A drying air production system with variable temperature and pressure swing adsorption and its operation method

Abstract

The present invention discloses a drying air production system with variable temperature and pressure swing adsorption and its operation method, which relates to the technical field of air drying. It is characterized in that it includes a condensation dehumidification subsystem, an air compression subsystem and a pressure swing adsorption subsystem. Among them, the condensation dehumidification subsystem includes an inlet filter, a surface cooler and a gas-water separator connected end to end in sequence through an air duct; the air compression subsystem includes a blower and a post-cooler connected end to end in sequence through an air duct; the pressure swing adsorption subsystem includes a first dehumidifier, a second dehumidifier, a first adsorption tower, a second adsorption tower and a regeneration fan. The present invention reduces the adsorption pressure and regeneration temperature of the system while meeting the requirement of efficiently and stably producing dry air with a dew point temperature as low as -70°C, effectively reducing the operating energy consumption and reducing the operation and maintenance costs. When the system is regenerated, the waste heat of the regeneration exhaust gas and the heating of a high-temperature heat pump / solar collector are used to further improve the energy utilization efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of air drying, and particularly to a drying air production system with variable temperature and pressure swing adsorption and its operation method. Background Art

[0002] In scenarios such as precision instruments, the electronics industry, cryogenic industries, and raw gas purification, there are strict requirements for the moisture content of air. For example, in the liquid injection and formation workshops of lithium batteries, the dew point temperature of the ambient air is required to reach below -40°C, and some precision workshops or laboratories have even higher requirements for the moisture content of dry air. If the moisture content of the air exceeds the standard, it may lead to inaccurate instrument operation or unqualified product quality, causing serious economic losses.

[0003] For industrial and experimental application scenarios that require extremely dry air, the currently commonly used dehumidification methods include refrigeration dehumidification and adsorption dehumidification. Refrigeration dehumidification requires reducing the air temperature below the condensation temperature corresponding to the required moisture content of the dry air. For dry air with a dew point below -40°C, deep cooling is often required, and reheating of the air is also needed to meet the air supply requirements. The process is complex and wastes a large amount of energy. Therefore, in practical applications, refrigeration dehumidification is often used for preliminary drying, and then adsorption dehumidification is used for further drying. Adsorption dehumidification includes liquid adsorption and solid adsorption dehumidification. The former is often used in comfort dehumidification systems, and it is difficult to obtain extremely dry air, and there are problems of liquid droplet entrainment and corrosion. Solid adsorption dehumidification is usually achieved based on dehumidification wheels, adsorption towers, or dehumidification heat exchangers, and variable temperature or pressure swing adsorption technology can be used to meet the requirements of deep dehumidification. However, in pure variable temperature adsorption dehumidification, the heating regeneration process has high energy consumption, long operation time, and large initial investment in the system; in pressure swing adsorption dehumidification, the adsorption pressure is often as high as several to dozens of atmospheres, the energy consumption of the air compression process is huge, and the system switching period is short, which poses high requirements on the reliability of valves, control systems, and desiccants.

[0004] Therefore, the technical personnel in this field are committed to developing a drying air production system with variable temperature and pressure swing adsorption and its operation method, which combines multi-stage dehumidification with the principle of variable temperature and pressure swing solid adsorption dehumidification, can significantly reduce the system operation energy consumption, improve the dehumidification efficiency and energy utilization efficiency, and enable the system to operate efficiently and stably. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to improve the energy utilization efficiency during the production of dry air.

