US1874860A - Treating hydrocarbon oils - Google Patents

Description

Aug. 30, 1932. o. BEHIMER 1,874,860

TREATING HYDROCARBON oILs original Filed May 18, 1927 2 sheets-sheet 1 FHAcT/oNAT/NG coL uM/v nEcE/v//ve @RUM Aug- 30, m32. B-EHIMER TREATING HYDROCARBON OILS original Filed May 18, v1927 2 Smets-sheet @theme43 .AWM

Patented Aug. 30, l1932 UNITED vSTATES PATENT oFFIcE OTTO BEHIMER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE TEXAS COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE TBEATING HYDROCARIBON OILS Application led May 18, 1927, Serial No. 192,226. Renewed October 3, 1929.

This invention relates essentially to certain novel methods of fractionating hydrocarbon oils and has special `reference to certain methods of treating the evolved vapors and distillates of pressure cracking stills.

My invention contemplates carrying on the dephlegmation and fractionation of the evolved vapors, and handling the condensates, in such a way as to obtain the well known advantages of fractionating and condensing under` pressure and at the same time produce a properly fractionated or stabilized gasoline or naphtha distillate. At the present timey gasoline specifications call for a 96% recovery as indicated on the Standard Engler distillation flask whereas in the gasoline distillate ,usually taken od' pressure cracking systems the percent recovery is considerably lower, for example about 92%. My invention enables the production of a suitably fractionated or rectified distillate and with a minimum of loss of liquid components in the'cxit gases from the system.

My invention contemplates the use of heat contained in products derived from the cracking re-action to supply the heat necessary to fractionate or rectify the distillate and the practice of my invention a portion of. the vapors is withdrawn and conducted to the rectifying or fractionating apparatus, thereby supplying the heat necessary for removing the fixed gases from the distillate. In one way of carrying on my invention the vapors from the cracking still are subjected to a primary'separation as by condensation, or preferably fractionation, to form a liquid comprising the heavier constituents which it is undesirable to have in the final distillate and a lighter vapor fraction comprising essentially the hydrocarbons desired in the final gasoline or naphtha distillate together with fixed gases; a portion of the vapor fraction is conducted to a condenser and the liquid condensate is drawn od and rectied or fraction-` ated, the heat required being supplied by the other portion of the vapor fraction.

paratus shown in Figure 1, 10 designates the primary separator or fractionating column, 11 the condenser for condensing the vapor fraction from the fractionating column and l2 the fractionating column employed in treating the final condensate. The vapor product to Jbe treated is introduced to the 35 separator 10 through a vapor line 13 which is in communication with a pressure cracking still not shown. The separator 10 is of any suitable form but is preferably a fractionating or rectifying column containing suitable contact material or apparatustov facilitate contact of the down dowing liquid and upl wardly rising vapors therein. The column may well be in the form of a bubble tower.

It is shown equipped with a redux condenser 14 interconnected with a vapor line 15 and a redux condensate line 16. A vapor l-ine 17 provided with a valve 18 extends from the fractionating apparatus, or more specifically `from the redux condenser 14, to a condenser 30 column 10.

A line 20 having a valve 21 serves to conduct the condensate from the coil 11 to a re- 85 ceiving drum 22 which is equipped with a valved gas outlet line 23 and a valved condensate outlet line 24. The line 24 is shown as terminating in a midpoint in the fractionating or rectifying column 12.' This 90 column is shown equipped with a redux condenser 25 with an interconnecting gas line 26 and redux condensate line 27. The redux condenser 25 as well as the redux condenserl 14 are supplied with cooling from any suit-l 95 able source and it is to be understood that the redux condensers constitute parts of, or are adjuncts to, their respective fractionating columns and that if desired other cooling means may be supplied, such for example as 19 lfrom the vapor line 17 to a coil 30 in the lower part of the fractionating column 12.

This coil is connected by a pipe 31 to a coil l32 mounted in suitable cooling apparatus 33,

and a pipe 34 connects the coil 32 with the receiving drum 22. The fractionating or rectifying column 12 may be provided with any suitable contact apparatus or material.

