Air separation supercharger system capable of stably conveying compressed air

Abstract

The invention relates to the technical field of air separation superchargers, in particular to an air separation supercharger system capable of stably conveying compressed air, which comprises a self-cleaning air filter, an air compressor, a pre-cooling system, a molecular sieve, an expansion machine, a supercharger, a user module II, a plate heat exchanger, a cold box, a nitrogen compressor, a storage tank and a user module I, the self-cleaning air filter is used for removing dust and other mechanical impurities in air, the air compressor is used for pressurizing the filtered air, the pre-cooling system is used for pre-cooling the pressurized air, and the molecular sieve is used for adsorbing carbon dioxide, hydrocarbon and moisture in the pre-cooled air; the expansion machine is used for expanding the adsorbed gas, the supercharger is used for supercharging the adsorbed gas, and the problems that an existing air separation supercharger system is high in consumption cost, high in maintenance cost and large in air consumption are solved.

Description

Technical Field

[0001] The invention relates to the technical field of air separation booster, and in particular to an air separation booster system for stably conveying compressed air. Background Art

[0002] The air separation booster system compresses the air purified by the molecular sieve purifier (adsorbing carbon dioxide, hydrocarbons and moisture in the air). The conventional air separation process air enters the air separation expander system and plate heat exchange system after being processed by the booster.

[0003] Compressed air is usually used in chemical plants for medium purging and instrumentation. Since chemical plants require stable and reliable compressed air and require air purification, chemical plants usually add new air compressors to ensure the reliability of compressed air pipelines. To ensure reliability, the number of online and standby air compressors in most chemical plants is 2:1, which leads to high project investment. High-speed rotating equipment also has operation and maintenance operations and status maintenance, resulting in low production efficiency and high costs. For this reason, we propose an air separation booster system that stably delivers compressed air. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art and to propose an air separation booster system for stably delivering compressed air. The air separation booster system for stably delivering compressed air solves the problems of high consumption cost, high maintenance cost and high air consumption of the existing air separation booster system.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An air separation booster system for stably delivering compressed air, comprising a self-cleaning air filter, an air compressor, a precooling system, a molecular sieve, an expander, a booster, a user module 2, a plate heat exchanger, a cold box, a nitrogen compressor, a storage tank and a user module 1, wherein the self-cleaning air filter is used to remove dust and other mechanical impurities in the air, the air compressor is used to pressurize the filtered air, the precooling system is used to precool the pressurized gas, the molecular sieve is used to adsorb carbon dioxide, hydrocarbons and moisture in the precooled air, the expander is used to expand the adsorbed gas, the booster is used to pressurize the adsorbed gas, the user module 2 is used to receive the air compressed by the booster, the plate heat exchanger is used to perform heat exchange operations on the expanded or pressurized gas, the cold box is used to collect the gas after heat exchange, the nitrogen compressor is used to nitrogen pressurize the gas collected by the cold box, the storage tank is used to store liquid oxygen, liquid nitrogen and liquid ammonia in the cold box, and the user module 1 is used to receive gas.

[0007] Through the above technical scheme, the raw air from the air is filtered through a self-cleaning air filter to remove dust and other mechanical impurities. The filtered air enters the air compressor, is compressed to a certain pressure by the air compressor, and then enters the precooling system for cooling. The air compressed by the air compressor passes through the air cooling tower of the precooling system from bottom to top, and is cleaned while being cooled. The air cooled by the precooling system enters the molecular sieve purifier for switching, and carbon dioxide, hydrocarbons and moisture in the air are adsorbed. The purified air is divided into two streams, one of which goes to the booster, and after being processed by the booster, the other enters the plate heat exchanger for heat exchange with liquid oxygen and liquid nitrogen. After the high-pressure air is liquefied, it is expanded by a liquid expander or throttled and reduced in pressure by a high-pressure throttle valve, and then enters the lower tower of the cold box to participate in distillation.

[0008] Preferably, the molecular sieve is used as a molecular sieve purifier, and the number of the molecular sieve purifiers is two.

[0009] Through the above technical solution, the molecular sieve purifier is used in two switching modes, one of which is working while the other is regenerating.

