US1649345A - Method of and apparatus for making gasoline - Google Patents

Description

Nov. 15, 1927. 1,649,345

F. E. GILMORE METHOD OF AND APPARATUS FOR MAKING GASOLINE Filed Auz. 5, 1924 L i m9 ymatfidf m #1: Arron/vars.

Patented Nov. 15, 1927.

UNITED STATES FORREST E. GILMORE, OF LOS .ANGELES 1,649,345 PATENT OFFICE.

CALIFORNIA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, OF ONE-SIXTH TO FRANK AHLBURG, OF LOS ANGELES, CALI- FORNIA, AND ONE-SIXTH TO WILLIAM K. WHITE, OF SAN FRANCISCO, CALIFORNIA.

Application filed August 5, 1924. Serial No. 730,197.

My invention .relates to the manufacture of gasoline and particularly to the condensation and stabilization of gasoline produced in an absorption plant. 0

One of the objects of the invention is the provision of an apparatus for and method of increasing the yield of stable gasohne in an absorption plant.

Another object of the invention is the utilization and control of the heat in the vapors received from the still so that additional heat is not required in the apparatus.

Another object of the invention is the provision'of an apparatus for and method of condensing the Vapors and stabilizing the product simultaneously.

Another object of the invention is to provide an apparatus for and method of handling the gasoline containing gases from the still in a closed circuit the condensed liquids being collected as they are formed and the uncondensible gases recirculated until" as residue gases which are practically non-con-- densible, they are finally eliminated.

My invention possesses other objects and features of advantage, some of which, with the foregoing, will be setforth in the following description of my invention. It is to be understood that I do not limit myself to the showing made by the said description as I may adopt variant forms of the invention within the scope of the claims.

In the accompanying drawing I have shown in diagra-mmatical form an apparatus which I have found satisfactory in the practice of my process.

Natural gas gasoline is a mixture of various hydrocarbon co'upounds, nearly all of which, under ordinary conditions of temperature and pressure, are in the liquid form. During the separation of the gasoline from the natural gas these liquidstend to absorb such hydrocarbons as propane and butane, which under ordinary conditions of temperature and pressure are gases and which therefore tend to return .to their natural gaseous condition from the gasoline in which they are absorbed. As a result of the low boiling point of propane, its presence in the natural gasoline. makes the gasoline extremely volatile or wild and in weathering the product to reduce the vapor tension much good gasoline is lost. Butane which has a higher boiling point and a lower vaordinary temperatures and pressures, and is a desirable part of the gasoline; hexane, heptane and octane, all being stable. liquids and with relatively high boiling points.

By the absorption process gasoline in the natural gas is absorbed by the absorption oil because of the aflinity between the two, the attraction of the oil being greater for the more stable hydrocarbons; and more of these are therefore absorbed into the oil. This attraction increases with an increase in pressure on thegas and 011, while the ElbSOIPlJlOIl process is taking place, as Well as with a decreasein temperature. In order to absorb nearly all of the stable constituents of the natural gas it is necessary to absorb a large proportion of the unstable constituents.

During the subsequent distillation both stable and unstable constituents pass over and are cooled and condensed together under pressure, the stable constituent absorbing part of the unstable ones and making a mixture which is very volatile. The uncondensed vapors are found to contain a large proportion of good gasoline. If these vapors are compressed and cooled, a very highly volatile liquid is obtained comprising some gasoline and some liquefied gas. Before this product can be used, it is necessary to Weather it, but in the ordinary way, the weathering process permits the liquefied gas to carry off much of the gasoline. Even after Weathering, enough of the liquefied gas staysin solution to make the product too volatile.

From the above it will be clear that it is highly desirable to handle the vapors from the still in such manner that substantially all of the gasoline is retained in liquid form in the condensed product and all the liquefied gases eliminated. This would give a product having a vapor tension'of not'over five pounds at 100 F. with an initial boiling point of about 95 F. While this desirable result cannot be attained wholly, I have provided an apparatus for and method of condensing the containing vapors and stabilizing the resultant product simultaneously with very considerable saving over -any process heretofore known in gasoline recovery, and giving a stabilized product of superior quality and desirable specification.

From the still 2 in which the absorption 011 is treated, the products of distillation are passed thru the pipe 3 to a condenser 4, in the coils 6 of which the containing vapors are inltlally cooled. The vapors are then passed thru the pipe 7 to a second condenser 8,

.' which brings the temperature of the vapors down to about 90 F. A port-ion of the vapors is here liquefied and flows thru the pipe 9 into the base of the tower 11, adjacent the bottom of which the pipe 9 is connected, where it collects in the body of gasoline 12. A pipe 13 extends upwardly from the pipe 9 and is connected into the tower above the level of the liquid 12 so as to provide a passage for the entrance of the uncondensed vapors from the condenser 8.

The supply of water to the co ndenser 8 is.

' regulated by the diaphragm valve 16- controlled by the thermostat 17, arranged in the vapor discharge passage, so that if the temperature of the gases falls, the amount of water flowing to the condenser 8 is restricted to permit the temperature to rise; and conversely if the temperature of the vapors to the accumulator tank 38.

rises, more water is supplied to the con- I denser 8 thus effecting a decrease in the tem- ,body 23 of bafiiing material such as small pieces of porcelain, the function of which is to divide the condensate flowing there over so that the ascending gases may come into the most intimate contact possible with the condensate. Two other masses of battling material 26 and 27'are disposed atintervals above the main body 23.