An advantageousarrangement is to have A.tanks not shown bubble trays in that portion. of the tower above the point in which the ipe 24 enters and merely baies or plates int e portion below the point of entry yand above the coil 30. A valved pipe 35 is provided for conducting the rectified or fractionated distillate to treating apparatus for purifying or rendering it stable from the chemical standpoint, or the ipe 35-ma extend to suitable storage In practicing the inventionillustrated in Figure y1, the vapors from the pressure still,

are conducted to the rectifying or fractionatling column 10 and subjected to rectication therein to' form a vapor fraction which is removed through thefline 15, reiux condenser 14' and vapor line 17. The liquid fraction is preferably returned to the cracking zone for regt'reatment. The valve 18 is normally l f open and the vapors pass without obstruc- A' tion 't'o the condenser 11 except such vportions i valve 29 being opened sufficiently to permit l asaredrawn off through the line 28, the

thehiwithdrawal of the desired portion of vapors and their admission to the coil 30. The primary separation 'or fractionation carried on in the column'lO is preferably con- ',ductd under amaterial superatmospheric p pressure and may Well be under approxi-y valve 21Amay be used as a pressure reducingmately .thesame pressure as that of the cracklng stilll from which the vapors to be treated are Withdrawn. While the valve 18 may be used as apressure reducing valve to reduce the ressure inthe condenser 11, it is general y preferable tjo maintain the high pressure through the condenser 11. The conden-- sate formed in f the condensate coil 11 together with the contained gases passes through the pipe' 20 lnto the receiving drum 22. The

valve to reduce the pressure to a greater or lesser extent Jin the receiving drfum 22. The condensate. collected in the receiver is f ed through the line 24 into the fractionating column 12. The valve inthe line 24 may serve as a means for dropping the pressure a further amount in the fractionating colf umn. The condensate thus introduced the fractionating column is subjected therein to fractionation or rectification and the heating coil 3() serves to heat the final or ultimate condensate formed inthe column and insure that practically all of the'gaseousconf lstituents are removed therefrom. While the rectifying operation carried on in the column pressure obtaining in the condenser 11 or the ,fractionating column 10, such a procedure is not to be recommended in view of the diiiiculty encountered in thoroughly removing the xed' gases from the liquid condensate at higher pressures. It is therefore desirable `to carry on the rectifying of the` *distillate in the column 12 at a pressure materially reduced from that obtaining in either the frac- 'tionating column 10 or the condenser 11 and in fact it is generally' preferable to maintain the column 1 2 under pressures approaching atmospheric. However, it is generally detifcation, as in apparatus 55, the 'pressure in the column may be advantageously used to force the distillate through the treating vessels. In cases where the cracking operation is carried on under several hundred pounds 12 may be conducted at substantially the s sirable to maintain some vpressure above atpressure, for example, and a similar pressure is maintained in the fractionating-column l 10 and condenserll, the column 12-may be conveniently held under pressures ranging from about 25 to 50 pounds.

The vapors and gases in the coil 30 togethj `er with condensate formed therein are con-4 ductedby the pipe 31 to the cooling coil 32 and passed thence through the line 34 into the receiving drum 22. In some cases the cooling coil 32 may be dispensed with but ordinaril there will not be sufficient cooling, by the eat exchange between the coil 30 and th'e liquid in the bottom ofthe fractionating column 12, to condense all the condensable constituents passing through the coil 3 0 andit is generally desirable to further cool the uids discharged from the coil 30 so that substantially `all the condensable Afractions may be liquified. It is of course desirable 'to have the gases passing out through'the line 23 and also the gases leaving'through the ipe 36 in as dry a condition as possiblef Orinarily the gases leaving through the pipe 23 will contain'some condensable fractions column 12, the gases removed from the'line 36 may be substantially dry.