[0010] Preferably, the working states of the supercharger are supercharging by the first-stage impeller of the supercharger, supercharging by the third-stage impeller of the supercharger, and supercharging by the fifth-stage impeller of the supercharger.

[0011] Through the above technical solution, the first-stage impeller of the booster is used as compressed air for the chemical plant after boosting, and the parameters match the design operating pressure and flow of the compressed air; the third-stage impeller is used to meet the peak demand of the chemical plant's compressed air after boosting; and the fifth-stage impeller is used as emergency security compressed air for the chemical plant after boosting.

[0012] Preferably, it also includes a compressed air delivery pressure regulating station and a compressed air delivery metering station, and the compressed air delivery pressure regulating station includes an emergency shut-off valve with pressure regulation, pressure monitoring, flow monitoring, temperature monitoring, a one-way valve, and an isolation valve.

[0013] Through the above technical solution, the user's compressed air demand and on-site pressure, flow, temperature and other parameters are monitored to control the corresponding regulating valves at the first, third and fifth stage outlets of the booster system, thereby achieving the function of stable compressed air delivery. Figure 3 The conveying flow chart of the booster system mainly includes the following three working conditions:

[0014] (1) Design conditions: The chemical industry has a relatively stable demand for air separation products, and the pressure and flow fluctuations are relatively low. The compressed air pressurized by the first-stage impeller of the booster system can ensure stable compressed air supply (design conditions: pressure is 0.9MPaG, flow is 20000Nm3 / h).

[0015] (2) Peak operating conditions: If the compressed air reaches a peak value of 30,000 Nm3 / h, the compressed air boosted by the third-stage impeller of the air separation booster system can be used to supplement the peak amount of compressed air in the chemical plant of 10,000 Nm3 / h through the compressed air pressure regulating device regulating valve to meet the production needs of the chemical plant.

[0016] (3) Emergency conditions: After the fifth-stage impeller of the air separation booster system is pressurized (pressure is 6.05MPaG, maximum flow rate is 118700Nm3 / h), a 645m3, 4.2MPaG compressed air buffer spherical tank is pressurized. When the air separation equipment is shut down in an emergency, the air stored in the spherical tank meets the safety compressed air consumption of the chemical user: 20000Nm3 / h, which lasts for 1 hour. The specific calculation is as follows:

[0017]

[0018] Where Vwater-spherical tank water volume (m3);

[0019] ΔP-ΔP=10*(P1-P2);

[0020] P1 - Maximum working pressure of storage tank (MPa);

[0021] P2 - user operating pressure (MPa);

[0022] T0 - standard state temperature, T0 = 273K;

[0023] T2-Gas temperature in the tank, can be ambient temperature (K)

[0024] Preferably, the precooling system adopts an air cooling tower.

[0025] Through the above technical solution, the water supply of the air cooling tower of the precooling system is divided into two sections, the lower section of the cooling tower uses normal temperature circulating water, and the upper section of the cooling tower uses low temperature water cooled by the water cooling tower.

[0026] In summary, the present invention produces compressed air that meets the production needs of chemical plants through an air separation booster system that stably delivers compressed air, and then uses a compressed air delivery pressure regulating station to meet the gas demand under different working conditions. The compressed air delivery metering station is optimized with high precision and stable delivery pressure, thereby achieving efficient use of the air separation booster system that stably delivers compressed air to deliver stable compressed air. On the one hand, an efficient and stable compressed air system for chemical plants is established, and on the other hand, the investment in the air compression system is saved and the cost of operation and maintenance is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the process structure of an air separation booster system for stably delivering compressed air according to the present invention;

[0028] Figure 2 A schematic diagram of the process flow of the air separation booster system for stably delivering compressed air according to the present invention;

