of gasoline by cracking higher boiling oils at temperatures exceeding 900 F., the improvement which comprises separating the raw cracked gasoline fraction into two liquid fractions, one containing those constituents higher boiling than butane and the other containing butane and lower boiling constituents, contacting the higher boiling separated fraction with an adsorptive catalyst at an elevated temperature upwards of about 385 F. and below its critical temperature under a pressure sufficient to maintain it substantially in liquid phase, distilling a gasoline fraction free from constituents higher boiling than suitable as components of the gasoline product from the contacted fraction, separating propane and lower boiling constituents from the lower boiling initially separated fraction, treating the higher boiling separated fraction from the last mentioned separation with caustic alkali, and combining the alkali treated fraction and the distilled gasoline fraction.

5. In the manufacture of gasoline by cracking higher boiling oils at temperatures exceeding 900 F., the improvement which comprises separating the raw cracked gasoline fraction into two liquid fractions, one containing those constituents higherboiling than butane and the other containing butane and lower boiling constituents, contacting the higher boiling separated fraction with an adsorptive catalyst at an elevated temperature upwards of about 350 F. and below its critical temperature under a pressure sufficient to maintain it substantially in liquid phase, distilling a gasoline fraction free from constituents higher boiling than suitable as components of the gasoline product from the contacted fraction by reducing the pressure thereon while at maintained elevated temperature, separating propane and lower boiling constituents from the lower boiling initially separated fraction, treating the higher boiling separated fraction from the last mentioned separation with caustic alkali, and combining the alkali treated fraction and the distilled gasoline fraction.

EUGENE C. HERTHEL.

@ERTIFHCATE 0F (IQRRECTION.

Patent No. l, 937, 759,

December 5, 1933.

EUGENE 6. HERTHEL.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Page 2, line 27, tor

"500" read 900; and that the said Letters Patent should be read with this correction therein that-the samemay conform to the record of the case in the Patent Office.

Signed and sealed this9th day of January, l). 1934.

(Seal) F. M. Hopkins Acting Commissioner of" Patents.