CN111578621A - Device and process capable of switching two natural gas towers for helium extraction - Google Patents

Device and process capable of switching two natural gas towers for helium extraction Download PDF

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Publication number
CN111578621A
CN111578621A CN202010553342.1A CN202010553342A CN111578621A CN 111578621 A CN111578621 A CN 111578621A CN 202010553342 A CN202010553342 A CN 202010553342A CN 111578621 A CN111578621 A CN 111578621A
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China
Prior art keywords
tower
natural gas
helium
cold box
primary
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CN202010553342.1A
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Chinese (zh)
Inventor
周璇
王科
蒲黎明
王刚
杨苗
汪贵
陈运强
李莹珂
陈渝
田静
汤晓勇
胡益武
邰建新
杜建莉
杨俊琦
李莎
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China National Petroleum Corp
China Petroleum Engineering and Construction Corp
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China Petroleum Engineering and Construction Corp
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Priority to CN202010553342.1A priority Critical patent/CN111578621A/en
Publication of CN111578621A publication Critical patent/CN111578621A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0209—Natural gas or substitute natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/028—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of noble gases
    • F25J3/029—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of noble gases of helium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0247—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 4 carbon atoms or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0257—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0295—Start-up or control of the process; Details of the apparatus used, e.g. sieve plates, packings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/04—Recovery of liquid products
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
    • F25J2240/40—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval
    • F25J2240/44—Expansion without extracting work, i.e. isenthalpic throttling, e.g. JT valve, regulating valve or venturi, or isentropic nozzle, e.g. Laval the fluid being nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
    • F25J2245/02—Recycle of a stream in general, e.g. a by-pass stream
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/02—Internal refrigeration with liquid vaporising loop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/12—External refrigeration with liquid vaporising loop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/42—Quasi-closed internal or closed external nitrogen refrigeration cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2280/00—Control of the process or apparatus
    • F25J2280/02—Control in general, load changes, different modes ("runs"), measurements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/42—Modularity, pre-fabrication of modules, assembling and erection, horizontal layout, i.e. plot plan, and vertical arrangement of parts of the cryogenic unit, e.g. of the cold box

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  • Engineering & Computer Science (AREA)
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  • Mechanical Engineering (AREA)
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  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
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Abstract

The invention relates to the technical field of helium recovery from natural gas, and provides a two-tower helium extraction device and a two-tower helium extraction process for switchable natural gas, wherein the two-tower helium extraction device comprises a precooling cold box, a primary concentration tower, a secondary concentration tower and a cryogenic cold box; the lower part of the primary concentrating tower is provided with a gas phase outlet, the gas phase outlet is communicated to the precooling cold box and then is connected with an inlet arranged in the middle of the primary concentrating tower, the side of the connecting section is connected with a stop valve, and a passage where the stop valve is arranged passes through the precooling cold box and outputs natural gas; the top of the primary concentration tower is provided with a gas phase outlet and at least outputs a passage communicated to the secondary concentration tower, and the secondary concentration tower outputs at least one passage to pass through the deep cooling cold box and output helium after secondary concentration treatment. The primary concentration tower and the secondary concentration tower are matched to realize primary extraction processing and natural gas production of helium in the primary concentration tower, realize crude product extraction of helium in the secondary concentration tower and continue production of residual natural gas. Simple process and obvious effect.

Description

Device and process capable of switching two natural gas towers for helium extraction
Technical Field
The invention relates to the technical field of helium recovery from natural gas, in particular to helium purification treatment, and particularly relates to a device and a process for switching two towers of natural gas to extract helium.
Background
Helium is an inert gas, generally colorless, odorless, and the only material that cannot be cured at standard atmospheric pressure.
Helium is an indispensable rare substance for engineering technology development, the stability of helium determines the important application of helium, and the helium is widely applied to the fields of petrifaction, refrigeration, medical treatment, semiconductors, superconducting experiments, photoelectron product production and the like at present. In the field of nuclear magnetic resonance (low-temperature superconducting), a nuclear Magnetic Resonance Imager (MRI) uses helium as a cooling medium of a low-temperature superconducting magnet; in the field of semiconductors and optical fibers, helium is mainly used as a protective gas for growing germanium and silicon crystals in the semiconductor industry, and as a cooling and protective atmosphere gas in the processes of manufacturing an optical fiber preform and drawing an optical fiber; in the field of low-temperature engineering, the refrigerant is generally used as a working medium of a closed-cycle low-temperature refrigerator; in addition, helium is widely applied to the fields of household appliance refrigeration and automobile manufacturing.
At present, helium is mainly prepared from natural gas, and the low-temperature helium extraction process of the existing primary concentration tower system needs natural gas self-expansion to provide cold energy and cannot be suitable for the gas condition with rich raw material gas components. When the natural gas needs to be purified, the production of helium can not be freely controlled while qualified natural gas is exported.
Disclosure of Invention
In order to overcome the defects of the prior art mentioned in the above, the invention provides a switchable natural gas two-tower helium extracting device, which is used for extracting helium from natural gas, and can freely and selectively control the production of helium while realizing natural gas purification treatment. One set of device can integrate the purification treatment process of natural gas and the preparation process of helium, and the device operation is simpler and more convenient, and resource consumption is also less.
