Gas treatment system and gas treatment method

Abstract

To provide a gas treatment system for use in recovering carbon dioxide, which operates with low power while achieving size reduction.SOLUTION: A gas treatment system 100 includes: a gas recovery system 200 including carbon dioxide recovery units 11, 12 that are supplied with exhaust g discharged from an engine 3 and recover carbon dioxide from the supplied exhaust g; and a carbon dioxide desorption system 300 that desorbs carbon dioxide from carbon dioxide recovery devices 21, 22 included in the carbon dioxide recovery units 11, 12. The gas recovery system 200 is mounted on a ship separately from the carbon dioxide desorption system 300.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas treatment system and a gas treatment method for recovering carbon dioxide from exhaust gas.

Background Art

[0002] Carbon pricing and carbon taxes are being considered in various countries, and the need for carbon dioxide (CO2) emission reduction technologies is increasing. Technical development for separating and recovering carbon dioxide from carbon dioxide emission sources is underway. For specific examples, carbon dioxide separation systems for boiler combustion exhaust gas from thermal power generation and biomass power generation, combustion exhaust gas from ship engines, combustion exhaust gas from waste incineration facilities, etc. are being considered.

[0003] Particularly in the maritime industry, regulations on carbon dioxide emissions reduction are being strengthened year by year. Specifically, in addition to the Energy Efficiency Design Index (EEDI) for new ships, the Energy Efficiency Existing Ship Index (EEXI) for existing ships has also been determined, and the need for CO2 emissions reduction for existing ships using heavy oil as fuel has become apparent.

[0004] Here, Patent Document 1 discloses a carbon dioxide recovery device that recovers carbon dioxide from combustion exhaust gas discharged from a combustor. In Patent Document 1, by cooling the combustion exhaust gas to about room temperature, moisture contained in the combustion exhaust gas is removed. Thereby, the amount of moisture adsorbed by the adsorbent for adsorbing carbon dioxide can be reduced, and it is possible to suppress a decrease in the adsorption performance of carbon dioxide by the adsorbent.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When recovering carbon dioxide using technologies such as those described in Patent Document 1, it is necessary to cool the combustion exhaust gas. When recovering carbon dioxide using other carbon dioxide separation methods, such as separation membranes, it is necessary to pressurize the combustion exhaust gas with a compressor, thus requiring a large amount of energy. However, on ships used in the shipping industry, there is a limited amount of energy available, so it is necessary to reduce energy consumption. In addition, on ships, there are space constraints for installation, so it is necessary to miniaturize the system.

[0007] This invention has been made in view of the above, and aims to provide a gas treatment system that can be miniaturized by carbon dioxide recovery and operated with low power consumption. [Means for solving the problem]

[0008] The gas treatment system of the present invention comprises a gas recovery system that includes a carbon dioxide recovery unit to which combustion exhaust gas discharged from a combustor is supplied and which recovers carbon dioxide from the supplied combustion exhaust gas, and a carbon dioxide desorption system that desorbs carbon dioxide from a carbon dioxide recoverer contained in the carbon dioxide recovery unit, wherein the gas recovery system is mounted on a ship separately from the carbon dioxide desorption system. [Effects of the Invention]

[0009] According to the present invention, the device can be miniaturized by carbon dioxide capture while operating with low power consumption. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing an example of a gas treatment system according to an embodiment of the present invention. [Figure 2] This figure shows an example of the configuration of a pre-processing device. [Figure 3]This figure shows an example of the configuration of a carbon dioxide capture unit. [Figure 4] This figure shows an example of a carbon dioxide desorption system. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1 is a schematic diagram showing an example of a gas treatment system according to an embodiment of the present invention. In this embodiment, the gas treatment system is considered to be a system for recovering carbon dioxide from exhaust gas discharged from an engine used in a ship as a combustor. As shown in Figure 1, the gas treatment system 100 comprises a gas recovery system 200 and a carbon dioxide desorption system 300.

[0012] The gas recovery system 200 includes an engine (combustor) 3 which is the source of combustion exhaust gas (hereinafter referred to as "exhaust gas") g, a pretreatment device 4, a heat removal / dewatering device 5, an exhaust gas reheat device 6, a blower 7, an inlet concentration sensor 8A, an outlet concentration sensor 8B, a unit switching valve 9, a unit switching valve 10, a carbon dioxide recovery unit 11, a carbon dioxide recovery unit 12, a cooling pump 13, a cooling pump 14, a cooling pump 15, an exhaust gas replacement purge valve 16, a control unit 31, a storage unit 32, and a communication unit 33.

[0013] Engine 3 may be a main engine or an auxiliary engine. The main engine is primarily used for propulsion. The auxiliary engine is primarily used for onboard power other than propulsion, propulsion during docking and undocking in harbors, and onboard power while at anchor. Engine 3 is supplied with fuel stored in a fuel tank (not shown). Engine 3 has a function to detect rotational speed as an operating load and outputs the detection result to the control unit 31 via a communication unit 33, which will be described later.

