CN-122015427-A - Oxygen-nitrogen liquid conversion and energy storage system of air separation device under peak-valley electricity condition

CN122015427ACN 122015427 ACN122015427 ACN 122015427ACN-122015427-A

Abstract

The invention discloses an oxygen-nitrogen liquid conversion and energy storage system of an air separation device under peak-valley electricity conditions, which relates to the technical field of gas separation and comprises a nitrogen compression system, a liquid oxygen vaporization system, an oxygen liquefaction system, a solid-state bed energy storage system, a nitrogen circulation refrigerating system and a control unit, wherein the nitrogen compression system comprises a nitrogen compressor, the liquid oxygen vaporization system comprises a vaporization heat exchanger, a liquid oxygen pump, a liquid nitrogen throttle valve and a liquid nitrogen vacuum tank, the oxygen liquefaction system comprises a liquefaction heat exchanger, a liquid nitrogen pump, a nitrogen expander, the liquid oxygen throttle valve and the liquid oxygen vacuum tank, the solid-state bed energy storage system comprises a solid-state bed regenerator and a nitrogen circulation fan, the nitrogen circulation refrigerating system comprises a circulation nitrogen compressor, a nitrogen pressurization expander pressurization section and a nitrogen pressurization expander expansion section, and the control unit. According to the invention, the oxygen liquefaction and solid-state bed energy storage system is started in the peak electricity period to recover surplus oxygen, and the nitrogen compression, the liquid oxygen vaporization and the solid-state bed energy storage system release and store oxygen in the valley electricity period, so that the synergistic capability of the air and a downstream air utilization device is improved, and the energy efficient utilization and the stable operation of the system are realized.

Inventors

LI GUIQUAN
SHEN WEI
HAO SHAOHUA
ZHANG YUZHE
JING CHAO
HUANG XUANXU
HUANG YIHUI

Assignees

盈德气体工程(浙江)有限公司

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (9)