In order to achieve the purpose, the invention adopts the technical scheme that:
a switchable natural gas two-tower helium extraction device comprises a precooling cold box, a primary concentration tower, a secondary concentration tower and a cryogenic cold box which are sequentially communicated; the lower part of the primary concentrating tower is provided with a gas phase outlet, the gas phase outlet is communicated to the precooling cold box and then is connected with an inlet arranged in the middle of the primary concentrating tower, the side of the connecting section is connected with a stop valve, and a passage where the stop valve is arranged passes through the precooling cold box and outputs natural gas; the top of the primary concentration tower is provided with a gas phase outlet and at least outputs a passage communicated to the secondary concentration tower, and the secondary concentration tower outputs at least one passage to pass through the deep cooling cold box and output helium after secondary concentration treatment.
According to the helium extraction device disclosed by the invention, the primary extraction processing and the natural gas production of helium are realized in the primary concentration tower through the matched work of the primary concentration tower and the secondary concentration tower, the crude product extraction of helium is realized in the secondary concentration tower, and the residual natural gas is continuously produced. The pre-cooling cold box and the deep cooling cold box respectively provide temperature environments for the process related to the primary concentration tower and the process related to the secondary concentration tower.
When the production of helium is controlled, the stop valve closes and blocks the passage, the passage output by the primary concentration tower and passing through the passage of the precooling cold box can be returned to the inlet in the middle of the primary concentration tower, and the passage is output to the secondary concentration tower after the flow is split, so that the subsequent helium preparation process is completed, and the production of natural gas can be realized.
When the natural gas production is controlled and helium gas does not need to be produced, the cut-off valve is opened to communicate the passage, and according to the Newton's third law, substances output by the primary concentrating tower and passing through the passage of the pre-cooling cold box do not flow back to the primary concentrating tower, but directly pass through the pre-cooling cold box and are output outwards.
According to the arrangement, the production of helium can be freely and selectively controlled under the condition of not influencing the production of natural gas.
Furthermore, the primary concentrating tower and the secondary concentrating tower are respectively communicated with matched equipment in the device, and the following specific schemes are given: the bottom of the primary concentration tower and the bottom of the secondary concentration tower are respectively provided with a primary reboiler and a secondary reboiler, and the paths output by the primary reboiler and the secondary reboiler are respectively communicated to the primary concentration tower and the secondary concentration tower after passing through a precooling cold box and a subzero cold box. The structure of the arrangement has a direct effect on producing natural gas when the primary concentration tower works, and can complete the first step of preparing helium; when helium is required to be prepared, the preparation work of the helium is completed through the intervention work of the secondary concentration tower.
Still further, the primary reboiler is integrated in the bottom of the primary concentration tower, and the secondary reboiler is integrated in the bottom of the secondary concentration tower and used as an integrated device, so that the loss of cold energy can be reduced.
Further, in order to facilitate the production of helium, the substances discharged from the primary concentration tower need to be concentrated again, so that the path is optimized, and the following specific schemes are provided: the top output of follow first concentration tower and with be equipped with first condenser in the route of secondary concentration tower intercommunication, the output of first condenser connect first reflux tank, the gaseous phase route at first reflux tank top communicates to the secondary concentration tower, and the liquid phase route of first reflux tank bottom communicates to a purification tower. As one of the feasible options, the significance of the arrangement is that the substance output by the primary condenser enters a primary reflux tank and is divided into a gas phase part and a liquid phase part through reflux, wherein the gas phase part contains helium and enters a secondary concentration tower for secondary treatment and concentration to obtain the helium; and refluxing part of the liquid phase to the primary concentration tower to be used as tower top reflux liquid.
Still further, first condenser and first reflux drum all integrate in the top of a concentration tower, the inside of a sled piece can be wholly integrated to precooling cold box and the concentration tower of integrating once, make things convenient for the whole cold insulation of equipment, improve the cold energy utilization in the transportation process.
Further, a part of concentrated liquid phase substances are accumulated at the bottom of the primary concentrating tower, the part of liquid phase substances are reprocessed, and required natural gas is obtained from the part of liquid phase substances, the structure of the primary concentrating tower is optimized, and the following specific scheme is provided: the bottom of the primary concentration tower outputs at least two paths, wherein at least one path outputs natural gas after passing through the primary condenser and the pre-cooling cold box, and at least one path outputs natural gas after directly passing through the pre-cooling cold box. This is in the sense that, as one of many possible options, the passage through the primary condenser first provides some cooling capacity to the primary condenser.
Further, when the natural gas produced in the above technical scheme is conveyed to an external natural gas pipe network, pretreatment needs to be performed to reach an output standard, so that a path for outputting the natural gas is optimized, and the following specific schemes are given as follows: and a compressor and a cooler are arranged in the path which passes through the precooling cold box and outputs the natural gas. The natural gas in the channel is pressurized and cooled by a compressor and a cooler to reach the pressure required by an external natural gas pipeline network, and then is transported to the outside.
Further, when carrying out secondary concentration and handling, rely on the cooperation of secondary concentration tower and cryrogenic cold box, it is specific, secondary concentration tower from at least one route intercommunication cryrogenic cold box of top output, and be equipped with secondary condenser and the secondary reflux jar that communicates in proper order in the route, secondary reflux jar top output gas phase route communicates to cryrogenic cold box, and secondary reflux jar bottom output liquid phase route communicates to secondary concentration tower. As one of a plurality of feasible choices, the arrangement is significant in that the deep cooling cold box removes hydrocarbon substances such as methane and the like from gas-phase substances in the secondary reflux tank to obtain a crude helium product, so that the preparation of helium is realized; liquid phase substances in the secondary reflux tank can be used as tower top reflux liquid by refluxing to the secondary concentration tower.