[0014] The pretreatment device 4 performs pretreatment of the exhaust gas g that flows into the carbon dioxide recovery units 11 and 12. The pretreatment device 4 separates and removes at least some of the impurities other than carbon dioxide (CO2) contained in the exhaust gas g. These impurities may include sulfur oxides (SOx), nitrogen oxides (NOx), or particulate matter (PM).

[0015] Figure 2 shows an example of the configuration of the pretreatment device 4. The pretreatment device 4 includes a nitrogen oxide treatment device 41, an exhaust gas waste heat utilization device 42, a dust removal device 43, and a sulfur oxide treatment device 44. Note that the pretreatment device 4 may be modified to include at least one of the above devices 41 to 44.

[0016] The nitrogen oxide treatment device 41 treats nitrogen oxides (NOx) contained in the exhaust gas g supplied from the engine 3. Treating nitrogen oxides (NOx) may mean removing nitrogen oxides (NOx). The nitrogen oxide treatment device 41 may be a denitrification device. The denitrification device may be, for example, a selective catalytic reduction (SCR) device. Alternatively, instead of the pretreatment device 4 having the nitrogen oxide treatment device 41, the engine 3 may have an exhaust gas recirculation (EGR) function.

[0017] The exhaust gas heat utilization device 42 is installed between the engine 3 and the dust removal device 43, and absorbs heat from the exhaust gas g to generate steam. The exhaust gas heat utilization device 42 may be an economizer.

[0018] The dust removal device 43 removes particulate matter (PM) contained in the exhaust gas g before it is supplied to the carbon dioxide recovery units 11 and 12. The dust removal device 43 may be an electrostatic precipitator (ESP), a diesel particulate filter (DPF), or an activated carbon filter.

[0019] The sulfur oxide treatment device 44 treats sulfur oxides (SOx) contained in the exhaust gas g after passing through the nitrogen oxide treatment device 41 and the dust removal device 43. Treating sulfur oxides (SOx) may refer to removing sulfur dioxide (SO2). When the gas recovery system 200 is installed on a ship, the sulfur oxide treatment device 44 may be a wet scrubber installed on the ship.

[0020] Returning to FIG. 1, when the temperature of the exhaust gas g exceeds the inlet allowable temperature of the carbon dioxide recovery units 21 and 22, the heat removal and dehydration device 5 removes the heat contained in the exhaust gas g. For example, the heat removal and dehydration device 5 performs heat exchange using seawater pumped up by a cooling pump 13 controlled by the control unit 31 via the communication unit 33, removes the heat of the exhaust gas g, and condenses and removes moisture from the exhaust gas g. For example, the dehydration means may be dehydration by an adsorbent such as silica gel, alumina, zeolite, activated carbon, etc. The exhaust gas reheating device 6 reheats the exhaust gas g using the circulating water of the cooling pump 13 heated by heat exchange with the heat removal and dehydration device 5. By reheating, condensation dripping when the saturated exhaust gas g radiates and cools is prevented. When the dehydration means is dehydration by an adsorbent, reheating by the exhaust gas reheating device 6 may not be necessary. For example, the exhaust gas reheating device 6 uses the cooling pump 13 controlled by the control unit 31 via the communication unit 33 to circulate the heated seawater and reheat the exhaust gas, thereby preventing condensation dripping of the water vapor in the exhaust gas g.

[0021] The exhaust gas g reheated by the exhaust gas reheating device 6 is sent to the carbon dioxide recovery unit 11 and the carbon dioxide recovery unit 12 by a blower 7 controlled by the control unit 31 via the communication unit 33. An inlet concentration sensor 8 is provided between the blower 7, the carbon dioxide recovery unit 11, and the carbon dioxide recovery unit 12. The inlet concentration sensor 8 has a function of measuring the concentration of carbon dioxide entering the carbon dioxide recovery unit 11 and the carbon dioxide recovery unit 12, and the measurement result is output to the control unit 31 via the communication unit 33.

[0022] Also, a unit switching valve 9 is arranged between the blower 7 and the carbon dioxide recovery unit 11, and a unit switching valve 10 is arranged between the blower 7 and the carbon dioxide recovery unit 12.

[0023] The control unit 31 can perform switching control to switch the carbon dioxide flowing into the carbon dioxide recovery units 11 and 12 by means of the unit switching valve 9 and the unit switching valve 10. In the initial state, the unit switching valve 9 and the unit switching valve 10 are in the closed state. When starting the recovery of carbon dioxide by the carbon dioxide recovery unit 11, the control unit 31 performs switching control to open the unit switching valve 9 and close the unit switching valve 10. Thereby, the exhaust gas g can start the recovery of carbon dioxide in the carbon dioxide recovery unit 11 as carbon dioxide flows through the unit switching valve 9. Then, the exhaust gas g sent from the engine 3 is sent to the carbon dioxide recovery unit 11 and recovered.

