CN117781606A - BOG helium extraction system and BOG helium extraction process - Google Patents
BOG helium extraction system and BOG helium extraction process Download PDFInfo
- Publication number
- CN117781606A CN117781606A CN202311870252.5A CN202311870252A CN117781606A CN 117781606 A CN117781606 A CN 117781606A CN 202311870252 A CN202311870252 A CN 202311870252A CN 117781606 A CN117781606 A CN 117781606A
- Authority
- CN
- China
- Prior art keywords
- helium
- inlet
- gas
- bog
- outlet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910052734 helium Inorganic materials 0.000 title claims abstract description 203
- 239000001307 helium Substances 0.000 title claims abstract description 201
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 title claims abstract description 201
- 238000000605 extraction Methods 0.000 title claims abstract description 55
- 239000007789 gas Substances 0.000 claims abstract description 212
- 239000012528 membrane Substances 0.000 claims abstract description 115
- 238000000926 separation method Methods 0.000 claims abstract description 75
- 238000001179 sorption measurement Methods 0.000 claims abstract description 66
- 238000006356 dehydrogenation reaction Methods 0.000 claims abstract description 58
- 230000003197 catalytic effect Effects 0.000 claims abstract description 47
- 239000012466 permeate Substances 0.000 claims abstract description 16
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 84
- 239000002994 raw material Substances 0.000 claims description 37
- 238000000034 method Methods 0.000 claims description 29
- 238000002156 mixing Methods 0.000 claims description 21
- 230000008569 process Effects 0.000 claims description 19
- 238000004891 communication Methods 0.000 claims description 18
- 229910052739 hydrogen Inorganic materials 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 10
- 239000012465 retentate Substances 0.000 claims description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 7
- 239000001301 oxygen Substances 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 239000006227 byproduct Substances 0.000 claims description 6
- 238000010792 warming Methods 0.000 claims 4
- 239000000047 product Substances 0.000 abstract description 9
- 238000007670 refining Methods 0.000 abstract description 3
- 238000005265 energy consumption Methods 0.000 description 11
- 239000007788 liquid Substances 0.000 description 9
- 239000003345 natural gas Substances 0.000 description 9
- 239000003949 liquefied natural gas Substances 0.000 description 7
- 239000000203 mixture Substances 0.000 description 6
- 238000011084 recovery Methods 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 239000003507 refrigerant Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000003463 adsorbent Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 2
- 230000007123 defense Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000013386 optimize process Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Abstract
The application provides a BOG helium extraction system and a BOG helium extraction process, and relates to the technical field of helium extraction. The BOG helium extraction system comprises a cryogenic system, a catalytic dehydrogenation system, a membrane separation system and a PSA system which are sequentially connected, wherein the membrane separation system comprises a pre-membrane compressor, a pre-membrane cooler and a membrane separation unit which are sequentially connected, the pre-membrane compressor is communicated with the catalytic dehydrogenation system, and a membrane inlet of the membrane separation unit is connected with the pre-membrane cooler; the PSA system comprises a pressure swing adsorption heater and a pressure swing adsorption unit which are sequentially connected, wherein an inlet of the pressure swing adsorption heater is connected with a permeate gas outlet. The BOG helium extraction process comprises a cryogenic treatment, a catalytic dehydrogenation treatment, a membrane separation treatment and a pressure swing adsorption treatment. The crude helium with helium concentration of more than 90% can be obtained through rectification of the cryogenic system, and the helium concentration of the obtained product reaches more than 99.99% after further refining treatment of the membrane separation system and the PSA system, so that the helium concentration meets the industrial application requirements.
Description
Technical Field
The application relates to the technical field of helium extraction, in particular to a BOG helium extraction system and a BOG helium extraction process.
Background
Helium has a plurality of good characteristics of stable chemical property, good thermal conductivity, low boiling point, strong permeability and the like, is a scarce strategic resource, and has very important roles in the fields of new energy development, national defense, refrigeration, medicine and the like. With the development of national defense industrial technology and continuous progress of low-temperature technology, the demand of China for helium and liquid helium is also increasing. Helium for commercial use is currently predominantly obtained from helium-rich natural gas (> 0.1%) and has been found to generally have helium contents of 0.024 to 7.5% (mol).
Currently, the detected helium-containing natural gas resources in China only account for 0.15 to 0.2 percent of the world helium resources, and the unit volume content of the natural gas is not more than 2 percent. The helium extraction technology and the process flow in China are still in a development stage, and have a large progress space, and the problems of single product, high energy consumption, small yield and the like in the process of extracting helium from natural gas exist.
When liquefied natural gas (Liquefied Natural Gas, LNG) is transported or stored in situ, the failure of the tank to be completely insulated may result in heat leak, or intense sloshing inside the liquid may generate heat, which may cause the liquefied natural gas to be gasified by heating to form boil-off gas (BOG), which is mainly composed of methane, nitrogen, hydrogen, helium, etc. The content of helium in the natural gas liquefied by testing the non-condensable gas generated in the natural gas liquefied process and the BOG component generated by LNG vaporization in China is found to be about 3%. Compared with a natural gas helium extraction process, the BOG helium extraction process can generally omit a pretreatment link, so that equipment investment is reduced, economy and efficiency are improved, and the BOG helium extraction process uses BOG as raw gas, so that the comprehensive utilization rate of natural gas can be improved. Therefore, the BOG gas helium extraction is taken as a new way for acquiring helium resources in China, and has great strategic significance.