[0006] To achieve the above object, the present invention provides a drying air production system with variable temperature and pressure swing adsorption, which is characterized by comprising a condensation dehumidification subsystem, an air compression subsystem and a pressure swing adsorption subsystem. Among them, the condensation dehumidification subsystem includes an inlet filter, a surface cooler and a gas-water separator connected end to end in sequence through an air duct. The air compression subsystem includes a blower and a post-cooler connected end to end in sequence through an air duct. The pressure swing adsorption subsystem includes a first dehumidifier, a second dehumidifier, a first adsorption tower, a second adsorption tower and a regeneration blower. The post-cooler is connected to the dehumidification inlet of the first dehumidifier through a first inlet gas valve. The dehumidification outlet of the first dehumidifier is connected to the dehumidification inlet of the second dehumidifier. The dehumidification outlet of the second dehumidifier is connected to the first port of the first adsorption tower through a first one-way gas valve. The dehumidification outlet of the second dehumidifier is connected to the first port of the second adsorption tower through a fifth one-way gas valve. The second port of the first adsorption tower is connected to the inlet of a product gas valve through a fourth one-way gas valve. The second port of the second adsorption tower is connected to the inlet of the product gas valve through an eighth one-way gas valve. The inlet of the product gas valve is also connected to the inlet of a regeneration pressure reducing valve. The regeneration pressure reducing valve is connected to the inlet of the regeneration blower through a regeneration heat exchange valve, a first regenerator, a second regenerator, an electric heater and a heating gas valve in sequence. The regeneration pressure reducing valve is also directly connected to the inlet of the regeneration blower through a cold blow gas valve. The outlet of the regeneration blower is connected to the second port of the second adsorption tower through a seventh one-way gas valve. The first port of the second adsorption tower is connected to the regeneration inlet of the second dehumidifier through a sixth one-way gas valve. The outlet of the regeneration blower is also connected to the second port of the first adsorption tower through a third one-way gas valve. The first port of the first adsorption tower is connected to the regeneration inlet of the second dehumidifier through a second one-way gas valve. The regeneration outlet of the second dehumidifier is connected to the regeneration inlet of the first dehumidifier after passing through the second regenerator. The regeneration outlet of the first dehumidifier is connected to the external environment after passing through a regeneration exhaust valve and the first regenerator in sequence.

[0007] Further, the outlet of the product gas valve is connected to the inlet of an outlet filter. There is also an air duct between the inlet of the first inlet gas valve and the dehumidification inlet of the second dehumidifier. A second inlet gas valve is provided on the air duct. A bypass exhaust valve is also provided between the regeneration outlet of the second dehumidifier and the second regenerator.

[0008] Further, the pressure swing adsorption subsystem further includes a regeneration hot water tank. The hot water outlet of the regeneration hot water tank is connected to the inlet of the regeneration hot water pipe of the second dehumidifier. The outlet of the regeneration hot water pipe of the second dehumidifier is connected to the inlet of the regeneration hot water pipe of the first dehumidifier. The outlet of the regeneration hot water pipe of the first dehumidifier is connected to the hot water inlet of the regeneration hot water tank.

[0009] Further, the pressure swing adsorption subsystem further includes a heating device, which is connected to the regenerated hot water tank, and the heating device is a solar collector or a high-temperature heat pump.

[0010] Further, both the first dehumidifier and the second dehumidifier contain two dehumidification heat exchangers, and the dehumidification heat exchanger is made by coating a molecular sieve desiccant on the surface of a finned-tube heat exchanger.

[0011] Further, the dry air production system further includes a chiller, and the chiller supplies water to the surface cooler, the aftercooler, the first dehumidifier, and the second dehumidifier through a chilled water pump.

[0012] Further, the desiccant in the first adsorption tower and the second adsorption tower is one or a combination of activated carbon, activated alumina, synthetic zeolite, and 13X molecular sieve.

[0013] An operation method of a dry air production system with temperature swing and pressure swing adsorption, characterized in that the operation method includes a dehumidification and regeneration mode, in which the first inlet gas valve, the first one-way gas valve, the fourth one-way gas valve, the product gas valve, the regeneration pressure reducing valve, the heat recovery gas valve, the heating gas valve, the sixth one-way gas valve, the seventh one-way gas valve, and the regeneration exhaust valve are in an open state; the second inlet gas valve, the second one-way gas valve, the third one-way gas valve, the fifth one-way gas valve, the eighth one-way gas valve, the cold purge gas valve, and the bypass exhaust valve are in a closed state.

