Ship greenhouse gas emission reduction devices and ships or offshore structures equipped with them

Abstract

The present invention discloses a greenhouse gas emission reduction device for a ship that includes a seawater supply unit 110 that supplies seawater, an absorbent circulation supply unit 120 that provides and circulates an absorbent that absorbs CO2, an absorption tower 130 including a CO2 removal unit 131 that reacts exhaust gas emitted from a ship engine 10 with seawater to cool it, and reacts the cooled exhaust gas with the absorbent to convert CO2 into a carbonate solution and capture CO2, an absorbent regeneration unit 140 that reacts the carbonate solution with a divalent metal oxide or a divalent metal hydroxide to regenerate the absorbent and generate a precipitate, and an overboard discharge unit 150 that separates the precipitate and discharges it overboard with seawater, mineralizing CO2 and discharging it overboard, thereby minimizing corrosion of a separator 152 by seawater.

Description

[Technical Field]

[0001] The present invention relates to a device for reducing greenhouse gas emissions from ships and a ship or offshore structure equipped therewith, and more particularly to a device for reducing greenhouse gas emissions from ships that mineralizes CO2 and discharges it overboard to meet the conditions for overboard discharge, thereby minimizing corrosion of the separator by seawater, and a ship or offshore structure equipped therewith. [Background technology]

[0002] In recent years, the indiscriminate use of fossil fuels has led to greenhouse gas emissions, causing global warming and the resulting natural disasters.

[0003] Therefore, a series of technologies related to capturing and storing carbon dioxide, a representative greenhouse gas, without releasing it, are called CCS (Carbon dioxide Capture and Storage) technologies, and have attracted considerable attention in recent years. Among CCS technologies, chemical absorption is the most commercially advanced due to its ability to handle large-scale processing.

[0004] Furthermore, while carbon dioxide emissions are regulated by the IMO's EEDI (Economic Development Initiative), the goal is to reduce emissions by more than 50% compared to 2008 levels by 2050, and by 40% compared to 2008 levels by 2030. Therefore, technologies that either eliminate CO2 emissions or capture emitted CO2 are attracting attention.

[0005] Of the carbon capture and storage (CCS) technologies that directly capture and store carbon dioxide, CO2 capture technology can be approached in various ways depending on the CO2 generation conditions of the target process. Currently, the representative technologies are absorption, adsorption, and membrane separation. Among these, wet absorption is considered the capture technology closest to commercialization of CCS technology because it is highly mature in onshore plants and can easily handle large quantities of CO2. The main absorbents used are amines and ammonia.

[0006] On the other hand, the aforementioned technologies for reducing carbon dioxide emissions or capturing generated carbon dioxide have not yet been commercialized for ships, and methods using hydrogen or ammonia as fuel are still under development and have not yet reached the commercialization stage.

[0007] Furthermore, in ships equipped with scrubbers that use high-sulfur fuel oil, SOx has a high solubility and is converted to NaSO3 compounds first. This presents a disadvantage in that CO2 removal is difficult until the SOx is completely dissolved. In particular, the use of other consumable absorbent materials for CO2 removal increases the cost of greenhouse gas removal.

[0008] Therefore, without requiring the provision of other consumable absorbent liquid raw materials, there is a need to apply technologies to ships that use fossil fuels to either convert CO2 from exhaust gases emitted from the ship's engines into substances that do not harm the environment before emission, or to convert it into useful substances for storage. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention has been made in view of the above circumstances, and its object is to provide a greenhouse gas emission reduction device for ships that can mineralize CO2 and discharge it overboard in a manner that satisfies the conditions for overboard discharge, thereby minimizing corrosion of the separator by seawater, and a ship or offshore structure equipped therewith. [Means for solving the problem]

[0010] To achieve the aforementioned objectives, one embodiment of the present invention provides a greenhouse gas emission reduction device for ships, comprising: an absorbent liquid circulation supply unit that provides and circulates an absorbent liquid that absorbs CO2; an exhaust gas cooling unit that cools exhaust gas discharged from a ship engine; an absorption tower that includes a CO2 removal unit that reacts the cooled exhaust gas with the absorbent liquid to convert CO2 into a carbonate aqueous solution and collect CO2; an absorbent liquid regeneration unit that regenerates the absorbent liquid by reacting the carbonate aqueous solution with a regeneration reactant and generates a precipitate; and an overboard discharge unit that separates the precipitate and discharges the precipitate overboard with seawater.

[0011] Here, the overboard discharge section can perform a separation step of the sediment and the absorbent liquid, a discharge step of the sediment with seawater, and further a washing step with fresh water.

[0012] At this time, the overboard discharge unit sucks in and separates the sediment and absorbent liquid from the absorbent liquid regeneration unit, dilutes the sediment with seawater and discharges it overboard so that the sediment satisfies the overboard discharge conditions, and if the sediment does not satisfy the overboard discharge conditions, the sediment can be temporarily stored.

