US1772331A - Method of and apparatus for treating hydrocarbons - Google Patents

Description

' Aug, 5, 1930 V1 E. WELLMAN 1,773,333I

METHOD OF AND APPARATUS FOR TREATING HYDROCARBONS Filed Feb. 29, 1928 fl ming. s, 1930 1,772,331

UNITED STATES PATENT orrlcr.

FRANK E. WELLMAN, OF KANSAS CITY, KANSAS METHOD OF APPARATUS FOR TREATING HYDROCABBONS I p 1 Application flied February 29, 1828. Serial No. 257,942.

My invention relates to methods of and sure which'drops in the condenser 7 and onl v apparatus for treatment ofhydrocarbon oils, a relatively low pressure is carried through Y and has for its object to recover the expanand beyond the condenser. The expansive sive energy which is now employed in such force represented by the pressure in pipe 4 5 methods and apparatus, and then lost. in this case is lost. 65

In systems for the refining of hydrocarbon I Examples might be multiplied indefinitely, oils in cracking plants, and elsewhere, it is as apparently no such efl'ort has been made to common to heat the oil to produce vapors conserve the pressure energy as there has been which are passed through a suitable pipe line to conserve heat energy, although, as already from the still orretort to a dephlegmator or pointed out, it represents a serious loss. 60 bubble tower on other apparatus. according to According to my present invention, and in the treatment being carried on. The temperaorder to attain my object, I connect a motor in tures and pressures employed in these systhe-vapor line or other portion of the system terms are frequently very high, a. pressure of carrying pressure and preceding a pressure 600 lbs. to the square inch being not uncomdrop, so that there can be no interference mon. These temperatures and pressures, with the normal operation. Accordin to after they have performed their useful func- What I now consider the best method of tions, in point of energy dissipated are very utilizlng this power, I couple. this motor, wasteful. Thus, in large plants of a certain which may convenientlybe a turbine, to a type, the power which goes to waste probably generator, and transmit power electrically to amounts to 100 horsepower. In many plants, points of utilization in the plant. Such turboheat energy is recovered to a certain extent, generator units have been developed to a usually by the use of heat exchangers, counterpoint of high efficiency, and are well known current circulators, or bubble towers. So far in the art. ()f'course, as a modification, it as I am aware, however, nothing of effort is possible to transmit the power mechanically 75 has been made to recover the energy repreand utilize it mechanically, but I have found a sented by the expansive forces due to the pres electrical transmission better for my purposes sure imposed upon the gases and liquids in because it is more flexible and is in line with the course of their treatment, and especially modern standard practice. in the initial or primary distillation and Another very important use which is inso 'cracking thereof. cluded within the scope of my invention is In every such system there are numerous that of supplying supplemental heat either applications of power, including pumps for to a cracking still or to a preheater. By ear the make-up, pressure pumps and pieces of ploying an electric generator unit, it 1s my retreatment apparatus, pumps for forcing purpose to produce current which may be reflux back into the header of a cracking resupplied to all the needs of the lam, intort or pressure still, fans or blowers for cludlng pumps, recirculation of no gases, recirculating flue gases, and electric lighting lighting and the like, and thereafter if there apparatus. Power is usually supplied for be any margin of power left, to add the 40 these from outside sources. V, same in the form of heat to raise the tempera- Specifically stated, my invention has for ture of stills, preheaters and the like. its object to recover the energy represented My invention is illustrated in the accomby the expansive force due to pressure in any panying drawing, in which the figure is a part of a system of the class mentioned and diagram showing a system for the treatment return it in the form of useful work into the of hydrocarbon oils, including a cracking still system, or otherwise usefully employ it. For and reflux line operated under high pressure, example, in a system such as that shown in with my invention applied thereto. U. S. Letters Patent No. 1,119,700, granted Referring'to the drawing, 1 is a substruc- December 1, 1914, to R. E. Humphreys, the ture or base, containing flue 2 leading to a vapor line 4 carries a super-atmospheric presstack and supporting a cracking still 3, from which a reflux line 4; extends obliquely upward to an elevated point where it is fitted with a pressure control valve 5, from which pipe 16 drops to a condenser 7 from which the outlet pipe 9 extends to a receiver 8. In the upper part of thesubstructure is a furnace 1U, fitted with the usual oil burner 11 and fine 2, already mentioned, extending to a stack 12.