[0014] Further, the operation method further includes a dehumidification and cold purge mode, in which the first inlet gas valve, the second inlet gas valve, the first one-way gas valve, the fourth one-way gas valve, the product gas valve, the regeneration pressure reducing valve, the cold purge gas valve, the sixth one-way gas valve, the seventh one-way gas valve, the bypass exhaust valve, and the regeneration exhaust valve are in an open state; the second one-way gas valve, the third one-way gas valve, the fifth one-way gas valve, the eighth one-way gas valve, the heat recovery gas valve, and the heating gas valve are in a closed state.

[0015] Further, after the dehumidification and regeneration mode and the dehumidification and cold purge mode, open the second one-way gas valve, the third one-way gas valve, the fifth one-way gas valve, and the eighth one-way gas valve, and close the first one-way gas valve, the fourth one-way gas valve, the sixth one-way gas valve, and the seventh one-way gas valve, so that the first adsorption tower enters the regeneration state and the second adsorption tower enters the dehumidification state, realizing continuous operation of the system.

[0016] Conventional deep dehumidification often employs single temperature swing or pressure swing adsorption dehumidification. The energy consumption during the heating regeneration or air compression process is huge, and the operating conditions are harsh, resulting in a high production cost of air with an extremely low dew point. The present invention introduces the principle of temperature swing and pressure swing adsorption, combines multi-stage dehumidification and staged series regeneration, significantly reduces the adsorption dehumidification load and energy loss, effectively reduces the operating temperature and pressure of the system. At the same time, the system further improves the energy utilization efficiency through the utilization of regeneration waste heat and the combination with high-temperature heat pumps / solar collectors. Temperature swing and pressure swing adsorption adsorbs at relatively high pressure and low temperature and regenerates at relatively low pressure and high temperature, avoiding the requirement for high temperature or high pressure in single temperature swing or pressure swing adsorption; at the same time, multi-stage dehumidification reduces the adsorption dehumidification load, and staged series regeneration helps to improve the regeneration effect; the regeneration temperature of the system is relatively low, so the regeneration waste heat can be utilized, and further combined with high-temperature heat pumps / solar collectors to reduce the regeneration energy consumption. When producing dry air with a dew point temperature as low as -70°C under the condition of efficient and stable production, the adsorption pressure and regeneration temperature of the system are reduced, effectively reducing the operating energy consumption. At the same time, multi-stage dehumidification and series regeneration reduce the adsorption dehumidification load and reduce the operation and maintenance costs. The utilization of regeneration exhaust waste heat and heating by high-temperature heat pumps / solar collectors during system regeneration further improves the energy utilization efficiency.

[0017] The following will further illustrate the concept, specific structure and technical effects of the present invention in conjunction with the accompanying drawings to fully understand the purpose, features and effects of the present invention. Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the working principle of the dehumidification and regeneration stage of a dry air production system with temperature swing and pressure swing adsorption according to a preferred embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the working principle of the dehumidification and cold blow stage of a dry air production system with temperature swing and pressure swing adsorption according to a preferred embodiment of the present invention;

[0020] Among them, 1 - condensation dehumidification subsystem, 2 - air compression subsystem, 3 - pressure swing adsorption subsystem, 4 - inlet filter, 5 - surface cooler, 6 - air-water separator, 7 - blower, 8 - aftercooler, 91 - first dehumidifier, 92 - second dehumidifier, 101 - first adsorption tower, 102 - second adsorption tower, 11 - outlet filter, 121 - first recuperator, 122 - second recuperator, 13 - electric heater, 14 - regeneration fan, 15 - regeneration hot water tank, 16 - heating equipment, 17 - chiller, 18 - chilled water pump, 191 - first inlet gas valve, 192 - second inlet gas valve, 201 - first one-way gas valve, 202 - second one-way gas valve, 203 - third one-way gas valve, 204 - fourth one-way gas valve, 205 - fifth one-way gas valve, 206 - sixth one-way gas valve, 207 - seventh one-way gas valve, 208 - eighth one-way gas valve, 21 - product gas valve, 22 - regeneration pressure reducing valve, 23 - recuperation gas valve, 24 - heating gas valve, 25 - cold blow gas valve, 26 - bypass exhaust valve, 27 - regeneration exhaust valve, 281 - first chilled water valve, 282 - second chilled water valve, 283 - third chilled water valve, 284 - fourth chilled water valve. Detailed implementation manners

[0021] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0022] In the drawings, components with the same structure are denoted by the same numeral labels, and components with similar structures or functions everywhere are denoted by similar numeral labels. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of some parts in the drawings is appropriately exaggerated.