Still further, similar with once-through concentration tower, secondary condenser and secondary reflux jar all integrate to the top of secondary concentration tower, integrated secondary concentration tower and cryrogenic cold box are integrated to a sled piece as an organic whole in, the scattering and disappearing of reducible cold volume in the transportation improves the utilization of cold energy.
When the transportation condition allows, can all integrate into a sled piece with first concentration tower, precooling cold box, secondary concentration tower and cryrogenic cold box, so can further reduce scattering and disappearing of cold volume, improve the cold energy utilization ratio in the transportation.
Still further, the interior bottom of tower is deposited to the liquid phase material in the secondary concentration tower, can reprocess and extract required material such as natural gas to the liquid phase material, it is specific, secondary concentration tower bottom output at least one route pass through cryrogenic cold box to the route of export to the precooling cold box from the top of primary concentration tower is exported to the intercommunication. As one of the feasible options, the significance of the arrangement is that the liquid phase is reheated by the cryogenic cooling box and then converted into a gas phase substance, the gas phase substance is mixed with the meteorological substance output by the primary concentration tower, and the gas phase substance can be output as natural gas after being reheated by the precooling cooling box.
Further, cryogenic refrigerator provides cold volume temperature environment in the course of the work, and this kind of effect is realized with multiple mode to cryogenic refrigerator's class, and the cold source to cryogenic refrigerator here is optimized, gives up following specific scheme: the nitrogen circulating refrigeration device comprises a circulating passage passing through the cryogenic cooling box, and a nitrogen inlet, a nitrogen compressor and a compressor unit cooler are arranged on the circulating passage; the circulating path comprises at least one circulating branch passing through the secondary condenser, and a co-production liquid nitrogen outlet is arranged on the circulating branch. As one of a plurality of feasible choices, the significance of the arrangement is that the nitrogen is used as refrigerant gas, the operation is very stable and safe, and the pollution is avoided, after the gaseous nitrogen passes through the circulating channel, the heat in the cryogenic cooling box and the heat of the secondary condenser can be taken away, the cold quantity is provided for the nitrogen and the secondary condenser, and meanwhile, the co-production liquid nitrogen outlet on the circulating branch can extract part of liquid nitrogen to be used as industrial practicality, and the preparation of liquid nitrogen can be realized.
Specifically, nitrogen after reheating in the cryogenic cooling tank and supplemented high-purity nitrogen enter a nitrogen compressor and a compressor unit cooler, are supercharged and cooled to 1.6-2.0 MPa.g, after the temperature of 40-50 ℃, a small part (about 15-40%) of nitrogen enters the cryogenic cooling tank and is condensed into a liquid phase (-170 ℃), can enter the nitrogen compressor after being throttled to 0.2MPa.g by a nitrogen refrigerant throttle valve, and the remaining high-pressure normal-temperature nitrogen enters the cryogenic cooling tank and is condensed to-170 ℃, then enters the nitrogen refrigerant throttle valve and is throttled to 0.2MPa.g, and then can enter a secondary condenser to provide cold energy for the nitrogen compressor, and meanwhile, part of the liquid can be extracted from a co-production liquid nitrogen outlet and is used as a liquid nitrogen product of a. The gas phase reheated by the secondary condenser enters the deep cooling cold box to be reheated and then enters the nitrogen compressor, so that the circulation of nitrogen refrigeration is completed.
Furthermore, the whole device purifies the natural gas before the natural gas and the helium are prepared from the raw material gas, and because a large amount of heavy hydrocarbon substances exist in the raw material gas, the purification part of the device is optimized, and the following specific schemes are given: the two-tower helium extracting device also comprises a heavy hydrocarbon removing device, the heavy hydrocarbon removing device comprises a heavy hydrocarbon washing tower, and a gas phase output passage of the heavy hydrocarbon washing tower passes through the precooling cold box and then is communicated to the heavy hydrocarbon reflux tank; the heavy hydrocarbon reflux tank at least outputs a passage communicated to the primary concentration tower, at least outputs a passage communicated to the primary concentration tower after passing through the precooling cold box, and also outputs at least one liquid phase passage provided with a reflux pump to reflux to the heavy hydrocarbon washing tower. As one of multiple feasible selection, the meaning that so sets up lies in, the heavy hydrocarbon scrubbing tower sets up in precooling cold box department, the feed gas gets into the heavy hydrocarbon scrubbing tower behind the precooling cold box, separable stable light hydrocarbon product that obtains and contain helium gaseous phase material, contain helium gaseous phase material behind precooling cold box environment and heavy hydrocarbon reflux tank, separate out and can carry to once the gaseous phase material and the residual liquid phase material of concentrating the tower, wherein gaseous phase material leads to once concentrating the tower through two gaseous phase routes of heavy hydrocarbon reflux tank output, residual liquid phase material flows back to the heavy hydrocarbon scrubbing tower as top of the tower washing liquid via liquid phase route.
The above disclosure discloses a switchable natural gas two-tower helium extraction device, which can realize purification treatment of raw gas, produce natural gas from the raw gas, and freely control production and preparation of helium. The invention also discloses a two-tower helium extraction process, and natural gas production and helium gas preparation are realized by applying the two-tower helium extraction device, and can be freely selected according to requirements in the process. The process will now be described.
