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CN-116267870-B - Rapid circulation mechanical nitrogen filling method and system for airtight cabin air-conditioning insect prevention

CN116267870BCN 116267870 BCN116267870 BCN 116267870BCN-116267870-B

Abstract

The invention belongs to the technical field of nitrogen filling, regulating and insect preventing of circulation machinery, and relates to a rapid circulation machinery nitrogen filling system for regulating and insect preventing of airtight cabins, which is characterized in that a vacuum pressure rotary adsorption nitrogen making machine and an airtight cabin with stored objects are mutually butted to construct a closed circulation rapid circulation machinery nitrogen filling system, a zeolite molecular sieve is used as an adsorbent to fill an adsorption tower in the nitrogen making machine, a dry vacuum pump is used for vacuumizing and desorbing nitrogen and water molecules adsorbed by the adsorption tower, and the nitrogen and water molecules are mechanically heated and then are directly pumped into the airtight cabin, and meanwhile, a process of 'forward thermal purge purification' is formed by intermittently extracting and returning a part of high-temperature product gas into the adsorption tower to form a comprehensive effect of 'temperature difference effect, moisturizing effect and thermal purge purification' mutually supporting, so that multiple effects of separating nitrogen and oxygen in raw material gas, heating product gas, conveying the product gas after heating, stabilizing humidity in the circulation machinery nitrogen filling process, improving purity of output nitrogen and accelerating nitrogen permeation and diffusion speed are presented.

Inventors

  • LAI ZHENLI
  • LI YIWEI

Assignees

  • 李翊玮

Dates

Publication Date
20260505
Application Date
20230515

Claims (10)

