Dry ice production system that also allows air supply for air conditioning and uses carbon dioxide in the air as a gas source

Abstract

Dry ice production system for the production of dry ice and optionally liquid carbon dioxide, which also allows air supply for air conditioning and turns carbon dioxide in the air into a gas source, which is a steam generation heat pump device (8) which recovers waste heat from a device that compresses, cools and liquefies carbon dioxide gas within a system and generates steam, a carbon dioxide gas separation and enrichment device that separates and enriches carbon dioxide gas in the air, introduces the steam, and desorbes and recovers it through the heat of condensation of the saturated steam, a device (10-1) which cools and dehumidifies a mixed gas of the saturation steam and the carbon dioxide gas recovered in a separation and enrichment device, a compression device (11-1) with one or more stages, which compresses the cooled and dehumidified carbon dioxide gas for liquefaction, an adsorption dehumidification device (13; 12) which dehumidifies the compressed carbon dioxide gas, a gas liquefaction device (15) and a freezer (14) which cool the dehumidified carbon dioxide gas to a liquefaction temperature, a liquefied carbon dioxide gas purification tank (16) in which the liquefied carbon dioxide gas is introduced and liquefied carbon dioxide is stored and non-liquefied gas is removed, and a dry ice production device (17) in which the liquid carbon dioxide is conveyed from the liquid carbon dioxide purification tank (16) and discharged under atmospheric pressure, and the carbon dioxide is cooled and desublimated by the latent heat of evaporation thereof, and dry ice is produced, and in which non-desublimated gas returns to the compression device (11-1) and is recovered during dry ice production, wherein the wet TSA carbon dioxide gas separation and enrichment device houses and rotates a rotor (1) having an adsorption capacity of carbon dioxide gas in a housing which has a treatment zone (4), a purge zone (6), and a desorption zone (5-1), at least in the order of the direction of rotation, and is sealed,wherein, in the treatment zone (4), air is introduced into the humidified state of the rotor (1) and the carbon dioxide gas is adsorbed under evaporative cooling; wherein, in the purging zone (6), the non-liquid gas removed from the liquid carbon dioxide purification tank (16) is introduced and air contained in the gap of the rotor (1) is purged and discharged; wherein, in the desorption zone (5-1), saturated steam of approximately 100°C generated by the steam generation heating pump device (8) is introduced, and the carbon dioxide gas is desorbed by the heat of condensation of the steam, and is enriched and recovered.

Description

[Technical field]

[0001] The present invention relates to an energy-saving system for the separation, recovery, enrichment, compression, cooling, dehumidification, liquefaction of carbon dioxide gas and the production of dry ice, which also allows air supply for air conditioning and makes carbon dioxide in the air a raw material, and a wet TSA method carbon dioxide separation and enrichment apparatus. [Technical background]

[0002] To combat global warming, efforts are being made worldwide to reduce carbon dioxide emissions from businesses, motor vehicles, and households. For example, efforts are being made to replace energy-intensive machines with energy-saving models, or to replace them with non-fossil renewable energy sources such as sunlight or wind power. Research and development is also being conducted into CSS (Carbon Dioxide Recovery and Storage) technologies, which recover the inevitably produced carbon dioxide gas and store it in the Earth's interior or deep sea, or technologies that utilize CO2-EOR (Enhanced Crude Oil Recovery Process), and technologies that chemically absorb and harden carbon dioxide into cement or rock.Until now, it has been considered that, as a technique for efficiently recovering and enriching carbon dioxide gas, sources capable of generating the highest possible concentration of gas, such as Patent Document 1, and sources capable of generating waste heat for recovery and enrichment, such as power plants and waste incineration plants, are suitable. Furthermore, Patent Document 2 discloses a device for improving the liquefaction efficiency of the recovered enriched gas by using the compression heat of a compression device as a regenerative heat source of a carbon dioxide gas dehumidifier for renewing the dehumidifier, thereby enhancing energy-saving characteristics.

[0003] CCU (Carbon Dioxide Recovery Utilization) technology, which uses recovered carbon dioxide as a resource, is a process that reuses it for raw materials such as urea base or polycarbonate resin, etc., but the total amount of carbon dioxide emitted is negligible. In recent years, various organizations in various countries have also been advancing research and development into renewable fuels that can convert recovered carbon dioxide gas into liquid fuel or gas fuel.

[0004] In addition, especially overseas, as DAC (Direct Air Capture) technology, which directly captures and recovers carbon dioxide gas in the atmosphere, the developments and demonstration experiments of Patent Document 3 and Patent Document 4 are being carried out. The advantages of DAC are the features that (1) it can affect dispersed and moving emission sources such as automobiles and aircraft, etc., (2) it can also affect carbon dioxide gas emitted in the past, and (3) it can obtain carbon dioxide raw materials near reuse factories without limiting the location of the recovery device to one emission source, etc. Therefore, there are examples of large-scale demonstration experiments in Europe and the United States, respectively.

[0005] To reduce carbon dioxide emissions, it is also necessary to consider the amount of carbon emissions resulting from the energy required for recovery, enrichment, and liquefaction. Therefore, Patent Document 3 discloses an energy source that utilizes everything from geothermal energy to nuclear power plant waste heat, due to the usability of combined heat and power (CHP) waste heat and various renewable energy sources.

[0006] Patent Document 4 discloses a method in which steam is introduced into a carbon dioxide adsorption structural body using a heat pump and desorbed, heat recovery of the desorption gas is performed by an evaporation coil mounted downstream of the adsorption structural body, and condensed water is recovered, and a condensation coil mounted upstream of the adsorption structural body uses the heat pump as a heat source to generate steam for desorption. Furthermore, a method in which high-humidity carbon dioxide gas desorbed from the adsorption structural body is recompressed and heated and introduced into a boiler evaporator, and condensed water of the desorption gas is recovered through heat exchange simultaneously with steam generation for desorption is recovered.As a technique implemented recently, Patent Document 6 discloses a heat pump that recovers heat from warm wastewater and generates steam.

[0007] There is a constant demand for carbon dioxide gas for welding, medical use, food storage, etc., and the raw gas is recovered and used as a by-product of petrochemical plants, ammonia synthesis plants, etc. In Japan, 1,100,000 tons of commercial carbon dioxide gas were sold in 2021, with the most common use being welding at 33% and dry ice at 32%.

[0008] Liquefied carbon dioxide gas products have quality standards depending on their intended use, and refinement and dehumidification processes to ensure quality also increase costs. JIS K1106:2008 specifies one to three types of quality standards for liquefied carbon dioxide, such as purity and water content. Gas for industrial use, such as welding, is specified in JIS Z 3253:2011.

[0009] In recent years, Japan has experienced a shortage of commercial carbon dioxide gas due to the decline in petrochemical plants and ammonia synthesis plants, etc., which were used as carbon dioxide gas recovery sources, or due to transfers abroad. Since 2010, imports from abroad have increased sharply, and a crisis awareness has arisen in the industry, which is why countermeasures are being considered. As a countermeasure, demonstration experiments, etc., are being carried out in many places, trying to use exhaust gases from steel mills, power plants, waste incinerators, etc., as carbon dioxide gas recovery sources. However, combustion gas contains many impurities such as NOx, SOx, dust, etc., and pretreatment is important. There are many tasks to be undertaken, such as ensuring the purity of the recovered carbon dioxide, recovery costs, transportation costs, etc. Furthermore, in remote islands or remote areas, there are also problems with the production of carbon dioxide.in remote areas, the problem of increasing carbon dioxide generation due to transportation from the carbon dioxide gas recovery base.