[0024] When a certain amount of carbon dioxide recovered by the carbon dioxide recovery unit has accumulated, the control unit 31 performs switching control to open the unit switching valve 10 and close the unit switching valve 9. Thereby, the destination of the exhaust gas g sent from the engine 3 can be switched from the carbon dioxide recovery unit 11 to the carbon dioxide recovery unit 12. Thereby, the exhaust gas g can start the recovery of carbon dioxide in the carbon dioxide recovery unit 12 as carbon dioxide flows through the unit switching valve 10. Then, the exhaust gas g sent from the engine 3 is sent to the carbon dioxide recovery unit 12 and recovered.

[0025] The control unit 31 determines whether the carbon dioxide concentration measured by the outlet concentration sensor 8B, located at the outlets of the carbon dioxide recovery units 21 and 22, exceeds a preset carbon dioxide concentration. If the carbon dioxide concentration measured by the outlet concentration sensor 8B exceeds a preset carbon dioxide concentration (for example, 95-98%), the control unit 31 performs switching control of the unit switching valves 9 and 10. Switching control of the unit switching valves 9 and 10 involves pressure fluctuations, which may damage the equipment including the carbon dioxide recovery units 21 and 22. In addition, it may increase the back pressure of the engine exhaust gas, potentially reducing the engine load or causing the engine to stop. Therefore, when performing switching control, a timer setting that allows setting any desired time may be used to set a period during which the unit switching valves 9 and 10 are simultaneously open. After a certain period of time has elapsed, one of the unit switching valves 9 and 10 (or unit switching valve 9) may be closed.

[0026] The exhaust gas replacement purge valve 16 purges the air in the exhaust gas flow paths of the pretreatment device 4, heat removal / dewatering device 5, and exhaust gas reheat device 6 within the gas recovery system 200 with exhaust gas g, based on the control of the control unit 31. Specifically, when the gas recovery system 200 starts operation, the control unit 31 closes the unit switching valve 9, the unit switching valve 10, and the exhaust gas replacement purge valve 16. As a result, when the gas recovery system 200 starts operation, it is filled with normal air. Next, the control unit 31 opens the exhaust gas replacement purge valve 16. Subsequently, the control unit 31 controls the blower 7 to push out the air in the gas recovery system 200 with exhaust gas g using the driving force of the blower 7 and perform purging. This allows the air in the gas recovery system 200 to be purged with exhaust gas g. Then, after a certain period of time has elapsed, the control unit 31 can close the exhaust gas replacement purge valve 16 and open the unit switching valve 9 to start operation of the gas recovery system 200.

[0027] Furthermore, the gas recovery system 200 may each be equipped with a unit temperature sensor (not shown) for measuring the temperature of the carbon dioxide recovery units 11 and 12. Since carbon dioxide adsorption is an exothermic reaction, the carbon dioxide recovery units 11 and 12 are cooled by cooling pumps 14 and 15. That is, it is desirable to prevent a decrease in carbon dioxide adsorption performance due to the rise in the adsorption temperature of the adsorbent in the carbon dioxide recovery containers 21 and 22 located inside the carbon dioxide recovery units 11 and 12, caused by the exothermic reaction when carbon dioxide from exhaust gas g is adsorbed onto the adsorbent. For this reason, the control unit 31 monitors the temperature of the carbon dioxide recovery units 11 and 12, as measured by the unit temperature sensor, so that the temperature of the adsorbent in the carbon dioxide recovery containers 21 and 22 remains constant. When the temperature measured by the unit temperature sensor exceeds a certain temperature, the control unit 31 controls the refrigerant flow rate of the cooling pumps 13 and 14 to cool the carbon dioxide recovery units 11 and 12. This prevents a decrease in carbon dioxide adsorption performance due to the rise in the adsorption temperature of the adsorbent caused by the exothermic reaction when adsorbing carbon dioxide. Cooling pumps 14 and 15 can use seawater as a refrigerant. The cooling pumps may also use refrigerants other than seawater.

[0028] Refer to Figure 3 for a detailed explanation of the carbon dioxide capture unit 11. Figure 3 is a diagram showing an example of the configuration of the carbon dioxide capture unit 11. Although Figure 3 explains the carbon dioxide capture unit 11, the configuration of the carbon dioxide capture unit 12 is the same as that of the carbon dioxide capture unit 11 explained in Figure 3, so its explanation is omitted. Exhaust gas g, which has undergone pretreatment and had impurities removed, flows into the carbon dioxide capture unit 11.

