Crude helium concentration system

Abstract

The utility model relates to the technical field of crude helium purification, in particular to a crude helium concentration system, which comprises a dehydrogenation unit, a separation unit, a separation unit and a purification unit, and is characterized in that the dehydrogenation unit is used for removing hydrogen in BOG feed gas to be concentrated, and the feed gas comprises helium, methane, nitrogen and hydrogen; the at least one heat exchanger is connected with an outlet of the dehydrogenation unit and is used for cooling the raw material gas subjected to hydrogen removal to a preset temperature; an inlet of the gas-liquid separator is connected with an outlet of the heat exchanger, the gas-liquid separator is used for carrying out gas-liquid separation on the gas flowing out of the heat exchanger to obtain a first liquid phase part and a first gas phase part, the first liquid phase part is condensate containing methane and nitrogen, and the first gas phase part is concentrated crude helium; an inlet of the throttling valve is connected with an outlet in the bottom end of the gas-liquid separator, and the throttling valve is used for throttling and cooling the first liquid phase part; and the first gas phase part and the first liquid phase part cooled by the throttling valve respectively flow through the heat exchanger for rewarming heat exchange. According to the system, the purification process does not need external cooling capacity, and energy is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of crude helium purification, and particularly relates to a crude helium concentration system. Background Art

[0002] In the BOG raw gas, it usually contains multiple components such as methane, nitrogen, hydrogen, helium, etc. Since the helium purity in the raw gas is relatively low and does not meet the usage requirements in some fields, it is necessary to purify the raw gas. In the prior art, a refrigerator, a GM machine or liquid nitrogen, etc. are usually used to provide cooling capacity for the purification system, and the cooling capacity consumption is relatively high. This kind of purification method is suitable for a fine purification system, while for some occasions with relatively low requirements for purification accuracy, it will cause great energy waste.

[0003] Therefore, there is an urgent need for a crude helium concentration system to solve the above technical problems. Summary of the Utility Model

[0004] An embodiment of the utility model provides a crude helium concentration system, and the purification process does not require external cooling capacity, thus saving energy.

[0005] An embodiment of the utility model provides a crude helium concentration system, which includes:

[0006] A dehydrogenation unit for removing hydrogen from the BOG raw gas to be concentrated, and the raw gas contains helium, methane, nitrogen and hydrogen;

[0007] At least one heat exchanger connected to the outlet of the dehydrogenation unit, and the heat exchanger is used to cool the raw gas after removing hydrogen to a preset temperature;

[0008] A gas-liquid separator, the inlet of which is connected to the outlet of the heat exchanger. The gas-liquid separator is used to perform gas-liquid separation on the gas flowing out of the heat exchanger to obtain a first liquid phase part and a first gas phase part. The first liquid phase part is a condensate containing methane and nitrogen, and the first gas phase part is concentrated crude helium gas;

[0009] A throttle valve, the inlet of which is connected to the bottom outlet of the gas-liquid separator, and the throttle valve is used to throttle and cool the first liquid phase part;

[0010] The first gas phase part and the first liquid phase part cooled by the throttle valve respectively flow through the heat exchanger for reheating and heat exchange to provide cooling capacity for the heat exchanger.

[0011] In a possible design, it further includes: a flash separator;

[0012] The inlet of the flash separator is connected to the outlet of the throttle valve, and the top outlet and the bottom outlet are respectively connected to the heat exchanger; the flash separator is used for flashing a first liquid phase part cooled by the throttle valve to obtain a second liquid phase part and a second gas phase part; the second gas phase part is helium gas separated from the first liquid phase part, and the second liquid phase part is a mixed liquid of methane and nitrogen after helium gas is separated;

[0013] The second gas phase part flows through the heat exchanger for rewarming and heat exchange and then converges with the raw material gas; the second liquid phase part flows through the heat exchanger for rewarming and heat exchange and then is discharged to the outside.

[0014] In a possible design, it further includes: a compressor;

[0015] The inlet of the compressor is connected to the outlet of the heat exchanger, and the outlet is connected to the inlet of the dehydrogenation unit; the compressor is used for pressurizing the second gas phase part flowing out of the heat exchanger and mixing it with the raw material gas.

[0016] In a possible design, it further includes: a tail gas recovery unit; the inlet is connected to the outlet of the heat exchanger and is used for recovering the second gas phase part flowing out of the heat exchanger.

[0017] In a possible design, the temperature range of the preset temperature is 80K to 100K.

[0018] In a possible design, the throttling pressure drop range of the throttle valve is 1.5MPa to 2.5MPa.

[0019] In a possible design, the heat exchanger is a multi-channel plate-fin heat exchanger.