[0010] Gas sources such as petrochemical plants, which were previously considered to be unproblematic because even if carbon dioxide gas is generated, it is recovered and used, are being re-examined in light of the rise of electric vehicles and the promotion of resource recycling, taking into account pollution from plastic waste, fuels that have even lower environmental impacts, production processes, and materials, and an even greater shortage is anticipated. It is conceivable that in the near future, it will be desirable for even commercial carbon dioxide gas recovery sources to be replaced by renewable models.

[0011] Japan has a dry ice market of 350,000 tons per year, of which 300,000 tons are used for transportation and delivery. In recent years, vaccinations have progressed worldwide as a countermeasure against the novel coronavirus pandemic, but vaccines require storage at very low temperatures, and the demand for dry ice for this transportation is increasing. Furthermore, the increased demand for refrigerated and frozen food delivery is also increasing the demand for dry ice as a cooling agent. The demand for dry ice fluctuates seasonally, and there is a shortage of dry ice every summer, resulting in the situation where 26,000 tons are imported from abroad. This is due to petrochemical plants, etc.Carbon dioxide gas recovered within the country is calculated based on the emission level at the recovery origin, but imported dry ice is calculated based on the emission level within the country, which is why carbon dioxide is imported and the emission level increases.

[0012] In areas with prolonged heat waves, such as Okinawa in Japan and worldwide in the Philippines, Vietnam, India, Mexico, Brazil, etc., there is a year-round need for dry ice as a cooling agent. However, many of these areas are remote from carbon dioxide gas sources, requiring transportation to the area of ​​need using special gas carriers, special tank trucks, or carbon dioxide cylinders or dry ice. Transportation also poses the problem of increasing carbon dioxide emissions. In improving the efficiency of dry ice production, Patent Document 7 discloses a method for increasing the yield of dry ice in an apparatus for producing dry ice from liquid carbon dioxide in a storage tank. Patent Document 8 discloses an apparatus for recovering and liquefying carbon dioxide gas that has not been desublimated (turned into dry ice) in an apparatus for producing dry ice using liquid carbon dioxide.

[0013] Dry ice is a refrigerant that utilizes the latent heat of carbon dioxide and is used for refrigeration for food storage and transportation, etc. Therefore, it does not require the purity required for other liquid carbon dioxide products. With dry ice made from carbon dioxide gas recovered from the atmosphere, the gas released into the atmosphere through the use of dry ice is not harmful to the environment. Therefore, it is conceivable that the implementation of a system marketed as renewable carbon dioxide could be a countermeasure to prevent global warming.

[0014] CN 102371104 A relates to an apparatus and a method for adsorbing, desorbing, and condensing carbon dioxide in gas, wherein the apparatus comprises an adsorption and desorption unit that provides an adsorption material for adsorbing and desorbing carbon dioxide in the gas to be treated, and a steam supply unit that provides a steam source for the adsorption and desorption unit. Carbon dioxide in the adsorption material can be removed by a desorption effect of superheated steam from the steam source on an adsorption material. [Prior Art Documents][Patent Documents] [Patent Document 1] JP H06-99034 A [Patent Document 2] JP 2010-266155 A [Patent Document 3] JP 2018-023976 A [Patent Document 4] JP 2017-528318 A [Patent Document 5] JP 6510702 B1 [Patent Document 6] JP ​​2007-232357 A [Patent Document 7] JP 2006-193377 A [Patent Document 8] JP 2016-204234 A [Patent Document 9] JP 2021-211907 A [Summary of the invention][Problem to be solved by the invention]

[0015] CCU technologies are being researched and developed by various companies and institutions worldwide, but in addition to the recovery costs of carbon dioxide gas, there are many issues related to the valuables it is converted into, as well as the conversion costs, the installation costs, how it is commercially realized, etc. Therefore, among the various conceivable CCU technologies, it is desirable to implement a CCU technology as a pioneer in which market introduction and dissemination are relatively rapid.

[0016] Therefore, a system for capturing, enriching, and liquefying carbon dioxide gas in the air and producing dry ice was aimed at, which is not arranged in a facility that emits large amounts of carbon dioxide gas, such as a general power plant or a petrochemical plant, but is a system that is relatively compact and applicable to a place where recovered carbon dioxide gas is used, on the scale of a small factory in the city, in which the waste heat or exhaust gases of the individual devices of the entire system are jointly used, the energy saving is high, and air supply for air conditioning is also possible.

[0017] As a prior art document, Patent Document 1 discloses an example of a system for separating and enriching liquid carbon dioxide from a combustion furnace. The carbon dioxide separation and enrichment method is implemented as a TSA method, a PSA method, and a PTSA method. A method for recirculating non-liquid gas after liquefaction is disclosed, increasing the recovery rate and purity of the liquid carbon dioxide, but no method for enhancing energy-saving properties is mentioned.

[0018] In the recovered carbon dioxide gas, the partial pressure of water vapor increases due to compression, and condensation is easily formed, so condensate drainage is performed along with cooling. Due to quality requirements, it is further dehumidified to a low dew point temperature by an adsorption dehumidifier such as an absorption type, a PSA method, or a TSA method. Patent Document 2 relates to energy saving of an apparatus for compressing, cooling, and liquefying recovered carbon dioxide gas. Therefore, a method is disclosed in which the cooling heat of a cooling medium returning from a carbon dioxide liquefaction and freezing coil is used for cooling and dehumidification in a pre-liquefaction process, thereby enhancing energy-saving properties. However, the energy-saving properties of the front-stage carbon dioxide gas separation and enrichment apparatus are not affected.the use of the waste heat generated by the compression and condensation device is taken into account.

[0019] Patent Document 3 mentions that a DAC technology uses process heat generated during the recovery and enrichment process as a heat source for carbon dioxide capture and enrichment, in addition to cogeneration waste heat, solar heat, biomass, geothermal energy, and nuclear power, but no specific method is disclosed. However, the implementation is certainly limited to locations or environments where heat source energy can be obtained.

[0020] Patent Document 4 relates to a DAC technique. A method is disclosed in which, in a carbon dioxide gas separation and enrichment device, carbon dioxide gas is desorbed and recovered through superheated steam during desorption by a heat exchanger element installed in an adsorption structural body along with heating. During adsorption, a cooling fluid flows into the heat exchanger element, and the carbon dioxide gas is adsorbed while cooling. During switching between adsorption and desorption, the heat capacity of the heat exchanger element itself affects and complicates the heat efficiency of the entire device. Furthermore, an example is also disclosed in which a steam generation heat exchanger and a steam condensation heat exchanger for recovering the condensation heat for steam generation are connected to a heat pump.Furthermore, a method is also disclosed in which the desorbed carbon dioxide-containing gas is recompressed, the temperature rises, and the partial vapor pressure is simultaneously increased. This method is introduced into a boiler evaporator as a heat source, generating water vapor for desorption via a heat exchanger, and simultaneously reusing the condensed water. Furthermore, to prevent heat deterioration of the amino adsorption structure and improve the purity of the recovered gas, repeated vacuum release and pressure build-up operations are necessary, which also consumes energy and makes the device complex.