[0029] The carbon dioxide recovery unit 11 includes a carbon dioxide recoverer 21, gate valves (first gate valves) 50A to 50F, gate valves (second gate valves) 51A to 51F, a vacuum pump 52, a blower 53, and a concentration sensor 54 for displacement purging. The carbon dioxide recoverer 21 is composed of multiple carbon dioxide recoverers 21A to 21F. The carbon dioxide recoverers 21A to 21F are loaded with adsorbents in the order of activated alumina, activated carbon, and zeolite from the primary side. Activated alumina removes moisture, activated carbon adsorbs carbon dioxide, and zeolite adsorbs N2, O2, and the remainder. The above-mentioned adsorbents are just examples, and other materials may be used. Gate valves 50A to 50F are located on the carbon dioxide inlet side of the carbon dioxide recoverers 21A to 21F, and gate valves 51A to 51F are located on the carbon dioxide discharge side of the carbon dioxide recoverers 21A to 21F. By opening gate valves 50A to 50F, the inflow of carbon dioxide into carbon dioxide recovery units 21A to 21F is permitted, and by closing gate valves 50A to 50F, the inflow of carbon dioxide into carbon dioxide recovery units 21A to 21F is blocked. Similarly, by opening gate valves 51A to 51F, the outflow of carbon dioxide from carbon dioxide recovery units 21A to 21F is permitted, and by closing gate valves 51A to 51F, the outflow of carbon dioxide from carbon dioxide recovery units 21A to 21F is blocked. Therefore, by opening the respective gate valves 50A to 50F and gate valves 51A to 51F located on the inflow and outflow sides of carbon dioxide recovery units 21A to 21F, the inflow and outflow of carbon dioxide into and out of carbon dioxide recovery units 21A to 21F can be permitted. Furthermore, by closing the gate valves 50A-50F and 51A-51F located on the inlet and outlet sides of the carbon dioxide recovery units 21A-21F, the inflow and outflow of carbon dioxide recovered by the carbon dioxide recovery units 21A-21F can be sealed.

[0030] The carbon dioxide capture unit 11 can concentrate carbon dioxide by adsorbing it onto an adsorbent using the following method. Carbon dioxide capturers 21A to 21E use recycled adsorbent. Carbon dioxide capturer 21F uses one that has already adsorbed carbon dioxide for displacement purging. Carbon dioxide capturers 21A to 21E are connected in parallel within the carbon dioxide capture unit 11 located on the ship.

[0031] After the ship's engine 3 starts operating, the gate valves 50A and 51A are opened, and the exhaust gas g sent out through the blower 7 is first directed to the carbon dioxide recovery unit (first carbon dioxide recovery unit) 21A to adsorb the carbon dioxide in the exhaust gas g. When the outlet carbon dioxide concentration measured by the outlet concentration sensor 8B of the carbon dioxide recovery unit 21A becomes equal to the carbon dioxide concentration measured by the inlet concentration sensor 8A of the carbon dioxide recovery unit 21A, the control unit 31 switches the flow of exhaust gas g from the carbon dioxide recovery unit 21A to the carbon dioxide recovery unit (second carbon dioxide recovery unit) 21B by closing the gate valves 50A and 51A and opening the gate valves 50B and 51B, thereby sending the exhaust gas g to the carbon dioxide recovery unit 21B. When switching from carbon dioxide recovery unit 21A to carbon dioxide recovery unit 21B, once the high-concentration adsorption of carbon dioxide in the exhaust gas g is complete, the control unit 31 closes both gate valves 50A and 51A connected to the carbon dioxide recovery unit 21, thereby preventing carbon dioxide from being released from the adsorbent due to changes in ambient temperature and respiration with the outside of the unit. Note that the switching control of the carbon dioxide recovery units may also be performed based on predetermined control values. For example, a constant concentration of carbon dioxide measured by the inlet concentration sensor 8A may be used as the control value. If the outlet carbon dioxide concentration measured by the outlet concentration sensor 8B of the carbon dioxide recovery unit 21A exceeds a certain concentration (for example, 95-98%) of the carbon dioxide concentration measured by the inlet concentration sensor 8A of the carbon dioxide recovery unit 21A, the control unit 31 may switch the flow of exhaust gas g from the carbon dioxide recovery unit 21A to the carbon dioxide recovery unit 21B by closing the gate valves 50A and 51A and opening the gate valves 50B and 51B. By performing switching control when the carbon dioxide concentration measured by the inlet concentration sensor 8A of the carbon dioxide recovery unit 21A exceeds a certain concentration, carbon dioxide that flows before the gate valves 50A and 51A are closed can also be recovered, allowing for continuous carbon dioxide recovery and improving the carbon dioxide recovery efficiency.

[0032] Furthermore, the gas recovery system 200 may also have an adsorption heat measurement temperature sensor installed inside the carbon dioxide recovery units 21A to 21E. The adsorption heat measurement temperature sensor can measure the heat of adsorption when carbon dioxide in exhaust gas g is adsorbed onto the adsorbent inside the carbon dioxide recovery units 21A to 21E. The control unit 31 determines whether the measured temperature measured by the adsorption heat measurement temperature sensor installed inside the carbon dioxide recovery unit 21A exceeds a predetermined inflection point (threshold). If the measured temperature measured by the adsorption heat measurement temperature sensor installed inside the carbon dioxide recovery unit 21A exceeds a predetermined inflection point, the control unit 31 determines that the adsorption of carbon dioxide inside the carbon dioxide recovery unit 21A is complete. When the control unit 31 determines that the adsorption of carbon dioxide inside the carbon dioxide recovery unit 21A is complete, it performs switching control to close the gate valves 50A and 51A of the carbon dioxide recovery unit 21A and open the gate valves 50B and 51B of the carbon dioxide recovery unit 21B. The temperature measured by the adsorption heat measurement temperature sensor gradually rises due to the heat of adsorption, but when the adsorption of carbon dioxide by the adsorbent is complete, the heat of adsorption rises rapidly. Therefore, by performing switching control to close the gate valves 50A and 51A of carbon dioxide recovery unit 21A and open the gate valves 50B and 51B of carbon dioxide recovery unit 21B depending on whether the measured temperature exceeds a predetermined inflection point, the switching operation of carbon dioxide recovery unit 21 can be performed accurately.