At present, the most main process for extracting helium in China is a low-temperature method, BOG is subjected to preliminary separation of methane and helium by adopting low-temperature equipment or preliminary purification by adopting rectifying tower equipment, then dehydrogenation, dehydration and impurity removal are carried out by tower equipment and reactor equipment, and finally 99.999% (Vol) liquid helium is extracted by cryogenic liquefaction (-268.9 ℃) in a cold box, the separation of helium and natural gas is mainly carried out at low temperature in the process, the requirements of cryogenic equipment are severe, the requirements of refrigerants are high (-268.9 ℃), and the equipment cost and the energy consumption are extremely high.
Disclosure of Invention
In order to solve the problems of high equipment cost and high energy consumption of the existing BOG helium extraction, the application provides a BOG helium extraction system and a BOG helium extraction process.
In a first aspect, the present application provides a BOG helium extraction system, which adopts the following technical scheme:
a BOG helium extraction system comprises a cryogenic system, a catalytic dehydrogenation system, a membrane separation system and a PSA system which are connected in sequence,
the membrane separation system comprises a pre-membrane compressor, a pre-membrane cooler and a membrane separation unit which are sequentially connected, wherein the pre-membrane compressor is communicated with the catalytic dehydrogenation system, the membrane separation unit is provided with a membrane inlet, a retentate outlet and a permeate outlet, and the membrane inlet is connected with the pre-membrane cooler;
the PSA system comprises a pressure swing adsorption heater and a pressure swing adsorption unit which are sequentially connected, wherein the bottom of the pressure swing adsorption unit is provided with a pressure swing adsorption inlet positioned on the side face, a pressure release gas outlet positioned on the bottom and a high-purity helium outlet positioned on the top, the inlet of the pressure swing adsorption heater is connected with the permeate gas outlet, and the outlet of the pressure swing adsorption heater is connected with the pressure swing adsorption inlet.
When the BOG raw material gas is used as a raw material to extract helium, methane gas in the BOG raw material gas can be separated by adopting a cryogenic system, hydrogen in the BOG raw material gas is removed by adopting a catalytic dehydrogenation system, and other impurity gases such as nitrogen are removed by adopting a membrane separation system and a PSA system in a matched manner, so that the helium with a high purity product can be finally obtained.
The helium extraction method mainly comprises the steps of taking a membrane separation system and a PSA system as main materials in the helium extraction process, and utilizing the membrane separation unit to be matched with a pressure swing adsorption unit when purifying the helium, and sequentially carrying out membrane separation treatment and pressure swing adsorption treatment on the helium. When the membrane separation treatment is carried out, helium can smoothly pass through the membrane separation unit under the action of pressure difference, and non-helium cannot pass through the membrane separation unit, so that the purpose of purifying helium is realized. In the pressure swing adsorption process, the impurity gas component is selectively adsorbed by the adsorbent in the pressure swing adsorption unit, and helium gas is discharged from the top as product gas.
Therefore, in the helium extraction system, the cryogenic system is only utilized in the process of removing methane gas from the BOG raw material gas, and the working temperature of the cryogenic system is only about-165 ℃, so that most of methane gas in the BOG raw material gas can be separated; and in the subsequent helium gas extraction process, a membrane separation system and a PSA system are adopted to extract a helium gas product with high purity; compared with the method for extracting helium by adopting a low-temperature method, the method adopts a mode of combining a cryogenic system, a catalytic dehydrogenation system, a membrane separation system and a PSA system, has no strict requirements on cryogenic equipment and refrigerant temperature, and can obtain a helium product with high purity in a low-cost mode.
Optionally, the membrane separation system further comprises a mixer having a first mixing inlet in communication with the catalytic dehydrogenation system, a second mixing inlet in communication with the pressure relief gas outlet, and a mixing outlet in communication with the pre-membrane compressor.
According to the pressure relief gas reflux device, the pressure relief gas of the pressure swing adsorption unit flows back to the front end inlet of the membrane separation unit, the gas to be fed into the pre-membrane compressor is mixed with the pressure relief gas of the pressure swing adsorption unit, and then the mixture is pressurized by the pre-membrane compressor and cooled by the pre-membrane cooler, and then the mixture is fed into the membrane separation unit for separation, so that the recovery rate of integral helium can be improved.
Optionally, the cryogenic system comprises a cryogenic tower having a cryogenic tower inlet on a side, a crude helium gas outlet on a top, and a methane outlet on a bottom, and a cryogenic tower inlet cooler in communication with the cryogenic tower inlet, the crude helium gas outlet in communication with the catalytic dehydrogenation system.
The BOG raw material gas is subjected to cryogenic treatment by adopting a cryogenic system, so that most of methane gas in the BOG raw material gas can be removed; specifically, the cryogenic tower inlet cooler is used for cooling the raw material gas entering the cryogenic tower, and reducing the temperature of the raw material gas to the operating temperature of the cryogenic tower, so that methane gas in the BOG raw material gas is liquefied and then discharged from the bottom of the cryogenic tower, and the rest substances are still discharged from a crude helium gas outlet at the top of the cryogenic tower in a gas state.
