CRUDE OIL STABILIZATION
20220325188 · 2022-10-13
Inventors
Cpc classification
B01D17/0214
PERFORMING OPERATIONS; TRANSPORTING
C10G7/02
CHEMISTRY; METALLURGY
International classification
C10G7/02
CHEMISTRY; METALLURGY
B01D3/14
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A system for stabilizing a hydrocarbon feedstock includes a High Pressure Separation (HPS) unit in fluid communication with a feedstock inlet. The HPS unit includes an oil outlet. The system includes a heated Low Pressure (LP) separator unit downstream from and in fluid communication with the oil outlet of the HPS unit. The heated LP separator unit includes an oil outlet. The system includes a heat exchanger positioned between the HPS unit and the heated LP separator unit.
Claims
1. A system for stabilizing a hydrocarbon feedstock, the system comprising: a High Pressure Separation (HPS) unit in fluid communication with a feedstock inlet, wherein the HPS unit includes an oil outlet; a heated Low Pressure (LP) separator unit downstream from and in fluid communication with the oil outlet of the HPS unit, wherein the heated LP separator unit includes an oil outlet; and a heat exchanger positioned between the HPS unit and the heated LP separator unit.
2. The system as recited in claim 1, wherein the heat exchanger operates at a pressure ranging from 3-10 psig.
3. The system as recited in claim 1, wherein the heat exchanger includes a vapor outlet, wherein the vapor outlet is routed to at least one of a gas outlet line from the HPS unit or the heated LP separator unit.
4. The system as recited in claim 1, further comprising a vapor recovery unit (VRU) downstream from and in fluid communication with a gas product outlet of the heated LP separator unit to recover hydrocarbon vapor therefrom.
5. The system as recited in claim 4, further comprising a gas injection input between the gas product outlet of the heated LP separator unit and the VRU.
6. The system as recited in claim 5, wherein the gas injection input is in fluid communication with a gas outlet of the HPS unit.
7. The system as recited in claim 1, wherein the heat exchanger includes a first heat exchanger circuit having an upstream side in fluid communication with the oil outlet of the heated LP separator unit and a downstream side in fluid communication with a Lease Automatic Custody Transfer (LACT) unit inlet.
8. The system as recited in claim 7, wherein the heat exchanger includes a second heat exchanger circuit in thermal communication with the first heat exchanger circuit, wherein the second heat exchanger circuit has an upstream side in fluid communication with the oil outlet of the HPS unit and a downstream side in fluid communication with a heated LP separator inlet.
9. The system as recited in claim 1, wherein the heated LP separator unit is configured to operate at a pressure less than 20 psig.
10. The system as recited in claim 1, wherein the heated LP separator unit is configured to operate at a pressure from 3 psig to 10 psig.
11. The system as recited in claim 1, wherein the heated LP separator unit is configured to operate at a temperature above 110° F.
12. The system as recited in claim 1, wherein the heated LP separator unit is configured to operate at a temperature ranging from 110° F. to 160° F.
13. The system as recited in claim 1, wherein the oil outlet of the heated LP separator unit is configured to discharge stabilized oil having a Reid Vapor Pressure (RVP) of less than 10 psi.
14. The system as recited in claim 1, wherein the system is a two-stage separation system.
15. The system as recited in claim 1, wherein the HPS unit is configured to operate at a pressure ranging from 75 psig to 250 psig.
16. A process for stabilizing a hydrocarbon feedstock comprising: delivering the hydrocarbon feedstock to a feedstock inlet of a High Pressure Separation (HPS) unit; pressurizing the hydrocarbon feedstock in the HPS unit to separate at least one of a gas product or a water product from the hydrocarbon feedstock to generate an un-stabilized oil portion of the hydrocarbon feedstock; discharging the un-stabilized oil portion of the hydrocarbon feedstock from an oil outlet of the HPS unit; delivering the un-stabilized oil portion of the hydrocarbon feedstock to a heat exchanger to generate a pre-heated un-stabilized oil portion of the hydrocarbon feedstock; delivering the pre-heated un-stabilized oil portion of the hydrocarbon feedstock to a heated Low Pressure (LP) separator unit downstream from the heat exchanger; heating the pre-heated un-stabilized oil portion of the hydrocarbon feedstock in the heated LP separator unit to separate at least one of a second gas product or a second water product from the pre-heated un-stabilized oil portion of the hydrocarbon feedstock to generate a stabilized oil portion of the hydrocarbon feedstock; and discharging the stabilized oil portion of the hydrocarbon feedstock from an oil outlet of the heated LP separator unit.
17. The process of claim 16, wherein the process is limited to two stages of separation.
18. The process of claim 16, wherein the heat exchanger operates at a pressure ranging from 3-10 psig.
19. The process of claim 16, further comprising delivering hydrocarbon vapor from a vapor outlet of the heat exchanger to at least one of a gas outlet line from the HPS unit or the heated LP separator unit.