[0033] Next, carbon dioxide (for example, about 1 / 5 of the amount of carbon dioxide) that has been desorbed by vacuum pump 52 is passed through carbon dioxide recovery unit 21F, which has already adsorbed carbon dioxide for displacement purging, to carbon dioxide recovery unit 21A, which has already recovered carbon dioxide. By replacing the co-adsorbed other gases (such as N2, CO, and O2) with a concentration gradient within the adsorbent, the carbon dioxide adsorption concentration of carbon dioxide recovery unit 21A is increased. The same procedure is repeated for carbon dioxide recovery units 21B to 21E. The displacement purging concentration sensor 54 can measure the concentration of carbon dioxide flowing into carbon dioxide recovery unit 21F for displacement purging.

[0034] The control unit 31 may also control the amount of carbon dioxide to be desorbed in each carbon dioxide recoverer (hereinafter also referred to as the "desorption amount") in the carbon dioxide recoverer 21F for displacement purging (displacement purging carbon dioxide recoverer) 21F, according to the number of carbon dioxide recoverers 21A to 21E other than carbon dioxide recoverer 21F. For example, if there are five carbon dioxide recoverers 21 other than the carbon dioxide recoverer 21F for displacement purging, the control unit 31 divides the carbon dioxide in carbon dioxide recoverer 21F into five equal parts, and if there are six carbon dioxide recoverers 21, the control unit 31 divides the carbon dioxide in carbon dioxide recoverer 21F into six equal parts. In this embodiment, the number of carbon dioxide recoverers for displacement purging is one, but it is not limited to one and may be multiple. The desorption amount can be calculated by the following formula 1.

[0035] Desorption amount = 1 / ((Total number of carbon dioxide capture devices) - (Number of carbon dioxide capture devices for displacement purging) ... Equation 1

[0036] In this way, by controlling the amount of carbon dioxide desorbed for displacement purging, the number of carbon dioxide recovery units 21 for displacement purging can be kept to a minimum. For example, in this embodiment, one carbon dioxide recovery unit 21F is sufficient for displacement purging. This reduces the cost of the system configuration and allows for a smaller system size.

[0037] Furthermore, if the carbon dioxide recovery unit 21F for displacement purging becomes empty midway through the process, the control unit 31 may select one of the carbon dioxide recovery units 21A to 21E that have already adsorbed carbon dioxide as the alternative carbon dioxide recovery unit 21 for displacement purging, and use the carbon dioxide adsorbed in the selected carbon dioxide recovery unit 21 for displacement purging. In this case, the carbon dioxide recovery unit for displacement purging can be switched during ship operation. This reduces the number of carbon dioxide recovery units for displacement purging, thereby reducing the cost of the system configuration and enabling system miniaturization. Moreover, even if there is a shortage of carbon dioxide for displacement purging, the already adsorbed carbon dioxide can be reused to avoid stopping the gas treatment system and allow the ship to continue operating.

[0038] After the carbon dioxide adsorption concentration in the five carbon dioxide recovery units 21A to 21E increases, the carbon dioxide adsorption capacity in carbon dioxide recovery unit 21F, which is used for displacement purging, becomes empty. Therefore, exhaust gas g is then flowed into carbon dioxide recovery unit 21F to adsorb carbon dioxide. Carbon dioxide recovery unit 21F receives a fixed amount (for example, about 1 / 5) of high-concentration carbon dioxide from carbon dioxide recovery unit 21E as displacement gas to increase the carbon dioxide adsorption concentration.

[0039] When carbon dioxide, which has been adsorbed by the vacuum pump 52, is flowed into carbon dioxide recoverers 21A to 21E that have also adsorbed carbon dioxide, using carbon dioxide recovery unit 21F for displacement purging, and other gases of co-adsorbed components are replaced according to the concentration gradient within the adsorbent, the control unit 31 determines whether the carbon dioxide concentration flowing into the carbon dioxide recovery unit 21F for displacement purging, as measured by the displacement purging concentration sensor 54, and the carbon dioxide concentration in each carbon dioxide recoverer 21A to 21E, as measured by the outlet concentration sensor 8B, are equal. If the carbon dioxide concentration flowing into the carbon dioxide recovery unit 21F for displacement purging, as measured by the displacement purging concentration sensor 54, and the carbon dioxide concentration in each carbon dioxide recoverer 21A to 21E, as measured by the outlet concentration sensor 8B, are equal, the control unit 31 determines that the operation method to increase the carbon dioxide adsorption concentration by each carbon dioxide recoverer 21A to 21E has been completed. This makes it possible to efficiently increase the carbon dioxide adsorption concentration.

