Energy-saving compressed air dehydration and decarbonization device

Abstract

In order to solve the technical problem that an existing compressed air dehydration and decarbonization device is high in energy consumption, the utility model provides an energy-saving compressed air dehydration and decarbonization device which comprises a dehydration device and a vacuum analysis molecular sieve suction and decarbonization device which are connected in sequence, the dehydration device is used for removing moisture contained in the compressed air, so that the moisture content in the compressed air meets the set requirement; according to the vacuum desorption molecular sieve suction decarburization device, decarburization is realized on the basis of minimum finished product gas consumption by utilizing a vacuum desorption principle, so that the carbon content in gas meets a set requirement, and compared with an existing dehydration decarburization device, the vacuum desorption molecular sieve suction decarburization device is lower in energy consumption.

Description

Technical Field

[0001] The utility model relates to the field of air drying and purification, in particular to a compressed air dehydration and decarbonization device. Background Art

[0002] In the production process of lithium battery precursors or in certain low-temperature environment tests, clean product gas with moisture and carbon content that meet the standards is often required. Therefore, the compressed air needs to be treated to remove water and carbon dioxide.

[0003] Existing compressed air dehydration and decarbonization devices mainly use the same micro-heat regeneration dryer as the air separation unit (one tower adsorbs the moisture and carbon dioxide contained in the gas, and the other tower uses the clean air without water and carbon dioxide produced by the adsorption tower to heat it to 160-220°C through a heater for analysis, and the analyzed gas is discharged into the atmosphere), or adopts a blast external heating drying process (one tower adsorbs the moisture and carbon dioxide contained in the gas, and the other tower uses a blower to draw the ambient air through a heater to heat it to 180-240°C before entering the analysis tower for analysis). Both of the above methods have major problems: the micro-heat regeneration dryer adopts the process route of the air separation unit, but the air separation unit will produce a large amount of contaminated nitrogen during the liquefaction process, which can be used for adsorption tower regeneration. However, as air dehydration and carbon dioxide removal, no liquefaction treatment is required, so qualified product gas must be used to analyze the regeneration tower, which consumes a lot of energy; and the blast external heating drying process, although the finished gas is not consumed during the heating stage, the blast heating extracts the gas containing water and carbon dioxide in the environment, which pollutes the molecular sieve at the adsorption outlet. After the blast is finished, a large amount of finished gas is still required for secondary analysis, and the compressed air is dehydrated and decarbonized in the same tower, which basically relies on micro-heat regeneration. A large amount of finished gas needs to be consumed as regeneration gas, which consumes a lot of energy. Summary of the invention

[0004] In order to solve the technical problem of high energy consumption of existing compressed air dehydration and decarbonization devices, the utility model provides an energy-saving compressed air dehydration and decarbonization device.

[0005] The technical solution of the utility model is:

[0006] The energy-saving compressed air dehydration and decarbonization device is special in that it includes a dehydration device and a vacuum analytical molecular sieve decarbonization device connected in sequence;

[0007] The dehydration device is used to remove moisture from the compressed air;

[0008] The vacuum analytical molecular sieve decarbonization device comprises an adsorption tower, a vacuum pump, a post-filter and a valve assembly connected by pipelines; an adsorbent for adsorbing carbon dioxide is arranged in the adsorption tower; the vacuum pump is used to extract the gas after the carbon dioxide is removed from the adsorption tower, and output the gas whose water and carbon dioxide content meet the set requirements; the post-filter is used to remove the adsorbent dust in the gas; and the valve assembly is used to realize the on-off control of the pipeline.

[0009] Furthermore, the dehydration device comprises a first dehydration device and a second dehydration device which are connected in sequence; the first dehydration device is a freezing dehydration device implemented based on the principle of freezing method.

[0010] Furthermore, the second dehydration device is a zero-gas-consumption external heating dehydration drying device, which is based on an energy-saving zero-gas-consumption blower external heating drying process, utilizes ambient atmosphere as a heating regeneration gas source, and adopts closed-cycle cooling to achieve zero-gas-consumption regeneration.

[0011] Furthermore, the zero-gas-consumption external heating dehydration drying device is a double-tower structure, including a tower A, a tower B, a fan, a circulating water cooler, a heater, a chilled water cooler, and a valve assembly connected by pipelines;

[0012] The structures of tower A and tower B are the same, and they are switched and controlled by corresponding valves in the valve assembly, so that when one tower is performing adsorption and dehydration, the other tower is performing adsorbent regeneration;

[0013] The fan and heater constitute a blast heating unit, which is used to extract ambient air to blast heat the regeneration tower until the outlet temperature of the regeneration tower reaches a set value;

[0014] The fan, chilled water cooler and circulating water cooler constitute a closed cooling unit, which is used to utilize the residual dry gas in the regeneration tower and use the fan as a power source to circulate and cool the regeneration tower until the tower top temperature drops to a set value;

[0015] The valve assembly includes a plurality of valves, which are respectively arranged on corresponding pipelines and are used to realize dehydration adsorption in one tower and regeneration of dehydration adsorbent in another tower by controlling the on-off of the pipelines; the regeneration of the dehydration adsorbent includes pressure relief, blast heating, displacement, closed-cycle cooling and pressure equalization of the regeneration tower in sequence.