` but if ,adequate cooling be supplied to the I In the apparatus shown in Figure 2, the

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any condensate formed in the coil 38. VThe tower is shown equipped with a reflux condenser 40 with an interconnecting vapor line 4l and refiux condensate line 42. The gases are Withdrawn through a pipe 43 and the rectified liquid is removed through a line 44. This particular type of equipment is Well adapted foroperations in which it is desired to carry on the fractionation in the column 374 under material superatmospheric pressures and this system is furthermore Well adapted for operations in which the liquid condensate drawn off through pipe 44 is forced through treating apparatus containing treating materials for purifying and stabilizing the distillate.

In the apparatus illustrated in Figure 3, the outlet pipe 20 extends to a receiving drum or chamber 45 andthe pipe 28 is in communication with a perforated pipe or coil 46 positioned in the bottom of the drum 45 so that the hot vapors and gases withdrawn from the pipe 17 may be introduced directly into the distillate to be stripped or fractionated. The vapors evolved in the receiving drum are Ifractionated or rectified in a column 47 which is connected to the drum by means of a vapor line 48 anda refiux condensate line 49. The rectifying column 47 is shown equipped with a refiux condenser 5() with an interconnecting vapor line 51 and a reflux condensa-te line 52. The gases are Withdrawn through a pipe 53 and the rectified condensate is drawn ofi' from the rect-ifying apparatus through a line 54. The method of operationillustrated in Figure 3 has the advantage of) efficient heatl exchange of the hot vapors by direct contact with the liquid to be rectified and also makes possible the utilization ,of the vapors and gases introduced through the line 28 to act as a carrier for removing the fixed gases from the liquid. This methodhas, however, a disadvantage as compared with the methods shown in Figures 1 and 2 since when the vapors and gases introduced through'line 28 are thus admitted into direct contact with the v liquid being rectified, there may be oppor-v tunity for some entrainment or absorption of gas in the liquid collected in the receiving drum. However, this tendency toward gas absorption is minimized by reason of the heated condition of the gases introduced.

Abviously many modifications and variations of the invention, as hereinbefore set forth, may be made Without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

What I claim is:

l. In the treatment of hydrocarbon oils, the process that comprises removing vapors from ay pressurerstill and While still maintaining them under pressure, effecting a primary separation thereof into a liquid and a. vapor fraction, subjecting a portion of the vapor fraction to cooling to form a condensate, subjecting this condensate to rectification to form a rectified liquid While'passing the other portion of said vapor fraction into heat exchange with the ultimate condensate 'of the rectification. v

2. In the treatment of hydrocarbon oils, the `process that comprises removing vapors from a pressure still and While still maintaining them under pressure, effecting a primary separation thereof into a liquid and a vapor fraction, subjecting a portion of the vapor fraction to cooling to form a condensate, subjecting this condensate to rectification under reduced pressure to form a substantially dry gas and a rectified liquid While passing the other portion of said vapor fraction into heat exchange relation with the ult-imate condensate of the rectification.

3. In the treatment of hydrocarbon oils,

the process that comprises removing vapors from a pressure still and While still maintaining them under pressure, effecting a primary separation thereof into a liquid and a vapor fraction, subjecting a portion of the vapor fraction while still under pressure to cooling to forni a condensate, reducing the pressure on the condensate, subjecting this condensate to rectification under the reduced pressure to form a rectified liquid while passing the other portion of said vapor fraction into heat exchange relation with the ultimate condensate of the rectification.

4. In the treatment of hydrocarbon oils, the process that comprises conducting vapors from a pressure still to a rectifying column and subjecting the vapors to rectification therein 'While still under a material superatmospheric pressure, removing evolved vapors from the rectifying column and subjecting a portion of them to cooling to form a condensate, introducing the condensate to a rectifying column and subjecting the condensate to rectification therein to form a substantially dry gas and an ultimate condensate While passing the other portion of the vapors from the rst rectifying column in heat exchange relation with the ultimate condensate of the second rectifying column.