  1. 1. A rapid circulation mechanical nitrogen charging method for air-conditioned insect prevention among closed cabins uses a vacuum pressure rotary adsorption nitrogen generator (A) as nitrogen charging equipment in a rapid circulation mechanical nitrogen charging system, a raw material air inlet (A1) of the vacuum pressure rotary adsorption nitrogen generator (A) is in butt joint communication with one end of the closed cabin (1) through a raw material air suction pipeline (L1), a product air outlet (A6) of the vacuum pressure rotary adsorption nitrogen generator (A) is in butt joint communication with the corresponding other end of the closed cabin (1) through a product air transmission pipeline (L2), so as to construct a rapid circulation mechanical nitrogen charging system capable of being used for air conditioning insect prevention and sealing circulation, a fresh air pipeline (L3) for supplementing is connected to the raw material air suction pipeline (L1) of the vacuum pressure rotary adsorption nitrogen generator (A), when the rapid circulation mechanical nitrogen charging system continuously separates and removes oxygen in raw material air to form system pipeline internal air pressure reduction, and further influences the stability of the rapid circulation mechanical nitrogen charging system operation, and the rapid circulation mechanical nitrogen charging system is controlled by an automatic control valve arranged on the pipeline (L3) to balance and the fresh air circulation mechanical nitrogen charging system from the outside according to a program; The vacuum pressure rotary adsorption nitrogen making machine is characterized in that the vacuum pressure rotary adsorption nitrogen making machine (A) comprises a fan (A2), an adsorption tower (A3) and a dry vacuum pump (A5), wherein the input end of the fan (A2) is a raw gas inlet (A1), the output end of the dry vacuum pump (A5) is a product gas outlet (A6), an oxygen discharge port (A4) for discharging raw gas generated by the adsorption tower in the raw gas separation process is arranged on the adsorption tower (A3), the air outlet of the fan (A2) is connected with the raw gas inlet of the adsorption tower through a communication pipeline (L11), the air suction port of the dry vacuum pump (A5) is connected with the air outlet of the adsorption tower in vacuum suction desorption through a communication pipeline (L22), the air outlet of the adsorption tower (A3) in vacuum suction desorption and the air inlet of the fan (A2) are all positioned at the same end of the adsorption tower, and the end outlet of oxygen flow after the raw gas enters the adsorption tower and is connected with the oxygen discharge port (A4) of the adsorption tower through a communication pipeline (L33); The zeolite molecular sieve is used as an adsorbent to fill an adsorption tower (A3) in the vacuum pressure rotary adsorption nitrogen generator (A) so as to complete adsorption and separation of raw gas entering the adsorption tower, a dry vacuum pump (A5) is used for vacuumizing and desorbing nitrogen and water molecules adsorbed by the adsorption tower and directly pumping the desorbed gas into a closed cabin (1), so that a brand new process combination mode of 'zeolite molecular sieve adsorption tower + dry vacuum pump + vacuum pump for directly pumping nitrogen into the closed cabin' of the vacuum pressure rotary adsorption nitrogen generator and a mechanical heating effect of output gas are formed; When a vacuum pressure rotary adsorption nitrogen making machine (A) in a rapid circulation mechanical nitrogen filling system is started up and runs, a fan (A2) in the vacuum pressure rotary adsorption nitrogen making machine (A) is started up through a feed gas suction pipeline (L1), gas in a closed cabin (1) is taken as feed gas to be extracted and flows into an adsorption tower (A3) filled with zeolite molecular sieves through a communication pipeline (L11), nitrogen and water molecules in the feed gas are adsorbed by the zeolite molecular sieve layers in the process of passing through the zeolite molecular sieve layers, oxygen in the feed gas can be removed through a packing layer of the adsorption tower (A3) and an oxygen discharge port (A4) of the adsorption tower under the control of a programmed program, a control valve on the communication pipeline through which the air flows is started, and after the adsorption step of the nitrogen and the water molecules in the feed gas is completed, a vacuum desorption process of the nitrogen and the water molecules in the adsorption tower (A3) is started up continuously, a dry pump (A5) is started up through a vacuum pump (L22) and a vacuum pump (C) and a product is formed by automatically mixing the water molecules in the vacuum pump (A) with the product at a high temperature of 20 DEG, and a product is formed by the vacuum pump (C) and a product is automatically pumped up through the control pipeline (C) and a product