[0016] Furthermore, the adsorbent in the A tower and the B tower adopts a mixed adsorption bed of activated alumina and molecular sieve, with the activated alumina at the bottom and the molecular sieve at the top.

[0017] Furthermore, the vacuum analytical molecular sieve decarbonization device is a double-tower structure, including a C tower, a D tower, a vacuum pump, a post-filter and a valve assembly connected by pipelines;

[0018] The C tower and the D tower have the same structure and are switched and controlled by corresponding valves in the valve assembly so that when one tower is performing adsorption and decarbonation, the other tower is performing adsorbent regeneration;

[0019] The valve assembly includes a plurality of valves, which are respectively arranged on corresponding pipelines, and are used to realize decarbonization adsorption in one tower and regeneration of decarbonization adsorbent in another tower by controlling the on-off of the pipelines; the decarbonization adsorbent regeneration includes pressure relief, vacuuming, pressure equalization, pressure relief, vacuuming and pressure equalization of the regeneration tower in sequence;

[0020] The vacuum pump is used for vacuuming;

[0021] The post-filter is used to remove adsorbent dust in the gas.

[0022] Furthermore, the vacuum analytical molecular sieve adsorption decarbonization device also includes an enhanced regeneration unit for enhanced regeneration of the adsorption tower in the vacuum analytical molecular sieve adsorption decarbonization device to release the carbon dioxide in the adsorbent in the adsorption tower.

[0023] Furthermore, the enhanced regeneration unit and the zero-gas-consumption external heating dehydration and drying device share a heater.

[0024] Furthermore, the adsorbents in the C tower and the D tower are a small amount of activated alumina and a large amount of molecular sieves dedicated to carbon dioxide.

[0025] The beneficial effects of the utility model are:

[0026] 1. The utility model firstly adopts a dehydration device to remove the moisture contained in the compressed air so that the water content in the gas meets the set requirements, and then adopts a vacuum analysis molecular sieve to absorb and decarbonize the device. By utilizing the vacuum analysis principle, decarbonization is achieved on the basis of minimum finished gas consumption so that the carbon content in the gas meets the set requirements. Compared with the existing dehydration and decarbonization devices, the energy consumption is lower.

[0027] 2. The dehydration device in the present invention comprises a first dehydration device and a second dehydration device, wherein the first dehydration device adopts a freezing dehydration device with the lowest energy consumption, thereby further reducing energy consumption.

[0028] 3. The second dehydration device in the utility model adopts a zero-gas consumption external heating drying device, which further reduces energy consumption.

[0029] 4. The vacuum analytical molecular sieve decarbonization device and the zero-gas-consumption external heating drying device in the utility model both adopt a double-tower structure, one tower for adsorption and the other for analysis, which can continuously supply air to the rear end and improve the purification efficiency of compressed air.

[0030] 5. The utility model provides an enhanced regeneration unit in the vacuum analytical molecular sieve decarburization device, by which the vacuum analytical molecular sieve decarburization device can be regenerated in an enhanced manner, and the carbon dioxide in the molecular sieve in the adsorbent is completely decomposed and released, thereby increasing the service life of the adsorbent; in addition, the enhanced regeneration unit also protects the vacuum analytical molecular sieve decarburization device, and can prevent the risk of moisture entering the vacuum analytical molecular sieve decarburization device due to the failure of the front-end zero-gas consumption external heating dehydration drying device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the working principle of the freezing and dehydration unit in the utility model.

[0032] Figure 2 It is a schematic diagram of the working principle of the zero-gas-consumption external heating dehydration drying device in the utility model.

[0033] Figure 3 It is a schematic diagram of the working principle of the vacuum analytical molecular sieve decarbonization device in the utility model.

[0034] Description of reference numerals:

[0035] 101-heat exchanger; 102-water chiller; 103-separator;

[0036] 201- fan; 202- circulating water cooler; 203- heater; 204- chilled water cooler; 205- A tower air inlet pipeline; 206- B tower air inlet pipeline; 207- A tower exhaust pipeline; 208- B tower exhaust pipeline; 209- finished gas output pipeline; 210- A tower pressure relief pipeline; 211- B tower pressure relief pipeline; 212- first pipeline; 213- second pipeline; 214- vent pipeline; 215- third pipeline; 216- fourth pipeline; 217- fifth pipeline; 218- sixth pipeline; 219- first branch; 220- second branch; 221- equalizing pressure pipeline; 222- seventh pipeline; 223- chilled water inlet pipeline; 224- dew point meter; 225- temperature detection port;

[0037] 301-vacuum pump; 302-heater; 303-filter; 304-C tower air inlet pipeline; 305-D tower air inlet pipeline; 306-C tower exhaust pipeline; 307-D tower exhaust pipeline; 308-finished gas output pipeline; 309-C tower pressure relief pipeline; 310-D tower pressure relief pipeline; 311-eighth pipeline; 312-ninth pipeline; 313-vent pipeline; 314-vacuum pipeline; 315-tenth pipeline; 316-eleventh pipeline; 317-equalizing pressure pipeline. DETAILED DESCRIPTION

[0038] The utility model is further described below in conjunction with the accompanying drawings.

