US1921246A

US1921246A - Process and apparatus for cracking hydrocarbon oil

Info

Publication number: US1921246A
Application number: US625456A
Authority: US
Inventors: Jean D Seguy
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1923-03-16
Filing date: 1923-03-16
Publication date: 1933-08-08
Anticipated expiration: 1950-08-08

Description

ug. 8, 1933. .x. D. SEGUY 92246 PROCESS AND APPARATUS FOR CRACKING HYDROCARBON OILS Original FiledxMarch 16, 1923 Patented Aug. 8, 1933 PROCESS AND APPARATUS FOR CRACKING HYDROCARBON OIL Jean D. Seguy, Chicago, Ill., assignor to The Universal Oil Products Company, Chicago, Ill., a Corporation of ASouth Dakota Application March 16, 1923, Serial No. 625,456 Renewed March 14, 1929 6 Claims.

This invention relates to improvements in a process and apparatus for cracking hydrocarbon oils, and refers more particularly to a process in which the oil vapors are treated in successive stages to relieve them of their objectionable high boiling point fractions, and in addition, to separate out the oil fractions which are outside a certain-predetermined range of boiling points ascertainable by temperatures maintained in different stages of the process.

Further objects of the invention are to utilize the heat in the preheating of the oil to prevent loss through radiation, and further objects as hereinafter specified. 1

35 The single figure is a diagrammatic side elevational vieW of the apparatus, partly in section.A

Referring to the drawing and describing the method of processing the oil, the charging stock is introduced from any convenient extraneous source through the line 1, and is charged by means of the pump 2 through the line 3 and either introduced directly into the top of the dephlegmator 4 through the spray pipe 5, or by closing the valve 6 and opening the valve 'l the oil may be diverted through the line 8 through a jacketed coil 9 Where it is preheated prior to its being introduced to the heating stage.

From the discharge end of the jacketed coil 9 the preheated oil flows through the line 10, thence through a second preheating coil 11 from which it is introduced into the line 12 which communicates with the heating coil 13. The heating coil is mounted in a furnace 14 which is preferably of the side red type. After being raised to a conversion temperature, the oil passes through the transfer line 15 into the expansion or vaporizing chamber 16. This chamber is equipped with try'- cocks 17 for ascertaining the liquid level in the chamber; also With residuum dravvoff lines 18 controlled by valves 19 and a vapor line 20 regulated by valve 21, through which the vapors evolved during conversion are directed from the vaporizing chamber to the refluxing column 4.

On being introduced to the dephlegmating or reuxing column 4 the vapors rise, their travel being baiiied by obstructions or perforated pans 22 positioned at intervalsL in the column. The vapors during their travel are also subjected to the dephlegmating effect of the raw oil introduced through the spray pipe 5. Any condensate separated from the vapors ows down throughthe dephlegmator leg and is drawn off through the line 23' which communicates with the line 12, r whereby it is redelivered to the heating coil 13.

The vaporized portion on the other hand passes over through the line 24 either to the

water condensers

25 and 33 through connection 42, and thence to the receiver 34 as distillate, or by closing the valve 27 and opening the valve 28 in the line 29, the vapors may be introduced into the bottom of a second reuxing column 30 through the spray pipe 31 positioned in the bottom thereof. In a similar manner the dephlegmator 30 is equipped with baliles or perforated pans 22, the vapors being caused to circulate through and about the pans in their passage to the top of the column. The dephlegmated vapors uncondensed, on rising to the top of the column 30 pass over through the line 32, and thence to the condenser 33 and receiver 34, the valve 43 being closed.

The liquid condensate separated out in the refluxing column 30 is drawn off from the lower leg of the column through the line 35, and may flow directly back to the heating coil 13 for retreatment, or by manipulation of the valves 36 and 37 in the line 38 this condensate may be charged totally or partially to the pressure pump 39 by means of which it is circulated in the jacketed portion of the coil 9 around the incoming raw oil stock for the purpose of preheating the latter. This not only preheats the raw oil, but also serves to cool the reflux condensate, thus this cool reflux condensate may be directed through the line 40 controlled by the valve 41 back into the top of the refluxing column 30.