A switchable natural gas two-tower helium extraction process, which uses the disclosed helium extraction device, comprises:
pre-cooling and decontaminating raw material gas;
when only natural gas is produced, carrying out primary concentration treatment including reboiling and condensation to obtain a treated natural gas product;
when natural gas is produced and helium is synchronously prepared, carrying out primary concentration treatment including reboiling and condensation to obtain a treated natural gas product, and carrying out reflux treatment to obtain crude helium; carrying out secondary concentration treatment including reboiling, condensation and reflux to obtain a helium product;
and (4) carrying out environmental treatment on the liquid-phase product obtained by the primary concentration treatment and the secondary concentration treatment through a precooling cold box or a subzero cold box to obtain the export natural gas.
Utilize above-mentioned two towers that disclose to carry helium device, to the precooling cold box of feed gas and the processing of decontaminating mainly accomplish at the continuous equipment of preorder, when to heavy hydrocarbon material, take off heavy hydrocarbon device as preorder continuous equipment, when needs carry out the desorption to other materials and purify, can pertinence selection suitable preorder continuous equipment.
When switching is carried out in two production modes of only producing natural gas and synchronously preparing helium, the switching is realized through a cut-off valve, when the cut-off valve is in a closed blocking state, natural gas can be produced and helium can be synchronously prepared, and when the cut-off valve is in an open communicating state, natural gas is only produced.
Compared with the prior art, the invention has the beneficial effects that:
according to the two-tower helium extraction device provided by the invention, the preparation and output of natural gas and helium gas are switched by controlling the primary concentration tower and the secondary concentration tower to participate in the production process; the device can be applied to the feed gas with various component ratios, and has the advantages of thorough separation of components in the feed gas, simple process and obvious effect.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a flow chart of a double stripping process;
FIG. 2 is a schematic diagram of the composition of a double-tower helium stripping apparatus.
In the above drawings, the meanings of the respective symbols are: 1. a pre-cooling cold box; 2. a heavy hydrocarbon washing column; 3. a tower bottom throttle valve; 4. a heavy hydrocarbon reflux tank; 5. a reflux pump; 6. a pressure balancing valve; 7. a throttle valve; 8. a primary concentrating tower; 9. a primary reboiler; 10. a primary condenser; 11. a primary reflux tank; 12. a compressor; 13. a cooler; 14. a shut-off valve; 15. a nitrogen compressor; 16. a compressor unit cooler; 17. a secondary reflux tank; 18. a cryogenic cooling box; 19. a secondary concentration tower; 20. a secondary reboiler; 21. and a secondary condenser.
Detailed Description
The invention is further explained below with reference to the drawings and the specific embodiments.
It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. Specific structural and functional details disclosed herein are merely illustrative of example embodiments of the invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein.
Example 1
As shown in fig. 1, this embodiment discloses a switchable natural gas two-tower helium extraction process, which can process a helium-containing feed gas to finally produce natural gas or synchronously produce helium. The process comprises the following steps:
s01: pre-cooling and decontaminating raw material gas;
s02 a: when only natural gas is produced, carrying out primary concentration treatment including reboiling and condensation to obtain a treated natural gas product;
s02 b: when natural gas is produced and helium is synchronously prepared, carrying out primary concentration treatment including reboiling and condensation to obtain a treated natural gas product, and carrying out reflux treatment to obtain crude helium; carrying out secondary concentration treatment including reboiling, condensation and reflux to obtain a helium product;
s03: liquid phase products obtained by the primary concentration treatment and the secondary concentration treatment are subjected to environmental treatment of a precooling cold box 1 or a subzero cold box 18 to obtain the export natural gas.
Utilize above-mentioned two towers that disclose to carry helium device, to the feed gas precooling handle with the scrubbing is mainly accomplished at precooling cold box 1 and the continuous equipment of preorder, when aiming at heavy hydrocarbon material, taking off heavy hydrocarbon device as preorder continuous equipment in the adoption, when needs carry out the desorption to other materials and purify, can pertinence selection suitable preorder continuous equipment.
When switching is carried out in two production modes of only producing natural gas and synchronously preparing helium, the switching is realized through the cut-off valve 14, when the cut-off valve 14 is in a closed blocking state, natural gas can be produced and helium can be synchronously prepared, and when the cut-off valve 14 is in an open communicating state, only natural gas is produced.
In the process of preparing helium, nitrogen is introduced into the nitrogen circulating refrigeration device, and gaseous nitrogen can be converted into liquid nitrogen by utilizing heat exchange in the circulating passage and output as a production product.
Example 2
This example provides a two-tower helium stripping apparatus for processing a helium-containing feed gas based on the process disclosed in example 1, and the details of the process in example 1 are disclosed in conjunction with the apparatus.
The helium-containing feed gas to be treated is 3.0-6.0 MPa.g, and is treated by the following device:
as shown in fig. 2, the present embodiment discloses a switchable natural gas two-tower helium extraction device, which includes a pre-cooling cold box 1, a primary concentration tower 8, a secondary concentration tower 19 and a cryogenic cold box 18, which are sequentially communicated; a gas phase outlet is arranged at the lower part of the primary concentrating tower 8, the gas phase outlet is communicated to the precooling cold box 1 and then is connected back to an inlet arranged at the middle part of the primary concentrating tower 8, a cut-off valve 14 is connected by the side of the connection section, and a passage where the cut-off valve 14 is located passes through the precooling cold box 1 and outputs natural gas; the top of the primary concentration tower 8 is provided with a gas phase outlet and at least outputs a passage which is communicated to a secondary concentration tower 19, and the secondary concentration tower 19 outputs at least one passage which passes through a deep cooling cold box 18 and outputs helium after secondary concentration treatment.