20. The process of claim 16, delivering a fraction of the gas product from the HPS unit to an inlet line of a vapor recovery unit (VRU) downstream from and in fluid communication with a gas product outlet of the heated LP separator unit.
21. The process of claim 16, further comprising transferring the stabilized oil portion of the hydrocarbon feedstock from an oil outlet of the heated LP separator unit through a first heat exchanger circuit and to a Lease Automatic Custody Transfer (LACT) unit inlet.
22. The process of claim 21, wherein delivering the un-stabilized oil portion of the hydrocarbon feedstock to a heat exchanger includes delivering the un-stabilized oil portion of the hydrocarbon feedstock through a second heat exchanger circuit of the heat exchanger in thermal communication with the first heat exchanger circuit, wherein the second heat exchanger circuit has an upstream side in fluid communication with the oil outlet of the HPS unit and a downstream side in fluid communication with a heated LP separator inlet.
23. The process of claim 16, wherein the heated LP separator operates at a pressure less than 20 psig.
24. The process of claim 16, wherein the heated LP separator unit operates at a pressure ranging from 3 psig to 10 psig.
25. The process of claim 16, wherein the heated LP separator unit operates at a temperature above 110° F.
26. The process of claim 16, wherein the heated LP separator unit operates at a temperature ranging from 110° F. to 160° F.
27. The process of claim 16, further comprising discharging stabilized oil having a Reid Vapor Pressure (RVP) of less than 10 psi from the oil outlet of the heated LP separator.
28. The process of claim 16, wherein the HPS operates at a pressure ranging from 75 psig to 250 psig.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the devices and methods of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
[0016]
[0017]
[0018]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject invention. For purposes of explanation and illustration, and not limitation, a schematic representation of an exemplary embodiment of a stabilization system in accordance with the invention is shown in
[0020] As shown in
[0021] A heated Low Pressure (LP) Separator unit 104, e.g., the second stage, is a heated three-phase separator and is downstream from un-stabilized oil outlet 119 of HPS unit 102. The heated LP separator unit 104 includes an inlet 114, a heating input 111, a gas product outlet 152 (gas phase), a water product outlet 117 (aqueous phase), and an oil outlet 116, e.g., a stabilized oil outlet 116 (hydrocarbon phase). A gas stream 118 associated with the gas product outlet 152 is indicated schematically by the arrow 118 extending from heated LP separator unit 104. Water product outlet and the water product stream associated therewith are both indicated schematically by the arrow 117 extending from heated LP separator unit 104. Stabilized oil outlet and the stabilized oil stream associated therewith are both indicated schematically by the arrow 116 extending from heated LP separator unit 104. Inlet 114 is configured to receive the un-stabilized oil portion of the hydrocarbon feedstock that is discharged from HPS unit 102 via un-stabilized oil outlet 119. The heated LP separator unit 104 includes an internal weir plate 124 that segregates water and oil.
[0022] With continued reference to
[0023] Heat is applied by way of heating input 111 to separate the un-stabilized oil stream 112 from the HPS unit 102 into the stabilized oil stream 116, the water stream 117 and the vapor stream 118. Because of the heat duty reduction described above, system 100 allows for the potential to reduce cost and size of crude oil heater, e.g. heating input 111, and the associated equipment, including the size of the heated LP separator 104. Depending on the composition and characteristics of the un-stabilized oil in stream 112, the operating pressure and temperature in the heated LP separator unit 104 is controlled to boil off the lighter hydrocarbons from the un-stabilized oil in stream 112 to result in the stabilized oil of oil stream 116. A typical Heater Treater, e.g., heater treater 4, is provided by flue gases from a fired heater flowing directly through internal fire tubes. While heating in the heated LP separator 104 an internal heat exchanger using external heating medium. Lower heat energy is needed by use of internal heater because flashed gas and separated water portion is not heated in this scheme.
[0024] Heated LP separator unit 104 is configured to operate at a pressure less than 20 psig (137.9 kPag), for example, in some embodiments heated LP separator unit 104 operates at a pressure ranging from 3 to 10 psig (21 to 69 kPag). This is different from Heater Treater 4 (of
[0025] Stabilized oil outlet 116 of heated LP separator unit 104 is configured to discharge stabilized oil that meets the desired specifications, e.g., in embodiments of the present disclosure, having a Reid Vapor Pressure (RVP) of less than 10 psi (68.9 kPa). RVP is a common measure of the volatility of crude oil and other petroleum products. It is defined as the absolute vapor pressure exerted by a liquid at 100° F. (37.8° C.) and is determined by the test method ASTM Standard D-323 or equivalent. The term “stabilized oil” or “stabilized oil portion” as used throughout this description means crude oil with a vapor pressure low enough to comply with transport and storage requirements, which is indicated by Reid Vapor Pressure (RVP) of less than 10 psi at 100° F. (37.78° C.). It will be readily appreciated by those skilled in the art that the requirements for stabilization may vary or can be based on other parameters.