A line 42 connects the condenser coil 25 With the condenser Vcoil 33 so that the distillates may be combined in a single receiver or separately collected by manipulating properly

valves

27, 28, 48 and 49. It will be understood that should the valve 43 in the line 42 be open and the valve 49 in the line leading to the receiver 26 be closed, While the valve 27 in the line 24 is open, all the distillate will be delivered to the receiver 34 through the valve 48 and it will also be appreciated that should the valve 27 be open or partly opened, the valve 43 closed and the valve 49 open, then certain of the vapors passingto the condenser 25` Willy be condensed. therein and the distillate passed to the re'- ceiver 26. Condensate from condenser 33 will, when the valve 48 is open, collect inthe receiver 34. In some operations it may be desirable to bypass'the .dephlegmator 30. This may be accomplished by closing the valve 28 and. opening the valve 27. The valve 43 is positioned in the line 42 for controlling the passage of the fluid oil constituents. Pressure on the system may be controlled by pressure relief valves 43" and 44 on the separate receivers, and the distillate drawn 01T through thevalves 45 and 46 if desired. Difv ferential pressures may be maintained upon the separate stages by regulation of the valves interposed in the connecting pipes.

As explained, in operation the raw 'oil is either preheated by circulation through the jacketed coil surrounded by the hot reflux, or may be introduced to the top, of the primary refluxing column. It is then charged to the heating coil where the major portion of the heating takes place.

In place. of introducing the entire charging st ock to the top of the dephlegmator, portions of the oil may be introduced in this manner, while the rest may be circulated and preheated by means of the jacketed coil, as explained. After being raised to a conversion temperature and permitted to vaporize, selected portions of the vapors may be passed over and immediately condensed or diverted, and treated in the secondary dephlegmating stage and afterwards condensed and collected in the separate receiving tank 34, or portions of the vapors may be passed over to the condenser coil 25 and portions diverted for further treatment in the column 30 as desired. In any case, the processing of the oil may be so regulated that distillates of the desired character may be collected in the separate receiving tanks, or blended in a single receiving tank through the communication between the condenser coils.

Thermo couples 47 are positioned in the different stages of the apparatus for ascertaining the temperatures maintained therein, 'Ihese temperature recording devices are particularly important in the top of the dephlegmating column where it is important to the character of the distillate collected to maintain temperatures between a predetermined range.

The apparatus may be also utilized to relieve the oil of any moisture content for when the raw charging stock is` introduced to the top of the dephlegmating column, the temperature is there suliicient to separate out any water contained in the oil which will pass over immediately and be collected as liquid in the receiving tank, where it may be drawn oir.

By treating Mid-Continent gas oil of approximately 32 Baum, yields of from 40% to 60% -an elongated passageway disposed within a furnace `wherein the oil is subjected to conversion conditions of heat andpressure, in directing the heated oil constituents from said enlongated passageway into an enlarged reacting zone, in passing the evolved vapors kto a primary dephlegmator, in passing the vapors uncondensed in said primary dephlegmator through a second zone of dephlegmation, in placing a streamer raw oil under a mechanical pressure, in splitting said stream of raw oil, in directing one portion thereof into said lprimary dephlegmator to aid in the dephlegmation of the evolved vapors and to preheat said portion of the: raw oil, in directing the other portion of said split stream of raw oil through a zone of heat interchange with reux .condensate withdrawn from said second zone of dephlegmation to preheat this portion of the split stream of raw oil, in then uniting the pre- L92r24e .heated portions of said split stream, and in introducing them together with reflux condensate .from said primary dephlegmator to the inlet side of said elongated passageway, and in maintaining regulated superatmospheric pressure on the oil undergoing conversion.'