[0040] When docking at a port, carbon dioxide recovery units 21B to 21E are unloaded and high-concentration carbon dioxide is extracted using the onshore carbon dioxide desorption system 300. Carbon dioxide recovery unit 21F is purged on land. Alternatively, carbon dioxide recovery unit 21A may be used onboard without being unloaded, as it will be used as carbon dioxide recovery unit 21F with adsorbed carbon dioxide for purging during the next voyage. Similarly, when docking at a port again, carbon dioxide recovery unit 21A may be designated as carbon dioxide recovery unit 21F and reused. The main electrical equipment required onboard is the blower 7, the vacuum pump 52 for vacuum-suctioning concentrated carbon dioxide gas (small amount) for purging the co-adsorbed residual gas, and the blower 53. These are considered low-power equipment compared to the compressor that compresses the entire exhaust gas to high pressure.

[0041] Figure 4 shows an example of a carbon dioxide desorption system 300. The carbon dioxide desorption system 300 is installed, for example, in a port where ships return. The carbon dioxide desorption system 300 includes a carbon dioxide concentration sensor 301, a carbon dioxide concentration sensor 302, a carbon dioxide recovery unit 21, a vacuum pump 303, and a carbon dioxide concentration, separation, and recovery unit 304.

[0042] The carbon dioxide recovery unit 21 is a container-shaped carbon dioxide recovery unit 21 (or carbon dioxide recovery unit 22) that is located inside the carbon dioxide recovery unit 11 or carbon dioxide recovery unit 12, which is then unloaded and placed in the port. Carbon dioxide can be removed from the placed carbon dioxide recovery unit 21 by suction using a vacuum pump 303. In this embodiment, carbon dioxide is removed using a vacuum pump 303, but this is not the only method. For example, carbon dioxide may be removed by heating the carbon dioxide recovery unit 21 with a heating device.

[0043] The carbon dioxide concentration can be measured by carbon dioxide concentration sensors 301 and 302, which are positioned before and after the carbon dioxide recovery unit 21. When the carbon dioxide concentrations become approximately the same, it can be determined that the desorption of carbon dioxide is complete. The carbon dioxide concentration can be measured by carbon dioxide concentration sensor 301 when the carbon dioxide recovery unit 21 is heated by a heating device and carbon dioxide is desorbed by flowing regenerated purge gas. The carbon dioxide concentration can be measured by carbon dioxide concentration sensor 302 to measure the concentration of carbon dioxide that is desorbed and flows out of the carbon dioxide recovery unit 21.

[0044] Furthermore, the gas recovery system 200 is further equipped with a control unit 31, a storage unit 32, and a communication unit 33.

[0045] Examples of devices having a control unit 31, a memory unit 32, and a communication unit 33 include a programmable controller (PLC) and a personal computer (PC). The control unit 31 consists of a central processing unit (CPU), etc., and controls the entire gas recovery system 200 through the control of each part of the system. The control unit 31 has functions such as performing various calculations on information input from the memory unit 32 and the communication unit 33 according to a program stored in the memory unit 32, and controlling the amount of seawater a supplied to the heat removal / dewatering device 23 by the seawater pump 40.

[0046] The memory unit 32 includes RAM (Random Access Memory) and ROM (Read Only Memory). The RAM is used as a workspace for the control unit 31, and information output from the communication unit 33 is stored in it via the control unit 31. The ROM stores programs for the control unit 31 to perform various calculations and controls, as well as programs and data for functioning as applications.

[0047] The communication unit 33 transmits and receives measurement results, data, command signals, etc. via wired or wireless communication as a communication interface. The communication unit 33 acquires detection results, measurement results, data, command signals, etc. output from the engine 3, nitrogen oxide treatment device 41, various temperature sensors, and other sensors not shown (including various sensors on the ship), and outputs them to the control unit 31.

[0048] As described above, according to the above embodiment, carbon dioxide can be recovered by installing only the gas recovery system 200 on board the ship, so that carbon dioxide can be separated from the ship's combustion gas with low power in the limited space on board.

[0049] Furthermore, while other carbon dioxide separation methods, such as separation membranes and chemical absorption methods, require a large amount of energy, the embodiments of the present invention do not require equipment that requires a large amount of energy, such as compressors, thus enabling low power consumption.

[0050] Furthermore, until now, in addition to separating and recovering carbon dioxide from exhaust gas, processes such as carbon dioxide storage, for example, liquefaction of carbon dioxide, were required, necessitating the construction of large plants. In contrast, in the embodiment of the present invention, the separation, recovery, and storage processes are integrated on a ship, and carbon dioxide is adsorbed, absorbed, and stored using an adsorbent or absorbent, thereby eliminating processes such as carbon dioxide liquefaction and resulting in a simpler configuration.

[0051] Furthermore, even if the size of the vessel (gross tonnage, displacement tonnage, etc.) or the voyage distance changes, the configuration of the number of carbon dioxide capturers and carbon dioxide capture units can be freely changed, thus avoiding the need to design the carbon dioxide capture and storage system plant each time according to the size of the vessel and the distance. This allows for the use of expandable units. In addition, in carbon dioxide desorption systems installed in ports, the carbon dioxide desorption process and desorption time can be set up to an optimal time schedule according to the port docking and undocking schedules of numerous vessels. This improves the operating rate of the port system.