Optionally, the catalytic dehydrogenation system comprises a heater and a catalytic dehydrogenation device which are sequentially connected, the catalytic dehydrogenation device is provided with a rough helium gas inlet, an oxygen inlet, a dehydrogenation gas outlet and a moisture outlet, the heater is communicated between the rough helium gas outlet and the rough helium gas inlet of the cryogenic tower, and the dehydrogenation gas outlet is communicated with the membrane separation system.
According to the method, most of hydrogen in the gas discharged from the crude helium gas outlet of the cryogenic tower is removed by heating the gas and then entering the catalytic dehydrogenation device together with pure oxygen gas, so that the gas is prevented from being interfered by the hydrogen when the gas subsequently enters the membrane separation system for treatment.
Optionally, the catalytic hydrogenation system further comprises a dryer, an inlet of the dryer is communicated with the dehydrogenation gas outlet, and an outlet of the dryer is communicated with the membrane separation system.
The dryer is arranged at the downstream of the catalytic hydrogenation device, residual moisture in gas treated by the catalytic dehydrogenation device can be removed, and the moisture is prevented from being brought into the next link.
Optionally, the system further comprises a rewarming pressurization system, wherein the rewarming pressurization system comprises a rewarming heater, a rewarming compressor and a heat exchanger which are sequentially connected, and the heat exchanger is communicated with the cryogenic tower inlet cooler.
According to the method, after the BOG raw material gas is heated, tempered and pressurized by the tempering and pressurizing system, the BOG raw material gas can reach the working pressure required by the cryogenic tower.
Optionally, the heat exchanger is provided with a first inlet of the heat exchanger, a second inlet of the heat exchanger, a first outlet of the heat exchanger and a second outlet of the heat exchanger; the first inlet of the heat exchanger is communicated with the first outlet of the heat exchanger, and the second inlet of the heat exchanger is communicated with the second outlet of the heat exchanger; the first inlet of the heat exchanger is connected with the rewarming compressor, and the first outlet of the heat exchanger is connected with the cryogenic tower inlet cooler.
Because BOG raw material gas is after the pressurization of rewarming compressor, the temperature also correspondingly rises, in order to be able to reach the temperature that the cryogenic tower adapts to, consequently this application carries out the cooling treatment to the BOG raw material gas after the pressurization through the heat exchanger, combines cryogenic tower entry cooler again simultaneously for the BOG raw material gas after the pressurization can reach the required operating temperature of cryogenic tower.
Optionally, the second inlet of the heat exchanger is connected with a methane outlet at the bottom of the cryogenic tower, and the second outlet of the heat exchanger is used for obtaining the by-product methane gas after rewarming.
According to the method, when the heat exchanger is adopted to treat the pressurized BOG raw material gas, the low-temperature liquid methane discharged from the bottom of the cryogenic tower is used as a refrigerant to cool the pressurized BOG raw material gas, so that the cooling capacity of methane can be recovered, and the purpose of cooling the pressurized BOG raw material gas is achieved, and the energy consumption of a system is reduced.
In a second aspect, the present application provides a BOG helium extraction process, which adopts the following technical scheme:
a BOG helium extraction process comprising the steps of:
step S1: performing cryogenic treatment on the BOG raw material gas to remove methane in the BOG raw material gas to obtain coarse helium gas;
step S2: removing hydrogen in the crude helium gas through catalytic dehydrogenation treatment to obtain refined helium gas;
step S3: and sequentially carrying out membrane separation treatment and pressure swing adsorption treatment on the refined helium to finally obtain the high-purity helium.
The process for extracting high-purity helium from BOG feed gas with helium content of about 3% is provided by adopting a combination mode of a cryogenic process, a membrane separation process and a pressure swing adsorption process, wherein the helium concentration in crude helium gas obtained through cryogenic treatment is more than 91%, the helium concentration in refined helium gas obtained through catalytic dehydrogenation treatment is more than 96%, the helium concentration in gas obtained through membrane separation treatment is more than 99.9%, and the helium concentration in gas obtained through pressure swing adsorption treatment is more than 99.999%.
Optionally, the step S1 is further performed with a rewarming and pressurizing process before the cryogenic process.
According to the method, the BOG raw material gas is subjected to rewarming and pressurizing treatment before the cryogenic treatment, so that the BOG raw material gas reaches the working pressure required by the cryogenic tower in advance.
In summary, the present application includes at least one of the following beneficial effects:
1. the process for extracting high-purity helium from the BOG feed gas has the advantages of low helium extraction energy consumption and strong adaptability to different gas sources.
2. The crude helium with helium concentration of more than 90% can be obtained through rectification of the cryogenic system, and the helium concentration of the obtained product reaches more than 99.99% after further refining treatment of the membrane separation system and the PSA system, so that the helium concentration meets the industrial application requirements.
3. The heat exchanger is adopted in the application, so that the cold quantity of byproduct methane in the process can be reasonably recovered, the energy consumption of the system is reduced, the pressure release gas of the pressure swing adsorption unit flows back to the inlet of the membrane separation unit, and the overall helium recovery rate is improved.
