CN114752401A - Recovery method of flare blow-down gas during maintenance of oilfield associated gas treatment plant - Google Patents

Recovery method of flare blow-down gas during maintenance of oilfield associated gas treatment plant Download PDF

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CN114752401A
CN114752401A CN202210465852.2A CN202210465852A CN114752401A CN 114752401 A CN114752401 A CN 114752401A CN 202210465852 A CN202210465852 A CN 202210465852A CN 114752401 A CN114752401 A CN 114752401A
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gas
channel
separator
pipeline
heat exchanger
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CN114752401B (en
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范庆虎
廖江芬
周燊
王启军
单悌禄
孙鑫科
吕刚颖
邹尚奇
王金宏
周洪达
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Hangzhou Hongze New Energy Co ltd
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Hangzhou Hongze New Energy Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G5/00—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G5/00—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas
    • C10G5/02—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas with solid adsorbents
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G5/00—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas
    • C10G5/06—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas by cooling or compressing
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/12—Liquefied petroleum gas

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  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

The invention relates to a recovery method of flare vent gas during overhaul of an oilfield associated gas treatment plant, which is implemented by adopting a recovery system, wherein the recovery system comprises a compressor unit sledge, a deep purification sledge and a low-temperature separation stabilization sledge, and the compressor unit sledge comprises a feed gas compressor unit and a CNG compressor unit; the deep purification sledge comprises a first adsorption tower, a second adsorption tower, a third adsorption tower, a regenerated gas cooler, a regenerated gas heater, a regenerated gas separator and a gas generator set; the low-temperature separation stabilizing sledge comprises a precooling heat exchanger, a cryogenic heat exchanger, a primary gas-liquid separator, a low-temperature separator, a low-pressure separator, a normal-temperature separator and a mixed hydrocarbon refrigerant compression throttling refrigerating unit. The recovery method of the flare blow-down gas during the overhaul period of the oilfield associated gas treatment plant realizes the flare gas treatment and recovery in different oilfield associated gas treatment plants, produces heavy hydrocarbon and Compressed Natural Gas (CNG) products, creates value for enterprises and meets the requirement of environmental protection.

Description

Recovery method of flare blow-down gas during maintenance of oilfield associated gas treatment plant
Technical Field
The invention relates to the technical field of oil gas recovery, in particular to a recovery method of flare vent gas during overhaul of an oilfield associated gas treatment plant.
Background
The oilfield associated gas treatment plant is used for producing products such as dry gas, LPG, light oil and the like from oilfield associated gas rich in methane, ethane, propane, butane and the components thereof by a low-temperature separation method. Every year, the oilfield associated gas treatment plant is stopped to be overhauled and maintained according to a plan, and the overhauling time is generally 30 days. During the maintenance, a large amount of oil field associated gas will burn through torch system and discharge, and this not only causes the natural gas wasting of resources, can cause the pollution of environment moreover, is not conform to national environmental protection requirement.
Because the overhaul period of the oilfield associated gas treatment plant is short, the oilfield associated gas treatment plant is not suitable for producing mixed hydrocarbon and liquefied natural gas products by adopting conventional oilfield associated gas, or else the investment is large, the construction period is long, and the economical efficiency is poor.
In view of the above situation, there is a need to develop a recovery method of flare vent gas during maintenance of an oilfield associated gas treatment plant, which can specifically treat and recover flare vent gas during maintenance of an oilfield associated gas treatment plant, and produce heavy hydrocarbon and Compressed Natural Gas (CNG) products, thereby creating value for enterprises and meeting the requirements of environmental protection.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a recovery method of flare vent gas during the overhaul period of an oilfield associated gas treatment plant.
The technical scheme adopted by the invention for solving the problems is as follows: a flare vent gas recovery method during overhaul of an oilfield associated gas treatment plant is implemented by adopting a flare vent gas recovery system during overhaul of the oilfield associated gas treatment plant, wherein the flare vent gas recovery system during overhaul of the oilfield associated gas treatment plant comprises a compressor unit sledge, a deep purification sledge and a low-temperature separation stabilization sledge, and the compressor unit sledge comprises a feed gas compressor unit and a CNG compressor unit; the deep purification sledge comprises a first adsorption tower, a second adsorption tower, a third adsorption tower, a regenerated gas cooler, a regenerated gas heater, a regenerated gas separator and a gas generator set; the low-temperature separation stabilizing sledge comprises a precooling heat exchanger, a cryogenic heat exchanger, a primary gas-liquid separator, a low-temperature separator, a low-pressure separator, a normal-temperature separator and a mixed hydrocarbon refrigerant compression throttling refrigerating unit; the mixed hydrocarbon refrigerant compression throttling refrigerating unit comprises a refrigerant separator and a refrigerant compressor; the interior of the pre-cooling heat exchanger is provided with a channel A1, a channel A2, a channel A3, a channel A4, a channel A5, a channel A6 and a channel A7; the interior of the cryogenic heat exchanger is provided with a channel B1, a channel B2, a channel B3, a channel B4 and a channel B5.