The helium extraction device disclosed above realizes primary extraction processing and natural gas production of helium gas in the primary concentration tower 8, realizes crude product extraction of helium gas in the secondary concentration tower 19, and continues production of residual natural gas through the cooperation of the primary concentration tower 8 and the secondary concentration tower 19. The pre-cooling cold box 1 and the cryogenic cold box 18 provide temperature environments for the process related to the primary concentration tower 8 and the process related to the secondary concentration tower 19 respectively.
Generally, the feed gas enters a precooling cold box 1, is precooled to-40 ℃ to-75 ℃, is subjected to primary purification treatment at a temperature of-55 ℃ to-90 ℃, and is adjusted to a pressure of 2.92 MPa.92 to 5.92MPa.g, so that the feed gas can enter a primary concentration tower 8 for primary concentration operation treatment.
When helium is controlled to be produced, the cut-off valve 14 is closed to block the passage, the passage is output by the primary concentration tower 8 and can be returned to the inlet in the middle of the primary concentration tower 8 through the passage of the precooling cold box 1, and the passage is output to the secondary concentration tower 19 after being shunted, so that the subsequent helium preparation process is completed, and meanwhile, the production of natural gas can be realized.
When the natural gas production is controlled and helium gas does not need to be produced, the cutoff valve 14 is opened to communicate the passage, and according to the Newton's third law, substances output by the primary concentrating tower 8 and passing through the passage of the pre-cooling cold box 1 do not flow back to the primary concentrating tower 8, but directly pass through the pre-cooling cold box 1 and are output outwards.
According to the arrangement of the embodiment, the production mode can be selected by controlling the on-off of the cut-off valve 14 under the condition of not influencing the production of natural gas, and the production of helium can be freely and selectively controlled.
The primary concentrating tower 8 and the secondary concentrating tower 19 are respectively communicated with matched equipment in the device, and the following specific schemes are taken as examples: the bottom of the primary concentration tower 8 and the bottom of the secondary concentration tower 19 are respectively provided with a primary reboiler 9 and a secondary reboiler 20, and the paths output by the primary reboiler 9 and the secondary reboiler 20 are respectively communicated to the primary concentration tower 8 and the secondary concentration tower 19 after passing through the precooling cold box 1 and the subzero cold box 18. With the adoption of the structure, the primary concentration tower 8 has a direct effect on the production of natural gas when working, and can complete the first step of preparing helium; when helium is required to be prepared, the secondary concentration tower 19 is involved in the work, so that the helium preparation work is completed.
The substance enters a primary concentration tower 8, a primary reboiler 9 carries out heat exchange on the substance, wherein the substance releases heat in the primary reboiler 9 and provides heat for the primary concentration tower 8, the temperature range of the substance passing through the primary reboiler 9 is changed to-62 ℃ to-97 ℃, the substance enters a precooling cold box 1 again, the temperature reaches-90 ℃ to-120 ℃ after passing through the temperature environment of the precooling cold box 1, and the substance is completely condensed into a liquid phase; and (3) adjusting the pressure of the condensed substance to 2-3.5 MPa.g after throttling treatment, and entering the middle inlet of a primary concentration tower 8 for concentration treatment.
The primary reboiler 9 is integrated at the bottom of the primary concentration tower 8, and the secondary reboiler 20 is integrated at the bottom of the secondary concentration tower 19 as an integrated device, so that the loss of cold energy can be reduced.
In order to facilitate the production of helium, the substances output from the primary concentration tower 8 need to be concentrated again, so the path is optimized, and the following specific schemes are provided: the path that export from the top of primary concentration tower 8 and communicate with secondary concentration tower 19 in be equipped with primary condenser 10, the output of primary condenser 10 connect primary reflux jar 11, the gaseous phase route at primary reflux jar 11 top communicates to secondary concentration tower 19, and the liquid phase route of primary reflux jar 11 bottom communicates to a purification tower. As one of the possible options, the arrangement is characterized in that a part of the substance output by the primary condenser 10 enters the primary reflux tank 11 and is separated into a gas phase part and a liquid phase part through reflux, wherein the gas phase part contains helium and enters the secondary concentration tower 19 for secondary treatment and concentration to obtain helium; the liquid phase is partially refluxed to the primary concentrating column 8 as overhead reflux.
First condenser 10 and first reflux drum 11 all integrate in the top of a concentration tower 8, precooling cold box 1 can wholly integrate the inside to a sled piece with an integrated a concentration tower, make things convenient for the whole cold insulation of equipment, improve the cold energy utilization in the transportation process.
The pressure and temperature of the gas phase substance output from the top of the primary concentration tower 8 are respectively 1.8-3.3 MPa.g and-100-130 ℃, the pressure and temperature value are changed to 1.75-3.25 MPa.g after passing through the primary condenser 10, the gas phase substance enters the primary reflux tank 11 after the temperature is changed to-120-145 ℃, the gas phase substance is output from the primary reflux tank 11 and is conveyed to the secondary concentration tower 19 through a passage, and the temperature exchange is carried out in a secondary reboiler 20 at the bottom of the secondary concentration tower 19.
The bottom of the primary concentrating tower 8 is accumulated with part of concentrated liquid phase substances, the part of liquid phase substances are reprocessed and required natural gas is obtained from the part of liquid phase substances, the structure of the primary concentrating tower 8 is optimized, and the following specific scheme is provided: at least two paths are output from the bottom of the primary concentrating tower 8, wherein at least one path outputs natural gas after passing through the primary condenser 10 and the pre-cooling cold box 1, and at least one path outputs natural gas after directly passing through the pre-cooling cold box 1. This is in the sense that the passage through the primary condenser 10 provides some cooling to the primary condenser 10, as one of many possible options.