In operation, the still 3 is charged with a heavy hydrocarbon liquid, heat is applied thereto, and vapors pass up through the line 4, wherein the heavier fractions are condensed and reflux back into the still for retreatment. The valve 5 is kept closed until the desired operating pressure is obtained, after which it serves to control the pressure and to permit the passage of the lighter fractions suitable for condensation and storage. The drop in pressure outside of the valve 5 is produced by expanding the vapors and condensing them in the condenser 7, and the energy represented by the expansive force due to pressure controlled by the valve 5 is in prior practice dissipated largely as heat in the cooling water, and is thereby lost.

According to my present invention I install a turbo-generator unit 13 with a turbine 14 whose intake 15 is connected to the reflux line 4 through the valve 5, and whose exhaust 16 is connected to the condenser 7. The generator 17 may conveniently be an alternator of standard construction, indicated as furnishing current at 220 volts to the mains 18, which may supply feeders leading to various points in the plant. I have shown an electric lighting circuit 19 thus supplied with current, and a power circuit 20 extending to a motor 21 driving a blower 22 for circulating flue gases, to be presently described. and an electric heater 23 installed in the still 3 for the purpose of returning a portion of the energy in the form of heat to the oil itself.

The circulation of flue gases in the Present case is accomplished as follows: The furnace 10 has a flue 2 extending to the stack 12. At an indifferent point, such as 24, in the flue 2, a breeching 25 is taken off to the blower 22 and continues therefrom to the furnace 10. In operation, the heated gases and products of combustion pass from the furnace through the fine 2 to the stack 12, but the blower 22 draws off a certain portion of them through the breeching 25 and conveys them back to the furnace 10 to be mingled therein with the hot gases and products of combustion from the burner 11 and thereby to soften the heat applied to the still. The relation between the total volume of gases passing through the flue-2 and the volume that is withdrawn at the point 24 may be varied, and is a matter of design, depending upon the capacity of the blower. These blowers are usually operated by motors under energy supplied from outside the system. According to my invention I connect the motor 21 through circuit 20 to the mains 18, to derive power from the generator 17.

Usually the amount of energy derivable from the drop in pressure between the reflux pipe and the condenser is sutlicient for the circulation of the flue gases, but in case a larger amount of energy is available I employ it in supplemental heating of the oil in the still For this purpose an enclosed heating unit is mounted in the still and its circuit connected through the insulating bushing 26 to the circuit 20. By this means the energy represented in expansive force in the vapors leaving the still under pressure is rest red to the oil in the form of heat.

Rv a modification of this electric heating moihtul. the heating unit 23 or its equivalent may llt applied to the reflux line 4 so as to supcrhcut the vapors therein, with the result of increased cracking in the vapor phase. I have not illustrated this species of the invention, because it will be clearly understood from the illustration given. It is to be noted, however, that the form of the heater may be changed in various ways, as for example by aiiplying heating coils to the pipe 4, and the li e.

It is unnecessary for the purposes of this specification to describe the pieces of apparatus in detail, as standard units are available in each case. and the structure and arrangement mav be varied and modified without departing from the scope and purview of the invention. provided they are adapted to my use and suitable for my purpose, as herein set forth.

Having thus described my invention. what I claim and desire to secure by Letters Pa ent is:

1. In treating hydrocarbon oils, the method of conserving energy which consists heating said oils in a closed vessel to produce cracking temperature and pressure therein conducting the vapors from said still while under ressure through a vapor line, expanding said vapors and ases through a suitable motor so as to produce mechanical power, and causing said power to resunply the energv so recovered in the form of heat to the oil be ng treated.

2. The method described in claim 1, in which the vapors and gases are caused to pass from the high pressure vapor line and be ex- 31 panded through a suitable motor into a cond nsing zone. and the energv developed in the motor thereby is caused to produce heat. which is continuously resupplied to the oil under treatment.

3. The method described in claim 1, which includes the step of expanding the vapors and gases from a high pressure vapor line through a suitable motor, causing the power developed in said motor to generate an electric current, and applying the energy in said electric current to produce heat in the oil under treatment.

4. The method of conserving energy rep- 5 resented by the expansive force due to compression in a system for treating hydrocarbon oils'as described in claim 1, which consists in expanding the vapors and gases through a suitable motor at a point of natural pressure drop in the system so as to generate mechanical power, and then causing said power to restore to the oil under treatment in the form of heat the energy lost in expansion.

5. In a system for the treatment of hydrocarbon oils, a still, a high pressure vapor line and alow pressure condenser adapted to re- 1 ceive vapors from said vapor line and forming an expansion chamber therefor, a motor connected so as to utilize the drop in pressure from said vapor line into said condenser, an electric generator connected to be driven by said motor, and translating devices connected to receive electrical energy from said generator and to transform the same into heat in the oil under treatment.

In testimony whereof I hereunto aifix my signature.

FRANK E. WELLMAN.

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