2. A process for the heat treatment of hydrocarbon oils to produce gasoline-like distillates suitable for use as motor fuels, which consists in passing a stream of oil through a heating coil wherein said oil is heated to a cracking temperature, delivering the oil to an enlarged zone oif reaction, wherein vapors are evolved from the heated oil, passing ev olved vapors through a series of dephlegmators, passing a stream of charging stock to the rst of said dephlegmators, recycling reflux condensate from and to the second of said dephlegmators, cooling said recycle reflux condensate by heat interchange with a second stream of charging stock, passing the charging stock from the heat exchange together with charging stock and reflux condensate from said first dephlegmator to the heating coil.

3. Apparatus for heat treatment of hydrocarbon oils, comprising in combination, means for heating the oil to a cracking temperature, an enlarged reaction chamber, means for passing the heated oil from said means to said chamber, a dephlegmator, means for taking off vapors from said chamber and passing them to said dephlegmator, a second dephlegmator, means forpassing uncondensed vapors from the first dephlegmator to the second, means for maintaining cyclic circulation of cooling medium in the second dephlegmator, means for supplying a divided stream of charging oil for the process under pressure, means for passing one portion of said stream to the first dephlegmator, means for passing the other portion of the divided stream in heat interchange relation with said cyclic cooling medium, and means for reuniting the streams and passing them to the heating means.

4. A process of oil conversion, consisting in passing a restricted stream of oil through a con` tinuous elongated passageway where said oil is 1 0 heated to a cracking temperature, in transferring the heated oil constituents to an enlarged reaction zone where conversion occurs, in preventing thegreturn of any unvaporized oil from said reaction zone to said elongated passageway, in

discharging generated vapors to a reiiux condenser, in placing a stream of charging stock under a forced pressure, in splitting said stream and in directing a section thereof to said reux condenser to condense insulciently cracked vapors and to heat said section of the stream, directing the other section of said split stream while out of contact with the vapors undergoing reflux condensation into heat interchange with reflux condensate produced in the process to preheat said last-mentioned section of the split stream, and to cool such reflux condensate, then bringthe, cooled reflux condensate into direct contact and countercurrent flow with vapors undergoing reiiux condensation in the process and in uniting the preheated split sections of said stream of charging stock together with reuxcondensate formed in said reflux condenser prior to the entrance of the o'il to the inlet side of said elongated passageway, and in maintaining a superatmospheric pressure on the oil undergoing conversion. 5. A hydrocarbon oil cracking process which comprises subjecting the oil to cracking conditions of 'temperature and pressure "in a heating zone, separating vapors from unvaporized oil..

passing the vapors to a primary dephiegmating zone and cooling the same therein by heat `er.- change with charging oil for the process thereby forming primary reux condensate and preheating the charging oil, subjecting the uncondensed vapors to secondary dephlegmation thereby forming secondary reflux condensate, preheating additional charging oil for the process by heat exchange with a portion of said secondary redux condensate, returning the thus cooled portion of the secondary reflux condensate to the secondary dephlegmation as a dephlegmating medium therefor, and supplying another portion of said secondary reflux condensate in admixture with the preheated charging oil and primary reux condensate to said heating zone.

6. A hydrocarbon oil cracking process which comprises subjecting the o il to cracking conditions ture to said heating zone.

of temperature and pressure in a heating zone, separating vapors from unvaporized cil, subjecting the vapors to primary dephlegmation thereby forming primary reux condensate, subjecting the uncondensed vapors to secondary dephlegmation thereby forming secondary reflux condensate, cooling a portion of said secondary reux condensate by heat exchange with charging oil for the process thereby preheating the latter, utilizing the thus cooled'portion of the secondary reui: condensate as the dephlegmating medium for said secondary dephlegmation, combining another portion of said secondary reux condensate With the preheated charging oil and primary reux condensate, and supplying the resultant mix- Jnan n. snoer,