Process for separating crude oil components

• US 4,673,490 A
• Filed: 08/23/1985
• Issued: 06/16/1987
• Est. Priority Date: 08/23/1985
• Status: Expired due to Fees

• Current Assignee: Fluor Corporation
• Original Assignee: Fluor Corporation
• Inventors: Johnson, David B., Subramanian, Mahadevan, Kleinschrodt, Frank J., Monday, Richard D.
• Primary Examiner(s): Metz, Andrew H.
• Assistant Examiner(s): Caldarola, Glenn A.
• Application Number:
  US06/768,615
• Time in Patent Office: 662 Days
• Field of Search: 208/351, 208/354, 208/356, 208/357, 208/358, 208/364
• US Class Current: 208/354
• CPC Class Codes: C10G 7/00 Distillation of hydrocarbon oils

Abstract

A more effective and efficient method for separating the components of crude oil, particularly off-gases and LSR naphtha and heavy naphtha, is disclosed. The crude oil is heated and fed to a prefractionator that operates at relatively high pressure and uses a multiple condenser/accumulator overhead system for collecting and separating off-gases and LSR naphtha while avoiding the problems of water condensation in the top section of the prefractionator and the need to compress overhead vapors to fuel gas system pressure. After heating, the bottoms from the prefractionator are fed to an atmospheric crude tower to recover desirable components such as diesel, kerosene, atmospheric gas oils and reduced crude. The overheads of such crude tower are processed through a set of overhead condensers/accumulators for collecting the small amounts of naphtha and sending them to a naphtha stripper column for further recovery and purification.

Claims

1. A method of separating components of crude Oil comprising:

feeding heated crude Oil containing non-readily condensible components and LSR naptha and heavy naphtha components to a tower operating at a relatively high pressure and a relatively high temperature;

separating the crude Oil into an overhead stream, containing essentially all of the non-readily condensible components and essentially all of the LSR naphtha component, a bottoms stream and one or more side streams containing essentially all of the heavy naphtha component in the tower at the relatively nigh pressure and the relatively high temperature;

feeding said bottoms stream to an atmospheric crude distillation unit operating at relatively low pressure;

separating said bottoms stream into a crude distillation unit overhead stream, a crude distillation unit bottoms stream, and one or more crude distillation unit side streams;

collecting a sidestream from the tower at a sidestreams outlet;

feeding said sidestream to a stripper column;

feeding an overhead vapor from the stripper column to a side inlet of the tower;

collecting a bottoms stream from said stripper column as heavy naphtha;

feeding the bottoms stream from the tower to a means for heating so that the lighter components of said bottoms stream are vaporized prior to being fed to the crude distillation unit operating at relatively low pressure;

feeding said bottoms stream into said atmospheric crude distillation unit at a crude feed inlet located at a point above a steam feed inlet;

separating the bottoms stream from the tower into components in the atmospheric crude distillation unit;

collecting a reduced crude product as the crude distillation unit bottoms stream;

feeding the crude distillation unit overhead stream to a pair of condensing units connected in series wherein the second of said pair of condensing units is a total condensing unit and the first of said pair of condensing units is a partial condensing unit;

feeding at least part of a petroleum condensate from the first of said pair of condensing units to an overhead reflux inlet of the atmospheric crude tower;

collecting the remainder of the petroleum condensate from the first of said pair of condensing units as a heavy naphtha product;

feeding the vapor from the first of said pair of condensing units to the second of said pair of condensing units; and

feeding a petroleum condensate from the second of said pair of condensing units to the stripper column.

2. The method of claim 1 wherein the tower is maintained at a pressure between approximately 50 and 100 psig.

3. The method of claim 1 wherein the tower is maintained at a pressure between approximately 75 and 85 psig.

4. The method of claim 2, 3, or 1 wherein the heated crude oil is fed to the tower at a pressure between approximately 50 and 100 psig.

