CN217737223U

CN217737223U - Recoverable thermal nitrogen gas purification device

Info

Publication number: CN217737223U
Application number: CN202122390459.5U
Authority: CN
Inventors: 孟雪; 孟令悦; 张蒙恩; 曹真真; 万银霞; 孙攀; 吴落民; 袁凤慧
Original assignee: Henan Xinlianxin Chemicals Group Co Ltd
Current assignee: Henan Xinlianxin Chemicals Group Co Ltd
Priority date: 2021-09-29
Filing date: 2021-09-29
Publication date: 2022-11-04
Anticipated expiration: 2031-09-29

Abstract

The utility model relates to a nitrogen purification device capable of recovering heat; the device comprises a purification unit and a heat recovery unit, wherein the purification unit comprises a waste nitrogen buffer tank for storing waste nitrogen and a synthetic air-release buffer tank for stabilizing pressure, the waste nitrogen buffer tank is connected with an inlet of a mixed gas buffer tank through a compression cooling unit, and an outlet of the mixed gas buffer tank is connected with a liquid nitrogen washing section through a shell pass of a deoxygenation reactor, a deoxygenation cooler and a separation unit; the synthetic bleed air buffer tank is connected with an inlet of the mixed gas buffer tank through a pressure reducing device; the heat recovery unit is connected with a gas phase outlet of the tube side of the deoxygenation reactor; the device has the advantages of being simple in structure and reasonable in design, not only being capable of effectively realizing purification of the waste nitrogen, but also being capable of realizing efficient utilization of the discharged air exhausted by synthesis, and then recycling the generated heat on the basis of purifying the waste nitrogen to obtain the low-pressure saturated steam as a byproduct, and realizing energy conservation and consumption reduction.

Description

Recoverable thermal nitrogen gas purification device

Technical Field

The utility model relates to a dirty nitrogen gas purifies technical field, specifically is a recoverable thermal nitrogen gas purification device.

Background

The cryogenic air separation is to separate each component by utilizing the difference of the boiling points of each component in liquefied air, namely, the air is taken as a raw material, the air is compressed and purified, then the air is liquefied into liquid air by utilizing heat exchange, and the separation of oxygen and nitrogen components is finally realized in a rectifying tower by utilizing the difference of the boiling points of liquid oxygen and liquid nitrogen through the rectification of the liquid air; the cryogenic air separation can obtain nitrogen with large quantity and high purity, but simultaneously generates polluted nitrogen due to process limitation, and the polluted nitrogen contains oxygen, so that the polluted nitrogen cannot be effectively utilized, and how to purify the part of the polluted nitrogen, so that the polluted nitrogen is effectively utilized, the utilization rate of the nitrogen is improved, and the technical problem to be solved is needed urgently.

SUMMERY OF THE UTILITY MODEL

The utility model provides a not enough to prior art, the utility model provides a simple structure, reasonable in design not only can effectively realize dirty nitrogen purification, can also realize carrying out high-efficient the utilization to synthetic evacuation's evacuation, and the heat of retrieving the production on going on purifying the basis to dirty nitrogen again is used for byproduct low pressure saturated steam to realize energy saving and consumption reduction's recoverable thermal nitrogen gas purification device.

In order to achieve the above purpose, the utility model adopts the technical scheme that:

a nitrogen purification device capable of recovering heat comprises a purification unit and a heat recovery unit, wherein the purification unit comprises a waste nitrogen buffer tank for storing waste nitrogen and a synthetic air release buffer tank for stabilizing pressure, the waste nitrogen buffer tank is connected with an inlet of a mixed gas buffer tank through a compression cooling unit, and an outlet of the mixed gas buffer tank is connected with a liquid nitrogen washing section through a shell pass of a deoxygenation reactor, a deoxygenation cooler and a separation unit; the synthetic bleed air buffer tank is connected with an inlet of the mixed gas buffer tank through a pressure reducing device; the heat recovery unit is connected with a gas phase outlet of the tube side of the deoxygenation reactor.

Preferably, the compression cooling unit comprises a low pressure compressor connected to the outlet of the waste nitrogen buffer tank, and a primary cooler disposed between the low pressure compressor and the inlet of the mixed gas buffer tank.

Preferably, the separation unit comprises a gas-liquid separator connected with an outlet of the deoxygenation cooler, a gas-phase outlet of the gas-liquid separator is connected with a gas inlet of the high-pressure compressor through the dryer, and a gas outlet of the high-pressure compressor is connected with the liquid nitrogen washing section through the high-pressure cooler.

