US1725067A - Method for cooling the heating coils of an oil-cracking apparatus - Google Patents

Description

Aug. 20, 1929. G. EGLOFF ET AL METHOD FOR COOLING THE HEATING COILS OF AN OIL" CRACKING APPARATUS Original Filed March 23, 1921 Patented Aug. 20, 1929.

UNITED STATES 1,725,067 PATENT OFFICE.

GUSTAV EGLOFI AND HARRY P. BENNER, OF CHICAGO, ILLINOIS, ASSIGNOBS TO UNIVERSAL OIL PRODUCTS COMPANY, F CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA.

METHOD FOR COOLING THE HEATING COILS OF AN OIL-CBACXING APPARATUS.

Original application led March 23, 1921, Serial No. 454,848. Divided and this application tied January 14,

1925. Serial No. 2,384.

This invention relates to a method for cooling an apparatus for treating hydrocarbon oils and is a division of our co-pending vapplication iled March 23, 1921, Serial N o.

454,848 which has eventuated into Patent N o.

1,541,553. The invention refers more particularly to that type of construction in which the oil is fed through a heating coil, thence delivered to an expansion chamber where vad through the entire apparatus. This 'takes time and also results in the oil being sent through a considerable part of the apparatus which is unnecessary. After that, 1t 1s sometimes necessary to clean the gases out of parts of the system by steam or otherwise and more particularly out of the expansion chamber where vaporization takes place and the uncondensable gas has been liberated. Time, vin the operation of cracking plants, particularly where there are a'large number of stills, is a matter of very considerable im. portance from a commercial standpoint.

The object of the present invention is to provide a method for quickly cooling down the heating coils whereby they may be examined and cleaned of carbon and likewise the expansion chamber.

The appara-tus in which this is accomplished is shown in the accompanying draw- 'ing in which the single li ure is a view, partly in side elevation, an partly in vertical section, of o'ur improved apparatus.

Referring in detail to the drawing, 1 designates the furnace in which is mounted the heating coil 2 Which-may take the form of a continuous coil of say, 4-inch pipe. The inlet side of thecoil is connected by feed pi e 3 to the charging pump 4 connected by tlie line 4 to the storage tank 18. The discharge side of the coil is connected b the line 6 in which is interposed a thrott e valve 5, to the expansion chamber 7 This chamber 7 is provided with a vaporl outlet pipe 8, controlled by a throttle valve 8, extending up into a horizontally disposed dephlegmator 5 9 having the alternately disposed battles 10. Vapor pipes 11 having throttle valve 12 are provided for conducting the va`pors out of the dephlcgmator to condenser coil 13. Condenser .coil 13 is connected by line 14s 6' having throttle valve 14 to the top of receiver 15. This receiver 15 is provided with suitable pressure gauge and liquid level gauge as shown, and with gas outlet pipe 15 having throttle valve as shown, and distillate drawoli' pipe 15" having a suitable throttle valve as shown. The reflux condensate is returned from the dephlegmator to the heating coil by means of the pipe 16 having throttle valve 17. The discharge or transfer line 6 is 0 provided with a branch 19 having throttle valve 20 leading back to the upper end of the receptacle 18. A throttle valve 21 is in terposed in the line 4 and throttle valve 22 is provided in the line 3. Steam ma be introduced to the vapor or expansion c amber through the pipe 23 controlled by throttle valve 24 and ma be drawn olf through the pipe 26 having throttle valve 25.

The apparatus may be operated as follows: Oil may be introduced throu h the feed/line 3 into the heating coil 2 and cated to a. temperature of say, 800 degrees F. in the transfer line and delivered in substantially liquid phase to the expansion chamber where vaporization takes place. In this case, the valves 5 and 8 are open. Valves 20 and 24 are closed. The vapors pass out-of the pipe 8 into the dephleginator 9 where the heavier portions are condensed and returned 0 as reiux condensate through the lino 16 to the heating coil 2. The uncondensed vapors pass out ot' the piple 11 through the condenser and thence to t e receiver. A pressure of about 140 pounds may be maintained on g5 the entire system, as for exam le, in the treatment of a mid-continent fue oil.

After the system has been run for a more or less extended period of time, carbon is bound to accumulate in the vapor chamber and there is likely to be a tendenc for some little carbon to be precipitated in the heating coil. Before cleanin out the heating coil it 1s necessary to coo? down the system and this generally takes a considerable period of time, which time, of course, is lost as far as use of the apparatus is concerned. However,

We have devised a very simple and eective method and means of accomplishing this. To this end We close the valves 5 and 17 open the valve 20 and circulate the cool oil through the closed circuit formed by the tank 18, coil 2 and pipes 4 and 19. This orms a relatively short circulation but is nevertheless very effective in cooling the lsystem. At the same time, the valve 8 may be closed and steam injected through the pipe 23 under sulticient pressure to clean out the gases and cool down the expansion chamber.

As another novel feature of the invention, We provide means for preventing the carbon which is precipitated in the expansion chamber from piling up around the draw-off line and thus retarding the discharge ot the residuum. This is accomplished by means of a segmental haihe plate 27 which is mounted in the expansion chamber near the draw-oit 26 and is segmental in orm so as to lit close- 1y around the lower side Walls of the drum and may be of the height shown in the drawing. I

We claim as our invention:

1. A method for cooling the heating coil of a coil and chamber oil cracking apparatus of the character in which oil is continuously supplied to the heating coil, raised to a cracking temperature therein, and thence delivered to e chamber and which includes pipe amper y connections for cyclically circulating oil from the bulk supply to the heating coil and back to the bulk supply comprising discontinuing the application of heat to the heating coil, ceasing the delivery of oil from the coil' to the chamber, continuing the passage oz? cool oil through the coil, returning the oil subsequent to its passage through the coil to a bulk supply of cool oil, -from which supply oil is being delivered to the coil until the coil is sufficiently cooled.

2. A method for cooling the heating coil of a tube and drum oil cracking apparatus of the character in which oil is continuously passed through the heating coil, raised to a cracking temperature therein, and thence delivered to the reaction drum and which includes pipe connections for cyclically circulating oil from 'the bulk sup ly to the heating coil and back to the bulli supply, comprising discontinuing the application of heat to the coil while continuing the passage of lcharging oil through the coil, returning the charging oil which has passed through the coil to. a source of cool oilsupply without admitting the same to said drum, and in continuing the supplyof oil romsaid source of supply to the coil until the temperature of the coil has been suiiiciently reduced.

GUSTAV EGLOFF. HARRY P. BENNER.

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