[0052] Furthermore, the control unit 31 may control the number of carbon dioxide recovery units 21A to 21F that operate simultaneously, according to the required amount of carbon dioxide to be processed. For example, the control unit 31 may control the number of carbon dioxide recovery units 21A to 21F that operate simultaneously, according to the amount of carbon dioxide to be processed, which changes depending on the size of the vessel and the load of the engine 3. For example, if the size of the vessel is small or the load of the engine 3 is low, the control unit 31 will set the number of carbon dioxide recovery units 21A to 21F that operate simultaneously to one. On the other hand, if the size of the vessel is large or the load of the engine 3 is high, the control unit 31 will set the number of carbon dioxide recovery units 21A to 21F that operate simultaneously to at least two or more. This allows for flexible response even if the exhaust gas g and carbon dioxide emissions increase or decrease due to changes in the load of the engine 3 or the size of the vessel, simply by changing the number of units that operate simultaneously, without changing the gas recovery system 200 itself. Therefore, it is possible to suppress an increase in the cost of system modification.

[0053] Furthermore, in the carbon dioxide desorption system 300, electricity generated from renewable energy sources may be used as the power source for separating and capturing carbon dioxide. Examples of the power source for separating and capturing carbon dioxide include the vacuum pump 303 and carbon dioxide concentration sensors 301 and 302. Examples of renewable energy sources include solar power, wind power, hydropower, wave power, geothermal power, solar thermal power, and biomass. By using electricity generated from renewable energy sources as the power source for separating and capturing carbon dioxide, it is expected that the system can contribute more to decarbonization.

[0054] The embodiments of the present invention are not limited to those described above, and may be modified, substituted, or transformed in various ways without departing from the spirit of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention.

[0055] When the cooling pumps 13 and 14 are composed of absorption chillers, the temperature of the chilled water supplied as refrigerant to the heat removal / dewatering device 5 can be controlled by the control unit 31. This makes it easy to adjust the amount of heat exchanged in the heat removal / dewatering device 5. Furthermore, when an absorption chiller is used, the hot water (chilled water) discharged from the heat removal / dewatering device 5 is 100°C, so it can be used as waste heat water as a heat source for the regenerator of the absorption chiller, thereby reducing the energy input to the absorption chiller.

[0056] When carbon dioxide from the exhaust gas is adsorbed onto the adsorbent in the carbon dioxide recovery unit 21, any remaining SOx, NOx, and moisture may be detected by an adsorption heat measurement temperature sensor installed in the carbon dioxide recovery unit. If the temperature rise from the adsorption exothermic reaction exceeds a value calculated in advance using an empirical formula corresponding to the amount of carbon dioxide separated and recovered, this may be considered a slip of SOx, NOx, and moisture from the pretreatment device or exhaust gas reheating device, and an alarm output may be issued. This allows for earlier detection of abnormalities when a slip of SOx, NOx, or moisture occurs. [Explanation of Symbols]

[0057] 3: Engine 4: Pretreatment device 5:Heat removal / dehydration equipment 6: Exhaust gas reheating device 7: Blower 8A: Inlet concentration sensor 8B: Outlet concentration sensor 9: Unit switching valve 10: Unit switching valve 11, 12: Carbon dioxide capture unit 13, 14, 15: Cooling pumps 16: Exhaust gas replacement purge valve 20: Cooling and reheating section 21, 21A~21F: Carbon dioxide recovery unit 22: Carbon dioxide recovery unit 31: Control Unit 32: Storage section 33: Communications Department 40: Seawater pump 41: Nitrogen oxide treatment equipment 42: Exhaust gas and waste heat utilization device 43: Dust removal equipment 44: Sulfur oxide treatment equipment 50A~50F: Gate valve 51A~51F: Gate valve 52: Vacuum pump 53: Blower 54: Concentration sensor for replacement purging 100: Gas processing system 200: Gas recovery system 300: Carbon dioxide desorption system 301, 302: Carbon dioxide concentration sensor 303: Vacuum pump 304: Carbon dioxide concentration, separation, and recovery device

Claims

1. A gas recovery system that includes a carbon dioxide recovery unit that receives combustion exhaust gas discharged from a combustor and recovers carbon dioxide from the supplied combustion exhaust gas, The carbon dioxide recovery unit includes a carbon dioxide desorption system that desorbs carbon dioxide from the carbon dioxide recovery device contained within the carbon dioxide recovery unit, The gas recovery system is mounted on a ship, while the carbon dioxide desorption system is located on land, separate from the gas recovery system. A gas treatment system characterized by the following features.

2. The gas recovery system further comprises a pretreatment device that removes at least one of NOx, SOx, and moisture contained in the combustion exhaust gas. The gas treatment system according to claim 1.

3. The pretreatment device further includes an exhaust gas exhaust heat utilization device that absorbs heat contained in the combustion exhaust gas to generate steam. The gas treatment system according to claim 2, characterized in that it is as described above.