[0023] As Figure 1As shown in the figure, a drying air production system and its operation method based on variable temperature and pressure swing adsorption according to the present invention include a condensation dehumidification subsystem 1, an air compression subsystem 2, a pressure swing adsorption subsystem 3, a chiller 17, and related pipelines and valves. Among them, the condensation dehumidification subsystem 1 includes an inlet filter 4, a surface cooler 5, and a gas-liquid separator 6 connected end to end in sequence through an air duct. The outlet of the gas-liquid separator 6 is connected to the inlet of a blower 7. The air compression subsystem 2 includes a blower 7 and a post-cooler 8 connected end to end in sequence through an air duct. The outlet of the post-cooler 8 is connected to the inlet of a first inlet gas valve 191. The pressure swing adsorption subsystem 3 includes a first inlet gas valve 191, a first dehumidifier 91, and a second dehumidifier 92 connected end to end in sequence through an air duct. The dehumidification outlet of the second dehumidifier 92 is connected to the first port of a first adsorption tower 101 through a first one-way gas valve 201, and the dehumidification outlet of the second dehumidifier 92 is connected to the first port of a second adsorption tower 102 through a fifth one-way gas valve 205. The second port of the first adsorption tower 101 is connected to the inlet of a product gas valve 21 through a fourth one-way gas valve 204, and the second port of the second adsorption tower 102 is connected to the inlet of the product gas valve 21 through an eighth one-way gas valve 208. The outlet of the product gas valve 21 is connected to the inlet of an outlet filter 11. The inlet of the product gas valve 21 is also connected to the inlet of a regeneration pressure reducing valve 22. The regeneration pressure reducing valve 22 is connected to the inlet of a regeneration blower 14 through a regeneration air valve 23, a first regenerator 121, a second regenerator 122, an electric heater 13, and a heating air valve 24 in sequence. The regeneration pressure reducing valve 22 is also directly connected to the inlet of the regeneration blower 14 through a cold blowing air valve 25. The outlet of the regeneration blower 14 is connected to the second port of the second adsorption tower 102 through a seventh one-way gas valve 207. The first port of the second adsorption tower 102 is connected to the regeneration inlet of the second dehumidifier 92 through a sixth one-way gas valve 206. The outlet of the regeneration blower 14 is also connected to the second port of the first adsorption tower 101 through a third one-way gas valve 203. The first port of the first adsorption tower 101 is connected to the regeneration inlet of the second dehumidifier 92 through a second one-way gas valve 202. The regeneration outlet of the second dehumidifier 92 is connected to the regeneration inlet of the first dehumidifier 91 after passing through the second regenerator 122. The regeneration outlet of the first dehumidifier 91 is connected to the external environment through a regeneration exhaust valve 27 and the first regenerator 121 in sequence.

[0024] In the pressure swing adsorption subsystem 3, there is also an air duct between the inlet of the first inlet gas valve 191 and the inlet of the second dehumidifier 92, and a second inlet gas valve 192 is provided on the air duct. A bypass exhaust valve 26 is provided between the outlet of the second dehumidifier 92 and the second regenerator 122. The opening degrees of both valves can be continuously adjusted between 0 - 100%, so as to realize the reasonable distribution of air volume among different pipelines to cope with different dehumidification loads under different working stages or changes in inlet conditions.