[0039] The energy-saving compressed air dehydration and decarbonization device in this embodiment includes a freezing dehydration device, a zero-gas consumption external heating dehydration and drying device, and a vacuum analytical molecular sieve decarbonization device connected in sequence. The utility model can maximize energy saving while meeting gas quality requirements. Among them:

[0040] The freezing dehydration device adopts the freezing method to achieve the purpose of preliminary dehydration of compressed air with minimum energy consumption, thereby reducing the water content of the gas entering the zero gas consumption external heating dehydration drying device and reducing the regeneration energy consumption of the zero gas consumption external heating dehydration drying device.

[0041] The zero-gas-consumption external heating dehydration drying device adopts an energy-saving zero-gas-consumption blast external heating drying process, uses the ambient atmosphere as the heating regeneration gas source, and adopts closed-loop cooling to achieve zero-gas-consumption regeneration. At the same time, it can ensure the dew point of the gas entering the subsequent vacuum analysis molecular sieve decarbonization device, and has a certain carbon dioxide adsorption capacity.

[0042] The vacuum analysis molecular sieve decarbonization device adopts the principle of vacuum analysis. After the carbon dioxide in the gas is adsorbed by the adsorbent, a vacuum pump is used to extract the gas after removing the carbon dioxide to achieve vacuum analysis, thereby maximizing the potential of vacuum analysis and also achieving carbon dioxide analysis on the basis of zero gas consumption.

[0043] The zero-gas-consumption external heating dehydration drying device and the vacuum analysis molecular sieve decarbonization device both adopt a double-tower structure, one tower for adsorption and the other for analysis, which can continuously supply the finished gas that meets the requirements to the back-end gas system. In other embodiments, if there is no continuous gas supply demand, a single-tower structure can also be used. In this case, adsorption and analysis can only be performed in a cycle in sequence.

[0044] 1. Freezing and dehydration device

[0045] like Figure 1 As shown, the freezing and water removal device in this embodiment includes a heat exchanger 101, a water chiller 102 and a separator 103. The saturated compressed air of the compressor enters the heat exchanger 101, and the water chiller 102 provides chilled water to the heat exchanger 101, and the intake temperature is reduced to the set temperature to remove about 70% of the water in the gas. The supersaturated compressed air output from the heat exchanger 101 then enters the separator 103, and the liquid water contained in the gas is removed by the separator 103, and the saturated compressed air of ≤25°C is output. The freezing and water removal device in this embodiment first uses the water chiller 102 to make chilled water, and then uses the chilled water to remove the refrigerated gas. When the intake temperature is low, the refrigerator can be operated intermittently, and the ability to adapt to variable loads is strong.

[0046] In other embodiments, Figure 1The refrigeration dehydration device shown can also be replaced by an existing precooler or cold dryer. The precooler and cold dryer directly cool down the temperature without an intermediate conversion process, but their ability to adapt to variable loads is not strong, and when the inlet temperature is low, it will cause overcooling.

[0047] 2. Zero gas consumption external heating dehydration drying device

[0048] like Figure 2 As shown, the zero-gas-consumption external heating dehydration drying device in this embodiment includes a tower A, a tower B, a fan 201, a circulating water cooler 202, a heater 203, a chilled water cooler 204 and a valve assembly for controlling the on-off of the pipeline connected by pipelines.

[0049] Tower A and Tower B have the same structure, and are switched and controlled by corresponding valves in the valve assembly, so that when one tower is performing adsorption dehydration, the other tower is performing adsorbent regeneration. The adsorbent is a mixed adsorption bed of activated alumina and molecular sieve, with activated alumina at the bottom and molecular sieve at the top.

[0050] The inlet of the fan 201 is connected to the atmosphere and the output end of the circulating water cooler 202 at the same time, and the outlet of the fan 201 is connected to the input end of the heater 203 and the input end of the chilled water cooler 204 at the same time. The input end of the circulating water cooler 202, the output end of the heater 203 and the input end of the heater 203 are respectively connected to the upper air outlets of Tower A and Tower B through pipelines, and the output end of the chilled water cooler 204 is connected to the air inlets of Tower A and Tower B through pipelines.