gas outlet (C) of the vacuum pump) and a product is formed at a high temperature of the product (20), at the moment, the temperature difference effect that the temperature of the output nitrogen gas flow is greater than the existing temperature of agricultural products and packages in the airtight cabin at normal temperature is formed, the moisture-preserving effect that the existing environmental humidity in the airtight cabin (1) is maintained in the process of deoxidizing and producing nitrogen by the vacuum pressure rotary adsorption nitrogen production machine (A) is formed, the two effects are mutually overlapped, the mixed product gas of the nitrogen gas and the water molecule which is fed into the airtight cabin is quickly diffused and permeated into the pores of the storage in the airtight cabin, the time of regulating and preventing insects by charging the nitrogen gas is shortened, and the stability of the original moisture and quality of the storage can be ensured.
  2. 2. A rapid circulation mechanical nitrogen charging method for air-conditioned insect prevention among closed cabins according to claim 1, wherein the adsorption tower (A3) is formed by connecting at least 2 adsorption towers in parallel to form an adsorption tower group, so as to execute a switchable alternating operation mode of one-tower adsorption and the other-tower desorption, the adsorption tower group comprises a first adsorption tower (A3-1) and a second adsorption tower (A3-2), a communication pipeline (L11) led out from an air outlet of a fan (A2) is divided into two gas conveying branch pipes, one branch pipe (L11-1) is communicated with a raw material gas inlet of the adsorption tower (A3-1), the other branch pipe (L11-2) is communicated with a raw material gas inlet of the adsorption tower (A3-2), a communication pipeline (L22) butted with an air extracting port of a vacuum pump (A5) is divided into two gas conveying branch pipes, one branch pipe (L22-1) is butted with an air extracting port of the adsorption tower (A3-1) when the adsorption tower is extracted by vacuum, the other branch pipe (L11-1) is butted with the air extracting port of the adsorption tower (A3-1), and the other branch pipe (L22-1) is butted with the adsorption tower (A2) when the other branch pipe is extracted by the vacuum pump (A2) and the adsorption tower (A3-2) is extracted by the vacuum tower (A2) when the other branch pipe is extracted by the vacuum tower (A2) is butted with the air outlet of the adsorption tower (A2) The gas inlets of the adsorption towers (A3-2) are all positioned at the same end part of the adsorption towers, the tail end gas outlets of the adsorption towers (A3-1) and (A3-2) after the raw gas enters the adsorption towers are respectively connected with the oxygen discharge ports (A4) for discharging the raw gas generated by the adsorption towers in the process of separating the raw gas through a branch pipe (L33-1) and another branch pipe (L33-2), and control valves are respectively arranged on each communication pipeline, the upper part of the branch pipe and the gas outlet for discharging the oxygen; When the rapid circulation mechanical nitrogen charging system is operated, an adsorption tower (A3-1) and an adsorption tower (A3-2) in the vacuum pressure rotary adsorption nitrogen making machine (A) alternately adsorb and desorb nitrogen and water molecules in raw material gas, a fan (A2) in the vacuum pressure rotary adsorption nitrogen making machine (A) extracts gas in a closed cabin (1) as raw material gas through a raw material gas suction pipeline (L1) and inputs the raw material gas into the adsorption tower (A3-1) filled with zeolite molecular sieves through a branch pipe (L11-1), the raw material gas is adsorbed by the zeolite molecular sieve layers in the process of passing through the zeolite molecular sieve layers, oxygen components in the raw material gas are emptied and removed through a packing layer, the branch pipe (L33-1) and an oxygen discharge port (A4) of the adsorption tower, the nitrogen and water molecules in the raw material gas are adsorbed by the adsorption tower (A3-1), the nitrogen and water molecules in the adsorption tower (A3-2) are simultaneously desorbed by the adsorption tower, and the vacuum desorption tower (A2) are synchronously mixed with water molecules in the vacuum pump (L2) in the vacuum process step (A2), the mixed product gas realizes the temperature rise of up to 20-80 ℃ in the high-temperature machine cavity process of the dry vacuum pump (A5) and is input into the closed cabin (1) through the product gas outlet (A6) and the product gas transmission pipeline (L2); according to the programmed program and the electric control signal, the control valves in the communication pipelines and the branch pipes are automatically opened and closed, so that more than two adsorption tower groups in the system can be ensured to synchronously operate under normal pressure adsorption and vacuum desorption respectively, and the automatic alternate switching operation of the mode of 'one-tower adsorption and one-tower desorption' is ensured.