Connecting into the top of the tower is a conduit 31, leading thru the back pressure regulator 32, to the compressor 33,

which discharges thru the pipe 34, into the condenser 36, and thence thru the, pipe 37 a The bottom oli the accumulator tank is connected by the pipe 41, with a plurality of branch pipes 42,

which terminate in spray heads 43, in vertical alinement centrally in the up er portion of the tower. The lower spray ead is disposed above theimain body of bafliing mate' rial 23, and the other two spray heads are "the top of the accumulator tank thru the .opened to mulator tank, This reduces gasoline condensed in the condenser 36, and

disposed in the spaces above the bodies of baliling' material 26 and 2'1 respectively. p

The passage from the accumulator tank into the pipe 41, is .controlled by a liquid level controller 44 of known design and the 7) top of the accumulator tank is vprovided with a residue or waste gas'discharge pipe 46, controlled by the valve 47 which in turn is controlled by a thermostat 48, arranged in the tower 11.

Uncondensed vapors are drawn out of the top of the tower thru the pipe'31, and the condensible portion liquefied by the action of the compressor and condenser 36. .This con densate which may be termed the secondary condensate to distinguish it from the initial condensate from the vapors when they first enter the tower, flowswith the non-condensible or residue gases into the accumulator tank 38, where the liquid settles to the bottom and the gases collect in the top. The pressure in the tower is much less than in the accumulator tank and is regulated to the required degree by the back pressure valve 32. Condensate from the accumulator tank therefore flows thru the pipe 41, and is introduced into the top of the tower thru the spray head'sl43, trickling down over the baffling material and absorbing gasoline from the rising vapors as it passes downwardly The sprays exert a pronounced cooling effect in the top of the towerdue to the evaporation of a portion ofthe condensate, and this further cools and condenses the ascending vapors. The condensed gasoline descends thru the tower and becoming warmer as it absorbs gasoline-from the warm rising vapors gives ofi the gases in solution and collects at the bottom of the tower as stable gasoline. All uncondensed gases released from the secondary condensate mingle with the ascending vapors and again pass thru the circuit of compressor. condenser and accumulator tank, the only escape being jrom valve 47. Only such gases as resolutely re-' sist condensation are found to pass this point. 'The valve 47 controlling the residue pipe 46, is regulated by the. thermostat 48, so that when the temperature .within the tower falls too low, the valve is somewhat release the residue gas and reduce the pressure on the condensate in the accuthe amount of also the amount of gasoline sprayed into the top of the tower. With a decrease in the amount of condensate sprayed into the top of the tower, the cooling effect of the sprays is lessened andthe temperature increases to apoint where the thermostat automatically lessens the escape of residue gas thus increasing the amount of condensation in the .condenser'36, andthe amount of gasoline or condensate sprayed into the top of the tower.

An automatic regulation of temperature Within the tower is thus maintained at a substantially constant point, and this is so balanced that all the heat required is that per mitted vtoremain in the still gases. This results in a stable product collecting in the bottom of the tower and having known characteristics which are the resultant of all of the controlled factors.

The circulation of the uncondensed gases from the top of the tower thru the compressor, condenser, accumulator tank and sprays, and the intimate contact between the descending condensate and the ascending vapors result in a product at the bottom of the tower substantially free from absorbed gases and containing substantially all of the gasoline content of the original vapors in a stable form.

The accumulations of gasoline in the bottom of the tower above a certain depth, pass from the tower thruthe look-box 51 and pipe 52, to the run tank 53 which is of usual construction and thence thru the trap- 54 to suitable storage tanks. The top of the run tank is ,connected by the pipe 56 into the tower so that gases rising from the product in the tank may pass back into the vapor stream in the tower to be again treated.

The resultant product of my process, while retaining substantially all of the gasoline constituents of the containing vapors, is substantially free from the practically non-con densible gas in solution and can be loaded, unloaded, transferred or blended with losses which are almost negligible. The transfer losses will average but a fraction of 1% and are in marked contrast with the heavy losses heretofore experienced in handling natural gas gasoline even when blended with the straight refinery product.

In distillation tests the superiority of my stabilized gasoline is very noticeable. Distillation recoveries of 97% to 98% are easily obtained in the finished motor gasoline. The higher recovery thus permits the addition of heavy naphtha fractions without detracting from the quality of the finished gasoline.

I claim:

1. An apparatus for recovering gasoline from vapors containing the same comprising a chamber, means for introducing the vapors into the chamber adjacent the bottom, an accumulator tank connected into the top of said chamber, a compressor and a condenser interposed in the connection between the tank and chamber, means for conveying condensate from the accumulator tank into the chamber adjacent the top, a valve controlled residuegas discharge pipe connected into said accumulator tank, means responsive to the temperature in said chamber for controlling said discharge-pipe valve, bafiling elements inv said chamber over which the condensate flows in contact with the ascending vapors, and a back pressure valve interposed between the compressor and the chamber.

2. An apparatus for recovering gasoline from vapors containing the same comprising atower thru which the vapors ascend and in the base of which the product collects, means for introducing the vapors into the tower adjacent the bottom, an accumulator tank connected into the top of said tower, a compressor and a condenser interposed in the connection between the tank and tower, means for conveying condensate from the accumulator tank into the tower adjacent the top, a valve controlled residue-gas discharge pipe 3 connected into sald accumulator tank, means r80 responsive to the temperature in said tower for controlling said discharge-pipe valve. bafiling elements in said tower'over which the condensate flows in contact with the ascending vapors, a back pressure valve interposed between the compressor and the tower, and means for continuously removing the product from the base of the tower.

In testimony whereof, I have hereunto set my hand.

FORREST E. GILMORE.

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