5. In the treatment of' hydrocarbon oils, the process that comprises conducting vapors from a pressure still to a .rectifying column and subjecting the vapors to rectification therein while still under a material supersecond rectifying column and subjecting the condensate to rectification therein to form a substantially ,dry gas and an ultimate condensate while passin the other portion of the vapors from the rst rectifying `column through a conduit in heat exchange with said ultimate condensate of the second rectifying column.

6. In the treatment of -hydrocarbon oils, 1Q the process that comprises conducting vapors from a pressure still to a rectifying column Aand subjecting the vapors to rectification therein while still under a material superatmospheric pressure, removing evolved vapors from the rectifying lcolumn and subjecting a portion of them lto cooling toiorm a condensate, introducing the condensate to a s econd rectifying colunm and subjecting ,the condensate4 to rectification therein vto form asubstantially dry gas and an ultimate `7.4 In the treatmentof hydrocarbon oils,-

ythe process-that comprises conducting -vapors from a pressure' still to a rectifying. column and subjecting the vapors to rectificationtherein while still under'a material superatmospheric pressure, removing evolved vapors from the rectifying column and subjecting a portion of them to cooling to form a condensate, collecting the condensate in a receiver wherein separation of gas and liquid constituents takes place, introducing the liquid from the receiver into a rectifying column and subjecting the liquid to rectification therein to form a substantially dry gas and an ultimate condensate while passing the other portion of the vapors from the irst rectifying column through a conduit in heat exchange with the ultimate condensate formed in the second re'ctifying column and discharging the fluids from said conduit into the receiver. l l p 8. In the treatment of hydrocarbon oils, the process that-comprises conducting vapors from a pressure still to a rectifying column and subjecting the vapors to rectiication therein while still under a material superatmospheric pressure, removing evolved vapors from the rec'tifying column and subjecting a portion of them to cooling to form a condensate, collecting the. condensate in a receiver wherein separation of gas and liquid constitutents takes place, introducing the liquid from the receiver into a rectifying column and subjecting the liquid to rectifikcation therein to form a substantially dry "gas and an ultimate condensate wliile. assing 65 the other portion of the vaporsfrom t e rst condensate while passing the other portion rectifying column through a conduit in heat exchange with lthe u timate condensate formed in the second rectifying column, conducting the fluid from said conduit toa. cooler 'wherein the liuid is subjected to cooling 70. and dischargingthe cooled fluid into the receiver. Y i

9. Inthe treatment of hydrocarbon oils, the process that comprises v conducting f vapors from a pressure still to a rectifying column and subjecting the vapors'to rectilication thereinJ while still under a material superatmospheric pressure, removing evolved vapors from the rectifying column and subjecting a portion' of them to cooling to form a condensate, collecting the condensate in a receiver wherein separation of gas and liquid constituents takes place, introducing the liquid from the receiver into rectifying column and subjecting the liquid to rectiication therein to form a substantially dry gas andan ultimate condensate while passing the other portion of the vapors fromL the first rectifying column through a conduit in heat exchange with the ultimate condensate contained in the second rectifying column, conducting the fluid from `said conj duit to a cooler wherein the fluid is subjectl ed to cooling and discharging the cooled fluid into the receiver, removing as a rectified liquid the ultimate condensate collected in the second rectifying column and taking 0E the substantially dry gas from the receiver and the second rectifying column.

10. In the treatment of hydrocarbon oils,

the process that comprisesremoving vapors from a pressure still and, while still maintaining them under pressure, effecting a primary separation thereof into a liquid and a vapor fraction, passing --vapors derived from such separation in heat exchange, but not in direct contact, with condensate in the lower part of a rectifying tower to thereby heat said condensate and eect partial condensation of said vapor, passing the partially con- Vdensed vapor to a cooler to be subjected therein to further coolino and condensation, directing the cooled product into said rectiying tower and\subjecting it to rectification therein while cooling the upper part of the tower and withdrawing theA rectified liquid from the lower part ofthe tower.

In witness whereof I have hereunto set my v hand this 16th day of May, 1927.

OTTO BEHIMER.

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