4. The gas treatment system according to any one of 1 to 3, wherein the carbon dioxide recovery unit is equipped with an adsorption heat measuring temperature sensor that detects the heat of adsorption as residual SOx, NOx, and moisture, and if the heat of adsorption exceeds an adsorption exothermic reaction temperature rise value calculated in advance using an empirical formula corresponding to the amount of carbon dioxide separated and recovered, the system determines that an abnormal condition has occurred in which SOx, NOx, and moisture, which are to be removed in the pretreatment unit or exhaust gas reheating unit, have flowed into the carbon dioxide recovery unit and outputs an alarm.

5. The gas recovery system further comprises a plurality of carbon dioxide recovery units, a first carbon dioxide sensor for measuring the concentration of carbon dioxide flowing into the plurality of carbon dioxide recovery units, a second carbon dioxide sensor for measuring the concentration of carbon dioxide emitted from the plurality of carbon dioxide recovery units, and a plurality of unit switching valves for switching the carbon dioxide flowing into the plurality of carbon dioxide recovery units. The gas recovery system is characterized in that, when the carbon dioxide concentration measured by the first carbon dioxide sensor and the carbon dioxide concentration measured by the second carbon dioxide sensor become equal, it controls the switching of the plurality of unit switching valves, as described in any one of claims 1 to 3.

6. The gas recovery system further comprises a plurality of carbon dioxide recovery units, a carbon dioxide sensor for measuring the concentration of carbon dioxide emitted from the plurality of carbon dioxide recovery units, and a plurality of unit switching valves for switching the carbon dioxide flowing into the plurality of carbon dioxide recovery units. The gas recovery system is characterized in that, when the carbon dioxide concentration measured by the carbon dioxide sensor exceeds a predetermined certain concentration of carbon dioxide, it controls the switching of the plurality of unit switching valves, as described in any one of claims 1 to 3.

7. The gas recovery system, when performing the switching control, is characterized in that a timer setting that allows any time to be set is used to provide a period of time during which the multiple unit switching valves are simultaneously open, and after a certain period of time set by the timer setting has elapsed, any of the multiple unit switching valves is closed.

8. The gas recovery system further comprises a cooling pump for cooling the carbon dioxide recovery unit and a unit temperature sensor for measuring the temperature of the carbon dioxide recovery unit. The gas recovery system is characterized in that, when the temperature measured by the unit temperature sensor exceeds a certain temperature, it controls the refrigerant flow rate of the cooling pump to cool the carbon dioxide recovery unit, as described in any one of claims 1 to 3.

9. The gas recovery system further comprises a first gate valve located on the carbon dioxide inflow side of the first carbon dioxide recoverer and the second carbon dioxide recoverer among the plurality of carbon dioxide recovery units, and a second gate valve located on the carbon dioxide discharge side of the first carbon dioxide recoverer and the second carbon dioxide recoverer. The gas recovery system is characterized in that, when the carbon dioxide concentration discharged from the first carbon dioxide recoverer exceeds a certain concentration of carbon dioxide concentration flowing into the first carbon dioxide recoverer, it performs switching control to close the first gate valve and the second gate valve of the first carbon dioxide recoverer and open the first gate valve and the second gate valve of the second carbon dioxide recoverer.

10. The carbon dioxide recovery device includes a replacement purge carbon dioxide recovery device that has already adsorbed carbon dioxide. The gas recovery system is characterized in that the carbon dioxide desorbed by vacuum suction in the displacement purge carbon dioxide recovery unit is flowed into the carbon dioxide recovery unit that has already recovered carbon dioxide, and the co-adsorbed gas of other compositions is replaced according to the concentration gradient within the adsorbent, as described in any one of 1 to 3.

11. The gas recovery system is characterized in that, when the carbon dioxide concentration flowing into the displacement purge carbon dioxide recovery unit and the carbon dioxide concentration discharged from the carbon dioxide recovery units other than the displacement purge carbon dioxide recovery unit become equal, the system determines that the operation method for increasing the carbon dioxide adsorption concentration by the carbon dioxide recovery units other than the displacement purge carbon dioxide recovery unit has been completed.

12. The gas recovery system controls the number of carbon dioxide recovery units operating simultaneously according to the required amount of carbon dioxide to be processed, which varies depending on the size of the vessel or the engine load. A gas treatment system according to any one of features 1 to 3.

13. The gas treatment system according to any one of 1 to 3, characterized in that the carbon dioxide desorption system uses electricity generated from renewable energy as power for the separation and recovery of carbon dioxide.

14. A gas treatment method performed by a gas treatment system comprising a gas recovery system mounted on a ship and equipped with a carbon dioxide capture unit, and a carbon dioxide desorption system located on land and separate from the gas recovery system, Combustion exhaust gas discharged from the combustor is supplied, and carbon dioxide is recovered from the supplied combustion exhaust gas. Carbon dioxide is removed from the carbon dioxide recoverer included in the carbon dioxide recovery unit. A gas treatment method characterized by the following:

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