The natural gas produced in the above technical scheme needs to be pretreated to reach the output standard when being transported to the external natural gas pipe network, so that the path for outputting the natural gas is optimized, and the following specific schemes are given out: a compressor 12 and a cooler 13 are arranged in the path which passes through the pre-cooling cold box 1 and outputs natural gas. As one of the possible options, the significance of this is that the natural gas in the passage is pressurized and cooled by the compressor 12 and the cooler 13 to reach the pressure required by the external natural gas pipeline network, and then is transported to the outside.
In this embodiment, the liquid phase substance at the bottom of the primary concentration tower 8 is LNG (Liquefied Natural Gas), the pressure is controlled to a certain value by the throttle valve 7, the LNG enters the precooling cold box 1, the LNG is reheated to 15 to 40 ℃ to form a Gas phase, the Gas phase enters the compressor 12 and the cooler 13, and finally reaches the pressure of the Natural Gas pipeline network for external transportation, and the Gas for external transportation is mainly methane. After the pressure of a small part of LNG at the bottom of the primary concentration tower 8 is controlled to be 0.35-1.3 MPa.g through the throttle valve 7, the LNG passes through the primary condenser 10 and provides cold energy for the LNG, the LNG enters the pre-cooling cold box 1 after being gasified to be reheated to 15-40 ℃ to form a gas phase, the gas phase reaches the pressure of an external natural gas pipeline network through the compressor 12 and the cooler 13 and can be used for external transportation, and the external gas is low-pressure gas.
When carrying out secondary concentration and handling, rely on secondary concentration tower 19 and 18 cooperation of cryrogenic cold box, it is specific, secondary concentration tower 19 from top output at least one route intercommunication cryrogenic cold box 18, and be equipped with secondary condenser 21 and the secondary reflux jar 17 that communicates in proper order in the route, secondary reflux jar 17 top output gas phase route communicates to cryrogenic cold box 18, and secondary reflux jar 17 bottom output liquid phase route communicates to secondary concentration tower 19. As one of a plurality of feasible options, the arrangement is significant in that the cryogenic cooling box 18 carries out hydrocarbon substance removal treatment such as methane and the like on the gas-phase substance in the secondary reflux tank 17 to obtain a crude helium product, so that the helium is prepared; the liquid phase material in the secondary reflux drum 17 can be used as overhead reflux liquid by refluxing to the secondary concentration tower 19.
Similar with once the concentration tower, secondary condenser 21 and secondary reflux tank 17 all integrate to the top of secondary concentration tower 19, integrated secondary concentration tower and cryrogenic cold box 18 are integrated to a sled piece as an organic whole in, the loss of reducible cold volume improves the utilization of cold energy in the transportation.
When the transportation condition allows, can all integrate into a sled piece with first concentration tower 8, precooling cold box 1, secondary concentration tower 19 and cryrogenic cold box 18, so can further reduce scattering and disappearing of cold volume, improve the cold energy utilization ratio in the transportation.
The substance entering the secondary concentration tower 19 is a gas phase from the primary reflux tank 11, the pressure and temperature ranges are respectively 1.75-3.25 MPa.g, the temperature ranges are-120 ℃ to-145 ℃, the bottom of the secondary concentration tower 19 is provided with a secondary reboiler 20, the secondary reboiler 20 carries out heat exchange on the substance, the substance releases heat in the secondary reboiler 20 and provides heat for the secondary concentration tower 19, the temperature range of the substance passing through the secondary reboiler 20 is changed to-133 ℃ to-155 ℃, the substance enters the cryogenic cooling box 18, the temperature reaches-165 ℃ to-175 ℃ after passing through the temperature environment of the cryogenic cooling box 18, and the substance is completely condensed into a liquid phase; the condensed substance enters the middle inlet of the secondary concentration tower 19 for concentration treatment.
After the secondary concentration treatment, the substance output from the top of the secondary concentration tower 19 is a gas phase, the temperature range of the substance is-155 ℃ to-170 ℃, the temperature is changed to-180 ℃ after condensation in the secondary condenser 21, then the substance enters the secondary reflux tank 17, the gas phase and the liquid phase are output by the secondary reflux tank 17, and the gas phase and the liquid phase respectively reach the deep cooling cold box 18 to output a crude helium product and reflux liquid of the secondary concentration tower 19.
The liquid phase material in secondary concentration tower 19 is deposited in the bottom in the tower, can reprocess and extract required material such as natural gas to liquid phase material, specifically, secondary concentration tower 19 bottom output at least one route through cryrogenic cold box 18 to the intercommunication is exported the route to precooling cold box 1 from the top of primary concentration tower 8. As one of the feasible options, the significance of the arrangement is that the liquid phase is reheated by the cryogenic cooling box 18 and then converted into a gas phase substance, and the gas phase substance is mixed with the meteorological substance output by the primary concentration tower 8, and the gas phase substance can be output as natural gas after being reheated by the precooling cooling box 1.
Example 3
On the basis of embodiment 2, the cold source structure of the cryogenic cooling box 18 is perfected, the structure of nitrogen circulation is used for providing cold for the cryogenic cooling box 18, and meanwhile, the preparation of liquid nitrogen can be realized.