[0026] As shown in
[0027] As shown in
[0028] With continued reference to
[0029] With reference now to
[0030] With continued reference to
[0031] As shown in
[0032] With continued reference to
[0033] A process for stabilizing a hydrocarbon feedstock includes delivering the hydrocarbon feedstock into a feedstock inlet, e.g., feedstock inlet 110 or 210, of a HPS unit, e.g., HPS unit 102 or 202, separating gas and water products from the hydrocarbon feedstock in the HPS unit to generate an un-stabilized oil portion of the hydrocarbon feedstock. Processing the hydrocarbon feedstock in the HPS unit includes maintaining a pressure ranging from 75 to 250 psig (517 to 1723 kPag) in the HPS unit. In some embodiments, this includes maintaining a pressure ranging from 125 to 200 psig (862 to 1379 kPag). The process includes discharging the un-stabilized oil portion of the hydrocarbon feedstock from an outlet, e.g., un-stabilized oil outlet 119 or 219, of the HPS unit. The process includes delivering the un-stabilized oil portion of the hydrocarbon feedstock to a heat exchanger, e.g., heat exchanger 128 or 228, to generate a pre-heated un-stabilized oil portion of the hydrocarbon feedstock.
[0034] The process includes delivering the pre-heated un-stabilized oil portion of the hydrocarbon feedstock into a heated LP separator unit, e.g., heated LP separator unit 104 or 204, downstream from the un-stabilized oil outlet of the HPS unit, heating the un-stabilized oil portion of the hydrocarbon feedstock in the heated LP separator unit to separate a second gas product, e.g., that indicated schematically by gas product outlet 118 or 218, and a second water product, e.g., that indicated schematically by second water product outlet 117 or 217, from the un-stabilized oil portion of the hydrocarbon feedstock to generate a stabilized portion of the hydrocarbon feedstock, and discharging the stabilized portion of the hydrocarbon feedstock from a stabilized oil outlet, e.g., stabilized oil outlet 116 or 216, of the heated LP separator unit. The process can include delivering a fraction, e.g. fraction 134 or 234, of the gas product from the HPS unit to an inlet line, e.g. inlet line 121 or 221, of a vapor recovery unit (VRU) downstream from and in fluid communication with a gas product outlet of the heated LP separator unit. In some embodiments, e.g., as shown in
[0035] The process includes pressurizing the un-stabilized oil portion of the hydrocarbon feedstock in the heated LP separator unit by operating the heated LP separator unit at a pressure less than 20 psig (137.9 kPag). Some embodiments include pressurizing the un-stabilized oil portion of the hydrocarbon feedstock in the heated LP separator unit by maintaining a pressure ranging from 3 psig to 10 psig (21 to 69 kPag) in the heated LP separator unit.
[0036] The stabilized oil portion of the hydrocarbon feedstock that is discharged from the stabilized oil outlet of the heated LP separator unit has a Reid Vapor Pressure (RVP) of less than 10 psi (68.9 kPa). The process includes transferring the stabilized oil portion of the hydrocarbon feedstock from the stabilized oil outlet of the heated LP separator unit through a first heat exchanger circuit, e.g. first heat exchanger circuit 136 or 236, and to a Lease Automatic Custody Transfer (LACT) unit, e.g., LACT unit 108 or 208, downstream from and in fluid communication with the stabilized oil outlet. Delivering the un-stabilized oil portion of the hydrocarbon feedstock to a heat exchanger includes delivering the un-stabilized oil portion of the hydrocarbon feedstock through a second heat exchanger circuit, e.g. second heat exchanger circuit 144 or 244, of the heat exchanger. The second heat exchanger circuit is in thermal communication with the first heat exchanger circuit. The process includes discharging the gas product through a gas product outlet, e.g., gas product outlet 115 or 215, of the HPS unit, discharging the second gas product from a gas product outlet, e.g., gas product outlet 118 or gas product outlet 218, of the heated LP separator unit, and/or recovering the second gas product with a vapor recovery unit (VRU) downstream, e.g., VRU unit 106 or 206, from and in fluid communication with the gas product outlet of the heated LP separator unit. While the described system and process are described in the context of light feedstocks, e.g., shale oil or tight oil, the claimed process and system can process other suitable types of feedstocks as well.
[0037] Embodiments of the present disclosure provide for stabilization systems, methods and processes that have reduced heat duty, reduced downtime, and reduced GHG emissions as compared with other systems having two separation stages. The processes, methods and systems of the embodiments of the present disclosure, as described above and shown in the drawings, provide for stabilization systems with increased efficiency, reduced cost and smaller size. While the system, processes and methods of the subject invention have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject invention. The above description and examples are merely illustrative of the invention and should not be construed as limiting the scope of the invention. Various modifications will become apparent to the skilled artisan in view of the foregoing disclosure. It is intended that all such modifications coming within the scope and spirit of the appended claims should be embraced thereby.