[0021] Patent Document 5 discloses a wet TSA method carbon dioxide gas separation and enrichment apparatus, in which a method for recovering and enriching carbon dioxide gas, comprising a process in which a honeycomb rotor having a function of adsorbing carbon dioxide gas is housed and rotated in a sealed casing having at least a treatment adsorption zone and a desorption zone, and in the adsorption zone, in a state in which the honeycomb is humidified, it comes into contact with a mixed gas containing carbon dioxide gas and adsorbs the carbon dioxide gas under evaporative cooling, and a process in which, in the desorption zone, saturated steam is introduced into the honeycomb that has adsorbed the carbon dioxide gas, a cycle in which the inlet and outlet of the desorption zone are communicated is constructed,and a fan and a steam generation heater are provided within the circuit. While the gas is circulated within the circuit, the heat transfer surface of the steam generation heater is heated by supplied water and saturated steam is supplied by boiling vapor pressure. The oxygen concentration of the circulating gas is reduced, and an effect of preventing deterioration due to thermal oxidation of the amino adsorbent is expected. However, conversely, a lack of desorption due to the partial pressure of the carbon dioxide gas and, consequently, a reduction in the recovery rate were observed.

[0022] Patent Document 6 discloses a heat pump type steam / hot water generation device that recovers heat from warm wastewater and generates and supplies steam and hot water through a heat pump. The application of a carbon dioxide capture and enrichment device can be easily conceived by an engineer, but creativity is required regarding how this steam is used.

[0023] Patent Document 7 discloses a device for increasing dry ice production efficiency. When liquid carbon dioxide gas is discharged under atmospheric pressure, the carbon dioxide gas is cooled and desublimated by the latent heat of gasification, and dry ice is generated. However, the resulting dry ice accounts for about 40% of the discharged carbon dioxide gas, and the remainder becomes gaseous. This patent discloses that by subcooling the liquid carbon dioxide before it is discharged, the yield is increased to 60 to 70%. Patent Document 8 discloses a technique in which, in a dry ice production process, the undesublimated carbon dioxide gas is recovered, recompressed, and liquefied, thereby preventing gas loss.

[0024] Patent Document 9 discloses a method for separating and enriching carbon dioxide gas in the air by a DAC technique and a wet TSA method, but the use of the recovered carbon dioxide gas and the desorption heat source of the carbon dioxide separation and enrichment device are not disclosed, and unless these two extremely important problems are solved, the popularization and promotion of a CCU technology are undesirable. [Means of solving the task]

[0025] Liquid carbon dioxide products are standardized, and depending on their intended use, they may be purified to an even higher purity than circulating products. When carbon dioxide gas is used for medical purposes, food, chemical raw materials, and welding, it affects the quality of the product, which is why there are quality requirements, with JIS specifying purity and water content, among other things. However, even though it is also a carbon dioxide product, there are no JIS standards for the use of dry ice as a coolant, and the manufacturer's quality guidelines specify that it be white or have no unpleasant odor. Commercial carbon dioxide gas must be dehumidified to a water content of a standard value or lower, but in dry ice production, liquid, etc., is added to solidify the snow-like dry ice, and it is hardened, etc., the purity is not strict and impurities such as oxygen or nitrogen and water content etc., which are considered to be a problem with commercial gas, are not a problem with dry ice.

[0026] Therefore, the present inventors aimed at a high-value-added system, which is a small and compact carbon dioxide gas separation and enrichment and dry ice production system with high energy saving, in which carbon dioxide gas is recovered from the air by a rotor having a function of adsorbing carbon dioxide gas, the system's internal compression waste heat, the cooling and dehumidification waste heat, the waste heat of the gas liquefaction and freezing machine, and the waste heat of the air conditioner, etc., which are generated in the process of compression and liquefaction of the recovered carbon dioxide gas are recovered and used as a heat source for desorption of a carbon dioxide gas separation and enrichment device, and the air after the treatment can be used as an air supply for air conditioning.

[0027] A dry ice production system has been invented, which is a system for separating, enriching, cooling, and liquefying carbon dioxide gas and producing dry ice, which is constructed by a wet TSA carbon dioxide gas separation and enrichment device, a saturation vapor generation device, a cooling and dehumidification device, a gas compression device, an adsorption dehumidification device, a cooling device, a liquefaction device, a freezer, a cooling tower, a liquid carbon dioxide purification tank, and a dry ice production device, wherein non-desublimated gas is recovered during dry ice production in the gas compression device, wherein the wet TSA carbon dioxide gas separation and enrichment device accommodates and rotates a rotor having a carbon dioxide gas adsorption capacity in a housing,in which a "purging and recovery block" of a structure with high thermal insulation is installed, which has, at least in the direction of rotation, a treatment zone, a purging zone, and a desorption zone, each of which is sealed, wherein in the treatment zone, in a humidified state of the rotor, the carbon dioxide gas is adsorbed by introducing and evaporatively cooling air; wherein in the purging zone, non-liquid gas is introduced from the liquid carbon dioxide purification tank, and air contained in the gap of the rotor is purged and discharged; wherein in the desorption zone, saturation steam generated by the steam generation device is introduced by the pressure of the steam generation; wherein the carbon dioxide gas is desorbed and recovered and enriched by the heat of condensation of the steam;whereby an air supply is possible for conditioning the outlet air of the treatment zone and the carbon dioxide in the air is turned into a gas source.

[0028] As a method for further increasing energy saving, a wet TSA carbon dioxide capture and enrichment device has been invented, in which a rotor having adsorption capacity for carbon dioxide gas is housed and rotated in a casing, into which a "purge and recovery block" of a structure with high thermal insulation is installed, which has a treatment zone, a purge zone, and a plurality of recovery zones with one or more stages, and a desorption zone in sequence in the direction of rotation, and each of which is sealed, wherein in the treatment zone, in a humidified state of the rotor, the carbon dioxide gas is adsorbed by introducing and evaporatively cooling air, wherein in the purge zone, non-liquid gas is introduced from the liquid carbon dioxide purification tank, and air contained in the gap of the rotor is discharged,Saturated steam is introduced into the desorption zone, and highly concentrated carbon dioxide gas is desorbed by the condensation heat of the steam and introduced into the recovery zone of the front stage of the rotation direction, passing through the recovery zone of the further front stage of the rotation direction and the multiple recovery zones toward the front stage of the rotation direction in sequence and being recovered. If the aforementioned wet carbon dioxide capture and enrichment device of the dry ice production system is replaced with this device, further energy savings are achieved.

[0029] By using treatment outlet air with a low carbon dioxide gas concentration as the air supply for air conditioning, the added value for the widespread use of the system of the present invention was taken into account. The air that has passed through the treatment zone of the wet TSA carbon dioxide gas separation and enrichment device is cooled and dehumidified by a cooling coil and used as the air supply for air conditioning. The effluent water of the cooling coil is recovered and used as the supply water of the saturation steam device, thereby enabling energy saving for air conditioning, increased added value of the dry ice production system of the present invention, and water conservation.

[0030] Furthermore, to enhance the energy-saving characteristics of the entire system, the recovery of waste heat generated in and around the system was considered. The saturation steam generation device is a heat pump steam generation device that utilizes waste heat. The waste heat from the freezer and a nearby refrigeration and air conditioning device, which perform compression heat cooling and liquefaction of the recovered carbon dioxide gas, is recovered and fed to a steam generation heat pump, generating saturation steam.