  3. 3. A rapid circulation mechanical nitrogen charging method for airtight cabin air-conditioning insect prevention according to claim 2, characterized in that a forward thermal purge purification process is implanted in a rapid circulation mechanical nitrogen charging system, firstly, a product gas return line (L4) with a control valve is connected between a raw gas inlet (A1) and a product gas transmission pipeline (L2), when the rapid circulation mechanical nitrogen charging system is started up and operates according to a programmed program to complete an adsorption step of an adsorption tower (A3-1) for nitrogen and water molecules in the raw gas, and then the adsorption step of vacuumizing and desorbing the adsorbed nitrogen and water molecules is carried out, the forward thermal purge purification process is continuously started, at this time, the adsorption tower (A3-2) in the rapid circulation mechanical nitrogen charging system is still in the vacuumizing and desorbing process step, the product gas return line (L4) in the rapid circulation mechanical nitrogen charging system, a branch pipe (L11-1) between an air outlet of a fan and the adsorption tower (A3-1), the control valve (L33-1) and a branch pipe (L22-2) are automatically opened, and the adsorption tower (A2) is partially opened, and the adsorption tower (A3-2) is partially pumped back into the adsorption tower (A3-1) through the vacuum pump (A3-2), and the adsorption tower (A3-2) is partially pumped back into the adsorption tower (A3-1) and the vacuum tower (A3-2) is partially pumped and the product gas return line (A3-2) is partially pumped into the vacuum tower (A3-3) The mixed product gas in a high temperature state plays roles of effectively endowing heat energy activation, desorption and forward sweeping replacement to the residual oxygen in the molecular sieve adsorption layer, and the swept oxygen is emptied and removed through a branch pipe (L33-1) and an oxygen discharge port (A4) of the adsorption tower; The high-temperature mixed product gas returned into the adsorption tower (A3-1) is purged and replaced by residual oxygen in the molecular sieve adsorption layer, and most of nitrogen and water molecules are adsorbed again by the adsorption layer, and the high-temperature mixed product gas is formed again when the adsorption tower (A3-1) is alternately switched to vacuum-pumping desorption and is input into the closed cabin (1) through the product gas outlet (A6) and the product gas transmission pipeline (L2).
  4. 4. A rapid circulation mechanical nitrogen charging method for airtight cabin air-conditioning insect prevention according to any one of claims 1,2 and 3 is characterized in that after a product gas return pipeline (L4) with a control valve is connected between a raw gas inlet (A1) and a product gas conveying pipeline (L2) of a vacuum pressure rotary adsorption nitrogen making machine (A), a nitrogen output pipeline of a new nitrogen source (B) is connected into a rapid circulation mechanical nitrogen charging system through any one of the following three forms to form a new structural combination mode of a vacuum pressure rotary adsorption nitrogen making machine (A) +the new nitrogen source (B) of a zeolite molecular sieve: (1) When the rapid circulation mechanical nitrogen charging system is started up and operates, the adsorption tower (A3-1) firstly completes adsorption of nitrogen and water molecules in raw material gas, and then a forward purging process is continuously started, during the period, part of the new nitrogen source (B) outputs nitrogen flow, passes through the section of product gas return pipeline (L4) between the tee joint (D) and the raw material gas inlet (A1) and flows through the fan (A2) and the branch pipe (L11-1) to be input into the adsorption tower (A3-1) so as to perform purging replacement action on residual oxygen molecules in the zeolite molecular sieve layer, and the rest part of nitrogen which does not participate in the purging replacement is discharged through the oxygen discharge port (A4) of the adsorption tower and enters a closed cabin through the section of product gas return pipeline (L4) and the product gas transmission pipeline (L2) between the tee joint (D) and the product gas transmission pipeline (L2); when the nitrogen flow output by the new nitrogen source (B) can not meet the requirement of the positive purging air consumption of the adsorption tower (A3-1), under the control of a programmed program, the fan (A2) depends on the negative pressure pumping effect at the air inlet to recycle part of the mixed product gas output by the dry vacuum pump (A5) to the adsorption tower (A3-1) through a product gas recycling pipeline (L4) and a branch pipe (L11-1), and the part of the high-temperature