[0020] The embodiment of the present utility model provides a crude helium concentration system. By setting a dehydrogenation unit, hydrogen in the raw material gas can be removed. By setting a heat exchanger, the raw material gas after dehydrogenation can be cooled down, so that most impurities are liquefied, and through a gas-liquid separator, the liquefied impurities and helium gas are separated. By setting a throttle valve, the liquid phase part can be throttled and cooled to provide a cold source for the heat exchanger, that is, the liquid after throttling cooling and the gas flowing out of the gas-liquid separator are used as the cold source for heat exchange of the heat exchanger, so that no other external cold source is required, achieving the purpose of energy conservation and consumption reduction. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 is a schematic flow diagram of a crude helium concentration system provided by an embodiment of the present utility model;

[0023] Figure 2 is a schematic flow diagram of a crude helium concentration system provided by another embodiment of the present utility model.

[0024] Reference numerals:

[0025] 1 - dehydrogenation unit;

[0026] 2 - heat exchanger;

[0027] 3 - gas - liquid separator;

[0028] 4 - throttle valve;

[0029] 5 - flash separator;

[0030] 6 - compressor;

[0031] 7 - tail gas recovery unit. Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0033] As Figure 1 shown, an embodiment of the present utility model provides a crude helium concentration system, including: a dehydrogenation unit 1 for removing hydrogen from the BOG raw material gas to be concentrated, and the raw material gas contains helium, methane, nitrogen and hydrogen;

[0034] at least one heat exchanger 2 connected to the outlet of the dehydrogenation unit 1, and the heat exchanger 2 is used to cool the raw material gas after hydrogen removal to a preset temperature;

[0035] a gas - liquid separator 3 with an inlet connected to the outlet of the heat exchanger 2, and the gas - liquid separator 3 is used to perform gas - liquid separation on the gas flowing out of the heat exchanger 2 to obtain a first liquid phase part and a first gas phase part. The first liquid phase part is a condensate containing methane and nitrogen, and the first gas phase part is concentrated crude helium gas;

[0036] a throttle valve 4 with an inlet connected to the bottom outlet of the gas - liquid separator 3, and the throttle valve 4 is used to throttle and cool the first liquid phase part;

[0037] The first gas phase part and the first liquid phase part cooled by the throttle valve 4 respectively flow through the heat exchanger 2 for reheating and heat exchange to provide cooling capacity for the heat exchanger 2.

[0038] In this embodiment, by setting the dehydrogenation unit 1, hydrogen in the raw material gas can be removed. By setting the heat exchanger 2, the raw material gas after dehydrogenation can be cooled down, so that most of the impurities are liquefied, and through the gas-liquid separator 3, the liquefied impurities and helium are separated. By setting the throttle valve 4, the liquid phase part can be throttled and cooled to provide a cold source for the heat exchanger 2, that is, the liquid after throttling and cooling and the gas flowing out of the gas-liquid separator 3 are used as the cold source for heat exchange of the heat exchanger 2, so that no other external cold source is required, achieving the purpose of energy conservation and consumption reduction.

[0039] It should be noted that the BOG raw material gas may also include other impurities such as neon, and the present application does not specifically limit the composition of the raw material gas. In addition, in order to improve the heat exchange effect of the heat exchanger, a multi-channel plate-fin heat exchanger is preferably used.

[0040] In addition, the raw material gas is usually at room temperature. Since most of the impurities in the raw material gas are methane and nitrogen, in order to liquefy methane and nitrogen, the preset temperature range is 80K - 100K. In order to make the throttling and cooling effect generated by the throttle valve 4 meet the cold source requirements of the heat exchanger 2, the pressure drop range of the throttle valve 4 is 1.5MPa - 2.5MPa, and this temperature drop range can cool the liquid after throttling by 3 - 5K.

[0041] In some embodiments, as Figure 2 shown, the dehydrogenation unit 1 can also be arranged at the outlet of the heat exchanger 2, and the inlet of the dehydrogenation unit 1 is connected to the outlet of the heat exchanger 2. At this time, the gas entering the heat exchanger 2 is the raw material gas containing hydrogen, and the first gas phase part is the mixed gas containing helium and hydrogen. The first gas phase part flowing out of the gas-liquid separator 3 returns to the heat exchanger 2, and after flowing out of the heat exchanger 2, it enters the dehydrogenation unit 1 for dehydrogenation to obtain the concentrated crude helium.

[0042] In some embodiments, it further includes: a flash separator 5;

[0043] The inlet of the flash separator 5 is connected to the outlet of the throttle valve 4, and the top outlet and the bottom outlet are respectively connected to the heat exchanger 2; the flash separator 5 is used to flash the first liquid phase part cooled by the throttle valve 4 to obtain a second liquid phase part and a second gas phase part; the second gas phase part is helium separated from the first liquid phase part, and the second liquid phase part is the mixed liquid of methane and nitrogen after helium is separated;

[0044] The second gas phase part flows through the heat exchanger 2 for reheating and heat exchange and then converges with the raw material gas; the second liquid phase part flows through the heat exchanger 2 for reheating and heat exchange and then is discharged to the outside.