[0025] Due to the requirements of the first dehumidifier 91 and the second dehumidifier 92 for the regeneration heat source, the pressure swing adsorption subsystem 3 further includes a regeneration hot water tank 15 and a heating device 16. The heating device 16 is a solar collector or a high-temperature heat pump. The hot water at 80-90 °C in the regeneration hot water tank 15 is supplied by the heating device 16. Compared with the regeneration of a rotary wheel or a packed bed dehumidifier that requires hot air at a temperature above 120 °C, its energy-saving and environmental protection effects are remarkable. The hot water outlet of the regeneration hot water tank 15 is connected to the inlet of the regeneration hot water pipe of the second dehumidifier 92. The outlet of the regeneration hot water pipe of the second dehumidifier 92 is connected to the inlet of the regeneration hot water pipe of the first dehumidifier 91. The outlet of the regeneration hot water pipe of the first dehumidifier 91 is connected to the hot water inlet of the regeneration hot water tank 15.

[0026] Both the first dehumidifier 91 and the second dehumidifier 92 in the pressure swing adsorption subsystem 3 each have two air inlets and two air outlets, which are the dehumidification inlets and outlets and the regeneration inlets and outlets respectively. Each dehumidifier includes two dehumidification heat exchanger components of the same specification, enabling the dehumidifier to carry out the dehumidification and regeneration processes simultaneously. The dehumidifier is connected to the regeneration hot water tank 15 through a regeneration hot water pipe and is connected to the chiller 17 through a dehumidification cold water pipe. The dehumidification heat exchanger is made by coating a molecular sieve desiccant on the surface of a finned tube heat exchanger and has high heat and mass transfer performance. The desiccant attached to the outside of the tube and the fins has good water adsorption capacity. When dehumidifying, the chilled water flowing in the copper tube provides cold energy to prevent the temperature of the desiccant from rising due to the adsorption heat generated during the adsorption process and reducing the adsorption capacity. When regenerating, the hot water flowing in the copper tube serves as a heat source to provide desorption heat, which helps to maintain the regeneration temperature and strengthen the regeneration effect.

[0027] In addition, the desiccant in the first adsorption tower 101 and the second adsorption tower 102 in the pressure swing adsorption subsystem 3 is one or a combination of activated carbon, activated alumina, synthetic zeolite, 13X molecular sieve, etc. The adsorption tower is a vertical packed adsorption tower or a vertical radial flow adsorption tower. Preferably, the adsorption tower can also be equipped with a desiccant pressing device to extend the service life of the desiccant.

[0028] The chiller 17 in the system supplies low-temperature chilled water to the surface cooler 5, the after-cooler 8, the first dehumidifier 91 and the second dehumidifier 92 through the chilled water pump 18 and the first chilled water valve 281, the second chilled water valve 282, the third chilled water valve 283, and the fourth chilled water valve 284, respectively realizing the functions of condensation dehumidification, air cooling, and two-stage dehumidification and cooling, with a compact structural layout.

[0029] The operation method of this system includes a dehumidification and regeneration stage and a dehumidification and cold blow stage; the switching between different working stages is achieved by adjusting the states of the first inlet air valve 191, the second inlet air valve 192, the first one-way air valve 201, the second one-way air valve 202, the third one-way air valve 203, the fourth one-way air valve 204, the fifth one-way air valve 205, the sixth one-way air valve 206, the seventh one-way air valve 207, the eighth one-way air valve 208, the cold blow air valve 25, the heat recovery air valve 23, the heating air valve 24, the bypass exhaust valve 26, and the regeneration exhaust valve 27.