[0031] Energy saving through low-dew point dehumidification of the recovered gas has also been considered. A honeycomb rotor adsorption dehumidifier, which has a treatment zone and a renewal zone, introduces high-temperature compressed gas from the gas compression device into a renewal zone, and desorbes the adsorption water of the rotor. This outlet gas is cooled and dehumidified through a cooling coil, introduced into the treatment zone, and then introduced into the dehumidification device, which adsorbs and dehumidifies. This also realizes energy saving through low-dew point dehumidification. [Advantages of the invention]

[0032] The dry ice production system of the present invention, which allows air supply for air conditioning and converts carbon dioxide in the air into a gas source, is configured by a wet TSA carbon dioxide gas separation and enrichment device, a saturation vapor generation device, a cooling and dehumidification device, a gas compression device, an adsorption dehumidification device, a cooling device, a gas liquefaction device, a freezing machine, a liquid carbon dioxide purification tank, and a dry ice production device. Each carbon dioxide gas separation and enrichment system requires compression, cooling, and liquefaction processes, and each process consumes energy and generates associated waste heat. The carbon dioxide gas compression and liquefaction processes generate considerable amounts of compression heat and conversion heat of cooling and liquefaction.The heat of compression and the heat of conversion from cooling and condensation are radiated into the atmosphere through a radiator, similar to a conventional cooling tower. By recovering this heat and using it as energy for capturing and enriching carbon dioxide in the air, a system can be implemented that can be located anywhere, away from large sources of carbon dioxide generation and usable waste heat sources.

[0033] Furthermore, when the liquefied carbon dioxide is charged into the purification tank, non-liquid gas also enters, but the non-liquid gas contains impurities derived from the air components, so it is discharged into the tank to increase purity and reduce the resistance of the liquefied gas to introduction. In the present invention, this non-liquid gas is used as the purge gas of the wet TSA carbon dioxide gas separation and enrichment device, thus producing an effect of increasing the concentration of the recovered gas. Furthermore, in the dry ice production system, the non-desublimated gas is returned to the gas compression device and recovered during dry ice production, thereby increasing the recovery efficiency and energy-saving characteristics of the entire system.

[0034] The wet TSA carbon dioxide gas separation and enrichment device comprises a treatment zone, a purge zone, and a desorption zone. In the treatment zone, the rotor is humidified and contacted with the air containing carbon dioxide gas, and the carbon dioxide gas is adsorbed under evaporative cooling. Non-liquid gas is introduced from the liquid-gas purification tank into the purge zone, and air contained in a gap of the rotor is purged and discharged, and then rotated and moved to the desorption zone. Therefore, the movement of the air to the desorption zone is prevented, the concentration of the recovered carbon dioxide gas is increased, and deterioration due to thermal oxidation of the adsorbent in the desorption zone is prevented. At the desorption zone, saturated steam of approximately 100°C is introduced by boiling pressure, and the adsorbed carbon dioxide gas is desorbed and recovered.Approximately 100 °C refers to the fact that the boiling point of water changes due to pressure, which is why a fluctuation of a few °C, including plus and minus, is assumed due to the resistance to the introduction of the saturation vapor into the desorption zone or the air pressure.

[0035] Furthermore, to enhance the energy-saving performance of the wet TSA carbon dioxide gas separation and enrichment device, a structure was invented in which the zones of the rotor are divided and sealed in the rotation direction sequentially into a treatment zone, a purge zone, and further into multiple recovery zones of one or more stages and a desorption zone. Similarly, non-liquid gas is introduced from the liquid gas purification tank into the purge zone, and air contained in the rotor gap is discharged. Saturated steam of approximately 100°C is introduced into the desorption zone, and highly concentrated carbon dioxide gas is desorbed by the condensation heat of the steam. However, a recovery zone is provided between the purge zone and the desorption zone.The enthalpy of the desorption outlet gas passes through the front stage side of the rotation direction of the desorption zone and is recovered, whereby an effect that the rotor is preheated before desorption and an effect that, by pre-cooling the recovery gas, the load of cooling and dehumidification in the post-process can be reduced, and the risk of air being mixed into the desorption zone can be further reduced.

[0036] For the recovery zones, multiple recovery zones with one or more stages can be provided. The desorption zone outlet gas is introduced into a recovery zone 1 of the front stage in the direction of rotation, and then passes through the multiple recovery zones in sequence toward a recovery zone 2 of the front stage in the direction of rotation and toward the front stage side of the direction of rotation and is recovered. Regarding the number of stages where there is no excess or deficiency, based on knowledge of the heat exchange efficiency of a rotary heat exchanger, it can be assumed that, even if there are differences due to the rotor width or the passage speed, it corresponds to a total passage length of the recovery zones of 200 to 400 mm. For example, ifthe number of cells is 190 and the rotor width is 500 mm, if the desirable total pass length is 200 mm, four passes can be estimated, but it should be determined by evaluating the economics and effect in experiments.

[0037] On the other hand, the carbon dioxide concentration of the air that has passed through the treatment zone decreases, and due to the evaporative cooling effect, the temperature changes little, but the absolute humidity increases. This air is cooled and dehumidified by the cooling coil. The air, which has high air quality and low carbon dioxide concentration, is used as air supply for air conditioning. It can be expected to increase the mental productivity of the people in the room. The effluent water from the cooling coil is reclaimed and fed into the saturation steam generator, further increasing the implementation advantage and cost-effectiveness in terms of initial and running costs.

[0038] To liquefy the recovered carbon dioxide gas, it must be compressed and cooled. When compressed through multi-stage compression to 6.4 MPa, the gas temperature reaches approximately 130°C, and steam generation is also possible through heat exchange with this gas. However, if the amount of steam generated is insufficient, the waste heat from the refrigerator or condenser, freezer, and, if necessary, the air conditioning machine, etc., of the adjacent facility is recovered within the system of the present invention. As a heat source of the steam generation heat pump, it can cover the desorption energy of the carbon dioxide gas separation, recovery, and enrichment devices.

[0039] For dehumidification at a low dew point of the recovered gas, it is best to combine it with a rotor adsorption dehumidifier. A honeycomb rotor adsorption dehumidifier, which has a treatment zone and a renewal zone, introduces high-temperature compressed gas from the gas compression device into the renewal zone, and the rotor's absorption water is desorbed. As the temperature of the passing gas decreases due to the heat of desorption, the dew point temperature (absolute humidity) simultaneously increases, and it is cooled and dehumidified by the next cooling coil pass. Furthermore, the recovered gas passes through the treatment zone of the rotor adsorption dehumidifier, is dehumidified to a low dew point temperature, and is introduced into the next-stage compressor.

[0040] This dehumidification method allows the dew point temperature of the recovery gas to be dehumidified to a negative dew point lower than the temperature of the cooling coil. Therefore, while achieving the same dehumidification effect as the conventional PSA, TSA, and PTSA methods, the excess heat within the system can be utilized for renewal energy. A honeycomb rotor rotary dehumidifier, which is one form of such a TSA dehumidification method, is well known, but by combining it in this way in the system of the present invention, a contribution is made to enhancing the energy-saving characteristics of the entire system.