[0051] The valve assembly includes valves A01-A04, B01-B04, F01-F06, F08.

[0052] Valves A01 and B01 are respectively arranged on the air inlet pipeline 205 of Tower A and the air inlet pipeline 206 of Tower B. The air inlet pipeline 205 of Tower A and the air inlet pipeline 206 of Tower B are respectively connected to the air outlet of the freezing and dehydration device of the previous link. The connection and disconnection of the air inlet pipeline 205 of Tower A and the air inlet pipeline 206 of Tower B with the air outlet of the freezing and dehydration device can be controlled respectively by valves A01 and B01.

[0053] Valves A04 and B04 are exhaust valves, which are respectively arranged on the exhaust pipeline 207 of Tower A and the exhaust pipeline 208 of Tower B. The exhaust pipeline 207 of Tower A and the exhaust pipeline 208 of Tower B are both connected to the finished gas output pipeline 209. The outlet end of the finished gas output pipeline 209 is the air outlet. The connection and disconnection of the exhaust pipeline 207 of Tower A and the exhaust pipeline 208 of Tower B with the finished gas output pipeline 209 can be controlled respectively by valves A04 and B04.

[0054] Valves A05 and B05 are both pressure relief valves, which are respectively arranged on the A tower pressure relief pipeline 210 and the B tower pressure relief pipeline 211. The A tower pressure relief pipeline 210 is connected with the A tower air inlet through the A tower air inlet pipeline 205, and the B tower pressure relief pipeline 211 is connected with the B tower air inlet through the B tower air inlet pipeline 206. The valves A05 and B05 can respectively control the connection and disconnection of the A tower pressure relief pipeline 210 and the B tower pressure relief pipeline 211 with the A tower air inlet and the B tower air inlet.

[0055] A first pipeline 212 connected to the air inlet pipeline 205 of tower A is led out, and a second pipeline 213 connected to the air inlet pipeline 206 of tower B is led out, and one end of the first pipeline 212 is connected to one end of the second pipeline 213, and valves A02 and B02 are respectively arranged on the first pipeline 212 and the second pipeline 213.

[0056] A vent line 214 is led out from between the first line 212 and the second line 213 and is connected thereto. A valve F04 is disposed on the vent line 214 .

[0057] A third pipeline 215 is also led out from between the first pipeline 212 and the second pipeline 213 and is connected thereto. The third pipeline 215 is used to connect the output end of the chilled water cooler 204 with the air inlets of Tower A and Tower B. A valve F03 is set on the third pipeline 215.

[0058] A fourth pipeline 216 is led out from the exhaust pipeline 207 of tower A and connected thereto, and a fifth pipeline 217 is led out from the exhaust pipeline 208 of tower B and connected thereto, and one end of the fourth pipeline 216 is connected to one end of the fifth pipeline 217, and valves A03 and B03 are respectively arranged on the fourth pipeline 216 and the fifth pipeline 217.

[0059] A sixth pipeline 218 connected to the fourth pipeline 216 and the fifth pipeline 217 is also led out from between them, and two branches are separated from the other end of the sixth pipeline 218: the first branch 219 is used to connect the output end of the heater 203 with the sixth pipeline 218, and then connect the output end of the heater 203 with the upper air outlets of Tower A and Tower B; the second branch 220 is used to connect the input end of the circulating water cooler 202 with the sixth pipeline 218, and then connect the input end of the circulating water cooler 202 with the upper air outlets of Tower A and Tower B; valves F02 and F05 are respectively arranged on the first branch 219 and the second branch 220.

[0060] A pressure equalizing pipeline 221 for connecting the gas outlet of Tower A and the gas outlet of Tower B is also provided between the exhaust pipeline 207 of Tower A and the exhaust pipeline 208 of Tower B, and a valve F09 is provided on the pressure equalizing pipeline 221 .

[0061] A seventh pipeline 222 is led out from the finished gas output pipeline 209 , the other end of the seventh pipeline 222 is connected to the input end of the heater 203 , and a valve F06 is disposed on the seventh pipeline 222 .

[0062] The valve F08 is disposed on the chilled water inlet pipeline 223 of the chilled water cooler 204 .

[0063] The valve F01 is disposed on a pipeline for connecting the outlet of the fan 201 and the input end of the heater 203 .

[0064] The fan 201, the heater 203 and the valves F01 and F02 constitute a blast heating unit for extracting ambient air to blast heat the regeneration tower (the tower for regenerating the adsorbent is called a regeneration tower) until the outlet temperature of the regeneration tower reaches a set value.

[0065] The fan 201, the chilled water cooler 204, the circulating water cooler 202 and the valves F03, F05 and F08 constitute a closed cooling unit for utilizing the residual dry gas in the regeneration tower and using the fan 201 as a power source to circulate and cool the regeneration tower until the top temperature drops to a set value.