The recovery method of the flare blow-down gas during the overhaul period of the oilfield associated gas treatment plant comprises the following steps:
the method comprises the following steps: after being pressurized and cooled by a feed gas compressor unit, the oilfield associated gas enters one of a first adsorption tower, a second adsorption tower or a third adsorption tower to remove saturated water in the oilfield associated gas, so that dehydration and drying indexes are achieved;
step two: the oil field associated gas dried by the adsorption tower enters a channel A2 of a precooling heat exchanger for precooling, the oil field associated gas coming out of a channel A2 enters a primary gas-liquid separator, liquid coming out of the bottom of the primary gas-liquid separator is throttled and depressurized by a throttle valve and then enters a low-pressure separator, and gas coming out of the top of the primary gas-liquid separator is cooled by a channel B2 of a cryogenic heat exchanger and then enters a low-temperature separator;
step three: the gas from the top of the low-temperature separator is rich in methane and ethane, the gas is used as high-pressure dry gas to pass through a channel B1 of a cryogenic heat exchanger and a channel A1 of a precooling heat exchanger for rewarming, and the rewarmed dry gas is sent to a CNG compressor unit to be compressed into high-pressure natural gas which is used as a CNG product; the liquid from the bottom of the low-temperature separator is depressurized and cooled by a throttle valve, then passes through a channel B3 of a cryogenic heat exchanger for rewarming, and then enters the low-pressure separator;
Step four: liquid from the bottom of the low-pressure separator enters a normal-temperature separator after being reheated by a channel A4 of a precooling heat exchanger, and the liquid separated from the normal-temperature separator is rich in propane, butane and heavy components above propane and butane and serves as a hydrocarbon mixture product;
step five: the gas from the top of the low-pressure separator is reheated by a passage A3 of the precooling heat exchanger and then mixed with the gas from the top of the normal-temperature separator, the mixed gas serving as low-pressure dry gas enters one of the first adsorption tower, the second adsorption tower and the third adsorption tower which is not in adsorption operation and serves as adsorbent cooling regeneration gas of the adsorption tower for cooling and sweeping, the cooled low-pressure dry gas is heated by a regeneration gas heater, the heated low-pressure dry gas enters the other one of the first adsorption tower, the second adsorption tower and the third adsorption tower which is not in adsorption operation and serves as heating regeneration gas of the adsorbent, the heated and regenerated gas is cooled by a regeneration gas cooler, and the cooled low-pressure dry gas enters a regeneration gas separator to separate free water and is discharged as sewage; gas from the regeneration gas separator enters a gas generator set to generate power, and the generated power is supplied to a feed gas compressor set, a CNG compressor set, a regeneration gas heater and a refrigerant compressor;
Step six: the cold energy of the precooling heat exchanger and the cryogenic heat exchanger is provided by a mixed hydrocarbon refrigerant compression throttling refrigerating unit, a low-pressure gas-phase refrigerant is compressed and cooled by a refrigerant compressor, a pressurized high-pressure refrigerant enters a refrigerant separator, liquid from the bottom of the refrigerant separator enters a channel A6 of the precooling heat exchanger, the refrigerant from the channel A6 is throttled and refrigerated by a throttling valve, and the low-pressure liquid refrigerant returns to a channel A7 of the precooling heat exchanger to provide cold energy for the precooling heat exchanger; the high-pressure gas-phase refrigerant coming out of the top of the refrigerant separator is cooled by the precooling heat exchanger and the cryogenic heat exchanger, the refrigerant which is changed into liquid is throttled and refrigerated by the throttling valve and returns to the channel B5 of the cryogenic heat exchanger to provide refrigeration capacity for the cryogenic heat exchanger, the refrigerant coming out of the channel B5 of the cryogenic heat exchanger enters the channel A7 of the precooling heat exchanger to provide refrigeration capacity for the precooling heat exchanger, and the low-pressure gas-phase refrigerant coming out of the channel A7 of the precooling heat exchanger enters the refrigerant compressor again to realize cyclic compression refrigeration.
Preferably, an air inlet of the raw gas compressor unit is connected with a first pipeline for introducing oilfield associated gas, an air outlet of the raw gas compressor unit is communicated with an air inlet at the bottom of an adsorption tower through a second pipeline, an air outlet at the top of the adsorption tower is communicated with an inlet end of a channel A2 of a precooling heat exchanger through a third pipeline, an outlet end of a channel A2 is communicated with an air inlet of a first-stage gas-liquid separator, a bottom liquid outlet of the first-stage gas-liquid separator is communicated with an inlet end of a low-pressure separator through a fourth pipeline, a top air outlet of the first-stage gas-liquid separator is communicated with a channel B2 of a cryogenic heat exchanger through a fifth pipeline, an outlet end of a channel B2 is communicated with an inlet end of the cryogenic separator through a sixth pipeline, a top air outlet of the cryogenic separator is communicated with a channel B1 of the cryogenic heat exchanger, a channel B1 is communicated with a channel A1, a channel A1 is communicated with the compressor unit through a seventh pipeline, a liquid outlet at the bottom of the low-temperature separator is communicated with an inlet end of a channel B3 of the cryogenic heat exchanger through an eighth pipeline, and an outlet end of a channel B3 is communicated with an inlet end of a low-pressure separator; the top gas outlet of low pressure separator and passageway A3's entrance point switch-on, passageway A3's exit end and dry gas discharge pipeline switch-on, the bottom liquid outlet of low pressure separator and passageway A4's entrance point pass through No. nine pipelines switch-ons, and passageway A4's exit end and normal temperature separator's entrance point pass through No. ten pipelines switch-ons, normal temperature separator's top gas outlet and dry gas discharge pipeline switch-ons, normal temperature separator's bottom liquid outlet and heavy hydrocarbon product pipeline switch-on.