[0045] In this embodiment, since there is some helium in the first liquid phase portion, most of the helium dissolved in the first liquid phase portion will flash out through the flash separator 5. The flashed helium is mixed with the feed gas and further concentrated, which can improve the concentration effect. In addition, after the second gas phase portion and the second liquid phase portion are heat-exchanged by the heat exchanger 2, it can further provide a cold source for the heat exchanger 2.

[0046] In some embodiments, it further includes: a compressor 6;

[0047] The inlet of the compressor 6 is connected to the outlet of the heat exchanger 2, and the outlet is connected to the inlet of the dehydrogenation unit 1; the compressor 6 is used to pressurize the second gas phase portion flowing out of the heat exchanger 2 and mix it with the feed gas.

[0048] In this embodiment, since the pressure of the second gas phase portion is relatively low, in order to enable it to be mixed with the feed gas, it is necessary to use the compressor 6 to pressurize it, and then mix it with the feed gas for cyclic concentration. After concentration in this application, the helium content in the crude helium can reach more than 90%, and the helium recovery rate in the feed gas is as high as more than 97%.

[0049] In addition, since the system provided in this application does not require an additional cold source, the energy consumption is extremely low. Therefore, even if the helium content in the feed gas is lower than 0.01%, the system of this application can be used for recovery, and the same high economic value can be generated.

[0050] In some embodiments, it further includes: a tail gas recovery unit 7; the inlet is connected to the outlet of the heat exchanger 2 and is used to recover the second gas phase portion flowing out of the heat exchanger 2.

[0051] In this embodiment, the second gas phase portion is recovered by the tail gas recovery unit 7, and after recovery, it can be sent to the fuel gas pipeline network as fuel, etc., thereby further improving the energy utilization rate.

[0052] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A crude helium concentration system, characterized in that, Comprising: A dehydrogenation unit (1) for removing hydrogen from the BOG raw gas to be concentrated, the raw gas containing helium, methane, nitrogen and hydrogen; At least one heat exchanger (2) connected to the outlet of the dehydrogenation unit (1), the heat exchanger (2) being used to cool the raw gas after hydrogen removal to a preset temperature; A gas-liquid separator (3) with an inlet connected to the outlet of the heat exchanger (2), the gas-liquid separator (3) being used to perform gas-liquid separation on the gas flowing out of the heat exchanger (2) to obtain a first liquid phase part and a first gas phase part, the first liquid phase part being a condensate containing methane and nitrogen, and the first gas phase part being the concentrated crude helium gas; A throttle valve (4) with an inlet connected to the bottom outlet of the gas-liquid separator (3), the throttle valve (4) being used to throttle and cool the first liquid phase part; The first gas phase part and the first liquid phase part cooled by the throttle valve (4) respectively flow through the heat exchanger (2) for reheating and heat exchange to provide cooling capacity for the heat exchanger (2).

2. The system according to claim 1, wherein Further comprising: A flash separator (5); The inlet of the flash separator (5) is connected to the outlet of the throttle valve (4), and the top outlet and the bottom outlet are respectively connected to the heat exchanger (2); the flash separator (5) is used to flash the first liquid phase part cooled by the throttle valve (4) to obtain a second liquid phase part and a second gas phase part; The second gas phase part is helium separated from the first liquid phase part, and the second liquid phase part is a mixture of methane and nitrogen after helium is separated; The second gas phase part flows through the heat exchanger (2) for reheating and heat exchange and then merges with the raw gas; the second liquid phase part flows through the heat exchanger (2) for reheating and heat exchange and then is discharged to the outside.

3. The system according to claim 2, wherein Further comprising: A compressor (6); The inlet of the compressor (6) is connected to the outlet of the heat exchanger (2), and the outlet is connected to the inlet of the dehydrogenation unit (1); the compressor (6) is used to pressurize the second gas phase part flowing out of the heat exchanger (2) and mix it with the raw gas.

4. The system according to claim 2, wherein Further comprising: A tail gas recovery unit (7); the inlet is connected to the outlet of the heat exchanger (2) and is used to recover the second gas phase part flowing out of the heat exchanger (2).

5. The system according to claim 1, wherein The temperature range of the preset temperature is 80K to 100K.

6. The system according to claim 1, characterized in that The throttling pressure drop range of the throttle valve (4) is 1.5MPa to 2.5MPa.

7. The system according to claim 1, wherein The heat exchanger (2) is a multi-channel plate-fin heat exchanger.

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