[0066] In order to provide a basis for the switching control of the valve assembly, pressure detection ports and temperature detection ports (not shown in the figure) are provided on Tower A and Tower B, a dew point meter 224 for measuring the dew point of the finished gas is provided near the gas outlet on the finished gas output pipeline 209, and a temperature detection port 225 is provided on the heater 203.

[0067] The process flow of zero gas consumption external heating dehydration drying device (taking tower A adsorption and tower B regeneration as an example):

[0068] A tower adsorption

[0069] The saturated compressed air with a temperature of ≤25℃ after cooling and separation from the front-end refrigeration and water removal device enters Tower A through valve A01 for adsorption. After removing the residual water vapor and part of the carbon dioxide in the saturated compressed air, it is output through valve A04 and enters the subsequent vacuum analysis molecular sieve decarbonization device.

[0070] Tower B Regeneration

[0071] While tower A is adsorbing, tower B is regenerating. The regeneration of tower B includes five stages: pressure relief, blast heating, displacement, closed cycle cooling, and pressure equalization:

[0072] Step 1: Depressurize Tower B

[0073] Close the air inlet valve B01 and the exhaust valve B04 of Tower B, and open the pressure relief valve B05 of Tower B to relieve the pressure of Tower B until the pressure drops to normal pressure.

[0074] Step 2: B tower blast heating

[0075] After the pressure relief of Tower B is completed, valves F01, F02, F04, B02, and B03 are opened, and fan 201 and heater 203 are started. Fan 201 draws ambient air and heats it to about 200°C through valve F01 and heater 203. Then, it enters Tower B through valves F02 and B03 to heat and decompose the adsorbent in Tower B. That is, the water and carbon dioxide adsorbed in the adsorbent are released by heating, and the decomposed gas is discharged to the atmosphere through valves B02 and F04 until the regeneration outlet temperature reaches the set value (about 100°C). The heating is completed, and heater 203 and fan 201 stop running.

[0076] Step 3: Replacement of Tower B

[0077] After the heating of Tower B is completed, valve F01 is closed, and valve F06 is opened to take a small amount of finished gas from Tower A and enter heater 203 to cool down heater 203. Then, the finished gas comes out of heater 203 and enters Tower B through valves F02 and B03 to replace Tower B (regeneration tower) so that the impurity gas and residual moisture in the adsorbent in Tower B are discharged, and the humidity in the Tower B body after blast heating is reduced. The replacement time lasts about 5 minutes.

[0078] Step 4: Closed cooling in tower B

[0079] After the replacement of Tower B is completed, valves F06, F02, and F04 are closed, valves F03, F05, and F08 are opened, and the fan is started. The residual dry gas in Tower B (now the regeneration tower) is used as the power source of fan 201. The gas is cooled by the chilled water cooler 204 and enters Tower B through valves F03 and B02 to cool Tower B. The hot gas is discharged from the outlet at the top of Tower B, enters the circulating water cooler 202 through valve B03, the sixth pipeline 218, and valve F05, and returns to the inlet of fan 201 after being cooled by the circulating water cooler 202. This cycle is repeated until the top temperature of Tower B drops to about 40°C, the cooling is completed, and the fan stops running.

[0080] Step 5: Tower B pressure equalization

[0081] After the closed cooling of Tower B is completed, close valves B03 and B02, and open valve F09 to equalize the pressure of Tower B until the pressure of Tower B is equal to that of Tower A (at this time, the adsorption tower), and the pressure equalization is completed.

[0082] After the regeneration of Tower B is completed, it will be on standby until the dew point of Tower A does not meet the standard. After the switch, Tower B adsorbs and Tower A is regenerated using the same regeneration method as Tower B. Only the corresponding opening and closing valves are different, which will not be repeated here.

[0083] 3. Vacuum analytical molecular sieve decarbonization device

[0084] like Figure 3As shown, the vacuum desorption molecular sieve decarbonization device includes a C tower, a D tower, a vacuum pump 301, a heater 302, a filter 303 connected by pipelines, and a valve assembly for controlling the on-off of the pipelines.

[0085] Tower C and Tower D have the same structure, and are switched and controlled by corresponding valves in the valve assembly, so that when one tower is performing adsorption decarbonization, the other tower is performing adsorbent regeneration. The adsorbent is a small amount of activated alumina + a large amount of molecular sieves for carbon dioxide.

[0086] The valve assembly includes valves F07, F10-F12, C01-C05, D01-D05.

[0087] Valves C01 and D01 are respectively arranged on the C tower air inlet pipeline 304 and the D tower air inlet pipeline 305. The C tower air inlet pipeline 304 and the D tower air inlet pipeline 305 are respectively connected to the air outlet of the zero-gas-consumption external heating dehydration drying device of the previous link. Valves C01 and D01 can respectively control the connection and disconnection of the C tower air inlet pipeline 304 and the D tower air inlet pipeline 305 with the air outlet of the zero-gas-consumption external heating dehydration drying device.