Preferably, the heat recovery unit comprises a steam drum connected with a gas phase outlet of the tube side of the deoxygenation reactor, a liquid phase outlet at the bottom of the steam drum is connected with a reflux port at the bottom of the tube side of the deoxygenation reactor, and a desalted water replenishing pipeline and a steam pipeline connected with a steam pipeline network are arranged at the top of the steam drum.

Preferably, the bottom of the waste nitrogen buffer tank, the synthetic vent gas buffer tank and the mixed gas buffer tank are respectively provided with a sewage discharge pipeline.

Preferably, the high-pressure compressor and the low-pressure compressor are multi-stage compressors provided with intercoolers.

Preferably, the pressure reducing device is a pressure reducing valve or a pressure turbine device.

Preferably, the deoxygenation reactor is a shell-and-tube reactor, and a catalyst bed layer is arranged in a shell side of the shell-and-tube reactor.

According to the nitrogen purification device capable of recovering heat, the waste nitrogen is filled in the waste nitrogen buffer tank, and the inside of the synthetic vent gas buffer tank is mixed gas of hydrogen and nitrogen; the utility model removes the oxygen in the nitrogen by utilizing the principle that the oxygen reacts with the hydrogen to realize the purification of the nitrogen; specifically, hydrogen in the synthesis vent gas is used as a reaction reducing agent, the reaction reducing agent is combusted with a noble metal catalyst in a deoxygenation reactor, a large amount of heat is released, meanwhile, the heat is recovered through a tube pass and a steam pocket of the deoxygenation reactor, oxygen in the polluted nitrogen can be effectively removed, nitrogen meeting the process requirements is provided for the synthetic ammonia process, and the nitrogen can be directly sent to a liquid nitrogen washing process for deep gas distribution; the purification of dirty nitrogen gas not only can be realized, the utilization ratio of nitrogen gas is improved, and hydrogen is provided by synthetic blow-down gas simultaneously, reaches the high-efficient synthetic blow-down gas that utilizes, realizes the cyclic utilization of effective gas to retrieve the heat at this in-process, the by-product steam reaches energy-conservation, consumption reduction, the purpose of increasing efficiency.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Referring to fig. 1: the utility model relates to a nitrogen purification device capable of recovering heat, which comprises a purification unit and a heat recovery unit, wherein the purification unit comprises a waste nitrogen buffer tank 3 for storing waste nitrogen and a synthetic air release buffer tank 1 for stabilizing pressure, the waste nitrogen buffer tank 3 is connected with an inlet of a mixed gas buffer tank 6 through a compression cooling unit, and an outlet of the mixed gas buffer tank 6 is connected with a liquid nitrogen washing section 14 through a shell pass of a deoxidation reactor 7, a deoxidation cooler 9 and a separation unit; the synthetic vented gas buffer tank 1 is connected with an inlet of a mixed gas buffer tank 6 through a pressure reducing device 2; the heat recovery unit is connected with a gas phase outlet of the tube side of the deoxygenation reactor 7. The utility model comprises a purification unit and a heat recovery unit, wherein the purification unit is mainly used for purifying the sewage nitrogen in the sewage nitrogen buffer tank 3, the purification process comprises the steps of mixing the synthesis gas and the sewage nitrogen, then entering a deoxidation reactor 7 for catalytic deoxidation reaction, then purifying and separating the synthesis gas through a deoxidation cooler 9 and a separation unit, and sending the mixture into a liquid nitrogen washing section 14; a large amount of heat is generated in the catalytic deoxidation reaction in the deoxidation reactor 7, and is recovered by a heat recovery unit, and steam is by-produced in the recovery process, so that the characteristics of energy conservation, consumption reduction and efficiency improvement are achieved. The compression cooling unit comprises a low-pressure compressor 4 connected with the outlet of the waste nitrogen buffer tank 3, and a primary cooler 5 arranged between the low-pressure compressor 4 and the inlet of the mixed gas buffer tank 6. The separation unit comprises a gas-liquid separator 10 connected with an outlet of the deoxidation cooler 9, a gas-phase outlet of the gas-liquid separator 10 is connected with an air inlet of a high-pressure compressor 12 through a dryer 11, and an exhaust port of the high-pressure compressor 12 is connected with a liquid nitrogen washing section 14 through a high-pressure cooler 13. The heat recovery unit comprises a steam drum 8 connected with a gas phase outlet of a tube pass of the deoxygenation reactor 7, a liquid phase outlet at the bottom of the steam drum 8 is connected with a return port 15 at the bottom of the tube pass of the deoxygenation reactor 7, and a desalted water replenishing pipeline 16 and a steam pipeline 18 connected with a steam pipe network 17 are arranged at the top of the steam drum 8. The bottom of the waste nitrogen buffer tank 3, the synthetic vent gas buffer tank 1 and the mixed gas buffer tank 6 are respectively provided with a sewage discharge pipeline 19. The high-pressure compressor 12 and the low-pressure compressor 4 are multistage compressors provided with intercoolers. The pressure reducing device 2 is a pressure reducing valve or a pressure turbine device. The deoxygenation reactor 7 is a shell-and-tube reactor, and a catalyst bed layer is arranged in the shell pass of the shell-and-tube reactor.