Preferably, the bottom air inlets of the second adsorption tower and the third adsorption tower are communicated with a second pipeline, and the top air outlets of the second adsorption tower and the third adsorption tower are communicated with a third pipeline; a dry gas input pipeline and a heating regeneration gas input pipeline are respectively connected to the top gas outlets of the first adsorption tower, the second adsorption tower and the third adsorption tower, a cooling regeneration gas output pipeline and a heating regeneration gas output pipeline are respectively connected to the bottom gas inlets of the first adsorption tower, the second adsorption tower and the third adsorption tower, the dry gas input pipeline is communicated with a dry gas discharge pipeline, the output end of the cooling regeneration gas output pipeline is connected to a regeneration gas heating main pipeline, the output end of the regeneration gas heating main pipeline is communicated with the heating regeneration gas input pipeline, and the regeneration gas heater is installed on the regeneration gas heating main pipeline; the output end of the heating regeneration gas output pipeline is connected to a regeneration gas cooling main pipeline, the regeneration gas cooler is installed on the regeneration gas cooling main pipeline, the output end of the regeneration gas cooling main pipeline is communicated with a gas inlet of a regeneration gas separator, a bottom liquid outlet of the regeneration gas separator is communicated with a free water output pipeline, and a top gas outlet of the regeneration gas separator is communicated with a gas generator set.
Preferably, the outlet end of the channel a7 is communicated with the inlet end of a refrigerant compressor through a first refrigerant circulation pipeline, the outlet end of the refrigerant compressor is communicated with the inlet of a refrigerant separator through a second refrigerant circulation pipeline, the bottom liquid outlet of the refrigerant separator is communicated with the inlet end of the channel a6 through a third refrigerant circulation pipeline, the outlet end of the channel a6 is communicated with the channel a7 through a fourth refrigerant circulation pipeline, a first throttle valve is installed on the fourth refrigerant circulation pipeline, the top air outlet of the refrigerant separator is communicated with the inlet end of the channel a5 through a fifth refrigerant circulation pipeline, the outlet end of the channel a5 is communicated with the channel B4, the channel B4 is communicated with the channel B5 through a sixth refrigerant circulation pipeline, a second throttle valve is installed on the sixth refrigerant circulation pipeline, and the channel B5 is communicated with the channel a7 through a seventh refrigerant circulation pipeline.
Compared with the prior art, the invention has the following advantages and effects: the recovery method of the flare discharged air during the overhaul of the oilfield associated gas treatment plant realizes the treatment and recovery of the flare gas in different oilfield associated gas treatment plants, produces heavy hydrocarbon and Compressed Natural Gas (CNG) products, creates value for enterprises and meets the requirement of environmental protection.
Drawings
In order to illustrate the embodiments of the present invention or the solutions in the prior art more clearly, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive effort.
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Description of the reference numerals:
a compressor skid 71; a deep cleaning sledge 72; cryogenic separation stabilization sled 73;
a feed gas compressor train 1; a CNG compressor unit 43; adsorption column 2; a second adsorption column 3; adsorption column three 4; a regeneration gas heater 5; a precooling heat exchanger 6; a cryogenic heat exchanger 7; a first-stage gas-liquid separator 8; a cryogenic separator 9; a low pressure separator 10; a normal temperature separator 11; a refrigerant separator 12; a refrigerant compressor 13; a gas-fired power generator unit 14; a regeneration gas cooler 15; a regeneration gas separator 16; line number one 17; line number two 18; line three 19; line No. four 20; a fifth pipeline 21; number six line 22; line # seven 23; line number eight 24; a dry gas discharge line 25; line No. nine 26; a ten-line 27; a heavy hydrocarbon product transfer line 28; a dry gas input line 29; a heating regeneration gas input line 30; a cooling regeneration gas output line 31; a heating regeneration gas output line 32; a regeneration gas heating main line 33; a main regenerative gas cooling line 34; a free water output line 35; a first refrigerant circulation line 36; the second refrigerant circulation line 37; a fifth refrigerant circulation line 38; a third refrigerant circulation line 39; a fourth refrigerant circulation line 40; a seventh refrigerant circulation line 41; and a sixth refrigerant circulation line 42.
Detailed Description
The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not intended to limit the present invention.
Examples are given.
Referring to fig. 1, this embodiment discloses a flare blowdown gas recovery system during overhaul of an oilfield associated gas treatment plant, and the recovery system includes a compressor unit skid 71, a deep purification skid 72, and a cryogenic separation stabilization skid 73, which are disposed on a moving vehicle plate, and according to a plan, flare gas treatment and recovery are performed in different oilfield associated gas treatment plants.