[0088] Valves C04 and D04 are exhaust valves, which are respectively arranged on the exhaust pipeline 306 of Tower C and the exhaust pipeline 307 of Tower D. The exhaust pipeline 306 of Tower C and the exhaust pipeline 307 of Tower D are both connected to the finished gas output pipeline 308. The outlet end of the finished gas output pipeline 308 is the gas outlet. The connection and disconnection of the exhaust pipeline 306 of Tower C and the exhaust pipeline 307 of Tower D with the finished gas output pipeline 308 can be controlled respectively by valves C04 and D04.

[0089] The filter 303 is arranged on the finished gas output pipeline 308 to remove adsorbent dust in the gas after dehydration and decarbonization.

[0090] Valves C05 and D05 are both pressure relief valves, which are respectively arranged on the C tower pressure relief pipeline 309 and the D tower pressure relief pipeline 310. The C tower pressure relief pipeline 309 is connected with the C tower air inlet through the C tower air inlet pipeline 304, and the D tower pressure relief pipeline 310 is connected with the D tower air inlet through the D tower air inlet pipeline 305. The valves C05 and D05 can respectively control the connection and disconnection of the C tower pressure relief pipeline 309 and the D tower pressure relief pipeline 310 with the C tower air inlet and the D tower air inlet.

[0091] An eighth pipeline 311 connected to the C tower air inlet pipeline 304 is led out, and a ninth pipeline 312 connected to the D tower air inlet pipeline 305 is led out, and one end of the eighth pipeline 311 is connected to one end of the ninth pipeline 312, and valves C02 and D02 are respectively arranged on the eighth pipeline 311 and the ninth pipeline 312.

[0092] A venting pipeline 313 connected to the eighth pipeline 311 and the ninth pipeline 312 is led out, and a valve F11 is an external venting valve provided on the venting pipeline 313 .

[0093] A vacuum line 314 is led out from the vent line 313 , and a valve F12 and a vacuum pump 301 are arranged on the vacuum line 314 . The connection and disconnection between the vacuum pump 301 and the vent line 313 can be controlled by the valve F12 .

[0094] A tenth pipeline 315 is led out from the exhaust pipeline 306 of tower C and connected thereto, and an eleventh pipeline 316 is led out from the exhaust pipeline 307 of tower D and connected thereto, and one end of the tenth pipeline 315 is connected to one end of the eleventh pipeline 316, and valves C03 and D03 are respectively arranged on the tenth pipeline 315 and the eleventh pipeline 316.

[0095] A pressure equalizing pipeline 317 for connecting the gas outlet of Tower C and the gas outlet of Tower D is further provided between the exhaust pipeline 306 of Tower C and the exhaust pipeline 307 of Tower D, and a valve F10 is provided on the pressure equalizing pipeline 317 .

[0096] In order to provide a basis for the switching control of the valve assembly, both Tower C and Tower D are provided with a pressure detection port and a temperature detection port (not shown in the figure), and the heater 302 is provided with a temperature detection port (not shown in the figure).

[0097] The process flow of vacuum analytical molecular sieve decarbonization device (taking C tower adsorption and D tower regeneration as an example):

[0098] C tower adsorption

[0099] The dry air from the zero-gas-consumption external heating dehydration drying device enters tower C through valve C01, where the adsorbent in tower C absorbs carbon dioxide in the gas for decarbonization. After the carbon dioxide is removed, the gas enters post-filter 303 through valve C04 to remove the adsorbent dust in the gas, and then delivers finished gas with water, dew point, carbon dioxide and dust particles meeting the standards.

[0100] D Tower Regeneration

[0101] While tower C is adsorbing, tower D is regenerating. The regeneration of tower D includes six stages: pressure relief, vacuuming, pressure equalization, pressure relief, vacuuming and pressure equalization:

[0102] Step 1: Depressurize Tower D

[0103] Close the D tower air inlet valve D01 and exhaust valve D04, open the D tower pressure relief valve D05 to relieve the pressure of the D tower. When the pressure of the D tower drops to 0.5-2 barg (preferably 1 barg, i.e. about 0.1 MPa, which can be adjusted according to actual needs), open the D tower vent valve D02 and the external vent valve F11, use the residual gas in the tower as the power source, and pre-regenerate the D tower adsorbent through instantaneous rapid pressure relief until the pressure drops to normal pressure.

[0104] Step 2: Vacuum Tower D

[0105] After the pressure relief of tower D is completed, close the external vent valve F11 and valve D05, open valve F12, and start the vacuum pump 301 to perform vacuum analysis on tower D, that is, use the vacuum pump to evacuate tower D (drying tower). While tower D forms a vacuum system, the adsorbent releases the adsorbed carbon dioxide. When the pressure of tower D reaches a vacuum degree of 0.1MPag, the vacuuming is completed, valve F12 is closed, and the vacuum pump 301 is turned off.