A method for purifying a nitrogen purification device capable of recovering heat and recovering the heat comprises the following steps: step 1: waste nitrogen generated in the air separation section enters a low-pressure compressor 4 after being stabilized in pressure by a waste nitrogen buffer tank 3, is subjected to multi-stage low-pressure compression and pressure increase, is cooled by a primary cooler 5, and then enters a mixed gas buffer tank 6; the components of the waste nitrogen from the air separation section are nitrogen and oxygen, and the temperature is as follows: 20-35 ℃, pressure: 5-15KPaG; the temperature of the waste nitrogen gas after being pressurized by the low-pressure compressor 11 is as follows: 175-185 ℃, pressure: 0.5-0.6MPaG; the temperature of the polluted nitrogen cooled by the primary cooler 5 is as follows: 115-125 ℃ and the pressure is as follows: 0.49-0.59MPaG. Step 2: the synthesis vent gas generated by synthesis is subjected to pressure stabilization through a synthesis vent gas buffer tank 1, then is subjected to pressure reduction through a pressure reduction device 2, and enters a mixed gas buffer tank 6 after being subjected to pressure reduction; the synthesis vent gas comprises nitrogen and hydrogen, and the temperature is as follows: 20-35 ℃, pressure: 5.0-5.5MPaG; the temperature of the synthesis vent gas after being decompressed by the decompressor 2 is as follows: 18-33 ℃, pressure: 0.5-0.6MPaG. And step 3: the sewage nitrogen pressurized by the low-pressure compressor 4 and the synthesis vent gas after pressure reduction are mixed and stabilized in the mixed gas buffer tank 6, and then enter a catalyst bed layer in the shell side of the deoxygenation reactor 7, and hydrogen and oxygen react and release a large amount of heat under the action of a catalyst; the mixed gas comprises the following components in percentage by weight: 110-120 ℃ and the pressure is: 0.48-0.59MPaG; the temperature of the deoxygenation reactor 7 is as follows: 160-190 ℃ and the pressure is as follows: 0.46-0.57MPaG, and the components after reaction are nitrogen, hydrogen, water and trace oxygen. And 4, step 4: when the deoxidation reactor 7 reacts, a large amount of heat is emitted, and for fully and effectively utilizing the heat, the utility model discloses a tube side of the deoxidation reactor 7 is connected with the heat recovery unit, the heat recovery unit continuously operates, the water coming down from the steam pocket 8 uniformly enters the tube side of the deoxidation reactor 7, and the reaction heat in the catalyst bed layer at the shell side of the deoxidation reactor 7 is absorbed, so that part of the water is vaporized, the steam-water mixture with smaller specific gravity rises into the steam pocket 8, and the water-steam separation is realized to generate saturated steam; the reaction is continuous reaction, so continuous water supplement is needed to ensure the reaction temperature; the moisturizing is mended by demineralized water input pipeline 16, and demineralized water input pipeline 16 can link to each other with the system pipe network, and the temperature is: 95-110 ℃, pressure: 0.35-0.5MPaG; the saturated steam temperature is: 150-160 ℃, pressure is: 0.35-0.5MPaG, and is sent to a steam pipe network 17. And 5: the product generated after the reaction in the deoxidation reactor 7 enters a deoxidation cooler 9 for cooling so as to have the condition of water-gas separation; the temperature of the mixture cooled by the deoxidation cooler 9 is as follows: 35-45 ℃ and the pressure is: 0.43-0.55MPaG. Step 6: the reaction product after being cooled enters a gas-liquid separator 10, and most of water in the product is separated and removed by utilizing the principle of different gas-liquid gravity; and 7: the gas with most of moisture removed enters a dryer 11 for deep drying, so that the moisture in the nitrogen-hydrogen mixed gas is completely removed; and 8: the deeply dried nitrogen and hydrogen enter a high-pressure compressor 12 for pressurization and are cooled by a high-pressure cooler 13; the temperature of the nitrogen and hydrogen after the pressurization and cooling is as follows: 35-45 ℃ and the pressure is: 5-6MPaG. And step 9: the nitrogen-hydrogen gas after being pressurized and cooled is sent to a liquid nitrogen washing section 14 for deep hydrogen distribution so as to meet the requirements of a synthesis section. The deoxygenation reactor 7 is a combustion deoxygenator; the purification process can realize the purification of the polluted nitrogen, the purification process can not only meet the use requirement in the liquid nitrogen washing working section 14, but also effectively recover the heat generated by the reaction, and the process of recovering the heat does not need power supply and is a continuous heat recovery process; the device has the characteristics of simple structure and reasonable design, can realize the purification of polluted nitrogen, improves the utilization rate of nitrogen, simultaneously provides hydrogen from synthesis vent gas, realizes the high-efficiency utilization of the synthesis vent gas, realizes the cyclic utilization of effective gas, recovers heat in the process, produces steam as a byproduct, and achieves the effects of energy conservation, consumption reduction and efficiency improvement.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims

1. A nitrogen gas purification device capable of recovering heat is characterized in that: the device comprises a purification unit and a heat recovery unit,

the purification unit comprises a waste nitrogen buffer tank (3) for storing waste nitrogen and a synthetic vent gas buffer tank (1) for stabilizing pressure, the waste nitrogen buffer tank (3) is connected with an inlet of the mixed gas buffer tank (6) through a compression cooling unit, and an outlet of the mixed gas buffer tank (6) is connected with a liquid nitrogen washing section (14) through a shell pass of a deoxygenation reactor (7), a deoxygenation cooler (9) and a separation unit;

the synthetic vented gas buffer tank (1) is connected with an inlet of a mixed gas buffer tank (6) through a pressure reducing device (2);

the heat recovery unit is connected with a gas phase outlet of the tube side of the deoxygenation reactor (7).

2. The heat recoverable nitrogen gas purification apparatus of claim 1, wherein: the compression cooling unit comprises a low-pressure compressor (4) connected with an outlet of the waste nitrogen buffer tank (3), and a primary cooler (5) arranged between the low-pressure compressor (4) and an inlet of the mixed gas buffer tank (6).

3. Heat recoverable nitrogen gas purification apparatus according to claim 1 or 2, characterized in that: the separation unit comprises a gas-liquid separator (10) connected with an outlet of the deoxidation cooler (9), a gas-phase outlet of the gas-liquid separator (10) is connected with a gas inlet of a high-pressure compressor (12) through a dryer (11), and a gas outlet of the high-pressure compressor (12) is connected with a liquid nitrogen washing section (14) through a high-pressure cooler (13).

4. The heat recoverable nitrogen gas purge apparatus of claim 1, wherein: the heat recovery unit comprises a steam drum (8) connected with a gas phase outlet of a tube pass of the deoxygenation reactor (7), a bottom liquid phase outlet of the steam drum (8) is connected with a return port (15) at the bottom of the tube pass of the deoxygenation reactor (7), and the top of the steam drum (8) is provided with a desalted water replenishing pipeline (16) and a steam pipeline (18) connected with a steam pipe network (17).

5. The heat recoverable nitrogen gas purification apparatus of claim 1, wherein: and the bottoms of the waste nitrogen buffer tank (3), the synthetic vent gas buffer tank (1) and the mixed gas buffer tank (6) are respectively provided with a sewage discharge pipeline (19).

6. The heat recoverable nitrogen gas purification apparatus of claim 3, wherein: the high-pressure compressor (12) and the low-pressure compressor (4) are multi-stage compressors provided with interstage coolers.

7. The heat recoverable nitrogen gas purge apparatus of claim 1, wherein: the pressure reducing device (2) is a pressure reducing valve or a pressure turbine device.

8. The heat recoverable nitrogen gas purification apparatus of claim 1, wherein: the deoxygenation reactor (7) is a shell-and-tube reactor, and a catalyst bed layer is arranged in the shell pass of the shell-and-tube reactor.