The method comprises the following specific steps: as shown in fig. 2, the cryogenic refrigerator 18 provides a cooling temperature environment during the operation, and the cryogenic refrigerator 18 achieves this effect in various ways, where the cooling source of the cryogenic refrigerator 18 is optimized, and the following specific schemes are given: the deep cooling cold box 18 is provided with a nitrogen circulating refrigeration device, the nitrogen circulating refrigeration device comprises a circulating passage passing through the deep cooling cold box 18, and the circulating passage is provided with a nitrogen inlet, a nitrogen compressor 15 and a compressor unit cooler 16; the circulation path comprises at least one circulation branch passing through the secondary condenser 21, and a co-production liquid nitrogen outlet is arranged on the circulation branch. As one of the feasible options, the significance of the arrangement is that the nitrogen is used as refrigerant gas, so that the nitrogen is stable and safe, and pollution-free, and after the gaseous nitrogen passes through the circulating channel, the heat in the cryogenic cooling box 18 and the heat of the secondary condenser 21 can be taken away, so that the refrigeration capacity can be provided for the nitrogen and the heat, and meanwhile, the liquid nitrogen can be prepared.
In the embodiment, nitrogen reheated by the cryogenic cooling tank 18 and supplemented high-purity nitrogen enter the nitrogen compressor 15 and the compressor unit cooler 16, are supercharged and cooled to 1.6-2.0 MPa.g, after the temperature of 40-50 ℃, a small part (about 15-40%) enters the cryogenic cooling tank 18 and is condensed into a liquid phase (-170 ℃), the liquid phase can enter the nitrogen compressor 15 after being throttled to 0.2MPa.g by a nitrogen throttling valve, most of the remaining high-pressure normal-temperature nitrogen enters the cryogenic cooling tank 18 and is condensed to-170 ℃, then enters the nitrogen throttling valve and is throttled to 0.2MPa.g, the liquid phase can enter the secondary condenser 21 to provide cold energy for the nitrogen compressor, and meanwhile, part of the liquid phase can be extracted from a coproduction liquid nitrogen outlet and serves as a liquid nitrogen product. The gas phase reheated by the secondary condenser 21 enters the cryogenic cooling box 18 for reheating and then enters the nitrogen compressor 15, so that the circulation of nitrogen refrigeration is completed.
The structure of the other parts in this embodiment is the same as that in embodiment 2, and will not be described herein.
Example 4
In the embodiment, on the basis of the embodiment 2, the purification and decontamination structure of the raw material gas is perfected. In particular to heavy hydrocarbon substances, which are separated and treated separately.
The method comprises the following specific steps: as shown in fig. 2, the whole plant purifies the natural gas before the natural gas and the helium are prepared from the feed gas, and because a large amount of heavy hydrocarbon substances exist in the feed gas, the purification part of the plant is optimized, and the following specific schemes are given: the two-tower helium extracting device further comprises a heavy hydrocarbon removing device, the heavy hydrocarbon removing device comprises a heavy hydrocarbon washing tower 2, and a gas phase output passage of the heavy hydrocarbon washing tower 2 is communicated to a heavy hydrocarbon reflux tank 4 after passing through the precooling cold box 1; heavy hydrocarbon backward flow jar 4 exports a passageway at least and communicates to once concentrating tower 8, exports a passageway at least and leads to once concentrating tower 8 behind the precooling cold box 1, still exports a liquid phase passageway that is equipped with backwash pump 5 at least and flows back to heavy hydrocarbon scrubbing tower 2.
The heavy hydrocarbon reflux tank 4 outputs a passage which passes through the precooling cold box 1 and reaches the primary concentration tower 8 again, a pressure balance valve 6 is arranged on the passage, and when the heat required by the primary reboiler 9 is larger than the heat given by the feed gas, part of the feed gas directly enters the precooling cold box 1 through the pressure balance valve 6.
The present embodiment can adopt various structures to realize the treatment of heavy hydrocarbon substances or other pollutants, and is one of various feasible choices, the significance of the present embodiment is that the heavy hydrocarbon washing tower 2 is arranged at the precooling cold box 1, the feed gas enters the heavy hydrocarbon washing tower 2 through the precooling cold box 1, stable light hydrocarbon products and helium-containing gas phase substances can be obtained through separation, wherein the light hydrocarbon products are limited and adjusted by the tower bottom throttle valve 3 and then output to the outside; contain helium gaseous phase material through 1 environment of precooling cold box and heavy hydrocarbon reflux tank 4 back, separate out gaseous phase material and the residual liquid phase material that can carry to concentration tower 8 once, wherein gaseous phase material leads to concentration tower 8 once through two gaseous phase routes of heavy hydrocarbon reflux tank 4 output, and residual liquid phase material flows back to heavy hydrocarbon scrubbing tower 2 as the top of the tower washing liquid through liquid phase route.
The present invention is not limited to the above-described alternative embodiments, and various other embodiments can be obtained by those skilled in the art from the above-described embodiments in any combination, and any other embodiments can be obtained in various forms while still being within the spirit of the present invention. The above detailed description should not be taken as limiting the scope of the invention, which is defined in the claims, and which the description is intended to be interpreted accordingly.

Claims (10)

1. A switchable natural gas two-tower helium extraction device is characterized in that: comprises a precooling cold box (1), a primary concentration tower (8), a secondary concentration tower (19) and a deep cooling cold box (18) which are communicated in sequence; a gas phase outlet is arranged at the lower part of the primary concentrating tower (8), the gas phase outlet is communicated to the precooling cold box (1) and then is connected back to an inlet arranged at the middle part of the primary concentrating tower (8), a stop valve (14) is connected by the back connection section, and a passage where the stop valve (14) is located passes through the precooling cold box (1) and outputs natural gas; the top of the primary concentration tower (8) is provided with a gas phase outlet and at least outputs a passage which is communicated to the secondary concentration tower (19), and the secondary concentration tower (19) outputs at least one passage which passes through the cryogenic cooling box (18) and outputs helium after carrying out secondary concentration treatment.