[0041] In the system of the present invention as above, the waste heat generated within the system is recovered, and saturated steam is generated and used as a desorption source for the adsorbed carbon dioxide gas, thus achieving energy savings in the entire system. Of course, electrical power is required to operate the system, but since solar radiation is high during periods and in areas where dry ice demand is high, it is well suited to solar power plants. Furthermore, since these are hot areas, waste heat from refrigeration can also be utilized, and the low supply of carbon dioxide gas after treatment enables high-quality air conditioning without excessive ventilation, and when the ambient air for air conditioning or cooling is sufficient, the system can be used to reduce the air quality.When the exhaust air is converted into treatment air, the carbon dioxide gas concentration is higher than in the outside air, which is why an effect that the recovery amount is increased or an energy saving effect of the air conditioning through enthalpy recovery of the ambient air during ambient air treatment can be expected.

[0042] Furthermore, the system of the present invention eliminates the carbon dioxide gas source or waste heat source required by the prior art, and can be deployed as a medium- and small-scale system. Therefore, it has the feature of being able to be distributed and deployed in any area requiring dry ice. It can reduce the amount of carbon dioxide gas discharged by transporting dry ice or carbon dioxide gas, and achieve efficiency improvement for the entire enterprise. Furthermore, the carbon dioxide gas separation and enrichment device of the present invention has a significantly lower heat capacity than that of a conventional absorption liquid method. The entire system can be easily started, stopped, and paused according to the dry ice production needs, and the associated heat loss is also low.

[0043] Together with the dry ice production as above, the combination with the energy-saving air conditioning use of air with low carbon dioxide gas concentration can promote the spread as a CCU technology and enable the acceleration of the reduction of petrochemical plants where the production of carbon dioxide was previously permitted. [Brief description of the drawings] [ Fig. 1] is a basic flow diagram of a dry ice production system using carbon dioxide in the air as a gas source, in which air supply for air conditioning is also possible, a first embodiment of the present invention. [ Fig. 2] is a detailed view of a carbon dioxide gas separation and enrichment apparatus of the first embodiment of the present invention. [ Fig. 3] is a basic flow diagram of a dry ice production system using carbon dioxide in the air as a gas source, in which air supply for air conditioning is also possible, a second embodiment of the present invention. [ Fig. 4] is a detailed view of a carbon dioxide gas separation and enrichment apparatus of the second embodiment of the present invention. [ Fig. 5] is an explanatory sectional view of the principle of a treatment, purging, second recovery, first recovery, and desorption zone section of the carbon dioxide gas separation and enrichment apparatus of the second embodiment of the present invention. [ Fig. 6] is an explanatory sectional view of the principle of the carbon dioxide gas separation and enrichment apparatus of a third embodiment of the present invention. [ Fig. 7] is an explanatory view of the principle of a honeycomb rotor dehumidifying apparatus of the second embodiment of the present invention. [ Fig. 8] is a flow diagram of a small-scale experimental device in which actual samples and experiments were carried out. [ Fig. 9] is an implementation design of a medium-sized cassette. [ Fig. 10] is an implementation design of a quad group unit of a medium-sized cassette. [Embodiments of the invention]

[0044] In the following, embodiments to which the present invention is applied will be explained in detail based on the drawings. Components, etc., designated by the same reference numerals in the drawings have the same or similar structures, and duplicate explanations thereof will be omitted as appropriate. Furthermore, for components, etc., that are not necessary for explanation, illustration will be omitted as appropriate.

[0045] The present inventors arrived at the present invention based on the fact that techniques for capturing and enriching carbon dioxide gas in the air have been researched and developed using rotor-type wet TSA (temperature swing) processes, which are compact and have high energy-saving characteristics. First, the principle and advantages of a wet TSA process will be explained. A wet TSA process is a process in which saturated steam, rather than superheated steam, is used to desorb carbon dioxide gas, and the carbon dioxide gas is desorbed, enriched, and recovered using the latent heat of the saturated steam. Unlike previous dry TSA processes, hot air or steam is not used.Gas is used for desorption, which not only enables high concentration enrichment and recovery, but also condenses water vapor at the same time as desorption, leaving the liquid on the surface in the honeycomb. In the treatment adsorption zone, carbon dioxide gas is adsorbed under evaporative cooling. Therefore, the rotor is quickly cooled immediately after desorption. At the same time, the adsorption heat of carbon dioxide gas is balanced and temperature rise is suppressed. Therefore, the adsorption efficiency and energy saving properties of carbon dioxide gas are rapidly increased compared with the previous dry TSA process or superheated steam TSA process.

[0046] Furthermore, since desorption is performed by a saturated vapor at approximately 100°C, which does not contain air, it has the effect of preventing deterioration due to thermal oxidation of the amino adsorbent. Furthermore, if a rotational movement is performed directly after desorption at high temperature toward the treatment zone and contact with air is established, the adsorbent surface is moistened with condensation, thus preventing direct contact with oxygen. Cooling is rapidly achieved through the evaporative cooling effect due to the passage of the treatment air, and deterioration due to thermal oxidation is also suppressed.

[0047] In the present invention, such an inventive achievement has been achieved that in the wet TSA method, further prevention of deterioration by thermal oxidation of the adsorbent and increase of the recovery rate and recovery concentration are achieved and the energy saving properties are enhanced. [Embodiment 1]

[0048] Fig. Figure 1 is an overall system of embodiment 1. The treatment gas is atmospheric or air-conditioning air, so no special pretreatment is required, and it is acceptable to have a dust filter, such as that used in general air conditioning, installed. If it is water-soluble impurities or fine dust, they are drained, removed, and expelled along with water condensed in a cooling coil within the system. If necessary, it is also easy to install an activated carbon deodorizing filter at the treatment air inlet. First, a carbon dioxide gas separation and enrichment device is constructed using Fig. 2. A rotor 1 capable of adsorbing carbon dioxide gas is driven and rotated by a rotor drive motor 2 through a belt 3. A chain drive is also available for large models. When treatment air is introduced into a treatment zone 4 of the rotor by a fan 7, the carbon dioxide gas is adsorbed while evaporatively cooling the rotor in a humidified state, and the adsorption heat is simultaneously cooled and removed.

[0049] As the rotor rotates toward a purge zone 6, non-liquid gas is introduced from a liquid carbon dioxide gas purification tank, and air contained in a gap of the rotor is purged and discharged to the treatment zone side. This purge has the effect of preventing air from interfering with the recovered gas and increasing the recovery concentration. It also prevents oxygen from interfering with the desorption zone, which reaches a high temperature, preventing deterioration due to thermal oxidation of the adsorbent, and increasing the durability. Furthermore, by adsorbing carbon dioxide gas, which has a higher concentration than air immediately before desorption, it is expected to increase the recovery amount.There is the effect that in any direction of passage of the purge gas, the air in the gap of the rotor is purged, but when it is discharged to the inlet side of the treatment zone and merges with the treatment air, the amount of purge gas is enormous, and even if the carbon dioxide gas is discharged with a relatively high concentration, it is re-adsorbed in the treatment zone, which is why it is not wasted.