Drawings
FIG. 1 is a process flow diagram of a BOG helium extraction system according to one embodiment of the present application.
In the figure: 10. a rewarming pressurization system; 11. a reheat heater; 12. a rewarming compressor; 13. a heat exchanger; 131. a heat exchanger first inlet; 132. a heat exchanger second inlet; 133. a first outlet of the heat exchanger; 134. a second outlet of the heat exchanger; 20. a cryogenic system; 21. an inlet cooler of the cryogenic tower; 22. a cryogenic tower; 221. an inlet of the cryogenic tower; 222. a crude helium gas outlet; 223. a methane outlet; 23. a reboiler; 24. a condenser; 30. a catalytic dehydrogenation system; 31. a heater; 32. a catalytic dehydrogenation unit; 321. a raw helium gas inlet, 322, an oxygen inlet; 323. a dehydrogenation gas outlet; 324. a moisture outlet; 33. a dryer; 40. a membrane separation system; 41. a mixer; 411. a first mixing inlet; 412. a second mixing inlet; 413. a mixing outlet; 42. a pre-membrane compressor; 43. a pre-membrane cooler; 44. a membrane separation unit; 441. a membrane inlet; 442. a permeate gas outlet; 443. a retentate outlet; 50. a PSA system; 51. a pressure swing adsorption heater; 52. a pressure swing adsorption unit; 521. a pressure swing adsorption inlet; 522. a pressure relief gas outlet; 523. and a high purity helium outlet.
Detailed Description
The present application is described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present application, but are not intended to limit the present application in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concepts of the present application. These are all within the scope of the present application.
FIG. 1 is a process flow diagram of a BOG helium extraction system according to one embodiment of the present application. Referring to fig. 1, a BOG helium extraction system is provided that includes a rewarming pressurization system 10, a cryogenic system 20, a catalytic dehydrogenation system 30, a membrane separation system 40, and a PSA system 50, connected in sequence.
Referring to fig. 1, the rewarming pressurization system 10 includes a rewarming heater 11, a rewarming compressor 12, and a heat exchanger 13, which are sequentially connected. Cryogenic system 20 includes a cryogenic column 22 and a cryogenic column inlet cooler 21. The heat exchanger 13 is in communication with a cryogenic column inlet cooler 21.
The rewarming heater 11 is provided with an inlet for entering the BOG raw material gas, and the rewarming heater 11 is used for heating and rewarming the BOG raw material gas and then sending the BOG raw material gas into the rewarming compressor 12 for pressurization treatment, so that the BOG raw material gas reaches the working pressure required by the cryogenic tower 22; the pressurized BOG feed gas sequentially passes through the heat exchanger 13 and the cryogenic column inlet cooler 21, and the temperature is reduced to the operating temperature of the cryogenic column 22.
Referring to fig. 1, the cryogenic column 22 has a cryogenic column inlet 221 on the side, a raw helium gas outlet 222 on the top, and a methane outlet 223 on the bottom. The bottom of the cryogenic tower 22 is provided with a reboiler 23, and the top is provided with a condenser 24. The BOG raw gas after pressurization and temperature reduction is in the cryogenic environment of the cryogenic tower 22, most of the methane is liquefied into methane liquid, the methane liquid is discharged from a methane outlet 223 at the bottom of the cryogenic tower 22, the methane liquid enters a reboiler 23 for heating and vaporization, finally, the methane liquid is discharged from the outlet of the reboiler 23, the rest of the non-liquefied gas forms coarse helium gas, and the coarse helium gas is discharged from a coarse helium gas outlet 222 at the top of the cryogenic tower 22.
Referring to fig. 1, the heat exchanger 13 has a heat exchanger first inlet 131, a heat exchanger second inlet 132, a heat exchanger first outlet 133, and a heat exchanger second outlet 134. The first inlet 131 of the heat exchanger is communicated with the first outlet 133 of the heat exchanger, the first inlet 131 of the heat exchanger is connected with the rewarming compressor 12, and the first outlet 133 of the heat exchanger is connected with the inlet cooler 21 of the cryogenic tower and is used for passing the pressurized BOG raw gas with higher temperature; the heat exchanger second inlet 132 communicates with the heat exchanger second outlet 134 for passage of the cooler gases.
As shown in fig. 1, the second inlet 132 of the heat exchanger is connected with the bottom of the cryogenic tower 22, the low-temperature methane liquid discharged from the bottom of the cryogenic tower 22 can be used as a refrigerant to be introduced into the heat exchanger 13 to cool the pressurized BOG raw gas, no additional refrigerant is required to be introduced into the heat exchanger 13, thereby being beneficial to reducing the energy consumption of the system, and correspondingly, the byproduct methane gas after the re-temperature is obtained from the second outlet 134 of the heat exchanger.
