Gas separation from crude oil

• US 4,369,047 A
• Filed: 04/29/1980
• Issued: 01/18/1983
• Est. Priority Date: 06/23/1977
• Status: Expired due to Term

• Current Assignee: BP PLC
• Original Assignee: BP PLC
• Inventors: Nebrensky, Jiri R., Wilson, Christopher J., Arscott, Hedley C.
• Primary Examiner(s): SPEAR JR, FRANK
• Application Number:
  US06/144,965
• Time in Patent Office: 994 Days
• Field of Search: 55/38, 55/41, 55/52, 55/184, 55/201, 55/202, 55/203, 55/204, 55/450 R, 55/459, 55/426, 55/178, 55/176, 55/191, 55/192, 55/193, 210/788, 210/512.1, 210/512.3, 210/294, 210/188
• US Class Current: 95/243
• CPC Class Codes: B01D 19/0057 the centrifugal movement being caused by a vortex, e.g. using a cyclone, or by a tangential inlet
• CPC Class Codes: B04C 5/00 Apparatus in which the axial direction of the vortex is reversed combined with other devices B04C9/00
• CPC Class Codes: B04C 5/04 Tangential inlets
• CPC Class Codes: B04C 5/103 Bodies or members, e.g. bulkheads, guides, in the vortex chamber cores B04C5/107
• CPC Class Codes: B04C 5/14 Construction of the underflow ducting; Apex constructions; Discharge arrangements ; discharge through sidewall provided with a few slits or perforations provided with a great number of slits or perforations B04C5/10
• CPC Class Codes: B04C 5/24 Multiple arrangement thereof combination types according to other /00 groups, B04C7/00

Abstract

A foaming crude oil is separated into (i) liquid oil containing not more than 10% by volume of gas and (ii) gas containing not more than 200 parts per million of liquid oil by passing the foaming crude oil into a cyclone separator which has means for controllably adjusting the size of the inlet thereto and in which the ratio of the diameter of the vortex finder to the diameter of the vessel in the region of the inlet is from about 0.40 to 0.80, and which is also provided with a disengaging chamber and means for maintaining a minimum liquid level in said disengaging chamber.

Claims

1. A process for separating a feed comprising crude oil containing gas dispersed therein so that the liquid is in the continuous phase into a liquid containing not more than 10% by volume of gas and a gas containing not more than 200 ppm by volume of liquid oil, which process comprises passing the feed under a pressure gradient into a separator, the separator comprising a vessel having an inlet for feed disposed so that feed introduced under a pressure gradient is caused to form a downwardly flowing vortex of liquid from which an upwardly flowing vortex of gas separates, the inlet having means for controllably adjusting the size thereof, an upper outlet for the vortex of enhanced gas comprising a pipe extending downwardly into the vessel from the top thereof herein referred to as a vortex finder, the ratio of the diameter of the vortex finder to the diameter of the vessel in the region of the inlet being between about 0.40 and about 0.80, a lower outlet for the liquid, the vessel having located therein below the inlet a downwardly extending conical surface for the downwardly extending conical surface for the downwardly flowing vortex of liquid, the vessel having an enlarged lower portion, the walls of the enlarged lower portion of the vessel being spaced apart from the conical surface to define therebetween a disengaging chamber, the volume of which is at least equal to the volume defined by the conical surface, the disengaging chamber having an outlet for the discharge of separated gas and means for maintaining a minimum liquid level in the disengaging chamber to reduce the gas entrainment in the liquid discharge therefrom, and wherein there is located in the region of the lower end of the conical surface one or more baffles to engage the downwardly flowing vortex of liquid, disposed substantially vertically, and collecting the liquid containing not more than 10% by volume of gas and the gas containing not more than 200 ppm by volume of liquid.