1. An oxygen-nitrogen liquid conversion and energy storage system of an air separation device under peak-valley electricity conditions, which is characterized by comprising: a nitrogen compression system including a Nitrogen Compressor (NC); The liquid oxygen vaporization system comprises a vaporization heat exchanger (EVAEH), a liquid Oxygen Pump (OP), a liquid nitrogen throttle valve (NV) and a liquid nitrogen vacuum tank (NT); an oxygen liquefaction system comprising a liquefaction heat exchanger (CONEH), a liquid Nitrogen Pump (NP), a nitrogen Expander (ET), a liquid oxygen throttle valve (OV) and a liquid oxygen vacuum tank (OT); A solid bed energy storage system comprising a solid bed regenerator (CSD) and a nitrogen recycle blower (NF); the nitrogen circulating refrigeration system comprises a circulating nitrogen compressor (RNC), a nitrogen booster expander booster section (ETC) and a nitrogen booster expander expansion section (ET); And the control unit is used for controlling each system to alternately operate in the peak electricity period and the valley electricity period according to the peak-valley electricity price signal and the historical oxygen supply and demand data.
2. The oxygen-nitrogen liquid conversion and energy storage system of an air separation plant under peak-to-valley electrical conditions of claim 1, wherein said Nitrogen Compressor (NC) is connected to a vaporization heat exchanger (EVAEH); the vaporizing heat exchanger (EVAEH) is connected with a liquid nitrogen throttle valve (NV), one path of the valve flows back to the vaporizing heat exchanger, and the other path of the valve is connected with a liquid nitrogen vacuum tank (NT); The liquid nitrogen vacuum tank (NT) is connected with a liquid Nitrogen Pump (NP).
3. The oxygen-nitrogen liquid conversion and energy storage system of an air separation plant under peak-to-valley electrical conditions of claim 2, wherein said liquid Nitrogen Pump (NP) is connected to a liquefaction heat exchanger (CONEH); The liquefying heat exchanger (CONEH) is connected with a nitrogen Expander (ET), and an outlet of the expander flows back to the liquefying heat exchanger; the liquefaction heat exchanger (CONEH) is connected with a liquid oxygen throttle valve (OV); the liquid oxygen throttle valve (OV) is connected with the liquid oxygen vacuum tank (OT); The liquid oxygen vacuum tank (OT) is connected with a liquid Oxygen Pump (OP); The liquid Oxygen Pump (OP) is connected with the vaporization heat exchanger (EVAEH).
4. A system for converting and storing oxygen and nitrogen liquids in an air separation unit under peak-to-valley electrical conditions according to claim 3, wherein said liquefaction heat exchanger (CONEH) is connected to a Recycle Nitrogen Compressor (RNC), said Recycle Nitrogen Compressor (RNC) is connected to a nitrogen booster expander booster stage (ETC), said nitrogen booster expander booster stage (ETC) is connected to a liquefaction heat exchanger CONEH, said liquefaction heat exchanger (CONEH) is connected to a nitrogen booster expander stage (ET), said nitrogen booster expander stage (ET) is in turn connected to a liquefaction heat exchanger (CONEH).
5. The oxygen-nitrogen liquid conversion and energy storage system of an air separation plant under peak-to-valley electricity conditions according to claim 4, wherein said nitrogen gas circulation fan (NF) is provided with two independent circulation paths and is controlled by switching through a valve, wherein: In the first path, an outlet of the nitrogen circulating fan (NF) is connected with a cold end inlet of the solid-state bed regenerator (CSD), the cold end outlet of the solid-state bed regenerator (CSD) is connected with a nitrogen channel inlet of the vaporization heat exchanger (EVAEH), and nitrogen after the release of cold energy is returned to a normal-pressure nitrogen pipe network; in the second path, the outlet of the nitrogen circulating fan (NF) is connected with the inlet of the nitrogen precooling channel of the liquefaction heat exchanger (CONEH), and cooled nitrogen enters the solid-state bed regenerator (CSD) for cold energy storage and then returns to the normal-pressure nitrogen pipe network.
6. The air separation plant oxygen nitrogen liquid conversion and storage system under peak to valley electrical conditions of claim 5, further comprising: the data acquisition module is used for acquiring oxygen output, liquid oxygen storage capacity, downstream gas load, pipe network pressure, temperature and time-of-use electricity price signals in real time; the historical database is used for storing oxygen supply and demand fluctuation data, system operation energy efficiency data and operation strategy records corresponding to electricity price time periods in at least one year; and the prediction analysis module adopts a time sequence analysis and machine learning algorithm, predicts oxygen demand trend, electricity price time period change and system optimal energy storage/release strategy within at least 24 hours to one week in the future based on historical data and real-time acquisition data, and outputs control advice to the control unit.
7. The oxygen-nitrogen liquid conversion and energy storage system of the air separation device under the peak-valley electricity condition according to claim 6, wherein the control unit dynamically adjusts the rotating speeds of the liquid Oxygen Pump (OP) and the liquid Nitrogen Pump (NP), the opening degrees of the liquid oxygen throttle valve (OV) and the liquid nitrogen throttle valve (NV), the operating frequency of the Nitrogen Compressor (NC), and the start-stop and wind of the nitrogen circulating fan (NF) according to the control proposal output by the prediction analysis module.
8. The oxygen-nitrogen liquid conversion and energy storage system of the air separation plant under peak-to-valley electrical conditions of claim 6, wherein during operation of said control unit: During peak electricity period, starting an oxygen liquefying system and a solid-state bed energy storage system, cooling and liquefying surplus oxygen generated by an air separator through a liquefying heat exchanger (CONEH), storing the liquefied surplus oxygen in a liquid oxygen vacuum tank (OT), and simultaneously storing cold energy in a solid-state bed cold accumulator (CSD) through a nitrogen circulating fan (NF); during the valley period, the nitrogen compression system and the liquid oxygen vaporization system are started, stored liquid oxygen is pressurized by a liquid Oxygen Pump (OP) and then is sent into a vaporization heat exchanger (EVAEH) to be vaporized, the liquid oxygen is supplemented to a low-pressure oxygen pipe network, and simultaneously, a solid-state bed regenerator (CSD) is utilized to release cold energy to assist in vaporization.
9. The air separation plant oxygen-nitrogen liquid conversion and energy storage system under peak-valley electricity conditions according to claim 8, further comprising comparing analysis based on historical data, automatically comparing data differences in oxygen recovery rate, energy consumption and air supply stability of the current period and the historical period after each operation period, and dynamically adjusting the residual threshold of oxygen for starting liquefaction, the timing and flow rate of vaporization release and the cold distribution proportion of a solid state bed regenerator (CSD) in the next period by combining the output of the predictive analysis module.