Referring to fig. 1, the catalytic dehydrogenation system 30 includes a heater 31, a catalytic dehydrogenation unit 32, and a dryer 33 connected in this order. Catalytic dehydrogenation unit 32 has a raw helium gas inlet 321, an oxygen inlet 322, a dehydrogenation gas outlet 323, and a moisture outlet 324. The inlet of the dryer 33 communicates with the dehydrogenation gas outlet 323, and the outlet of the dryer 33 communicates with the membrane separation system 40. The heater 31 is connected between the raw helium gas outlet 222 of the cryogenic tower 22 and the raw helium gas inlet 321 of the catalytic dehydrogenation device 32, and is used for heating the raw helium gas discharged from the cryogenic tower 22 to the operating temperature of the catalytic dehydrogenation device 32, allowing the raw helium gas to enter the catalytic dehydrogenation device 32 from the raw helium gas inlet 321, allowing pure oxygen to enter the oxygen inlet 322 of the catalytic dehydrogenation device 32 to react with hydrogen in the raw helium gas, discharging water generated by the reaction from the water outlet 324 of the catalytic dehydrogenation device 32, discharging the rest of the gas from the dehydrogenation gas outlet 323 of the catalytic dehydrogenation device 32, and allowing the rest of the gas to enter the dryer 33 to remove water.
Referring to fig. 1, the membrane separation system 40 includes a mixer 41, a pre-membrane compressor 42, a pre-membrane cooler 43, and a membrane separation unit 44, which are connected in order. The membrane separation unit 44 has a membrane inlet 441, a retentate outlet 443, and a permeate outlet 442, the membrane inlet 441 being connected to the pre-membrane cooler 43, and the permeate outlet 442 being connected to the pressure swing adsorption heater 51.
The mixer 41 has a first mixing inlet 411, a second mixing inlet 412 and a mixing outlet 413, the first mixing inlet 411 being in communication with the dryer 33 for receiving refined helium gas after removal of moisture in the dryer 33, the second mixing inlet 412 being in communication with a pressure relief gas outlet 522 for receiving pressure relief gas in the pressure swing adsorption unit 52. The mixing outlet 413 communicates with the pre-membrane compressor 42.
Referring to fig. 1, the psa system 50 includes a pressure swing adsorption heater 51 and a pressure swing adsorption unit 52 connected in sequence, the bottom of the pressure swing adsorption unit 52 has a pressure swing adsorption inlet 521 at the side, a pressure release gas outlet 522 at the bottom, and a high purity helium gas outlet 523 at the top, the inlet of the pressure swing adsorption heater 51 is connected to a permeate gas outlet 442, and the outlet of the pressure swing adsorption heater 51 is connected to the pressure swing adsorption inlet 521. In the pressure swing adsorption unit 52, the adsorbent adsorbs impurity gases in the gas introduced from the pressure swing adsorption inlet 521, and only helium gas can be discharged from the high purity helium gas outlet 523 at the top of the pressure swing adsorption unit 52, while the rest is discharged from the pressure release gas outlet 522.
As shown in fig. 1, the purified helium gas from the dryer 33 after the removal of the moisture is fed into the mixer 41 and uniformly mixed with the pressure release gas flowing back from the pressure release gas outlet 522 of the pressure swing adsorption unit 52, then fed into the pre-membrane compressor 42 for the pressurization treatment, cooled by the pre-membrane cooler 43 to the operating temperature of the membrane separation unit 44, then fed into the membrane separation unit 44 through the membrane inlet 441 for the membrane separation treatment, the retentate gas which does not pass through the membrane separation unit 44 is discharged from the retentate gas outlet 443, the permeate gas which passes through the membrane separation unit 44 is discharged from the permeate gas outlet 442 and fed into the pressure swing adsorption heater 51 for the heating treatment, then fed into the pressure swing adsorption unit 52 through the pressure swing adsorption inlet 521 for the pressure swing adsorption treatment, and the pressure release gas discharged from the pressure release gas outlet 522 is fed back into the mixer 41 for the membrane separation treatment again, and the permeate gas discharged from the high purity helium gas outlet 523 is the target product high purity helium gas.
The application also provides a BOG helium extraction process, which adopts the BOG helium extraction system and specifically comprises the following steps:
step S1: the BOG raw material gas is firstly introduced into a rewarming heater 11 in a rewarming and pressurizing system for heating and rewarming, and then the pressure treatment is carried out by a rewarming compressor 12, so that the working pressure of a cryogenic tower 22 is reached; the pressurized BOG raw gas sequentially passes through a heat exchanger 13 and a cryogenic tower inlet cooler 21, the temperature is reduced to the operating temperature of a cryogenic tower 22, then the raw gas is introduced into the cryogenic tower 22 in a cryogenic system 20 for cryogenic treatment, methane in the raw gas is removed, crude helium gas is obtained, and in addition, the byproduct methane is used for recovering cold energy through the heat exchanger 13, so that the BOG raw gas is cooled, and the energy consumption of the system is reduced;
step S2: introducing crude helium gas into a catalytic dehydrogenation system 30, heating the crude helium gas by a heater 31, introducing the crude helium gas and pure oxygen gas into a catalytic dehydrogenation device 32 for catalytic dehydrogenation treatment to remove most of hydrogen, and then drying the crude helium gas by a dryer 33 to obtain refined helium gas;
step S3: mixing the refined helium gas with the pressure-release gas flowing back from the pressure-swing adsorption unit 52 by the mixer 41, sequentially introducing the mixture into the pre-membrane compressor 42 for pressurization, the pre-membrane cooler 43 for cooling, and introducing the mixture into the membrane separation unit 44 for membrane separation treatment; the permeate gas passing through the membrane separation unit 44 is heated by the pressure swing adsorption heater 51 and then enters the pressure swing adsorption unit 52 to be subjected to pressure swing adsorption treatment, and finally high-purity helium gas is obtained from the high-purity helium gas outlet 523 of the pressure swing adsorption unit 52.