2. A process for separating a feed comprising crude oil containing gas dispersed therein so that the liquid is in the continuous phase into a liquid containing not more than 10% by volume of gas and a gas containing not more than 200 ppm by volume of liquid oil which process comprises:

(a) passing the feed under a pressure gradient into a first separator disposed substantially vertically, the first separator comprising a first vessel having an inlet for feed disposed so that feed introduced under a pressure gradient is caused to form a downwardly flowing vortex of liquid from which an upwardly flowing vortex of gas separates, the inlet having means for controllably adjusting the size thereof, an upper outlet for the vortex of gas comprising a pipe extending downwardly into the first vessel from the top thereof herein referred to as a vortex finder, the ratio of the diameter of the vortex finder to the diameter of the vessel in the region of the inlet being between about 0.40 and about 0.80, a lower outlet for the liquid, the first vessel having located therein below the inlet a downwardly extending conical surface for the downwardly flowing vortex of liquid, the vessel having an enlarged lower portion, the walls of the enlarged lower portion of the first vessel being spaced apart from the conical surface to define therebetween a disengaging chamber, the volume of which is at least equal to the volume defined by the conical surface, the disengaging chamber having an outlet for the discharge of separated gas and means for maintaining a minimum liquid level in the disengaging chamber to reduce the gas entrainment in the liquid discharge therefrom, and wherein there is located in the region of the lower end of the conical surface one or more baffles to engage the downwardly flowing vortex of liquid, and collecting the liquid containing not more than 10% by volume gas, and either

(b) passing the gas under a pressure gradient into a second separator disposed substantially vertically, the second separator comprising a second vessel having an inlet for feed disposed so that feed introduced under a pressure gradient is caused to form a downwardly flowing vortex of liquid from which an upwardly flowing vortex of gas separates, the inlet having means for controllably adjusting the size thereof, an upper outlet for the vortex of gas comprising a pipe extending downwardly into the second vessel from the top thereof herein referred to as a vortex finder, the ratio of the diameter of the vortex finder to the diameter of the vessel in the region of the inlet being between about 0.40 and about 0.80, a lower outlet for the liquid, the second vessel having located therein below the inlet a downwardly extending conical surface for the downwardly flowing vortex of liquid, the vessel having an enlarged lower portion, the walls of the enlarged lower portion of the second vessel being spaced apart from the conical surface to define therebetween a disengaging chamber, the volume of which is at least equal to the volume defined by the conical surface, the disengaging chamber having an outlet for the discharge of separated gas and means for maintaining a minimum liquid level in the disengaging chamber to reduce the gas entrainment in the liquid discharge therefrom, and wherein there is located in the region of the lower end of the conical surface one or more baffles to engage the downwardly flowing vortex of liquid, and withdrawing the gas containing less than 200 ppm by volume of liquid oil from the second vessel, or

(c) passing the gas into a gas scrubber to remove liquid oil therefrom and yield a gas containing less than 200 ppm by volume of liquid oil.

3. A process as claimed in claim 2 wherein the feed has a gas/liquid ratio by volume of from 2.5:

1 to 15;

1 and wherein the pressure inside the first vessel is from 1 to 70 bar absolute and the pressure difference between the vessels is from 0.1 to 1 bar absolute, and controlling the operating conditions to obtain a separated gas containing not more than 200 ppm volume of liquid oil and a separated liquid oil containing not more than 10% gas.

4. A process as claimed in claim 3 wherein the feed contains water in an amount up to 50% by volume.

5. A process for separating a feed comprising crude oil containing gas dispersed therein so that the liquid is in the continuous phase into a liquid containing not more than 10% by volume of gas and a gas containing not more than 200 ppm by volume of liquid oil which process comprises passing the feed under a pressure gradient into a separator, the separator comprising a vessel having an inlet for feed disposed so that feed introduced under a pressure gradient is caused to form a downwardly flowing vortex of liquid from which an upwardly flowing vortex of gas separates, the inlet having means for controllably adjusting the size thereof, an upper outlet for the vortex of enhanced gas comprising a pipe extending downwardly into the vessel from the top thereof herein referred to as a vortex finder, the ratio of the diameter of the vortex finder to the diameter of the vessel in the region of the inlet being between about 0.40 and about 0.80, a lower outlet for the liquid, the vessel having located therein below the inlet a downwardly extending surface for the downwardly flowing vortex of liquid, the vessel having an enlarged lower portion, the walls of the enlarged lower portion of the vessel being spaced apart from the downwardly extending surface to define therebetween a disengaging chamber, the volume of which is at least equal to the volume defined by the downwardly extending surface, the disengaging chamber having an outlet for the discharge of separated gas and means for maintaining a minimum liquid level in the disengaging chamber to reduce the gas entrainment in the liquid discharged therefrom, and wherein there is located in the region of the lower end of the downwardly extending surface one or more baffles to engage the downwardly flowing vortex of liquid, disposed substantially vertically, and collecting the liquid containing not more than 10% by volume of gas and the gas containing not more than 200 ppm by volume of liquid.