mixed gas recycled to the adsorption tower (A3-1) is converged with the nitrogen flow output by the new nitrogen source (B) to effectively endow heat energy activation, desorption and positive purging replacement effects to the residual oxygen in the molecular sieve adsorption layer; (2) The method comprises the steps of connecting a nitrogen output pipeline of a new nitrogen source (B) to a product gas transmission pipeline (L2) through a tee joint (D), when a rapid circulation mechanical nitrogen charging system is started, firstly completing adsorption of nitrogen and water molecules in raw material gas by an adsorption tower (A3-1), then starting a forward purging process continuously, during the period, collecting part of mixed product gas output by a dry vacuum pump (A5) into the adsorption tower (A3-1) through a product gas feedback pipeline (L4) and a branch pipe (L11-1), effectively endowing heat energy activation, desorption and forward purging replacement to residual oxygen in a molecular sieve adsorption layer by the part of mixed gas fed back into the adsorption tower (A3-1), exhausting the purged oxygen through a branch pipe (L33-1) and an oxygen discharge port (A4) of the adsorption tower, collecting part of nitrogen output by the dry vacuum pump (A5) into the product gas transmission pipeline (L2) through the tee joint (D), simultaneously ensuring that the purity of the fresh air fed into the air pump (A3-1) is not balanced by the pressure of the fresh air pump (A) and simultaneously avoiding the air flow (3-5), part of the nitrogen flow output by the new nitrogen source (B) is input into the adsorption tower (A3-1) through the product gas transmission pipeline (L2) between the tee joint (D) and the gas inlet (A1) of the raw material gas, the product gas return pipeline (L4) and flows through the fan (A2), a communicating pipeline branch pipe (L11-1) between the air outlet of the fan and the adsorption tower, so as to cooperatively perform the purging replacement function on the residual oxygen molecules in the zeolite molecular sieve; (3) A new nitrogen source (B) is connected with a raw material gas inlet (A1) of a fan (A2) through a fresh air pipeline (L3), a rapid circulation mechanical nitrogen charging system is started to operate, under the control of a programmed program, an adsorption tower (A3-1) in the rapid circulation mechanical nitrogen charging system firstly completes adsorption of nitrogen and water molecules in raw material gas, then a forward purging process is continuously started, at the moment, a part of the new nitrogen source (B) outputs nitrogen flow and passes through the fresh air pipeline (L3) and the fan (A2) is input into the adsorption tower (A3-1) to perform purging and replacement of residual oxygen molecules in the zeolite molecular sieve, the purged oxygen is discharged through an oxygen discharge port (A4) of the adsorption tower, the residual nitrogen flow which is output by the new nitrogen source (B) and does not participate in the purging and replacement of the residual oxygen molecules in the zeolite molecular sieve is transmitted through the fresh air pipeline (L3), the product gas return pipeline (L4) and the product gas pipeline (L2) enter a closed cabin to participate in gas regulation and prevention, and when the new nitrogen source (B) outputs nitrogen flow and does not meet the requirement of blowing and the residual oxygen molecules in the adsorption tower (A2) to form a vacuum pump (A-1) through the vacuum pump (A3-3) and a part of the vacuum pump (A1), the part of the high-temperature mixed gas which is returned into the adsorption tower (A3-1) is cooperated to endow heat energy activation, desorption and forward sweeping and replacement effects to the residual oxygen molecules in the molecular sieve adsorption layer; In the three forms (1), (2) and (3), part of nitrogen which is output from the new nitrogen source (B) and participates in purging and replacement is adsorbed by the zeolite molecular sieve adsorption layer, desorption is completed again under the vacuumizing effect of a continuous dry vacuum pump (A5) through a branch pipe (L22-1) or a branch pipe (L22-2) and is collected into the mixed product gas, and the rest part of nitrogen which does not participate in purging and replacement enters a closed cabin through a product gas pipeline (L2).
  5. 5. The method for rapid circulation mechanical nitrogen filling of air-conditioned insect prevention in a closed cabin according to claim 4, wherein the nitrogen source (B) is one of a membrane nitrogen making machine, a PSA nitrogen making machine, a deoxidizing machine and a vacuum pressure rotary adsorption nitrogen making machine.
  6. 6. The method for rapid circulation mechanical nitrogen filling of air-conditioned insect prevention in a closed cabin according to claim 1, wherein the dry vacuum pump comprises one of a dry screw vacuum pump, a claw vacuum pump, a Lotz vacuum pump and a vortex vacuum pump.