In this embodiment, the compressor unit skid 71 includes the feed gas compressor unit 1, the CNG compressor unit 43, and valves, pipes, etc. matching with the feed gas compressor unit and the CNG compressor unit, wherein both the feed gas compressor and the CNG compressor are reciprocating compressors. The raw gas compressor unit 1 is used for compressing raw gas of associated gas in an oil field, and the CNG compressor unit 43 is used for compressing the recovered natural gas to prepare a CNG product.
In this embodiment, the deep purification skid 72 includes a first adsorption tower 2, a second adsorption tower 3, a third adsorption tower 4, a regeneration gas cooler 15, a regeneration gas heater 5, a regeneration gas separator 16, a gas generator set 14, and valves, pipes, etc. associated therewith. The first adsorption tower 2, the second adsorption tower 3 and the third adsorption tower 4 have the same structure, different adsorbents are filled in the first adsorption tower 2, the second adsorption tower 3 and the third adsorption tower 4, and phi 8-phi 6 ceramic balls, A-type silica gel, 3A-type molecular sieves and phi 6-phi 8 ceramic balls are sequentially filled from bottom to top. The deep purification sledge 72 is mainly used for removing saturated water from the oilfield associated gas to achieve the dehydration and drying indexes.
In this embodiment, the cryogenic separation stabilizing skid 73 is mainly used for separating heavy hydrocarbon products, CNG products, and dry gas from oilfield associated gas, and includes a pre-cooling heat exchanger 6, a cryogenic heat exchanger 7, a primary gas-liquid separator 8, a cryogenic separator 9, a low-pressure separator 10, and a normal-temperature separator 11, where the pre-cooling heat exchanger 6 and the cryogenic heat exchanger 7 both use aluminum plate-fin heat exchangers, the pre-cooling heat exchanger 6 has a channel a1, a channel a2, a channel A3, a channel a4, a channel a5, a channel a6, and a channel a7 inside, and the cryogenic heat exchanger 7 has a channel B1, a channel B2, a channel B3, a channel B4, and a channel B5 inside.
In this embodiment, the air inlet of feed gas compressor unit 1 is connected with a pipeline 17 that is used for letting in oil field associated gas, the gas outlet of feed gas compressor unit 1 is all switched on through No. two pipelines 18 and adsorption tower 2, No. two adsorption towers 3 and No. three adsorption tower 4's bottom air inlet, and the concrete design is divided into three branch road with No. two pipeline 18's output end, and all install the valve on three branch road, be used for controlling oil field associated gas and let in a certain adsorption tower in three adsorption tower.
In this embodiment, the top gas outlets of the first adsorption tower 2, the second adsorption tower 3, and the third adsorption tower 4 are all communicated with the inlet end of the channel a2 of the pre-cooling heat exchanger 6 through a third pipeline 19, and the specific design is that the input starting end of the third pipeline 19 is divided into three branches, and valves are installed on the three branches, so as to control the oil field associated gas dried by one of the three adsorption towers to be introduced into the channel a2 of the pre-cooling heat exchanger 6.
In this embodiment, the outlet end of the channel a2 is communicated with the air inlet of the first-stage gas-liquid separator 8, the bottom liquid outlet of the first-stage gas-liquid separator 8 is communicated with the inlet end of the low-pressure separator 10 through a fourth pipeline 20, the top air outlet of the first-stage gas-liquid separator 8 is communicated with the channel B2 of the cryogenic heat exchanger 7 through a fifth pipeline 21, the outlet end of the channel B2 is communicated with the inlet end of the cryogenic separator 9 through a sixth pipeline 22, the top air outlet of the cryogenic separator 9 is communicated with the channel B1 of the cryogenic heat exchanger 7, the channel B1 is communicated with the channel 1, and the channel a1 is communicated with the CNG compressor unit 43 through a seventh pipeline 23.
In this embodiment, the outlet port at the bottom of cryogenic separator 9 is connected to the inlet port of channel B3 of cryogenic heat exchanger 7 via eighth line 24, and the outlet port of channel B3 is connected to the inlet port of low pressure separator 10.
In this embodiment, the top gas outlet of the low-pressure separator 10 is connected to the inlet end of the passage A3, the outlet end of the passage A3 is connected to the dry gas discharge pipeline 25, the bottom liquid outlet of the low-pressure separator 10 is connected to the inlet end of the passage a4 through the No. nine pipeline 26, the outlet end of the passage a4 is connected to the inlet end of the normal-temperature separator 11 through the No. ten pipeline 27, the top gas outlet of the normal-temperature separator 11 is connected to the dry gas discharge pipeline 25, and the bottom liquid outlet of the normal-temperature separator 11 is connected to the heavy hydrocarbon product conveying pipeline 28.
In this embodiment, a dry gas input pipeline 29 and a heating regeneration gas input pipeline 30 are connected to the top gas outlets of the first adsorption tower 2, the second adsorption tower 3 and the third adsorption tower 4, and a cooling regeneration gas output pipeline 31 and a heating regeneration gas output pipeline 32 are connected to the bottom gas inlets of the first adsorption tower 2, the second adsorption tower 3 and the third adsorption tower 4.