[0050] When the rotor rotates toward the desorption zone 5-1, saturation steam is introduced by the steam generation pressure from the saturation steam generation device, and the carbon dioxide gas is desorbed by the condensation heat, and the condensed water remains in the rotor. The mixed gas of the desorbed carbon dioxide gas and water vapor is cooled by a cooling coil 10-1 of the Fig. 1. Next, the cooled and dehumidified recovered gas is introduced into a compression device 11-1, pressurized, and heated. Liquefaction of carbon dioxide gas by single-stage compression is difficult, so the heated gas is cooled again by a cooling coil 10-2, introduced into a second-stage compressor 11-2, and pressurized to about 4 MPa, and although it is in Fig. 1, it may also be further cooled and pressurized to approximately 6.4 MPa in a third-stage compression device. The finally pressurized gas is cooled again and, after being dehumidified to a low dew point temperature by an adsorption dehumidifier 13, is cooled and liquefied to a condensing temperature or below by a condenser 15.

[0051] The higher the pressure, the easier it is for carbon dioxide to liquefy, but the compression energy becomes large, the melting rate of contaminated gas to liquefied gas increases, and the purity decreases. Conversely, at low pressure, cooling to a lower liquefaction temperature is required, and the cooling load increases. Furthermore, the COP (Coefficient of Performance) of the freezer also decreases, resulting in a trade-off relationship where the energy consumption of the freezer increases. The liquefied carbon dioxide is transferred to the purification tank, and the non-liquid gas is removed, improving its purity and storing it. The removed gas is used for purging the separation and enrichment device.

[0052] The extraction amount of the non-liquid gas from the purification tank must be an excess amount, which can sufficiently purge the amount contained and moving in the rotor gap. If there is a shortage, air will be mixed into the recovery gas. Even if the amount is excessive, the non-liquid gas that has passed through the purging zone merges with the treatment air and passes through the treatment zone again, being adsorbed, and thus not wasted. The volume of the purge gas fluctuates due to changes in temperature and humidity and the adsorption of carbon dioxide, so it is convenient to measure and regulate the carbon dioxide gas concentration at the gas outlet of the purge zone 5-1.

[0053] The recovered gas is heated to 100 °C or more by a compressor 11-1, 11-2, and saturation steam generation is also possible using the heat of this gas, but when there is a lack of desorption energy only by the heat of this gas, the waste heat such as the cooling and dehumidification heat or the compression heat and the liquefaction heat are recovered to liquefy the recovered gas by the steam generation heat pump, and saturation steam is generated and introduced into the desorption zone of the carbon dioxide capture and enrichment device.Through the above structure, the waste heat generated in the compression, cooling and dehumidification, cooling and liquefaction process of the captured and enriched carbon dioxide gas is recovered and utilized, and the capture and enrichment of the carbon dioxide gas in the air is enabled, and a dry ice making system with carbon dioxide gas in the air as the gas source, which is more energy-saving and compact than the prior art, is possible. [Embodiment 2]

[0054] Fig. 3 is a view of the entire system of Embodiment 2. Such an inventive achievement has been achieved that, in the aforementioned wet TSA method, further prevention of deterioration by thermal oxidation of the adsorbent and an increase in the recovery rate and recovery concentration are achieved, and the energy-saving properties are enhanced. First, in Fig. Figure 4 explains the details of the carbon dioxide gas separation and enrichment device. The rotor 1, which can adsorb carbon dioxide gas, is divided sequentially into a treatment zone 4, a purge zone 6, a stage 2 recovery zone 5-3, a stage 1 recovery zone 5-2, and a desorption zone 5-1 in the rotation direction, and is driven and rotated by the belt 3 at the rotor drive motor 2.

[0055] When air is introduced into the treatment zone 4 of the rotor by the fan 7, the rotor in a humidified state promotes the adsorption of carbon dioxide gas and simultaneous evaporative cooling of the liquid, while the generated adsorption heat is also cooled and eliminated. In the gas purging zone 6, which has been rotating, non-liquid gas is introduced from the liquid carbon dioxide gas purification tank 16, and air contained in the gap of the rotor is purged. Saturated steam is introduced into the desorption zone 5-1. The carbon dioxide gas adsorbed by the rotor is desorbed and recovered through the stage 1 recovery zone 5-2 and further through the recovery zone 5-3 on the side of the previous stage of rotation.

[0056] In Fig. Figure 5 illustrates the gas flow in the rotor in more detail. The rotor rotates from treatment zone 4 to purge zone 6, and non-liquid gas is introduced. Air contained in the rotor gap is purged and discharged to the inlet side of treatment zone 4, mixed with the treatment air, and reintroduced into the treatment zone. This purging has the effect of preventing air from mixing into the recovered gas and increasing the recovery concentration. It also has the effect of preventing deterioration due to thermal oxidation of the adsorbent in the desorption zone 5-1, which reaches a high temperature, and increasing its durability. It also has the effect of increasing the recovery amount through contact adsorption with carbon dioxide gas, which has a higher concentration than air immediately before desorption.At the same time, by removing the non-liquid gas from the gas purification tank 16, there is the effect of increasing the purity of the liquid gas.

[0057] In the desorption zone 5-1, saturated steam is introduced, and the carbon dioxide gas is desorbed by the latent heat of condensation, leaving the condensed water in the rotor. The mixed gas of desorbed carbon dioxide gas and water vapor passes through the stage 1 recovery zone 5-2 of the previous stage of rotation, is redirected, passes through the stage 2 recovery zone 5-3, and is recovered. Thus, the enthalpy (self-heat and latent heat) of the desorption outlet gas is recovered by the residual heat of the rotor before desorption. Conversely, the passage of the recovered gas reduces the enthalpy and reduces the load on the cooling and dehumidification coil 10-1 of the next process.

[0058] The abundance and deficiency of the effect of the recovery zone's number of stages is tested and confirmed, and three or four stages can be added to the previous stage of the rotation direction. Experiments to date have confirmed the effectiveness of one stage, and the necessity of additional equipment and the potential for improving energy-saving performance have been recognized. Thus, complicated flow path structures and thermal insulation treatments are difficult to implement in the prior art, but they can be realized by a "laminate purge and recovery block" structure (Patent Document 9).It is a laminated structural body of fan-shaped films each having or not having zone spaces, wherein, in a sliding surface in contact with a rotor end face, a heat-resistant and friction-resistant sliding film, a foam rubber layer at the lower layer thereof, a foam rubber layer or a foam board layer in which communication paths are provided between the zone layers at the lower layer thereof, and a heat insulation board in which the bottom surface layer has no spaces are laminated, bonded, and made into a block, and it can be easily and inexpensively manufactured by a "laminate structure purge and recovery block" of a structure with high heat insulation in which a steam introduction part, a desorption gas recovery part, and a purge gas inlet and outlet part are provided at the outer peripheral part or the bottom surface. [Third embodiment of the carbon dioxide gas separation and enrichment device]

[0059] In Fig. 5, an example is shown in which, toward the front stage side of the rotor rotation direction, a desorption zone, a stage-1 recovery zone, and a stage-2 recovery zone are introduced into the rotor in sequence while reversing the gas flow direction, but the desorption zone, the stage-1 recovery zone, and the stage-2 recovery zone may be arranged as shown in Fig. 6, all of which are also set to the same gas flow direction. From each zone, the outer peripheral side of the rotor is diverted and sequentially travels in a spiral to the front stage of the rotation direction. From the perspective of processability, assembly adjustment, and thermal insulation properties, the diverter can be constructed by stacking and bonding a foam silicone rubber tube or multiple foam silicone rubber sheets, etc., with the gas flow path cut out or not removed. This method is desirable from a thermodynamic point of view, but the structure becomes quite complicated, so it should be chosen from a cost-effectiveness perspective. If it is for air conditioning a confined enclosed space such as a spacecraft, etc., performance is considered more important than cost.