[0106] Step 3: D tower pressure equalization

[0107] After the D tower has been vacuum analyzed once, open valve F10 to take part of the finished gas from the C tower and inject it into the D tower to equalize the pressure of the D tower until the pressure of the D tower is equal to that of the C tower.

[0108] Steps 4-5, secondary pressure relief, vacuum analysis, and pressure equalization, are respectively the same as steps 1-3 above.

[0109] After the regeneration of Tower D is completed, Tower D is on standby and is switched when the carbon dioxide index of Tower C exceeds the standard. After the switch, Tower D adsorbs and Tower C is regenerated using the same regeneration method as Tower D. Only the corresponding opening and closing valves are different, which will not be repeated here.

[0110] In addition, in order to improve the life of the adsorbent, the utility model also includes an enhanced regeneration unit, which includes a heater 302, valves F07, C03 and D03 and corresponding pipelines; since the zero gas consumption heating dehydration drying device uses the heater intermittently, the heater can be used as an enhanced regeneration heater of the enhanced regeneration unit when the heater is not used. Of course, the heater 302 in the enhanced regeneration unit can also be set separately. In this embodiment, the enhanced regeneration unit relies on the heater in the zero gas consumption heating dehydration drying device. When the zero gas consumption heating dehydration drying device is in the cooling, pressure equalization and standby stages (the zero gas consumption heating dehydration drying device does not use a heater in these three stages), the enhanced regeneration unit can be used to enhance the regeneration of the vacuum analytical molecular sieve decarbonization device. The enhanced regeneration process is as follows (taking C tower adsorption and D tower enhanced regeneration as an example):

[0111] C tower adsorption

[0112] The dry air from the zero-gas-consumption external heating dehydration drying device enters the C tower through valve C01, where the C tower adsorbent absorbs the carbon dioxide in the gas for decarbonization. After the carbon dioxide is removed, the gas enters the post-filter through valve C04 to remove the adsorbent dust in the gas, and then delivers finished gas with water, dew point, carbon dioxide and dust particles meeting the standards.

[0113] D tower enhanced regeneration

[0114] While tower C is adsorbing, tower D is undergoing enhanced regeneration. The enhanced regeneration of tower D includes four stages: pressure relief, heating, cooling, and pressure equalization:

[0115] Step 1: Depressurize Tower D

[0116] Close the D tower air inlet valve D01 and exhaust valve D04, open the D tower pressure relief valve D05 to relieve the pressure of the D tower. When the pressure of the D tower drops to about 1 barg (adjustable), open the D tower vent valve D02 and the external vent valve F11, use the residual gas as the power source, and use instantaneous rapid pressure relief to pre-regenerate the D tower adsorbent until the pressure drops to normal pressure.

[0117] Step 2: D tower heating

[0118] After the pressure relief of tower D is completed, valves F07 and D03 are opened, and part of the finished gas is taken from tower C and heated to about 200°C by heater 302. Then, it enters tower D through valve D03, where it is heated and analyzed to release the carbon dioxide adsorbed by the adsorbent, and the regenerated gas is discharged through valves D02 and F11.

[0119] Step 3: Cooling in tower D

[0120] After the heating of tower D is completed (the heating time is controlled at about 1.5 hours), the heater 302 is turned off, and the finished gas is continuously taken from tower C through valve F07 to cool tower D until the outlet temperature of tower D reaches the set temperature.

[0121] Step 4: D tower pressure equalization

[0122] After the cooling of tower D is completed, close valves F07, D02, and D03, open valve F10 to take the finished gas from tower C to equalize the pressure of tower D until the pressure of tower D is the same as that of tower C. At this time, the enhanced regeneration of tower D is completed.

[0123] After the enhanced regeneration of tower D is completed, the adsorption is switched to tower D, and tower C is enhanced and regenerated in the same way to restore the activity of the adsorbent.

[0124] The above only describes the present invention with the optimal embodiment with the lowest energy consumption. In fact, only by replacing the existing decarburization device with the vacuum analytical molecular sieve decarburization device of the present invention, the purpose of relatively significant energy saving and consumption reduction can be achieved. In other embodiments, for example, in scenarios where it is not necessary to reduce energy consumption to a minimum, taking into account both cost and energy consumption, the freezing dehydration device and the zero gas consumption external heating dehydration drying device can also be replaced by other existing dehydration devices.

Claims

1. Energy-saving compressed air dehydration and decarbonization device, characterized by: It includes a dehydration device and a vacuum analytical molecular sieve decarbonization device connected in sequence; The dehydration device is used to remove moisture from the compressed air; The vacuum analytical molecular sieve decarbonization device comprises an adsorption tower, a vacuum pump, a post-filter and a valve assembly connected by pipelines; an adsorbent for adsorbing carbon dioxide is arranged in the adsorption tower; the vacuum pump is used to extract the gas after the carbon dioxide is removed from the adsorption tower, and output the gas whose water and carbon dioxide content meet the set requirements; the post-filter is used to remove the adsorbent dust in the gas; and the valve assembly is used to realize the on-off control of the pipeline.