It should be noted that the structures of the membrane separation system 40 and the PSA system 50 in the present application may also be changed into a structure in which a plurality of membrane separation systems or PSA systems 50 are connected in series, and the retentate of the membrane separation unit 44 of the subsequent stage or the retentate of the pressure swing system device may be returned to the inlet of the previous stage device, so as to improve the overall helium recovery rate of the device.
According to the process, a combination mode of a cryogenic method, a membrane separation method and a pressure swing adsorption method is adopted, and a process for extracting high-purity helium from BOG feed gas with helium content of about 3% is provided, wherein the helium concentration in crude helium gas obtained through cryogenic treatment is more than 91%, the helium concentration in refined helium gas obtained through catalytic dehydrogenation treatment is more than 96%, the helium concentration in gas obtained through membrane separation treatment is more than 99.9%, and the helium concentration in gas obtained through pressure swing adsorption treatment is more than 99.999%.
Two specific examples are provided below to further illustrate the present application.
Example 1
The BOG feed gas used in this example comprises the following components in molar ratio: 77.12% CH 4 、19.73％N 2 、2.71％He、0.26％C 2 H 6 、0.18％H 2 . The BOG raw material gas has a pressure of 84.25kPa, a temperature of-155 ℃ and a flow rate of 650Nm 3 The specific flow of helium extraction by the BOG helium extraction system shown in fig. 1 is as follows.
BOG raw material gas with helium content of about 2.71% is heated by a rewarming heater 11 and then enters a rewarming compressor 12 to be compressed to 1410kPa, then cold energy of methane-rich flow at the bottom of a cryogenic tower 22 is recovered in an LNG multi-flow heat exchanger 13, the cooled BOG raw material gas is further cooled to-164.9 ℃ by a cryogenic tower inlet cooler 21, and the cooled BOG raw material gas is introduced into the cryogenic tower 22 to separate most CH 4 Wherein CH in the bottom material 4 The content of the helium gas is about 80%, the tower top is coarse helium gas, and the helium gas content reaches about 90%. The crude helium gas is heated to the working temperature of the catalytic dehydrogenation device 32 by the heater 31, namely 34.58 ℃, then enters the catalytic dehydrogenation device 32, hydrogen in the crude helium gas reacts with oxygen in the catalytic dehydrogenation device 32, and the crude helium gas is dehydrated and dried by the dryer 33 to obtain refined helium gas, wherein the helium gas content is about 96.85%. After being uniformly mixed with the pressure release gas of the pressure swing adsorption unit 52, the refined helium enters the pre-membrane compressor 42 to be pressurized to 2400kPa, is cooled by the pre-membrane cooler 43 to the working temperature 34 ℃ of the membrane separation unit 44, and then enters the membrane separation unit 44 to be subjected to membrane separation treatment, wherein the membrane area is 80m 2 In the case where the membrane permeation side pressure is 1000kPa, the helium content of the gas obtained from the permeate gas outlet 442, which is separated by the membrane separation unit 44 and which is heated to 60 c by the pressure swing adsorption heater 51, reaches about 99.86%, is introducedThe pressure swing adsorption unit 52 performs pressure swing adsorption treatment, and the helium content in the gas obtained from the high purity helium outlet 523 reaches more than 99.9964%, so that the helium extraction production requirement is met. Because the gas from the pressure release gas outlet 522 still contains helium with higher concentration, the gas is returned to the second mixing inlet 412 of the mixer 41, and is uniformly mixed with refined helium and then subjected to membrane separation again, so that the overall helium recovery rate of the system is improved.
Table 1 shows the corresponding parameters of temperature, pressure, flow and composition in the main streams (BOG feed gas, A, B, C, D, E, F) involved in the BOG helium extraction system of fig. 1 for example 1.
Table 1 corresponding parameters in each major stream in example 1
Example 2
The BOG feed gas used in this example comprises the following components in molar ratio: 72.19% CH 4 、24.05％N 2 、3.30％He、0.24％C 2 H 6 、0.22％H 2 . The BOG raw material gas has a pressure of 600kPa, a temperature of 25deg.C and a flow rate of 2.35X10 5 Nm 3 The specific flow of helium extraction by the BOG helium extraction system shown in fig. 1 is as follows.