[0060] Here, the recovery amount and scale sense in a case where the wet TSA carbon dioxide capture and enrichment device was actually implemented are estimated based on actual experiment results (Patent Document 9). Fig. Fig. 8 is a block diagram of an actually implemented small-scale experimental device, wherein it is Fig. 4 of the present invention, but slightly different from it. For example, the purge gas is not a non-liquid gas, but it is a structure in which, via circulating purge zones 6-1, 6-2 provided at the front and rear portions of the recovery and desorption zone, gas contained in the gap of the rotor immediately after it rotates from the desorption zone 5-1 to the desorption gas purge zone 6-1 is removed and introduced into the treatment air purge zone 6-2 immediately behind the treatment zone. By purging the air contained in the gap of the rotor, air mixing into the recovered gas is prevented.

[0061] The rotor is an amino adsorbent honeycomb with about 190 cells, and it is experimental data in the midst of optimization regulation, so the concentration of recovered carbon dioxide gas is limited to about 50%, but through regulation, a further concentration increase is possible, and moreover, by purging by the non-liquid gas of the present invention, a high-concentration recovery close to 100% is assumed.

[0062] Furthermore, the recovery rate (removal rate from the through-flow air side) of carbon dioxide gas from the outside air is not high at about 45%, but this is based on a rotor width of 50 mm and a treatment air flow velocity of 3.3 m / s. The rotor width affects the heat exchange efficiency of the entire heat exchanger, the dehumidification efficiency of a dehumidifier, and the removal rate of a VOC enrichment rotor. When high performance is required, a wide rotor width such as 200 to 600 mm is selected. Since pressure loss occurs in the flow area of ​​the layers, it increases in direct proportion to the rotor width and flow velocity, and also changes depending on the gas components and temperature., at an air flow velocity of 3.3 m / s and at 30 °C it reaches 550 Pa with 190 cells and a width of 400 mm and about 140 Pa with a width of 50 mm.

[0063] The carbon dioxide gas in air capture and enrichment device of the present invention has a sufficient recovery rate at a width of 50 mm. This is because, rather than aiming for an even higher recovery rate, the low pressure loss, which is an advantage of a narrow-width rotor, makes it an axial fan, which is simple and inexpensive like a ventilation fan, and can absorb large amounts of treatment air and adsorb large amounts of carbon dioxide gas with lower electrical power than a centrifugal fan.On the other hand, the narrow width is feared to reduce the desorption efficiency, but in the present invention, the desorption outlet gas passes through the treatment zones of one or more stages of the front stage of the rotation direction and is recovered, thereby enhancing the energy-saving characteristics by the sufficient desorption effect, preheating before desorption of the rotor by the enthalpy recovery effect, and the effect that the desorption gas can be cooled and dehumidified.

[0064] The scale of the actual machine is estimated based on experimental data. Fig. 9 is a medium-sized cassette of a single separation and enrichment rotor with a rotor diameter of approximately Φ 2000 mm and a rotor width of 50 mm, with a treatment air volume of 40000 m 3 / h and at a carbon dioxide concentration of 400 ppm and a recovery rate of 45%, the recovery amount of carbon dioxide gas is 8 m 3 / h≈14.2 kg / h / piece. If this rotor cassette, as shown in Fig. 10, square is combined in a group of four, it is good if the treatment blower is a single large model and it is expected that the separation and enrichment of carbon dioxide in the air will be 56 kg / h with an arrangement area of ​​6.6 m 2 enabled.

[0065] It is used to explain the system of Fig. 3. The recovered gas passes through the cooling coil 10-1, is cooled and dehumidified, introduced into the compression device 11-1 of the next stage, and pressurized and heated. The heated gas is next introduced into the desorption zone 12-1 of the rotor-rotary adsorption dehumidifier 12 (a detailed view is shown in Fig. 7) and the liquid adsorbed by the rotor is desorbed, and due to the heat of desorption, the gas temperature decreases and the absolute humidity increases. Next, it is cooled and simultaneously dehumidified by the cooling and dehumidifying coil 10-2, introduced into the treatment zone of 12-2, adsorbed and dehumidified, and introduced into the compression device 11-2 and further compressed. By combining the cooling and dehumidifying coil 10-2 and the rotor dehumidifier 12, dehumidification can be achieved down to a dew point temperature lower than the cooling water temperature, which is why the Fig. 1 of Embodiment 1 becomes unnecessary and energy is saved.

[0066] When liquefying carbon dioxide gas, single-stage compression is difficult, so the gas leaving the treatment zone 12-2 of the rotor dehumidifier 12 is introduced into the second-stage compressor 11-2 and pressurized to approximately 4 MPa. It is Fig. 3, but if further demand arises, it is cooled again and pressurized to approximately 6.4 MPa by the third-stage compression device. The pressurized gas is cooled again and cooled and liquefied by the liquefaction device 15.

[0067] At the condensation temperature, cooling to -15°C or less is required at a pressure of 2.2 MPa, to 5°C or less at 3.9 MPa, and to 25°C or less at 6.4 MPa. When high compression is applied, condensation is easy, but a lot of compressor energy is required. Conversely, when the pressure is low, cooling to a low temperature is required for condensation, but the melting of the contaminated gas decreases and the purity of the liquid carbon dioxide is increased. On the other hand, the load on the freezer increases and the performance coefficient of the freezer deteriorates, thus increasing the required energy. In the case of dry ice production according to Patent Document 7, it is disclosed that, from the viewpoint of dry ice production yield, it is desirable to perform cooling to a subcooling state.The design should take various factors into account.

[0068] The saturation steam for desorption of the carbon dioxide gas capture and enrichment device is generated by the steam generation heat pump, recovering and utilizing the waste heat generated within the system, such as the aforementioned refrigeration device, condensing and freezing device, etc. Therefore, the increase in the compression load or cooling load for dry ice production is combined with the increase in waste heat sources for saturation steam generation, and is supplemented throughout the entire system, enhancing energy-saving properties. If waste heat sources are scarce, cooling waste heat and abundant solar heat are available during the dry ice demand period, so they can be used as supplemental heat.

[0069] The treatment outlet gas has a low carbon dioxide concentration, which allows it to be used as air supply for air conditioning. The air that has passed through the treatment zone of the carbon dioxide gas separation and enrichment rotor is cooled and dehumidified by the cooling coil and supplied to the air conditioning system. By reclaiming the effluent water from the cooling coil and supplying it to the saturation steam generator, this enables energy savings for air conditioning, increased value of the system of the present invention, and water conservation. This method has the advantage of being applicable to air conditioning of enclosed spaces such as space facilities, etc.

[0070] The liquefied gas is charged into the purification tank, but it contains non-liquid gas, and the non-liquid gas is discharged in the conventional manner to increase the purity of the liquefied gas. The non-liquid gas contains impurities, but its main component is carbon dioxide gas. This non-liquid gas is introduced into the purge zone of the rotor separation and enrichment device, thereby eliminating various problems caused by the air contained in the rotor gap moving to the desorption zone due to the rotation of the rotor. First, the purge of air increases the concentration of recovered carbon dioxide. Second, by passing through the recovery zones of the highly concentrated carbon dioxide gas, gas adsorption to the rotor further progresses, and the recovery amount of carbon dioxide gas is increased.Thirdly, since no oxygen-containing gas enters the desorption zone, there is also the effect of preventing the deterioration by thermal oxidation of the amino carbon dioxide adsorbent in the desorption zone.