Description

Oxygen-nitrogen liquid conversion and energy storage system of air separation device under peak-valley electricity condition Technical Field The invention relates to the technical field of gas separation, in particular to an oxygen-nitrogen liquid conversion and energy storage system of an air separation device under peak-valley electricity conditions. Background In the prior art, the air separation device has the following defects when running under the fluctuation condition of peak-valley electricity price: and in the peak electricity period, oxygen is discharged, the load of a downstream gas utilization device is reduced, even the downstream gas utilization device is stopped, the oxygen produced by the air separation device cannot be consumed, and only the oxygen can be discharged, so that resource waste and energy efficiency reduction are caused. The air supply is insufficient in the valley electricity period, the downstream air consumption requirement is greatly improved, and even if the air separation device runs at full load, the air consumption requirement is still difficult to meet, so that the production stability is restricted. The operation flexibility is insufficient, the air separation device is difficult to start and stop, the response of large-amplitude load fluctuation is inflexible, and the air separation device cannot be effectively matched with the downstream gas demand. Disclosure of Invention Aiming at the technical problems, the technical scheme adopted by the invention is an oxygen-nitrogen liquid conversion and energy storage system of an air separation device under peak-valley electricity conditions, comprising: A nitrogen compression system comprising a nitrogen compressor; the liquid oxygen vaporization system comprises a vaporization heat exchanger, a liquid oxygen pump, a liquid nitrogen throttle valve and a liquid nitrogen vacuum tank; The oxygen liquefying system comprises a liquefying heat exchanger, a liquid nitrogen pump, a nitrogen expander, a liquid oxygen throttle valve and a liquid oxygen vacuum tank; The solid-state bed energy storage system comprises a solid-state bed regenerator and a nitrogen circulating fan; The nitrogen circulating refrigeration system comprises a circulating nitrogen compressor, a nitrogen booster expander booster section and a nitrogen booster expander expansion section; And the control unit is used for controlling each system to alternately operate in the peak electricity period and the valley electricity period according to the peak-valley electricity price signal and the historical oxygen supply and demand data. Preferably, the nitrogen compressor is connected with the vaporization heat exchanger; The vaporization heat exchanger is connected with a liquid nitrogen throttle valve, one path of the valve flows back to the vaporization heat exchanger, and the other path of the valve is connected to a liquid nitrogen vacuum tank; The liquid nitrogen vacuum tank is connected with a liquid nitrogen pump. Preferably, the liquid nitrogen pump is connected with the liquefaction heat exchanger; The liquefying heat exchanger is connected with the nitrogen expander, and the outlet of the expander flows back to the liquefying heat exchanger; the liquefying heat exchanger is connected with a liquid oxygen throttle valve; The liquid oxygen throttle valve is connected with the liquid oxygen vacuum tank; The liquid oxygen vacuum tank is connected with a liquid oxygen pump; The liquid oxygen pump is connected with the vaporization heat exchanger. Preferably, the liquefaction heat exchanger is connected with a circulating nitrogen compressor, the circulating nitrogen compressor is connected with a nitrogen booster expander booster section, the nitrogen booster expander booster section is connected with the liquefaction heat exchanger CONEH, the liquefaction heat exchanger is connected with a nitrogen booster expander expansion section, and the nitrogen booster expander expansion section is connected with the liquefaction heat exchanger. Preferably, the nitrogen gas circulating fan is provided with two independent circulating paths and is controlled by switching through a valve, wherein: In the first path, the outlet of the nitrogen circulating fan is connected with the cold end inlet of the solid-state bed regenerator, the cold end outlet of the solid-state bed regenerator is connected with the nitrogen channel inlet of the vaporization heat exchanger, and nitrogen after the release of cold energy is returned to the normal-pressure nitrogen pipe network; In the second path, the outlet of the nitrogen circulating fan is connected with the inlet of the nitrogen precooling channel of the liquefaction heat exchanger, cooled nitrogen enters the solid-state bed regenerator for cold energy storage, and then returns to the normal-pressure nitrogen pipe network. Preferably, the method further comprises: the data acquisition module is used for acquiring oxygen output, li