[0030] As Figure 1 shown, for the dehumidification and regeneration stage: open the first inlet air valve 191, the first one-way air valve 201, the fourth one-way air valve 204, the product air valve 21, the regeneration pressure reducing valve 22, the heat recovery air valve 23, the heating air valve 24, the sixth one-way air valve 206, the seventh one-way air valve 207, and the regeneration exhaust valve 27, and close the other valves. The inlet air first enters the condensation dehumidification subsystem 1, is filtered by the inlet filter 4 and condensed and dehumidified by the surface cooler 5 to achieve preliminary purification and drying, and the dew point temperature is reduced to slightly higher than the inlet temperature of the chilled water; then the air enters the compressed air subsystem 2, is pressurized by the blower 7 and then cooled by the aftercooler 8 to the inlet temperature of the blower 7; subsequently, the air enters the pressure swing adsorption subsystem 3, flows through the first dehumidifier 91 and the second dehumidifier 92 successively after flowing through the first inlet air valve 191, and is further dehumidified by the dehumidification heat exchanger therein. The dew point temperature of the air is reduced to below -30°C, and then flows into the first adsorption tower 101 after passing through the first one-way air valve 201, and is deeply dried by the desiccant in the first adsorption tower 101, and the dew point temperature is reduced to -70°C; after the dried air flows through the fourth one-way air valve 204 behind the tower, most of the gas flows through the product air valve 21 and the outlet filter 11 to become extremely dry clean product air, while a small part of the air passes through the regeneration pressure reducing valve 22 to reduce the pressure, and then continues to flow through the heat recovery air valve 23, the first heat recovery unit 121, the second heat recovery unit 122, and the electric heater 13 in sequence, and the temperature rises to above 100 degrees Celsius, and is introduced into the second adsorption tower 102 by the regeneration fan 14 through the heating air valve 24 to regenerate the second adsorption tower 102 under low pressure and high temperature conditions; due to the multi-stage dehumidification of the system, the dehumidification load of the adsorption tower is extremely small, so the moisture content of the regeneration gas is still very low and the temperature is still relatively high. Let the regeneration gas continue to flow through the second dehumidifier 92, the second heat recovery unit 122, the first dehumidifier 91, the regeneration exhaust valve 27, and the first heat recovery unit 121 in sequence to realize the regeneration of the dehumidifier and the utilization of the waste heat of the regeneration gas, and then discharge it to the environment.

[0031] After the dehumidification and regeneration stage is completed, since the adsorption tower uses temperature and pressure swing adsorption, the temperature of the desiccant in the regeneration tower is significantly higher than the inlet temperature of the dehumidified air, and there is still a small amount of moisture remaining in the tower that has not been carried away. If the regeneration tower is directly switched to the dehumidification state, it is not conducive to the deep dehumidification of the air. Therefore, a small amount of normal-temperature dry product gas needs to be introduced for cold blowing to reduce the temperature of the desiccant and carry away the remaining moisture to restore its dehumidification ability.

[0032] As Figure 2 shown, for the dehumidification cold blowing stage: Open the first inlet gas valve 191, the second inlet gas valve 192, the first one-way gas valve 201, the fourth one-way gas valve 204, the product gas valve 21, the regeneration pressure reducing valve 22, the cold blowing gas valve 25, the sixth one-way gas valve 206, the seventh one-way gas valve 207, the bypass exhaust valve 26, and the regeneration exhaust valve 27, and close the rest of the valves. The inlet air first enters the condensation dehumidification subsystem 1, is filtered by the inlet filter 4 and condensed and dehumidified by the surface cooler 5 to achieve preliminary purification and drying, and the dew point temperature is reduced to slightly higher than the inlet temperature of the chilled water; then the air enters the compressed air subsystem 2, is pressurized by the blower 7, and then cooled by the aftercooler 8 to the inlet temperature of the blower 7; subsequently, the air enters the pressure swing adsorption subsystem 3 and is divided into two paths. According to the change of the product gas dew point and the system wet load, the opening degrees of the first inlet gas valve 191 and the second inlet gas valve 192 are adjusted, so that a part of the air flows through the first dehumidifier 91 after flowing through the first inlet gas valve 191, and another part of the air flows through the second inlet gas valve 192. The two airflows converge and then flow through the second dehumidifier 92, and are further dehumidified by the dehumidification heat exchanger therein. The dew point temperature of the air is reduced to below -30°C, and then it flows into the first adsorption tower 101 after passing through the first one-way gas valve 201 and is deeply dried by the desiccant in the first adsorption tower 101, and the dew point temperature is reduced to -70°C; after the dried air passes through the fourth one-way gas valve 204 behind the tower, most of the gas flows through the product gas valve 21 and the outlet filter 11 to become extremely dry clean product air, while a small part of the air passes through the regeneration pressure reducing valve 22 to reduce the pressure, and then flows through the cold blowing gas valve 25 into the regeneration fan 14 and flows into the second adsorption tower 102 to blow cold air to the adsorption tower; the moisture content of the cold blowing exhaust is lower than that of the adsorption tower regeneration exhaust in the dehumidification and regeneration stage, and the regeneration ability of the dehumidifier is also stronger. Therefore, the opening degrees of the bypass exhaust valve 26 and the regeneration exhaust valve 27 are adjusted, so that a part of the cold blowing air flows through the second dehumidifier 92 for regeneration and then is discharged to the environment through the bypass exhaust valve 26, and the remaining cold blowing air continues to flow through the second recuperator 122, the first dehumidifier 91, the regeneration exhaust valve 27, the first recuperator 121 and is discharged to the environment after regenerating the first dehumidifier 91, so that the two dehumidifiers reach different dehumidification / regeneration amounts; note that although the regeneration air flows through the first recuperator 121 and the second recuperator 122 at this time, since the cold blowing air is not heated in the cold blowing stage, the recuperator does not work.