2. The energy-saving compressed air dehydration and decarbonization device according to claim 1 is characterized in that: The dehydration device comprises a first dehydration device and a second dehydration device connected in sequence; the first dehydration device is a freezing dehydration device based on the principle of freezing.

3. The energy-saving compressed air dehydration and decarbonization device according to claim 2 is characterized in that: The second dehydration device is a zero-gas-consumption external heating dehydration drying device, which is based on an energy-saving zero-gas-consumption blower external heating drying process, utilizes ambient atmosphere as a heating regeneration gas source, and adopts closed-cycle cooling to achieve zero-gas-consumption regeneration.

4. The energy-saving compressed air dehydration and decarbonization device according to claim 3 is characterized in that: The zero-gas-consumption external heating dehydration drying device is a double-tower structure, including a tower A, a tower B, a fan, a circulating water cooler, a heater, a chilled water cooler and a valve assembly connected by pipelines; The structures of tower A and tower B are the same, and they are switched and controlled by corresponding valves in the valve assembly, so that when one tower is performing adsorption and dehydration, the other tower is performing adsorbent regeneration; The fan and heater constitute a blast heating unit, which is used to extract ambient air to blast heat the regeneration tower until the outlet temperature of the regeneration tower reaches a set value; The fan, chilled water cooler and circulating water cooler constitute a closed cooling unit, which is used to utilize the residual dry gas in the regeneration tower and use the fan as a power source to circulate and cool the regeneration tower until the tower top temperature drops to a set value; The valve assembly includes a plurality of valves, which are respectively arranged on corresponding pipelines and are used to realize dehydration adsorption in one tower and regeneration of dehydration adsorbent in another tower by controlling the on-off of the pipelines; the regeneration of the dehydration adsorbent includes pressure relief, blast heating, displacement, closed-cycle cooling and pressure equalization of the regeneration tower in sequence.

5. The energy-saving compressed air dehydration and decarbonization device according to claim 1 or 2, characterized in that: The vacuum analytical molecular sieve decarbonization device is a double-tower structure, including a C tower, a D tower, a vacuum pump, a post-filter and a valve assembly connected by pipelines; The C tower and the D tower have the same structure and are switched and controlled by corresponding valves in the valve assembly so that when one tower is performing adsorption and decarbonation, the other tower is performing adsorbent regeneration; The valve assembly includes a plurality of valves, which are respectively arranged on corresponding pipelines, and are used to realize decarbonization adsorption in one tower and regeneration of decarbonization adsorbent in another tower by controlling the on-off of the pipelines; the decarbonization adsorbent regeneration includes pressure relief, vacuuming, pressure equalization, pressure relief, vacuuming and pressure equalization of the regeneration tower in sequence; The vacuum pump is used for vacuuming.

6. The energy-saving compressed air dehydration and decarbonization device according to claim 5 is characterized in that: The vacuum analytical molecular sieve adsorption decarbonization device also includes an enhanced regeneration unit, which is used to perform enhanced regeneration on the adsorption tower in the vacuum analytical molecular sieve adsorption decarbonization device to release the carbon dioxide in the adsorbent in the adsorption tower.

7. The energy-saving compressed air dehydration and decarbonization device according to claim 3 or 4, characterized in that: The vacuum analytical molecular sieve decarbonization device is a double-tower structure, including a C tower, a D tower, a vacuum pump, a post-filter and a valve assembly connected by pipelines; The C tower and the D tower have the same structure and are switched and controlled by corresponding valves in the valve assembly so that when one tower is performing adsorption and decarbonation, the other tower is performing adsorbent regeneration; The valve assembly includes a plurality of valves, which are respectively arranged on corresponding pipelines, and are used to realize decarbonization adsorption in one tower and regeneration of decarbonization adsorbent in another tower by controlling the on-off of the pipelines; the decarbonization adsorbent regeneration includes pressure relief, vacuuming, pressure equalization, pressure relief, vacuuming and pressure equalization of the regeneration tower in sequence; The vacuum pump is used for vacuuming.

8. The energy-saving compressed air dehydration and decarbonization device according to claim 7 is characterized in that: The vacuum analytical molecular sieve adsorption decarbonization device also includes an enhanced regeneration unit, which is used to perform enhanced regeneration on the adsorption tower in the vacuum analytical molecular sieve adsorption decarbonization device to release the carbon dioxide in the adsorbent in the adsorption tower.

9. The energy-saving compressed air dehydration and decarbonization device according to claim 8 is characterized in that: The enhanced regeneration unit and the zero-gas-consumption external heating dehydration and drying device share a heater.

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