  7. 7. The rapid circulation mechanical nitrogen charging system for realizing the method of claim 1 is characterized by comprising a vacuum pressure rotary adsorption nitrogen making machine (A), a closed cabin (1), a raw material gas suction pipeline (L1) and a product gas transmission pipeline (L2), wherein the vacuum pressure rotary adsorption nitrogen making machine (A) comprises a fan (A2), an adsorption tower (A3) filled with zeolite molecular sieves, a communicating pipeline (L11) between an air outlet of the fan and the adsorption tower, a dry vacuum pump (A5) and a communicating pipeline (L22) between a vacuum pump air outlet and the adsorption tower, the air outlet of the fan (A2) is communicated with the raw material gas inlet of the adsorption tower (A3) through the pipeline (L11), the air outlet of the adsorption tower (A3) during vacuum suction and desorption is communicated with the air suction port of the dry vacuum pump (A5) through the pipeline (L22), the air outlet of the adsorption tower (A3) during vacuum suction and the raw material gas output of the fan (A2) are all positioned at the same end of the adsorption tower, the air inlet of the fan (A2) is the air inlet of the air inlet (A2) is communicated with the raw material gas outlet of the adsorption tower (A1) during vacuum suction and the raw material gas output of the adsorption tower (A3) is arranged at the air inlet port (1) of the vacuum pump air outlet (1), the product gas outlet (A6) is communicated with the closed cabin (1) through a product gas transmission pipeline (L2).
  8. 8. A rapid circulating mechanical nitrogen charging system according to claim 7, wherein the adsorption tower (A3) is composed of an adsorption tower group formed by connecting at least 2 adsorption towers in parallel, the adsorption tower group comprises an adsorption tower (A3-1) and an adsorption tower (A3-2), a communication pipeline (L11) led out from an air outlet of a fan (A2) is divided into two branch pipes, one branch pipe (L11-1) is communicated with a raw material gas inlet of the adsorption tower (A3-1), the other branch pipe (L11-2) is communicated with a raw material gas inlet of the adsorption tower (A3-2), a communication pipeline (L22) which is in butt joint with an air extracting opening of a vacuum pump (A5) is divided into two branch pipes, one branch pipe (L22-1) is in butt joint with an air outlet of the adsorption tower (A3-1) when being vacuumized and desorbed, the other branch pipe (L22-2) is in butt joint with an air outlet of the adsorption tower (A3-2) when being vacuumized and desorbed, the adsorption tower (A3-1), the adsorption tower (A3-2) and the adsorption tower (A3-2) are in butt joint with the same air inlet of the adsorption tower (A3-2) when being vacuumized and the adsorption tower (A2) are in the end part of the adsorption tower (A3-2) when the adsorption tower is vacuumized and the raw material gas is discharged from the adsorption tower (A2) The tail end air outlet of the oxygen formed by the adsorption tower (A3-2) after adsorption and separation is connected with the discharge port (A4) for discharging the oxygen through a branch pipe (L33-1) and a branch pipe (L33-2), and control valves are respectively arranged on each communication pipeline and the branch pipe and the discharge port for discharging the oxygen.
  9. 9. The rapid circulation mechanical nitrogen charging system according to any one of claims 7 and 8, wherein a product gas return pipeline (L4) for a forward thermal blowing purification process is connected between a raw material gas inlet (A1) of the fan (A2) and a product gas transmission pipeline (L2), the product gas return pipeline (L4) is provided with a control valve, the gas inlet end of the product gas return pipeline (L4) is communicated with the product gas transmission pipeline (L2), the gas outlet end of the product gas return pipeline (L4) is connected with the raw material gas inlet (A1) of the fan (A2), and the raw material gas outlet of the fan (A2) is respectively communicated with the raw material gas inlets of two adsorption towers of the adsorption tower group through a branch pipe (L11-1) and a branch pipe (L11-2).
  10. 10. The rapid circulation mechanical nitrogen charging system according to claim 4, wherein a nitrogen output pipeline of a new nitrogen source (B) is connected into the rapid circulation mechanical nitrogen charging system by any one of the following three forms: (1) The nitrogen output pipeline of the new nitrogen source (B) is communicated to the product gas feedback pipeline (L4) through a tee joint (D); (2) The nitrogen output pipeline of the new nitrogen source (B) is communicated to the upper surface of the product gas transmission pipeline (L2) through a tee joint (D); (3) And a new nitrogen source (B) is connected with a raw material gas inlet (A1) of a fan (A2) through a fresh air pipeline (L3).