[0033] After the above two working stages are completed, the adsorption capacity of the first adsorption tower 101 is close to saturation, and the second adsorption tower 102 basically resumes its moisture absorption capacity. At this time, the one-way air valve is switched, the second one-way air valve 202, the third one-way air valve 203, the fifth one-way air valve 205, and the eighth one-way air valve 208 are opened, and the first one-way air valve 201, the fourth one-way air valve 204, the sixth one-way air valve 206, and the seventh one-way air valve 207 are closed, so that the first adsorption tower 101 enters the regeneration state and the second adsorption tower 102 enters the dehumidification state, and the system runs continuously in this cycle.

[0034] A dry air production system based on temperature swing and pressure swing adsorption and its operation method proposed by the present invention, based on the principle of temperature swing and pressure swing adsorption, effectively improves the cyclic dehumidification amount of the solid desiccant; by combining condensation dehumidification and multi-stage adsorption, the dehumidification load and working pressure of the adsorption tower are reduced, and the operation energy consumption is significantly reduced compared with the traditional single-stage pressure swing adsorption dehumidification, the service life of the adsorbent is improved, and the maintenance cost is reduced; at the same time, the system combines the utilization of renewable energy and waste heat recovery to further improve the energy utilization rate, and the work is efficient and stable.

[0035] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field of the present invention through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the protection scope determined by the claims.

Claims

1. A drying air production system with temperature and pressure swing adsorption, characterized in that, It includes a condensation dehumidification subsystem, an air compression subsystem and a pressure swing adsorption subsystem. Among them, the condensation dehumidification subsystem includes an inlet filter, a surface cooler and a gas-water separator connected end to end in sequence through an air duct. The air compression subsystem includes a blower and a post-cooler connected end to end in sequence through an air duct. The pressure swing adsorption subsystem includes a first dehumidifier, a second dehumidifier, a first adsorption tower, a second adsorption tower and a regeneration blower. The post-cooler is connected to the dehumidification inlet of the first dehumidifier through a first inlet air valve. The dehumidification outlet of the first dehumidifier is connected to the dehumidification inlet of the second dehumidifier. The dehumidification outlet of the second dehumidifier is connected to the first port of the first adsorption tower through a first one-way air valve. The dehumidification outlet of the second dehumidifier is connected to the first port of the second adsorption tower through a fifth one-way air valve. The second port of the first adsorption tower is connected to the inlet of the product gas valve through a fourth one-way air valve. The second port of the second adsorption tower is connected to the inlet of the product gas valve through an eighth one-way air valve. The inlet of the product gas valve is also connected to the inlet of a regeneration pressure reducing valve. The regeneration pressure reducing valve is connected to the inlet of the regeneration blower through a regeneration heat exchange valve, a first regenerator, a second regenerator, an electric heater and a heating air valve in sequence. The regeneration pressure reducing valve is also directly connected to the inlet of the regeneration blower through a cold blowing air valve. The outlet of the regeneration blower is connected to the second port of the second adsorption tower through a seventh one-way air valve. The first port of the second adsorption tower is connected to the regeneration inlet of the second dehumidifier through a sixth one-way air valve. The outlet of the regeneration blower is also connected to the second port of the first adsorption tower through a third one-way air valve. The first port of the first adsorption tower is connected to the regeneration inlet of the second dehumidifier through a second one-way air valve. The regeneration outlet of the second dehumidifier is connected to the regeneration inlet of the first dehumidifier after passing through the second regenerator. The regeneration outlet of the first dehumidifier is connected to the external environment after passing through a regeneration exhaust valve and the first regenerator in sequence. The outlet of the product gas valve is connected to the inlet of an outlet filter. There is also an air duct between the inlet of the first inlet air valve and the dehumidification inlet of the second dehumidifier, and a second inlet air valve is provided on the air duct. A bypass exhaust valve is also provided between the regeneration outlet of the second dehumidifier and the second regenerator.

