LIGHT HYDROCARBON ABSORPTION AND FRACTIONATION

• US 3,607,734 A
• Filed: 11/06/1969
• Issued: 09/21/1971
• Est. Priority Date: 11/06/1969
• Status: Expired due to Term

• Current Assignee: Thomas R. Stafford Sr
• Original Assignee: Thomas R. Stafford Sr
• Inventors: Stafford, Thomas R. Sr.
• Primary Examiner(s): Levine, Herbert
• Application Number:
  US04/874,592
• Time in Patent Office: 684 Days
• Field of Search: 208/341,358,351
• US Class Current: 208/341
• CPC Class Codes: C10G 5/04 with liquid absorbents
• CPC Class Codes: C10G 7/00 Distillation of hydrocarbon oils
• CPC Class Codes: C10G 7/02 Stabilising gasoline by removing gases by fractioning

Abstract

A mixture of gaseous and liquid hydrocarbons are processed in an integrated column in which absorbing, demethanizing (or deethanizing or depropanizing) and splitting operations are combined. Gaseous feed is introduced to the absorber section and liquid feed to the absorber section and/or the splitter section. A light naphtha fraction from the splitter section is used as the primary absorbing medium in the absorber section. Heavy naphtha, also from the splitter section is used as lean oil in a sponge section, primarily to remove light lean oil from absorber section overhead. Absorber fat oil, light naphtha, heavy naphtha, bottoms and fuel gas are or can be produced as products.

Claims

2. An improved unitary distillation and absorption process which comprises introducing a light fraction (in gaseous state or a mixture of gas and liquid) to a column at a point a substantial distance from the top thereof, scrubbing said light fraction with light absorber oil introduced at a point above the point of introduction of the light feed, permitting enriched absorber oils and liquid components of said light feed to descent through an intermediate portion of said column while stabilizing the liquid to remove all the lighter undesirable components therefrom, removing a portion of the thus stabilized liquid from said intermediate portion of said column as product, passing the remainder thereof downwardly through the lower portion of the column wherein it is stripped of lighter undesirable components by countercurrent contact with ascending hotter vApors, introducing a heavy liquid fraction into the said lower portion of said column and mixing it with the stabilized liquid, withdrawing a light fraction just above the point of entry of the said heavy feed portion and returning said light fraction to the upper portion of said column as the light absorber oil therein;

passing the mixture of heavy feed and remaining stabilized liquid downwardly through the remaining portion of the column, withdrawing a heavy fraction from the lower portion of said column as product and withdrawing a slightly heavier fraction from a slightly lower portion of said column and introducing it to the top thereof as heavy absorber oil;

passing said heavy absorber oil countercurrent to vapors to remove lean oil therefrom, and removing all of the enriched heavy absorber oil from the upper portion of said column at a point just above the point of introduction of the light absorber oil and reintroducing it into the lower section of said column at a point intermediate the point of removal of the light lean oil fraction and the said heavy fraction, reboiling the stripped remainder of said stabilized liquid and heavy feed mixture by heat exchange with a heating medium, passing the resultant vaporized portions thereof upwardly through the lower portion of the column as said ascending vapors, and withdrawing a reboiled fraction from the bottom of said column as product.

3. An improved unitary hydrocarbon distillation and absorption process comprising introducing a light (in gaseous or mixed gas and liquid states) hydrocarbon fraction boiling C1 to 250* F. to a column at a point a substantial distance from the top thereof, scrubbing vapors with a light absorber oil introduced at a point above the point of introduction of the light feed, permitting enriched absorber oils and liquid components of said light feed to descend through an intermediate portion of said column while stabilizing the liquid to remove the undesirable material therefrom, removing a portion of the thus stabilized liquid boiling up to 330* F. as product, passing the remainder thereof downwardly through the lower portion of the column wherein it is stripped of lighter components by countercurrent content with ascending vapors, introducing a heavy hydrocarbon fraction feed, boiling primarily C1 to 450* F., into the said lower portion of said column and mixing it with the stripped liquid, withdrawing a light fraction just above the point of entry of the said heavy portion of the feed and returning said light fraction to the upper portion of said column as the light absorber oil therein;

passing the mixture of heavy feed and remaining stripped liquid downwardly through the remaining portion of the column;

withdrawing a heavy fraction boiling 330*-430* F. from the lower portion of said column as product, withdrawing a slightly heavier fraction at a slightly lower point in said column and introducing it to the top thereof as the heavy absorber oil therein;

removing all of the enriched heavy absorber oil from the upper portion of said column at a point just above the point of introduction of the light absorber oil and reintroducing it into the lower section of said column at a point intermediate the point of removal of the light lean oil fraction and the fraction boiling 330*-430* F., reboiling the stripped remainder of said liquid and heavy feed mixture by heat exchange with a heating medium, passing the resulting vaporized portions thereof upwardly through the lower portion of the column of said ascending vapors and withdrawing a reboiled fraction boiling 430* F. and higher from the bottom of said column as product.

4. An improved distillation and absorption process which comprises introducing the overhead liquid product from a catalytic cracking fractionator to the absorption section of a unitary absorption-stripping-splitting column at a point a distance from the top thereof, intRoducing a lean absorption oil at or near the same point, introducing a heavier lean absorption oil at a higher point scrubbing ascending vapors with these lean absorption oils, withdrawing enriched absorber oils from the bottom of said absorption section and introducing said bottom fraction into a separator together with the overhead from the stripper-splitter section and the total product of the compressor discharge of a catalytic cracking unit, producing a vapor fraction and a liquid fraction from said separator, introducing said vapor fraction into the lower portion of said absorber section, introducing said liquid fraction into the upper portion of said stripper-splitter section of said unitary column, passing the liquid fraction downward through said column, withdrawing an intermediate fraction from the upper portion of said stripper-splitter -splitter section as product, withdrawing a heavier fraction from the lower portion of said stripper-splitter section and returning it to said absorption section as the light absorber oil therein, reboiling the remainder of said liquid fraction by heat exchange with a heating medium, passing the resulting vaporized portions thereof upwardly through the low portion of the column and withdrawing a reboiled fraction from the bottom of said column and returning it to the upper portion of said absorption section as the heavy absorption oil therein, withdrawing vapor overhead from said absorption section and introducing it into a sponge absorber tower, and passing it countercurrent to a sponge absorber oil introduced to the upper part of said sponge absorber, withdrawing lean gas as overhead from the sponge-absorber tower and withdrawing fat sponge absorption oil from the bottom thereof.