Description

Rapid circulation mechanical nitrogen filling method and system for airtight cabin air-conditioning insect prevention Technical Field The invention belongs to the technical field of circulating mechanical nitrogen filling, and particularly relates to a rapid circulating mechanical nitrogen filling method and a system thereof for air-controlled insect prevention between closed cabins. Background The circulating mechanical nitrogen-filling insect-proofing technology is applied to a large scale in a closed space or a closed warehouse which is used for storing grains, feeds, tobacco, traditional Chinese medicinal materials, books, archives, cultural relics, clothes, cabins and the like and is easy to nourish insect and mildew, and equipment applied by the circulating mechanical nitrogen-filling insect-proofing technology is mainly a PSA pressure swing adsorption nitrogen making machine, a vacuum pressure swing adsorption nitrogen making machine, membrane separation nitrogen making equipment and the like, wherein the equipment model which can be better matched with a circulating mechanical nitrogen filling system under a closed circulating condition is the vacuum pressure swing adsorption nitrogen making machine. The vacuum pressure rotary adsorption nitrogen making machine adopts an operation mode of normal pressure adsorption and vacuum desorption, the equipment system is communicated with a closed air-conditioning bin by means of a closed or semi-closed circulating air-taking mode, and an ordinary pressure fan is adopted to extract air and input the air into an adsorption tower for separation treatment of nitrogen and oxygen. The method is characterized in that a carbon molecular sieve is generally used for absorbing oxygen in air, a fan is used as a power device for gas extraction and conveying, a vacuum pump is used for desorbing and removing oxygen molecules absorbed by the carbon molecular sieve and extracting oxygen components through the vacuum pump, namely, the separation of nitrogen and oxygen in raw material gas is realized by adopting a process mode of 'the fan extraction and conveying airtight space gas into an adsorption tower+the carbon molecular sieve adsorption tower for absorbing oxygen+the vacuum pump for vacuum desorption of oxygen and evacuation'. The vacuum pressure rotary adsorption nitrogen making machine is usually connected in parallel by using two groups of adsorption towers, and four operation steps of normal pressure adsorption, pressure equalizing, vacuum desorption and back blowing are controlled by a control program to continuously perform normal pressure adsorption and vacuum desorption regeneration on the carbon molecular sieve according to the process requirements so as to finish nitrogen-oxygen separation and obtain the required nitrogen-rich gas. The two groups of adsorption towers of the equipment adopt an alternating operation mode of 'one tower adsorption and one tower desorption', namely, one group of adsorption towers is firstly used for normal pressure adsorption, the other group of adsorption towers is used for vacuum desorption, and after the process steps are finished, the group of adsorption towers for normal pressure adsorption is switched into vacuum desorption, so that the operation is continuously and alternately carried out. Firstly, a fan in an equipment system extracts air in a closed cabin to be used as raw material gas of the nitrogen making machine, the raw material gas enters an adsorption tower through an air inlet valve and an air suction valve, oxygen molecules in the raw material gas are adsorbed by a carbon molecular sieve, unadsorbed nitrogen molecules are returned to the closed cabin through a carbon molecular sieve adsorption bed, an exhaust valve, a nitrogen flow control valve and an air flow pipeline, meanwhile, a vacuum pump carries out vacuum desorption on an adsorption tower (called a desorption tower at the moment) adsorbed with oxygen, at the moment, the oxygen on the carbon molecular sieve in the desorption tower is desorbed in vacuum and is discharged into the atmosphere from an exhaust port of the vacuum pump, and the duration of the whole process is generally tens of seconds. And then, entering a pressure equalizing mode, connecting an adsorption tower and a desorption tower which has completed vacuum desorption by using an upper pressure equalizing valve and a lower pressure equalizing valve so as to maintain the pressure balance in the two towers, wherein the duration is 2-3 seconds, and in order to enable the carbon molecular sieve in the adsorption tower to release oxygen to perform more thoroughly, part of nitrogen generated after normal pressure adsorption enters the desorption tower to purge through a reverse purge valve under the action of negative pressure formed by vacuum desorption, so as to blow oxygen components in the tower out of the adsorption tower, wherein the duration of the process is generally 1-5 seconds, the two