In this embodiment, the dry gas input pipeline 29 is connected to the dry gas discharge pipeline 25, the output end of the cooling regeneration gas output pipeline 31 is connected to a regeneration gas heating main pipeline 33, the output end of the regeneration gas heating main pipeline 33 is connected to the heating regeneration gas input pipeline 30, and the regeneration gas heater 5 is installed on the regeneration gas heating main pipeline 33.
In this embodiment, the output end of the heating regeneration gas output pipeline 32 is connected to a regeneration gas cooling main pipeline 34, the regeneration gas cooler 15 is installed on the regeneration gas cooling main pipeline 34, the output end of the regeneration gas cooling main pipeline 34 is communicated with the gas inlet of the regeneration gas separator 16, the bottom liquid outlet of the regeneration gas separator 16 is communicated with the free water output pipeline 35, and the top gas outlet of the regeneration gas separator 16 is communicated with the gas generator set 14.
In this embodiment, the low-temperature separation stabilizing sledge 73 is further integrated with a mixed hydrocarbon refrigerant compression throttling refrigeration unit, and the cold energy of the precooling heat exchanger 6 and the cryogenic heat exchanger 7 is provided by the mixed hydrocarbon refrigerant compression throttling refrigeration unit. The mixed hydrocarbon refrigerant adopts a low-pressure refrigerant which is composed of three components of methane, ethylene, isobutane and the like.
In this embodiment, the mixed hydrocarbon refrigerant compression-throttling refrigeration unit includes a refrigerant separator 12 and a refrigerant compressor 13, and the refrigerant compressor 13 is a screw compressor.
In this embodiment, the outlet end of the passage a7 is connected to the inlet end of the refrigerant compressor 13 through the first refrigerant circulation line 36, and the outlet end of the refrigerant compressor 13 is connected to the inlet of the refrigerant separator 12 through the second refrigerant circulation line 37.
The bottom liquid outlet of the refrigerant separator 12 is connected with the inlet end of the passage a6 through a third refrigerant circulation line 39, the outlet end of the passage a6 is connected with the passage a7 through a fourth refrigerant circulation line 40, and a first throttle valve is installed on the fourth refrigerant circulation line 40.
The top air outlet of the refrigerant separator 12 is communicated with the inlet end of the passage a5 through a fifth refrigerant circulating pipeline 38, the outlet end of the passage a5 is communicated with the passage B4, the passage B4 is communicated with the passage B5 through a sixth refrigerant circulating pipeline 42, a second throttle valve is arranged on the sixth refrigerant circulating pipeline 42, and the passage B5 is communicated with the passage a7 through a seventh refrigerant circulating pipeline 41.
In this embodiment, the working method of the flare vent gas recovery system during the overhaul period of the oilfield associated gas treatment plant is as follows:
the method comprises the following steps: after being pressurized and cooled by a feed gas compressor unit 1, the oilfield associated gas enters one of a first adsorption tower 2, a second adsorption tower 3 or a third adsorption tower 4 to remove saturated water in the oilfield associated gas, so that dehydration and drying indexes are achieved;
step two: the oil field associated gas dried by the adsorption tower enters a channel A2 of a precooling heat exchanger 6 for precooling, the oil field associated gas from a channel A2 enters a primary gas-liquid separator 8, liquid from the bottom of the primary gas-liquid separator 8 enters a low-pressure separator 10 after throttling and pressure reduction by a throttle valve, and gas from the top of the primary gas-liquid separator 8 is cooled by a channel B2 of a cryogenic heat exchanger 7 and then enters a low-temperature separator 9;
step three: the gas from the top of the low-temperature separator 9 is rich in methane and ethane, the gas is used as high-pressure dry gas to pass through a channel B1 of the cryogenic heat exchanger 7 and a channel A1 of the precooling heat exchanger 6 for rewarming, and the rewarmed dry gas is sent to a CNG compressor unit 43 to be compressed into high-pressure natural gas as a CNG product; the liquid from the bottom of the low-temperature separator 9 is depressurized and cooled by a throttle valve, then passes through a channel B3 of the cryogenic heat exchanger 7 for rewarming, and then enters a low-pressure separator 10;
Step four: liquid from the bottom of the low-pressure separator 10 enters the normal-temperature separator 11 after being reheated by a channel A4 of the precooling heat exchanger 6, and the liquid separated from the normal-temperature separator 11 is rich in propane, butane and heavy components above propane, and serves as a hydrocarbon mixture product;
step five: the gas from the top of the low-pressure separator 10 is reheated by a channel A3 of the precooling heat exchanger 6 and then mixed with the gas from the top of the normal-temperature separator 11, the mixed gas is used as low-pressure dry gas and enters one of the first adsorption tower 2, the second adsorption tower 3 and the third adsorption tower 4 which is not used as an adsorption tower adsorbent to cool regenerated gas for cooling and blowing, the cooled low-pressure dry gas is heated by a regenerated gas heater 5, the heated low-pressure dry gas enters the first adsorption tower 2, the other of the second adsorption tower 3 and the third adsorption tower 4 is used as the heating regeneration gas of the adsorbent in the adsorption tower which is not subjected to adsorption operation, the gas after heating regeneration is cooled by a regeneration gas cooler 15, and the cooled low-pressure dry gas enters a regeneration gas separator 16 to separate free water and is discharged as sewage; the gas from the regeneration gas separator 16 enters a gas generator set 14 for power generation, and the generated power is supplied to a raw gas compressor set 1, a CNG compressor set 43, a regeneration gas heater 5 and a refrigerant compressor 13;