[0029] Figure 3 The present invention is a schematic diagram of the structure of the delivery process of the air separation booster system for stably delivering compressed air. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] Reference Figure 1-Figure 3 , an air separation booster system for stably delivering compressed air, including a self-cleaning air filter, an air compressor, a precooling system, a molecular sieve, an expander, a booster, a user module 2, a plate heat exchanger, a cold box, a nitrogen compressor, a storage tank and a user module 1, the self-cleaning air filter is used to remove dust and other mechanical impurities in the air, the air compressor is used to pressurize the filtered air, the precooling system is used to precool the pressurized gas, the molecular sieve is used to adsorb carbon dioxide, hydrocarbons and moisture in the precooled air, the expander It is used to expand the adsorbed gas, the booster is used to pressurize the adsorbed gas, the user module two is used to receive the air compressed by the booster, the plate heat exchanger is used to perform heat exchange operations on the expanded or pressurized gas, the cold box is used to collect the gas after heat exchange, the nitrogen compressor is used to nitrogen pressurize the gas collected by the cold box, the storage tank is used to store liquid oxygen, liquid nitrogen and liquid ammonia in the cold box, the user module one is used to receive gas, the molecular sieve adopts a molecular sieve purifier, the number of molecular sieve purifiers is two, and the pre-cooling system adopts an air cooling tower.

[0032] In this embodiment, the raw air from the air is filtered through a self-cleaning air filter to remove dust and other mechanical impurities. The filtered air enters the air compressor, is compressed to a certain pressure by the air compressor, and then enters the precooling system for cooling. The air compressed by the air compressor passes through the air cooling tower of the precooling system from bottom to top, and is cleaned while being cooled. The water supply of the air cooling tower of the precooling system is divided into two sections. The lower section of the cooling tower uses normal temperature circulating water, and the upper section of the cooling tower uses low-temperature water cooled by a water cooling tower. The air cooled by the precooling system enters the molecular sieve purifier that is switched to use, and the carbon dioxide, hydrocarbons and moisture in the air are adsorbed. The purified air The air is divided into two streams. One stream goes to the booster compressor. After being processed by the booster compressor, a part of the air is pressurized by the first-stage impeller of the booster compressor and then extracted as compressed air for the chemical plant. A part of the air is extracted from the third stage of the booster compressor and divided into two streams. One stream is throttled by the compressed air pressure regulating station to meet the peak demand of compressed air in the chemical plant. The other stream is pressurized by the booster impeller of the expander and then enters the expansion impeller of the expander to expand, doing work externally and consuming its own internal energy. The expanded air is sent to the lower tower. The last part of the air continues to be pressurized by the fifth stage of the booster compressor as high-pressure air and is divided into two streams. One stream passes through the compressed air pressure regulating station as emergency security compressed air for the chemical plant.

[0033] The other stream enters the plate heat exchanger to exchange heat with liquid oxygen and liquid nitrogen. After the high-pressure air is liquefied, it is expanded by the liquid expander or throttled and depressurized by the high-pressure throttle valve before entering the lower tower of the cold box to participate in distillation.

[0034] Or another stream of air enters the plate heat exchanger, is cooled by the reflux gas and directly enters the lower tower of the cold box.

[0035] The working states of the supercharger are supercharged by the first-stage impeller of the supercharger, supercharged by the third-stage impeller of the supercharger, and supercharged by the fifth-stage impeller of the supercharger.

[0036] In this embodiment, the first-stage impeller of the booster is used as compressed air for the chemical plant after boosting, and the parameters match the design operating pressure and flow rate of the compressed air; the third-stage impeller is used to meet the peak demand of the chemical plant's compressed air after boosting; and the fifth-stage impeller is used as emergency security compressed air for the chemical plant after boosting.

[0037] The air separation booster system for stably delivering compressed air also includes a compressed air delivery pressure regulating station and a compressed air delivery metering station. The compressed air delivery pressure regulating station includes an emergency shut-off valve with pressure regulation, pressure monitoring, flow monitoring, temperature monitoring, a one-way valve, and an isolation valve.

[0038] In this embodiment, the user's demand for compressed air and on-site pressure, flow, temperature and other parameters are monitored to control the regulating valves corresponding to the first, third and fifth stage outlets of the booster system, thereby achieving the function of stable compressed air delivery. Figure 3 The conveying flow chart of the booster system mainly includes the following three working conditions:

[0039] (1) Design conditions: The chemical industry has a relatively stable demand for air separation products, and the pressure and flow fluctuations are relatively low. The compressed air pressurized by the first-stage impeller of the booster system can ensure stable compressed air supply (design conditions: pressure is 0.9MPaG, flow is 20000Nm3 / h).