2. The drying air production system with variable temperature and pressure swing adsorption according to claim 1, wherein The pressure swing adsorption subsystem further includes a regeneration hot water tank. The hot water outlet of the regeneration hot water tank is connected to the regeneration hot water pipe inlet of the second dehumidifier. The regeneration hot water pipe outlet of the second dehumidifier is connected to the regeneration hot water pipe inlet of the first dehumidifier. The regeneration hot water pipe outlet of the first dehumidifier is connected to the hot water inlet of the regeneration hot water tank.

3. The drying air production system of variable temperature and pressure swing adsorption according to claim 2, characterized in that, The pressure swing adsorption subsystem further includes a heating device, and the heating device is connected to the regeneration hot water tank. The heating device is a solar collector or a high-temperature heat pump.

4. The dry air production system for temperature-variable and pressure-variable adsorption according to claim 1, wherein Both the first dehumidifier and the second dehumidifier contain two dehumidification heat exchangers, and the dehumidification heat exchanger is made by coating a molecular sieve desiccant on the surface of a finned tube heat exchanger.

5. The drying air production system of variable temperature and pressure swing adsorption according to claim 1, characterized in that, The dry air production system further includes a chiller, and the chiller supplies water to the surface cooler, the after-cooler, the first dehumidifier, and the second dehumidifier through a chilled water pump.

6. The drying air production system with variable temperature and pressure swing adsorption according to claim 1, wherein, The desiccant in the first adsorption tower and the second adsorption tower is one or a combination of activated carbon, activated alumina, synthetic zeolite, and 13X molecular sieve.

7. A method for operating a drying air production system by temperature and pressure swing adsorption, which is used for the drying air production system according to any one of claims 1-6, characterized in that, The operation method includes a dehumidification and regeneration mode. In the dehumidification and regeneration mode, the first inlet gas valve, the first check valve, the fourth check valve, the product gas valve, the regeneration pressure reducing valve, the regenerative heat exchange valve, the heating gas valve, the sixth check valve, the seventh check valve, and the regeneration exhaust valve are in the open state; the second inlet gas valve, the second check valve, the third check valve, the fifth check valve, the eighth check valve, the cold purge valve, and the bypass exhaust valve are in the closed state.

8. The operating method of a drying air production system by variable temperature and pressure swing adsorption according to claim 7, characterized in that, The operation method further includes a dehumidification and cold purge mode. In the dehumidification and cold purge mode, the first inlet gas valve, the second inlet gas valve, the first check valve, the fourth check valve, the product gas valve, the regeneration pressure reducing valve, the cold purge valve, the sixth check valve, the seventh check valve, the bypass exhaust valve, and the regeneration exhaust valve are in the open state; the second check valve, the third check valve, the fifth check valve, the eighth check valve, the regenerative heat exchange valve, and the heating gas valve are in the closed state.

9. The operating method of a drying air production system with variable temperature and pressure swing adsorption according to claim 8, characterized in that, After the dehumidification and regeneration mode and the dehumidification and cold purge mode, open the second check valve, the third check valve, the fifth check valve, and the eighth check valve, and close the first check valve, the fourth check valve, the sixth check valve, and the seventh check valve, so that the first adsorption tower enters the regeneration state and the second adsorption tower enters the dehumidification state, realizing the continuous operation of the system.

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