Step six: the cold energy of the pre-cooling heat exchanger 6 and the cryogenic heat exchanger 7 is provided by a mixed hydrocarbon refrigerant compression throttling refrigerating unit, low-pressure gas-phase refrigerant is compressed and cooled by a refrigerant compressor 13, pressurized high-pressure refrigerant enters a refrigerant separator 12, liquid from the bottom of the refrigerant separator 12 enters a channel A6 of the pre-cooling heat exchanger 6, the refrigerant from the channel A6 is throttled and refrigerated by a throttling valve, and low-pressure liquid refrigerant returns to a channel A7 of the pre-cooling heat exchanger 6 to provide cold energy for the pre-cooling heat exchanger 6; high-pressure gas-phase refrigerant coming out of the top of the refrigerant separator 12 is cooled by the precooling heat exchanger 6 and the cryogenic heat exchanger 7, the refrigerant which is changed into liquid is throttled and refrigerated by the throttle valve and returns to the channel B5 of the cryogenic heat exchanger 7 to provide cold energy for the cryogenic heat exchanger 7, the refrigerant coming out of the channel B5 of the cryogenic heat exchanger 7 enters the channel A7 of the precooling heat exchanger 6 to provide cold energy for the precooling heat exchanger 6, and the low-pressure gas-phase refrigerant coming out of the channel A7 of the precooling heat exchanger 6 enters the refrigerant compressor 13 again to realize circulating compression refrigeration.
In this embodiment, the first adsorption tower 2, the second adsorption tower 3, and the third adsorption tower 4 adopt a three-tower switching process, for example, when the first adsorption tower 2 is saturated in water, the second adsorption tower 3 is switched to an adsorption state, the third adsorption tower 4 is switched to a cold blowing state, and the first adsorption tower 2 is switched to a heating regeneration state by a program control valve; when the second adsorption tower 3 is saturated in water, the third adsorption tower 4 is switched to an adsorption state, the first adsorption tower 2 is switched to a cold blowing state, and the second adsorption tower 3 is switched to a heating regeneration state through a program control valve; when the adsorption water of the adsorption tower III 4 reaches saturation, the adsorption tower I2 is switched to an adsorption state, the adsorption tower II 3 is switched to a cold blowing state, and the adsorption tower III 4 is switched to a heating regeneration state through the program control valve, so that the cyclic adsorption, heating regeneration and cooling are realized.
In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an illustration of the structure of the present invention. Equivalent or simple changes in the structure, characteristics and principles of the invention are included in the protection scope of the present patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the invention as defined in the accompanying claims.

Claims (4)

1. A flare blow-down gas recovery method during overhaul of an oilfield associated gas treatment plant is implemented by adopting a flare blow-down gas recovery system during overhaul of the oilfield associated gas treatment plant, wherein the flare blow-down gas recovery system during overhaul of the oilfield associated gas treatment plant comprises a compressor unit sledge (71), a deep purification sledge (72) and a low-temperature separation stabilization sledge (73), and the compressor unit sledge (71) comprises a feed gas compressor unit (1) and a CNG compressor unit (43); the deep purification sledge (72) comprises a first adsorption tower (2), a second adsorption tower (3), a third adsorption tower (4), a regenerated gas cooler (15), a regenerated gas heater (5), a regenerated gas separator (16) and a gas generator set (14); the low-temperature separation stabilizing sledge (73) comprises a precooling heat exchanger (6), a cryogenic heat exchanger (7), a primary gas-liquid separator (8), a low-temperature separator (9), a low-pressure separator (10), a normal-temperature separator (11) and a mixed hydrocarbon refrigerant compression throttling refrigerating unit; the mixed hydrocarbon refrigerant compression throttling refrigeration unit comprises a refrigerant separator (12) and a refrigerant compressor (13); the interior of the pre-cooling heat exchanger (6) is provided with a channel A1, a channel A2, a channel A3, a channel A4, a channel A5, a channel A6 and a channel A7; the interior of the cryogenic heat exchanger (7) is provided with a channel B1, a channel B2, a channel B3, a channel B4 and a channel B5; the method is characterized in that: the recovery method of the flare blow-down gas during the overhaul period of the oilfield associated gas treatment plant comprises the following steps:
The method comprises the following steps: the oil field associated gas is pressurized and cooled by a feed gas compressor unit (1) and then enters one of a first adsorption tower (2), a second adsorption tower (3) or a third adsorption tower (4) to remove saturated water in the oil field associated gas, so that the dehydration and drying indexes are achieved;
step two: the oil field associated gas dried by the adsorption tower enters a channel A2 of a precooling heat exchanger (6) for precooling, the oil field associated gas from the channel A2 enters a primary gas-liquid separator (8), liquid from the bottom of the primary gas-liquid separator (8) enters a low-pressure separator (10) after throttling and pressure reduction by a throttle valve, and gas from the top of the primary gas-liquid separator (8) is cooled by a channel B2 of a cryogenic heat exchanger (7) and then enters a low-temperature separator (9);