2. The switchable natural gas two-tower helium extraction plant of claim 1, wherein: the bottom of first concentration tower (8) and secondary concentration tower (19) be provided with first reboiler (9) and secondary reboiler (20) respectively, the passageway of first reboiler (9) and secondary reboiler (20) output respectively through precooling cold box (1), cryrogenic cold box (18) back, the reconverting respectively to first concentration tower (8) and secondary concentration tower (19).
3. A switchable natural gas two-tower helium extraction plant as claimed in claim 1 or 2, wherein: the top output of follow primary concentration tower (8) and with secondary concentration tower (19) intercommunication be equipped with first condenser (10) in the route, the output of first condenser (10) connect first reflux tank (11), the gaseous phase route at first reflux tank (11) top communicates to secondary concentration tower (19), and the liquid phase route of first reflux tank (11) bottom communicates to a purification tower.
4. A switchable natural gas two-tower helium extraction plant as claimed in claim 3, wherein: the bottom of the primary concentration tower (8) outputs at least two paths, wherein at least one path outputs natural gas after passing through the primary condenser (10) and the pre-cooling cold box (1), and at least one path outputs natural gas after directly passing through the pre-cooling cold box (1).
5. The switchable natural gas two-tower helium extraction plant of claim 4, wherein: a compressor (12) and a cooler (13) are arranged in a path which passes through the precooling cold box (1) and outputs natural gas.
6. The switchable natural gas two-tower helium extraction plant of claim 1, wherein: secondary concentration tower (19) export at least one route from the top and communicate cryrogenic cold box (18), and be equipped with secondary condenser (21) and secondary reflux jar (17) that communicate in proper order in the route, secondary reflux jar (17) top output gaseous phase route communicates to cryrogenic cold box (18), and secondary reflux jar (17) bottom output liquid phase route communicates to secondary concentration tower (19).
7. The switchable natural gas two-tower helium extraction plant of claim 1 or 6, wherein: at least one passage is output from the bottom of the secondary concentration tower (19) and passes through the deep cooling cold box (18) and is communicated with a passage which is output from the top of the primary concentration tower (8) to the pre-cooling cold box (1).
8. The switchable natural gas two-tower helium extraction plant of claim 6, wherein: the nitrogen circulating refrigeration device is arranged on the cryogenic cooling box (18) and comprises a circulating passage passing through the cryogenic cooling box (18), and a nitrogen inlet, a nitrogen compressor (15) and a compressor unit cooler (16) are arranged on the circulating passage; the circulation path comprises at least one circulation branch passing through the secondary condenser (21), and a co-production liquid nitrogen outlet is arranged on the circulation branch.
9. The switchable natural gas two-tower helium extraction plant of claim 1, wherein: the heavy hydrocarbon removal device comprises a heavy hydrocarbon washing tower (2), and a gas phase output passage of the heavy hydrocarbon washing tower (2) is communicated to a heavy hydrocarbon reflux tank (4) after passing through the precooling cold box (1); heavy hydrocarbon backward flow jar (4) export a passageway at least and lead to once concentrating tower (8), export a passageway at least and lead to once concentrating tower (8) behind precooling cold box (1), still export a liquid phase passageway that is equipped with backwash pump (5) at least and flow back to heavy hydrocarbon scrubbing tower (2).
10. A switchable natural gas two-tower helium extraction process using the helium extraction device as claimed in any one of claims 1 to 10, comprising:
pre-cooling and decontaminating raw material gas;
when only natural gas is produced, carrying out primary concentration treatment including reboiling and condensation to obtain a treated natural gas product;
when natural gas is produced and helium is synchronously prepared, carrying out primary concentration treatment including reboiling and condensation to obtain a treated natural gas product, and carrying out reflux treatment to obtain crude helium; carrying out secondary concentration treatment including reboiling, condensation and reflux to obtain a helium product;
liquid phase products obtained by the primary concentration treatment and the secondary concentration treatment are subjected to environmental treatment of a pre-cooling cold box (1) or a cryogenic cold box (18) to obtain the export natural gas.
CN202010553342.1A 2020-06-17 2020-06-17 Device and process capable of switching two natural gas towers for helium extraction Pending CN111578621A (en)

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CN113670002A (en) * 2021-09-27 2021-11-19 西南石油大学 Double-tower natural gas helium recovery method
CN113865263A (en) * 2021-09-15 2021-12-31 中国石油天然气股份有限公司西南油气田分公司成都天然气化工总厂 Production system for extracting crude helium and co-producing liquefied natural gas by natural gas
CN113983761A (en) * 2021-10-25 2022-01-28 中石化石油工程技术服务有限公司 Helium extracting device and natural gas helium extracting method

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113865263A (en) * 2021-09-15 2021-12-31 中国石油天然气股份有限公司西南油气田分公司成都天然气化工总厂 Production system for extracting crude helium and co-producing liquefied natural gas by natural gas
CN113670002A (en) * 2021-09-27 2021-11-19 西南石油大学 Double-tower natural gas helium recovery method
CN113983761A (en) * 2021-10-25 2022-01-28 中石化石油工程技术服务有限公司 Helium extracting device and natural gas helium extracting method

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