BOG raw material gas with helium content of about 3.30% is heated by a rewarming heater 11 and then enters a rewarming compressor 12 to be compressed to 1405kPa, then the cold energy of methane at the bottom of a cryogenic tower 22 is recovered in an LNG multi-stream heat exchanger 13, the cooled BOG raw material gas is further cooled to-164.9 ℃ by a cryogenic tower inlet cooler 21, and is introduced into the cryogenic tower 22 to separate most CH 4 Wherein CH in the bottom material 4 The content of the helium gas is about 75%, the tower top is coarse helium gas, and the helium gas content is more than 90%. The crude helium gas is heated to the working temperature of the catalytic dehydrogenation device 32 by the heater 31, namely 34.58 ℃, then enters the catalytic dehydrogenation device 32, hydrogen in the crude helium gas reacts with oxygen in the catalytic dehydrogenation device 32, and is dehydrated and dried by the dryer 33 to obtain refined helium gas,wherein the helium content is up to about 95.74%. After being uniformly mixed with the pressure release gas of the pressure swing adsorption unit 52, the refined helium enters the pre-membrane compressor 42 to be pressurized to 2400kPa, is cooled by the pre-membrane cooler 43 to the working temperature 34 ℃ of the membrane separation unit 44, and then enters the membrane separation unit 44 to be subjected to membrane separation treatment, wherein the membrane area is 80m 2 When the membrane permeation side pressure is 1000kPa, the helium content in the gas obtained from the permeate gas outlet 442 after separation by the membrane separation unit 44 reaches about 99.990%, and the permeate gas is heated to 60 ℃ by the pressure swing adsorption heater 51 and then enters the pressure swing adsorption unit 52 for pressure swing adsorption treatment, and the helium content in the gas obtained from the high purity helium outlet 523 reaches about 99.9997%, thereby meeting the requirements of helium extraction production. Because the gas from the pressure release gas outlet 522 still contains helium with higher concentration, the gas is returned to the second mixing inlet 412 of the mixer 41, and is uniformly mixed with refined helium and then subjected to membrane separation again, so that the overall helium recovery rate of the system is improved.
Table 2 shows the corresponding parameters of temperature, pressure, flow and composition in the main streams (BOG feed gas, A, B, C, D, E, F) involved in the BOG helium extraction system of fig. 1 for example 2.
Table 2 corresponding parameters in each major stream in example 2
In conclusion, according to the BOG helium extraction process provided by the application, simulation calculation is performed through HYSYS software widely adopted in the oil and gas industry, and unit energy consumption of the optimized process is 6.5469 kWh/(Nm) 3 Helium) proves that the helium extraction process has low energy consumption and strong adaptability to different gas sources; the helium extraction process can obtain crude helium gas with helium concentration of more than 90% by rectifying in a cryogenic tower 22, and further refining by a membrane separation unit and a pressure swing adsorption unit 52 to obtain a product with helium concentration of more than 99.99%, which accords with the industryThe industrial application requirement provides new possibility for reasonably utilizing liquefied natural gas to evaporate stripping helium; wherein the heat exchanger 13 reasonably recovers the cold energy of byproduct methane, reduces the energy consumption of the system, and the retentate gas of the pressure swing adsorption unit 52 flows back to the inlet of the membrane separation unit 44, so that the recovery rate of helium gas of the system can be improved.
In the description of the present application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, merely to facilitate description of the present application and simplify the description, and do not indicate or imply that the devices or elements being referred to must have a specific orientation, be configured and operated in a specific orientation, and are not to be construed as limiting the present application.
The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.
Claims (10)
1. A BOG helium extraction system is characterized by comprising a cryogenic system (20), a catalytic dehydrogenation system (30), a membrane separation system (40) and a PSA system (50) which are connected in sequence,
the membrane separation system (40) comprises a pre-membrane compressor (42), a pre-membrane cooler (43) and a membrane separation unit (44) which are sequentially connected, wherein the pre-membrane compressor (42) is communicated with the catalytic dehydrogenation system (30), the membrane separation unit (44) is provided with a membrane inlet (441), a retentate outlet (443) and a permeate outlet (442), and the membrane inlet (441) is connected with the pre-membrane cooler (43);
PSA system (50) are including pressure swing adsorption heater (51) and pressure swing adsorption unit (52) that connect gradually, pressure swing adsorption unit (52) bottom has pressure swing adsorption entry (521) that are located the side, pressure release gas outlet (522) that are located the bottom and high purity helium gas outlet (523) that are located the top, pressure swing adsorption heater (51)'s entry with permeate gas outlet (442) link to each other, pressure swing adsorption heater (51)'s export with pressure swing adsorption entry (521) link to each other.
2. BOG helium extraction system according to claim 1, wherein the membrane separation system (40) further comprises a mixer (41), the mixer (41) having a first mixing inlet (411), a second mixing inlet (412) and a mixing outlet (413), the first mixing inlet (411) being in communication with the catalytic dehydrogenation system (30), the second mixing inlet (412) being in communication with the pressure relief gas outlet, the mixing outlet (413) being in communication with the pre-membrane compressor (42).
3. The BOG helium extraction system according to claim 1, wherein the cryogenic system (20) comprises a cryogenic tower (22) and a cryogenic tower inlet cooler (21), the cryogenic tower (22) having a cryogenic tower inlet (221) at the side, a crude helium gas outlet (222) at the top and a methane outlet (223) at the bottom, the cryogenic tower inlet cooler (21) being in communication with the cryogenic tower inlet (221), the crude helium gas outlet (222) being in communication with the catalytic dehydrogenation system (30).
4. A BOG helium extraction system according to claim 3, wherein the catalytic dehydrogenation system (30) comprises a heater (31) and a catalytic dehydrogenation device (32) connected in sequence, the catalytic dehydrogenation device (32) having a raw helium gas inlet (321), an oxygen inlet (322), a dehydrogenation gas outlet (323) and a moisture outlet (324), the heater (31) being in communication between the raw helium gas outlet (222) of the cryogenic tower (22) and the raw helium gas inlet (321) of the catalytic dehydrogenation device (32), the dehydrogenation gas outlet (323) being in communication with the membrane separation system (40).