6. The method of claim 1 further comprising the steps of:

feeding the overhead stream from said tower to a second pair of partial condensing units connected in series;

feeding the petroleum condensate from a first partial condensing unit of said second pair to a reflux inlet of the tower;

feeding a vapor from the first partial condensing unit of said second pair to the second partial condensing unit of said second pair;

collecting a petroleum condensate from the second of said partial condensing units of said second pair as light straight run naphtha; and

feeding a vapor from the second of said partial condensing units of said second pair to a fuel gas system.

7. The method of claim 1 wherein the tower is maintained at a pressure higher than the pressure of the fuel gas system.

8. The method of claim 6 further comprising the step of separating sour water from the petroleum condensates in each of the condensing units of said second pair of partial condensing units.

9. The method of claim 1 further comprising the step of separating sour water from the petroleum condensate in each of the condensing units of said pair of condensing units.

10. The method of claim 1 further comprising the steps of:

collecting side streams from the atmospheric crude distillation unit at points above the crude feed inlet of said atmospheric crude distillation unit;

feeding said side streams from the atmospheric crude distillation unit to one or more side stream product strippers;

feeding the overheads from said side stream product strippers to side stream inlets of the atmospheric crude distillation unit located at points above the crude feed inlet of said atmospheric crude distillation; and

collecting a bottoms stream from each of said side stream product strippers as petroleum products.

5. The method of 2, 3 or 1 wherein the heated crude oil is fed to the tower at a pressure between approximately 75 and 85 psig.

11. A method for separating components of crude oil comprising:

feeding heated crude oil containing non-readily condensible components and LSR naptha and heavy naphtha components to a tower operating at a pressure between approximately 75 and 85 psig and at a relatively high temperature;

separating the crude oil into an overhead stream containing essentially all of the non-readily condensible components and essentially all of the LSR naphtha component, a bottoms stream and one or more side streams containing essentially all of the heavy naphtha component in the tower;

feeding the overhead stream from the tower to a pair of partial condensing unit connected in series;

feeding a petroleum condensate from the first partial condensing unit of said pair to a reflux inlet of said tower;

feeding a vapor from the first partial condensing unit to the second partial condensing unit of said pair;

collecting a petroleum condensate from the second of said partial condensing units of said pair as light straight run naphtha product;

feeding a vapor from the second of said partial condensing units to a fuel gas system;

collecting a side stream from the tower at a side stream outlet;

feeding said side stream to a stripper column;

feeding an overhead vapor from said stripper column to a side inlet of said tower;

collecting a bottoms stream from said stripper column as heavy naphtha product;

feeding the bottoms stream from the tower to a means for heating so that the lighter components of said bottoms stream are vaporized;

feeding said bottoms stream from the means for heating to an atmospheric crude distillation unit having a crude feed inlet and a steam feed inlet, said crude feed inlet located at a point above said steam feed inlet;

separating the bottoms stream from the tower into components in the atmospheric crude distillation unit;

collecting a reduced crude product as a bottoms stream from said atmospheric crude distillation unit;

feeding an overhead stream from said atmospheric crude distillation unit to a second pair of condensing units connected in series wherein the second of said second pair of condensing units is a total condensing unit in the first of said second pair is a partial condensing unit;

feeding at least part of a petroleum condensate from the first of said second pair of condensing units to an overhead reflux inlet of the atmospheric crude distillation unit;

p1 collecting the remainder of the petroleum condensate from the first of said second pair of condensing units as heavy naphtha product;

feeding a vapor from the first of said second pair of condensing units to the second of said second pair of condensing units;

feeding a petroleum condensate from the second of said second pair of condensing units to the stripper column;

collecting side streams from the atmospheric crude distillation unit at point above the crude feed inlet said atmospheric crude distillation unit;

feeding said side streams from the atmospheric crude distillation unit to one or more side stream products strippers;

feeding the overheads from said side stream product strippers to side stream inlets of the atmospheric crude distillation unit located at points above the crude feed inlet of said atmospheric crude distillation unit;

collecting a bottoms stream from each of said side stream product strippers as petroleum products; and

separating sour water from the petroleum condensate in each of the condensing units of each of said first and second pair of condensing units.