step three: the gas from the top of the low-temperature separator (9) is rich in methane and ethane, the gas is used as high-pressure dry gas to be reheated through a channel B1 of the cryogenic heat exchanger (7) and a channel A1 of the precooling heat exchanger (6), and the reheated dry gas is sent to a CNG compressor unit (43) to be compressed into high-pressure natural gas which is used as a CNG product; the liquid from the bottom of the low-temperature separator (9) is depressurized and cooled by a throttle valve, then passes through a channel B3 of the cryogenic heat exchanger (7) for rewarming, and then enters the low-pressure separator (10);
Step four: liquid coming out of the bottom of the low-pressure separator (10) enters a normal-temperature separator (11) after being reheated by a channel A4 of the precooling heat exchanger (6), and the liquid separated from the normal-temperature separator (11) is rich in propane, butane and heavy components above propane and butane and serves as a hydrocarbon mixture product;
step five: the gas from the top of the low-pressure separator (10) is reheated by a channel A3 of a precooling heat exchanger (6) and then mixed with the gas from the top of a normal-temperature separator (11), the mixed gas serving as low-pressure dry gas enters one of a first adsorption tower (2), a second adsorption tower (3) and a third adsorption tower (4) which is not used as an adsorption tower adsorbent to cool and purge the regenerated gas, the cooled low-pressure dry gas is heated by a regenerated gas heater (5), the heated low-pressure dry gas enters the other one of the first adsorption tower (2), the second adsorption tower (3) and the third adsorption tower (4) which is not used as a heated regenerated gas of the adsorbent, the heated and regenerated gas is cooled by a regenerated gas cooler (15), the cooled low-pressure dry gas enters a regenerated gas separator (16) to separate free water, discharging as sewage; gas from the regeneration gas separator (16) enters a gas generator set (14) to generate electricity, and the generated electricity is supplied to a raw gas compressor set (1), a CNG compressor set (43), a regeneration gas heater (5) and a refrigerant compressor (13);
Step six: the cold energy of the precooling heat exchanger (6) and the cryogenic heat exchanger (7) is provided by a mixed hydrocarbon refrigerant compression throttling refrigerating unit, low-pressure gas-phase refrigerant is compressed and cooled by a refrigerant compressor (13), pressurized high-pressure refrigerant enters a refrigerant separator (12), liquid from the bottom of the refrigerant separator (12) enters a channel A6 of the precooling heat exchanger (6), refrigerant from a channel A6 is throttled and refrigerated by a throttling valve, and low-pressure liquid refrigerant returns to a channel A7 of the precooling heat exchanger (6) to provide cold energy for the precooling heat exchanger (6); high-pressure gas-phase refrigerant coming out of the top of the refrigerant separator (12) is cooled by the precooling heat exchanger (6) and the cryogenic heat exchanger (7), the refrigerant which is changed into liquid is throttled and refrigerated by the throttle valve and returns to the channel B5 of the cryogenic heat exchanger (7) to provide cold energy for the cryogenic heat exchanger (7), refrigerant (49) coming out of the channel B5 of the cryogenic heat exchanger (7) enters the channel A7 of the precooling heat exchanger (6) to provide cold energy for the precooling heat exchanger (6), and low-pressure gas-phase refrigerant coming out of the channel A7 of the precooling heat exchanger (6) enters the refrigerant compressor (13) again to realize circulating compression refrigeration.
2. The process for recovery of flare vent gas during service in an oilfield associated gas processing plant of claim 1, wherein the flare vent gas comprises: the gas inlet of the raw gas compressor unit (1) is connected with a first pipeline (17) for introducing oilfield associated gas, the gas outlet of the raw gas compressor unit (1) is communicated with the gas inlet at the bottom of a first adsorption tower (2) through a second pipeline (18), the gas outlet at the top of the first adsorption tower (2) is communicated with the inlet end of a channel A2 of the precooling heat exchanger (6) through a third pipeline (19), the outlet end of the channel A2 is communicated with the gas inlet of a first-stage gas-liquid separator (8),
The bottom liquid outlet of the first-stage gas-liquid separator (8) is communicated with the inlet end of the low-pressure separator (10) through a fourth pipeline (20), the top gas outlet of the first-stage gas-liquid separator (8) is communicated with the channel B2 of the cryogenic heat exchanger (7) through a fifth pipeline (21), the outlet end of the channel B2 is communicated with the inlet end of the low-temperature separator (9) through a sixth pipeline (22),
a top air outlet of the low-temperature separator (9) is communicated with a channel B1 of the cryogenic heat exchanger (7), a channel B1 is communicated with a channel A1, a channel A1 is communicated with a CNG compressor unit (43) through a seventh pipeline (23), a bottom liquid outlet of the low-temperature separator (9) is communicated with an inlet end of a channel B3 of the cryogenic heat exchanger (7) through an eighth pipeline (24), and an outlet end of a channel B3 is communicated with an inlet end of the low-pressure separator (10);
the top air outlet of the low-pressure separator (10) is communicated with the inlet end of the channel A3, the outlet end of the channel A3 is communicated with the dry gas discharge pipeline (25), the bottom liquid outlet of the low-pressure separator (10) is communicated with the inlet end of the channel A4 through a ninth pipeline (26), the outlet end of the channel A4 is communicated with the inlet end of the normal-temperature separator (11) through a tenth pipeline (27),
And a top gas outlet of the normal temperature separator (11) is communicated with a dry gas discharge pipeline (25), and a bottom liquid outlet of the normal temperature separator (11) is communicated with a heavy hydrocarbon product conveying pipeline (28).