5. The BOG helium extraction system according to claim 4, further comprising a dryer (33), an inlet of the dryer (33) being in communication with the dehydrogenation gas outlet (323), an outlet of the dryer (33) being in communication with the membrane separation system (40).
6. A BOG helium extraction system according to claim 3, further comprising a re-warming and pressurization system (10), said re-warming and pressurization system (10) comprising a re-warming heater (11), a re-warming compressor (12) and a heat exchanger (13) connected in sequence, said heat exchanger (13) being in communication with said cryogenic tower inlet cooler (21).
7. BOG helium extraction system according to claim 6, wherein the heat exchanger (13) has a heat exchanger first inlet (131), a heat exchanger second inlet (132), a heat exchanger first outlet (133), a heat exchanger second outlet (134); the first inlet (131) of the heat exchanger is communicated with the first outlet (133) of the heat exchanger, and the second inlet (132) of the heat exchanger is communicated with the second outlet (134) of the heat exchanger; the first inlet (131) of the heat exchanger is connected with the rewarming compressor (12), and the first outlet (133) of the heat exchanger is connected with the cryogenic tower inlet cooler (21).
8. The BOG helium extraction system according to claim 7, wherein the second inlet (132) of the heat exchanger is connected with a methane outlet (223) at the bottom of the cryogenic tower (22), and the second outlet (134) of the heat exchanger is used for obtaining the by-product methane gas after the re-heating.
9. The BOG helium extraction process is characterized by comprising the following steps of:
step S1: performing cryogenic treatment on the BOG raw material gas to remove methane in the BOG raw material gas to obtain coarse helium gas;
step S2: removing hydrogen in the crude helium gas through catalytic dehydrogenation treatment to obtain refined helium gas;
step S3: and sequentially carrying out membrane separation treatment and pressure swing adsorption treatment on the refined helium to finally obtain the high-purity helium.
10. The BOG helium extraction process according to claim 9, wherein the step S1 is further followed by a re-heating and pressurizing process before the cryogenic treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311870252.5A CN117781606A (en) | 2023-12-29 | 2023-12-29 | BOG helium extraction system and BOG helium extraction process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311870252.5A CN117781606A (en) | 2023-12-29 | 2023-12-29 | BOG helium extraction system and BOG helium extraction process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117781606A true CN117781606A (en) | 2024-03-29 |
Family
ID=90400219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311870252.5A Pending CN117781606A (en) | 2023-12-29 | 2023-12-29 | BOG helium extraction system and BOG helium extraction process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117781606A (en) |
-
2023
- 2023-12-29 CN CN202311870252.5A patent/CN117781606A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104528647A (en) | Method and device for preparing hydrogen and high-purity carbon monoxide by separating synthetic gas | |
| CN101723338B (en) | Method for extracting krypton-xenon from liquid oxygen | |
| CN113108551A (en) | Process and device for extracting high-purity helium in liquefied natural gas production process | |
| CN111533095A (en) | Equipment and process for purifying helium from BOG gas | |
| CN108955086B (en) | Device and method for purifying a gas mixture | |
| CN101264862B (en) | Method for preparing heavy water and deuterium gas | |
| CN103523751A (en) | Device and method for performing cryogenic separation and purification on carbon monoxide and hydrogen | |
| CN113144821A (en) | Multi-technology integrated separation process for producing high-purity helium gas from helium-rich natural gas liquefaction tail gas | |
| CN113277471A (en) | Method and device for recovering reduction tail gas in polycrystalline silicon production | |
| CN109631494A (en) | A kind of helium production system and production method | |
| CN111547691A (en) | Equipment and process for extracting helium from BOG gas with high hydrogen content | |
| CN113501508B (en) | System and method for extracting helium from natural gas or BOG | |
| CN202522015U (en) | Neon and helium separation and purification device with refrigeration equipment | |
| CN1952569A (en) | Process and equipment for liquefying air-containing coal-bed gas | |
| CN204702504U (en) | A kind of synthetic gas is separated hydrogen making and high-purity CO device | |
| CN117781606A (en) | BOG helium extraction system and BOG helium extraction process | |
| CN103629894A (en) | Air separation method of single-stage distillation device | |
| CN106979665B (en) | Method and equipment for purifying synthetic gas | |
| CN212842469U (en) | Single-tower cryogenic rectification argon recovery system with argon circulation and hydrogen circulation | |
| CN117824295A (en) | Liquefied natural gas evaporation gas helium extraction system and helium extraction process | |
| CN107473223A (en) | A kind of CO cryogenic separation system and method using nitrogen cycle | |
| JP3325805B2 (en) | Air separation method and air separation device | |
| CN111637684A (en) | Single-tower cryogenic rectification argon recovery system with circulation and method | |
| CN111637685A (en) | Single-tower cryogenic rectification argon recovery system and method with argon circulation and hydrogen circulation | |
| CN106731497B (en) | Decarbonizing and extracting N from nitric acid industrial tail gas 2 O purification device and process method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |