US1819760A - Removal of gas and low-boiling fractions from petroleum products - Google Patents

Description

Aug. 18, 1931. w, G. WHITMAN ET AL, 1,819,760

REMOVAL OF GAS AND LOW BOILING FRACTIONS FROM PETROLEUM PRODUCTS I Filed March 9, 1927 Patented Aug. 18, 1931 PA-TENT OFFICE UNITED I STATES WALTER G. WHITMA AND CLABKE- C. MILLER, OF WRITING, INDIANA, .ASSIGNOBS T STANDARD OIL COMPANY,` 0F- 'WHITING, INDIANA, A COBPOATION, OF INDIANA.

EEMovAL or GAS Ami Low- Bourne rnacv'rIoNsrRoM PETROLEUM rnonucrrs Application filed March 9, 1927. Serial No. 173,918.

This invention relates to the removal of gases and low boiling fractions from petroeum products and particularly from gasoline and gasoline-containingdistillates from pressure cracking operations.

The invention will be readily understood from the following description of a preferred method of operatingA in conjunction with y the accompanying drawings in which: Figure 1 is an elevation partly in section ofdan apparatus suitable for this purpose; an v Fig. 2 is a fragmentary view illustrating a modification of the apparatus.

Referring to the drawin s, 10 is a receiving drum, adapted to be supp ied With distillate by pipe 11 which is provided witha reducing valve 12. From the top of drum 10, a pipe 13 leads to suitable collecting or absorbing ap- 20 paratus (not shown) and pipe 13 is provided with suitable means (not shovvn) for maintaining the pressure in drum 10 at a desired degree. Fromthe bottomof drum 10 a pipe f 14 leads to a heat exchanger 15, which may' 25 suitably be o f the double tube type. The outlet from the heat exchanger 15 feeds into a pipe 16 lwhich leads into'a separating chamber or drum 17. A pipe 18 and suitable valves r may be provided s0 as to enable the heat ex- 30 changer to be by-passed when desired. VIn the pipe 16 a suitable reducin valve 19 is provided. From the bottom o theseparatmg drum 17, a pipe 20 leads into a coil 21 in the upper part of a fractionating column 22.k

3? A i e 23 and suitable valves may beprovi ed) so as to enable the separating drum 17 tov be bypassed when desired. The outlet ipe24 from the coil 21 passes through the liest exchanger 15 and leads into an inter- 4 mediate part of the column 22. From the top of the separating drum 17, a valved pipe 25 leads into an intermediate part of the co umn 22. A valvgd pipe4 37 connects with the pipe,

25 and leads to an absorbing apparatus or storage system (not shown). Thecolumn 22 is provided with suitable fractionating devices, which may suitably be bubble-cap plates provided with bubble-caps and over-v 4 flow pipes. From the top of the column a vaw por outlet leads to an absorption plant .(not shown). In the base of thecolumn 22 suitable heating means may be provided. As shown in Fig. 1 the heating means may be a perforated pipe 26 which is adapted to inject lsteam into the distillate'which collects in the base of the' column. From the base of the column 22 a pipe 27 leads to a receiver 28 provided with a gauge glass 29, avalved Water outlet pipe 30 anda distillate outlet ipe 31. The ipe 31 leads into a cooler w ich may vsuita ly be a chamber 32 providedwith a coolingcoil 33 and an outlet 34.

As shownl in Fig. 2 the heating means may be a closed steam coil 35 and in this modification the receiver 28 may be omitted, the outy letpipe 27 leading directly into the cooling chamber 32.

The operation will be fully understood from the following illustrative example.

`Pressure distillate condensed and further cooled with Water, under about 300 lbs. gauge pressure, is admitted by pipe 11 through reducing valve 12 into the drum 10 which is maintained at a pressure of about 8.0 lbs. gauge. `The gas and vapors separating in drum 10 are passed by Apipe 13 to suitable absorption apparatus (not shown) The temperature of the oil drops about 10 F. owing to the expansion effected at valve'l12, the temperature of the oil in drum 10'being, for ex'- ample, about F. Oil from drum 10 is passed by pipel 14 to heat exchanger 15, and passing through theI outer pipe thereoLis cooled to about 50 The oil then passes through reducing valve 19 and its pressure is reduced to substantially atmospheric, its tempoint of the column, or, if desired, is removed from the system by pipe 37. The liquid oil is passed through the coil 21,-thereby maintaining a low temperature in the head of the column, thus providing reflux for the columnV and reducin to the extent desired the amount of gasoline constituents carried off by the gases which pass out of the column by pipe 36.

The oil issuing from the coil 21 has a temperature of about 39 F. and passing through the heat exchanger 15, serves to effect the precooling of the incoming oil as hereinbefore described. The oil emerging from the heat exchanger 15 by pipe 24 has been heated therein to about 50 F. and is fed by said pipe into an intermediate point of the-column 22. Before being thus supplied to the column, the oil may be further heated, if desired, by any suitable means, for example, by the khot oil withdrawn from the still. The oil thus supplied, together with reflux from the u per part of the column descends through t e column over the bubble-cap plates below its point of ent gradually increasing in temperature and eing intimately contacted with gas and vapors derived from the heated lower end of the colunm. A body of oil is collected and maintained in the lower portion of the column and is maintained at a temperature such as about 130 F. sufficiently high to ensure absence of any substantial quantities of ases and wild ends in 'the finished distillate.

his temperature may be maintained by injecting open steam into the body of oil as lllustrated in Fig. l or by -passing steam lirough a closed coil therein as illustrated in The gases and vapors fed into the column by pipe 25 together With'the gases and vapors liberated in the lower part of the column, ascend through the upper part of the column, being therein. intimately contacted with the reflux condensed by coil 21, and subjected to gradually decreasing temperature. treatment gasoline constitutents are condensed from the ascending gases and contact with the coil 21 effects a further condensation of such constituents.

Pre-cooler 15 may be by-passed andsupplementary cooling means may be used in the apparatus, if desired. Further, the separating drum 17 may be omitted or by-passed, if desired, and both gases and liquid may be passed through the cooling coil 21.

The method exemplified by the foregoing detailed example el'ects the removal of gases and wild va ors while retaining substantial quantities oi) valuable low-boiling gasoline constituents which would be carried olf by said gases and vapors if the distillate .were

subjected to natural weathering or rerunning.

Although the present invention has been' described in connection with the details of a specific embodiment thereof, it is not intended that such details shall be regarded as limitationsupon the scope of the invention, except in so'far as included in the accompanying claims.

We claim: v 1. The method of removing gases and low,- boiling fractions from hydrocarbon distil- 4lates. which consists in reducing the resmre on such distillate thereby liberating gas In this therefrom, expanding the gas while in the presence of said distillate to reduce the temperature of the distillate, passing the chilledl .mg the distillate in heat exchange relationship with incoming distillate, passing .said first mentioned distillate into an intermediate part of said column, and applying heat at a lower part of said column.

3'. The method of removing gases and lowboiling fractions from 'hydrocarbon distillates which consists in reducin the pressure on such. distillate thereby li eratmg ga's therefrom, and causin the Gas to expand while in the presence o said distillate to re.- duce the temperature of the distillate,pass ing the chilled distillate through a' closed conduit in the upper part of a fractionating column, supplyingv said distillate and gasto an intermediate point of said column, and apvplying heat at a lower part of said column.

4. The method of removing gases and low- 'boiling fractions from hydrocarbon distillate which consists in reducing the pressure on slch distillate thereby liberating gas therefrom, expanding the gas and reducing the temperature of the distillate, separatin said gas from said distillate, passing the c illed distillate through a closed conduit in the upper part lof`a fractionating column, supplying said distillate to an intermediate point of said column, supplying said separated gas separately to an intermediate point of said column, and supplying heat at a lower part of said column.

5. The method of removing gases and lowboiling fractions from hydrocarbon distillate which consists in reducing the pressure of such distillate thereby liberatinggas therefrom, expanding the as and reducing the temperature of the distillate, separatingisaid is from said distillate, assing the chilled 'stillate through a close conduit in the upper part of a fractionating column, then pass- 1n the distillate in heat exchange relationship with incoming distillate, passing said first mentioned distillate into anintermediate point of said column, passing the separated gas into an intermediate point of said column, and applying heat at a lower part of said column.

6. The method of removing gases and lowlmi - plying distillate under boiling fractions from hydrocarbon distillates under high pressure which consists in reducing the pressure thereon to a pressure substantially above atmospheric pressure, rep,

into the column at an intermediate point of` v said column and applying heat at a lower part of said column.

7. The method of removing gases and lowboiling fractions from hydrocarbon distillates under high pressure which consists in reducing the pressure thereon to a pressure substantially above atmospheric pressure, removing the gases and vapors thereby liberated, then reducing'the pressure on said distillate to substantially atmospheric pressure, thereby liberating gas therefrom while causing the liberated gas to expand in the presence of said distillate to reduce the temperature of the distillate, passing the chilled distillate through a closed conduit in the upper art of a fractionating column, then passing the distillate in heat exchange relationship with incoming distillate at superatmospheric pressure, then introducing the first mentioned distillate into the column at an intermediate point of said column and applying heat at a lower part of said column. e

8. An apparatus for removing gases and low-boiling fractions from hydrocarbon distillates which comprises a conduit for supplying distillate under pressure, a reducing valve therein, a ractionating column, a closed conduit in the upper part of said column and adapted to be supplied with distillate from the first said conduit, a heat exchanger, a conduit leading from the closed conduit in the upper part of the column into an intermediate ypoint of said column and located in heat exchange relationship with therst said conduit so as to cool the distillate under said pressure passing therethrough, and means for supplying heat to the lower part of said column.

9. An apparatus for removing gases and "low-boiling fractions from hydrocarbon distillates which comprises a conduit for suppressure, a reducing valve therein, a separating drum into which said-conduit feeds, a fractionating column, a closed conduit in the upper part of said column adapted to be supplied with distillate from said drum, means for conveying distilate from the conduit in the column into an intermediate point of said column, means for supplying gases from the separatingdrum into an intermediate point of said column, and means for supplying heat to the lower part of said column. v

10. An apparatus for removing gases and low-boiling fractions from hydrocarbon distillates which comprises an' expansion drum, aconduit leading thereinto, a reducing valve 1n sald conduit, a second expansion drum, a condult for leading liquid from the first drum into the second drum, a reducingvalve in said conduit, a fractionating column, means for supplying heat to thelower part of said column, a closed conduit in the upper part of sald column, means for supplying liquid oil from the second separating drum thereto, means for supplying gases and vapors separated 1n the secondexpansion drum to an intermediate point of said4 column, a heat exchanger and means for conveying liquid oil .from the closed conduit in the column to an lntermediate point of the column, the last said means and the conduit leading from the first expansion drum to the second being located in heat exchange relationship so as to cool'the incoming oilbefore it passes through the second reducing valve.

11. A method of utilizing pressure distillate from cracking operations, which comprises cooling said distillate by reducing the pressure thereon to liberate gas therefrom and cause sald liberated gas to expand in the presence of said distillate, passing the cooled distillate in a confined stream through the upper part of a fractionating column, then intrpduclng said distillate with its contained gas into an intermediate point of said column,

. and supplying heat ata lower part of said column.

WALTER G. 'WHITMAN CLARKE C. MILLER.

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