3. The process for recovery of flare vent gas during service at an oilfield associated gas processing plant of claim 2, wherein: the bottom air inlets of the second adsorption tower (3) and the third adsorption tower (4) are communicated with a second pipeline (18), and the top air outlets of the second adsorption tower (3) and the third adsorption tower (4) are communicated with a third pipeline (19);
a dry gas input pipeline (29) and a heating regeneration gas input pipeline (30) are respectively connected to the top gas outlets of the first adsorption tower (2), the second adsorption tower (3) and the third adsorption tower (4), a cooling regeneration gas output pipeline (31) and a heating regeneration gas output pipeline (32) are respectively connected to the bottom gas inlets of the first adsorption tower (2), the second adsorption tower (3) and the third adsorption tower (4), the dry gas input pipeline (29) is communicated with a dry gas discharge pipeline (25), the output end of the cooling regeneration gas output pipeline (31) is connected to a regeneration gas heating main pipeline (33), the output end of the regeneration gas heating main pipeline (33) is communicated with the heating regeneration gas input pipeline (30), and the regeneration gas heater (5) is installed on the regeneration gas heating main pipeline (33); the output end of the heating regeneration gas output pipeline (32) is connected to a regeneration gas cooling main pipeline (34), the regeneration gas cooler (15) is installed on the regeneration gas cooling main pipeline (34), the output end of the regeneration gas cooling main pipeline (34) is communicated with an air inlet of a regeneration gas separator (16), a liquid outlet in the bottom of the regeneration gas separator (16) is communicated with a free water output pipeline (35), and a gas outlet in the top of the regeneration gas separator (16) is communicated with the gas generator set (14).
4. The process for recovery of flare vent gas during service at an oilfield associated gas processing plant of claim 1, wherein: the outlet end of the channel A7 is communicated with the inlet end of a refrigerant compressor (13) through a first refrigerant circulation pipeline (36), the outlet end of the refrigerant compressor (13) is communicated with the inlet of a refrigerant separator (12) through a second refrigerant circulation pipeline (37), the bottom liquid outlet of the refrigerant separator (12) is communicated with the inlet end of a channel A6 through a third refrigerant circulation pipeline (39), the outlet end of the channel A6 is communicated with the channel A7 through a fourth refrigerant circulation pipeline (40), a first throttling valve is arranged on the fourth refrigerant circulation pipeline (40), the top air outlet of the refrigerant separator (12) is communicated with the inlet end of a channel A5 through a fifth refrigerant circulation pipeline (38), the outlet end of the channel A5 is communicated with a channel B4, a channel B4 and a channel B5 are communicated through a sixth refrigerant circulation pipeline (42), and a second throttling valve is arranged on the sixth refrigerant circulation pipeline (42), the passage B5 is communicated with the passage A7 through a No. seven refrigerant circulating pipeline (41).
CN202210465852.2A 2022-04-29 2022-04-29 Method for recycling flare release air during overhaul of oilfield associated gas treatment plant Active CN114752401B (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105038882A (en) * 2015-05-29 2015-11-11 西安长庆科技工程有限责任公司 Comprehensive fine dewatering technique for recovering LNG/LPG/NGL (liquefied natural gas/liquefied petroleum gas/natural gas liquid) product from saturated hydrous petroleum associated gas
WO2019071869A1 (en) * 2017-10-12 2019-04-18 中国石油工程建设有限公司 Device and method using stepped cooling to recover ethane from natural gas
CN111578620A (en) * 2020-06-05 2020-08-25 杭州弘泽新能源有限公司 Vehicle-mounted mobile system and process method for recovering hydrocarbon mixture and liquefied natural gas in oil field vent gas

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105038882A (en) * 2015-05-29 2015-11-11 西安长庆科技工程有限责任公司 Comprehensive fine dewatering technique for recovering LNG/LPG/NGL (liquefied natural gas/liquefied petroleum gas/natural gas liquid) product from saturated hydrous petroleum associated gas
WO2019071869A1 (en) * 2017-10-12 2019-04-18 中国石油工程建设有限公司 Device and method using stepped cooling to recover ethane from natural gas
CN111578620A (en) * 2020-06-05 2020-08-25 杭州弘泽新能源有限公司 Vehicle-mounted mobile system and process method for recovering hydrocarbon mixture and liquefied natural gas in oil field vent gas

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