[0040] (2) Peak operating conditions: If the compressed air reaches a peak value of 30,000 Nm3 / h, the compressed air boosted by the third-stage impeller of the air separation booster system can be used to supplement the peak amount of compressed air in the chemical plant of 10,000 Nm3 / h through the compressed air pressure regulating device regulating valve to meet the production needs of the chemical plant.

[0041] (3) Emergency conditions: After the fifth-stage impeller of the air separation booster system is pressurized (pressure is 6.05MPaG, maximum flow rate is 118700Nm3 / h), a 645m3, 4.2MPaG compressed air buffer spherical tank is pressurized. When the air separation equipment is shut down in an emergency, the air stored in the spherical tank meets the safety compressed air consumption of the chemical user: 20000Nm3 / h, which lasts for 1 hour. The specific calculation is as follows:

[0042]

[0043] Where Vwater-spherical tank water volume (m3);

[0044] ΔP-ΔP=10*(P1-P2);

[0045] P1 - Maximum working pressure of storage tank (MPa);

[0046] P2 - user operating pressure (MPa);

[0047] T0 - standard state temperature, T0 = 273K;

[0048] T2-gas temperature in the tank, which can be ambient temperature (K);

[0049] To ensure constant compressed air pressure, the pressure change rate is less than 200mbar / second. The accuracy error of metering selection is less than ±0.5%. At the same time, considering the hydraulic loss of the pipeline network, the user's metering facility uses a mass flow meter, which has small resistance loss and high metering accuracy, and can effectively reduce pipeline resistance loss;

[0050] The hydraulic loss of the pipe network and the selection parameters of the mass flow meter are shown in the following table:

[0051] Table 1 Hydraulic calculation of transmission and distribution pipelines

[0052]

[0053] Table 2 Mass flow meter selection parameters

[0054] Selection parameters Minimum Nominal value Maximum unit Design flow 2000 20000 30000 <![CDATA[Nm 3 / h]]> Flow rate 3.918 39.18 58.78 m / s Flow rate sensor 9.286 92.86 139.3 m / s Resistance loss 0.25 19.28 42.01 kPa Mass flow measurement error 1.24 0.25 0.25 ％ Reynolds number 350659 3506590 5259885

[0055] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An air separation booster system for stably delivering compressed air, characterized in that: include A self-cleaning air filter, which is used to remove dust and other mechanical impurities in the air; An air compressor, the air compressor is used to pressurize the filtered air; A precooling system, wherein the precooling system is used to precool the pressurized gas; Molecular sieve, the molecular sieve is used to adsorb carbon dioxide, hydrocarbons and moisture in the pre-cooled air; An expander, the expander is used to expand the adsorbed gas; A supercharger, the supercharger is used to pressurize the adsorbed gas; User module 2, the user module 2 is used to receive air compressed by the supercharger; A plate heat exchanger, wherein the plate heat exchanger is used to perform heat exchange operations on expanded or pressurized gas; A cold box, the cold box is used to collect the gas after heat exchange; A nitrogen compressor, which is used to nitrogen-compress the gas collected by the cold box; A storage tank, wherein the storage tank is used to store liquid oxygen, liquid nitrogen and liquid ammonia in the cold box; User module one, the user module one is used for receiving gas.

2. The air separation booster system for stably delivering compressed air according to claim 1, characterized in that: The molecular sieve adopts a molecular sieve purifier, and the number of the molecular sieve purifiers is two.

3. The air separation booster system for stably delivering compressed air according to claim 1, characterized in that: The working states of the supercharger are supercharging of the first-stage impeller of the supercharger, supercharging of the third-stage impeller of the supercharger and supercharging of the fifth-stage impeller of the supercharger.

4. The air separation booster system for stably delivering compressed air according to claim 1, characterized in that: It also includes a compressed air delivery pressure regulating station and a compressed air delivery metering station. The compressed air delivery pressure regulating station includes an emergency shut-off valve with pressure regulation, pressure monitoring, flow monitoring, temperature monitoring, a one-way valve, and an isolation valve.

5. The air separation booster system for stably delivering compressed air according to claim 1, characterized in that: The precooling system adopts an air cooling tower.

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