[0071] For liquid carbon dioxide products, it is necessary to dehumidify them to ensure that the water content is within the standard, but in the production of block dry ice, hardening agents such as liquid, etc. are included to harden the snow-like dry ice, so for carbon dioxide gas used for dry ice, it is not necessary to be highly dehumidified like liquid gas.

[0072] The present invention was designed as a dry ice production system with consideration for dissemination, so that it becomes a pioneer of the CCU technology, but it is also possible that the liquid carbon dioxide is further purified without being converted into dry ice and implemented as a liquid carbon dioxide product. Furthermore, dry ice with about 1.56 g / cm 3 twice the specific weight of liquid carbon dioxide at about 0.77 g / cm 3 , meaning that the capacity is half and no high-pressure cylinder, which increases the weight, is necessary, which is why it is also assumed that a method will be developed in which dry ice for a CCUS plant is transported and accumulated in containers with high thermal insulation and low carbon emissions. [Industrial applicability]

[0073] The present invention relates to a dry ice production system in which air supply for air conditioning is also possible and carbon dioxide in the air is made into a gas source, and it is not limited to a carbon dioxide emission source or a waste heat source as before, but a dry ice production system can be provided in which dry ice can be produced in a necessary amount at a necessary time in necessary areas, therefore stockpiling associated with the change of seasons is unnecessary and waste heat orThe exhaust gas generated in the capture, enrichment, compression, cooling, dehumidification, and liquefaction processes is used together in the entire system, which has high energy-saving characteristics and is a complete system from carbon dioxide capture / enrichment to product manufacturing. Therefore, it can be arranged in a location where dry ice is needed, the size of a small factory in the city, there is no increase in the amount of carbon dioxide gas discharged due to transportation, air supply for air conditioning is possible, and carbon dioxide in the air is turned into a gas source. [List of reference symbols] 1 carbon dioxide adsorption rotor 2 rotor drive motor 3 rotor drive belts 4 Treatment zone 5-1 Desorption zone 5-2 Recovery Zone 1 5-3 Recovery Zone 2 6 rinsing zones 6-1 Desorption gas purge zone 6-2 Treatment air purge zone 7 treatment air blowers 8 Steam generating device 9 Cooling tower 10-1 Gas cooling coil 1 10-2 Gas cooling coil 2 10-3 Gas cooling coil 3 11-1 Gas Compressor 1 11-2 Gas Compressor 2 12 honeycomb rotor rotary adsorption dehumidifiers 12-1 Renewal Zone 12-2 Treatment zone 13 adsorption two-tower dehumidifiers 14 freezer 15 Carbon dioxide gas liquefaction device 16 Liquid carbon dioxide cleaning tank 17 Dry ice production device 18 Circulation flushing pump

Claims

[1] Dry ice production system for the production of dry ice and optionally liquid carbon dioxide, where air supply for air conditioning is also possible and carbon dioxide in the air is turned into a gas source, which is a steam generation heat pump device (8) which recovers waste heat from a device that compresses, cools and liquefies carbon dioxide gas within a system and generates steam, a carbon dioxide gas separation and enrichment device that separates and enriches carbon dioxide gas in the air, introduces the steam, and desorbes and recovers it through the latent heat of condensation of the saturated steam, a device (10-1) which cools and dehumidifies a mixed gas of the saturation steam and the carbon dioxide gas recovered in a separation and enrichment device, a compression device (11-1) with one or more stages, which compresses the cooled and dehumidified carbon dioxide gas for liquefaction, an adsorption dehumidification device (13; 12) which dehumidifies the compressed carbon dioxide gas, a gas liquefaction device (15) and a freezer (14) which cool the dehumidified carbon dioxide gas to a liquefaction temperature, a liquefied carbon dioxide gas purification tank (16) in which the liquefied carbon dioxide gas is introduced and liquefied carbon dioxide is stored and non-liquefied gas is removed, and a dry ice production device (17) in which the liquid carbon dioxide is conveyed from the liquid carbon dioxide purification tank (16) and released under atmospheric pressure, and the carbon dioxide is cooled and desublimated by the latent heat of evaporation thereof, and dry ice is produced, and in which non-desublimated gas returns to the compression device (11-1) and is recovered during dry ice production, wherein the device is a wet TSA carbon dioxide gas separation and enrichment device, in which the carbon dioxide gas separation and enrichment device houses and rotates a rotor (1) having an adsorption capacity of carbon dioxide gas in a housing which has a treatment zone (4), a purge zone (6), and a desorption zone (5-1), at least in the order of the direction of rotation, and is sealed,wherein in the treatment zone (4) in a humidified state of the rotor (1), air is introduced and the carbon dioxide gas is adsorbed under evaporative cooling; wherein in the purging zone (6), the non-liquid gas removed from the liquid carbon dioxide purification tank (16) is introduced and air contained in the gap of the rotor (1) is purged and discharged; wherein in the desorption zone (5-1), saturated steam of approximately 100°C generated by the steam generation heating pump device (8) is introduced and the carbon dioxide gas is desorbed by the heat of condensation of the steam and is enriched and recovered. [2] The dry ice production system according to claim 1, wherein it is a wet TSA carbon dioxide gas separation and enrichment device, wherein the wet TSA carbon dioxide gas separation and enrichment device accommodates and rotates a rotor (1) having an adsorption performance of carbon dioxide gas in a casing comprising, in the order of the rotation direction, a treatment zone (4), a purge zone (6), a plurality of recovery zones (5-2;5-3) with one or more stages and a desorption zone (5-1) and is sealed, wherein in the treatment zone (4) in a humidified state of the rotor (1), air is introduced and the carbon dioxide gas is adsorbed under evaporative cooling, wherein in the purge zone (6) the non-liquid gas from the liquid carbon dioxide purification tank (16) is introduced and air contained in the gap of the rotor (1) is discharged, wherein in the desorption zone (5-1) the saturation steam of approximately 100°C is introduced and highly concentrated carbon dioxide gas is desorbed by the condensation heat of the steam, wherein in the recovery zones (5-2; 5-3) the desorption gas passes through the recovery zones (5-2; 5-3) with one or more stages in sequence towards the front stage side of the direction of rotation and is recovered. [3] The dry ice production system according to claim 1, wherein air having passed through the treatment zone (4) of the wet TSA carbon dioxide gas separation and enrichment device is cooled and dehumidified by a cooling coil and used as air supply for air conditioning, wherein effluent water of the cooling coil is recovered and used as supply water of the saturation steam generation device (8). [4] The dry ice production system according to claim 1, wherein in the adsorption-dehumidification device (12), high-temperature gas compressed is introduced from a gas compression device (11-1) into a renewal zone (12-1) of a honeycomb rotor dehumidifier (12) having a treatment zone (12-2) and a renewal zone (12-1), and the adsorption water of the rotor (1) is desorbed, the outlet gas is cooled and dehumidified by a cooling coil (10-2) and introduced into a treatment zone (12-2) to adsorb and dehumidify it.

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