[0013] Specifically, the overboard discharge section may include a separation pump that sucks in the sediment and absorbent liquid from the absorbent liquid regeneration section, a separator that separates the sediment and absorbent liquid transferred from the separation pump, discharging the sediment overboard and returning the absorbent liquid to the absorbent liquid circulation supply section, and a discharge seawater pump that supplies seawater to the separator to dilute the sediment before discharging it overboard.

[0014] Here, the separator may be a filter-shaped separator or a centrifuge-shaped separator that separates the precipitate and the absorbent liquid from each other.

[0015] Furthermore, the overboard discharge section may further include a freshwater supply valve that supplies freshwater to the separator to clean it.

[0016] Here, the outboard discharge section may further include a fresh water cooler that cools the seawater supplied to the seawater pump for discharge with fresh water for cooling.

[0017] At this time, the seawater cooled by the fresh water cooler can be supplied to the precipitate discharged from the separator, diluted, and discharged outboard.

[0018] In addition, the outboard discharge section includes a sensor for measuring any one or more of the turbidity, pH, and oil content of the precipitate separated from the separator, and whether the measured value by the sensor meets the outboard discharge conditions determines whether to discharge outboard or temporarily store it.

[0019] Furthermore, the precipitate contains carbonate, and the absorption liquid is a monovalent alkali aqueous solution, which can include any one of an aqueous LiOH solution, an aqueous NaOH solution, an aqueous KOH solution, and an aqueous NH4OH solution.

[0020] In addition, it further includes a seawater supply section for supplying seawater from outside the ship. The seawater supply section includes a seawater pump that receives the supply of the seawater from outside the ship through a sea chest and pumps it to the absorption tower, and a seawater control valve that adjusts the injection amount of the seawater supplied from the seawater pump to the absorption tower according to the amount of exhaust gas.

[0021] Here, the exhaust gas cooling section can cool the exhaust gas discharged from the ship engine by reacting it with the seawater supplied from the seawater supply section.

[0022] In addition, the exhaust gas cooling section can cool the exhaust gas discharged from the ship engine by reacting it with fresh water.

[0023] Furthermore, the exhaust gas cooling section can cool the exhaust gas by circulating fresh water provided from the in-ship cooling system through heat exchange pipes that enclose the exhaust gas discharge pipe.

[0024] In addition, the exhaust gas cooling section can be provided inside the absorption tower.

[0025] Furthermore, the absorption liquid circulation supply unit may include an absorption liquid storage tank for storing the absorption liquid, an absorption liquid pump for pumping and transferring the absorption liquid from the absorption liquid storage tank, an absorption liquid circulation tank for mixing and storing the aqueous carbonate solution discharged from the absorption tower and the absorption liquid supplied from the absorption liquid pump, and an absorption liquid circulation pump for supplying the absorption liquid from the absorption liquid circulation tank to the upper stage of the CO2 removal unit and circulating it.

[0026] Here, the absorption liquid pump can supply the absorption liquid to the absorption liquid circulation tank so as to fill the shortage of the absorption liquid discharged to the outside of the ship by the outboard discharge unit.

[0027] Also, the absorption liquid can be generated by electrolyzing seawater and fresh water respectively, and stored in the absorption liquid storage tank.

[0028] Furthermore, it further includes a seawater supply unit for supplying seawater from outside the ship. The exhaust gas cooling unit is provided inside the absorption tower. The absorption tower further includes a SOx absorption unit as the exhaust gas cooling unit, which reacts the exhaust gas with the seawater supplied from the seawater supply unit to cool it while dissolving and removing SOx. The CO2 removal unit can react the cooled exhaust gas from which SOx has been removed with the absorption liquid from the absorption liquid circulation supply unit to convert it into an aqueous carbonate solution and collect CO2.

[0029] Or, it further includes a seawater supply unit for supplying seawater from outside the ship. The absorption tower further includes a NOx absorption unit for absorbing and removing NOx of the exhaust gas. The exhaust gas cooling unit is provided inside the absorption tower. The exhaust gas from which NOx has been removed is reacted with the seawater supplied from the seawater supply unit to be cooled. The CO^2 removal unit can react the cooled exhaust gas with the absorption liquid from the absorption liquid circulation supply unit to convert it into an aqueous carbonate solution and collect CO2.

[0030] Alternatively, the system may further include a seawater supply unit that supplies seawater from outside the ship, and the exhaust gas cooling unit is provided inside the absorption tower. The absorption tower may be sequentially stacked and formed including a NOx absorption unit that absorbs and removes NOx from the exhaust gas, an SOx absorption unit that cools the exhaust gas from which NOx has been removed by reacting it with seawater supplied from the seawater supply unit, dissolving and removing SOx, and a CO2 removal unit that reacts the cooled exhaust gas from which SOx has been removed with an absorbent liquid from the absorbent liquid circulation supply unit to convert it into a carbonate aqueous solution, which is then collected and used to remove CO2.

[0031] Furthermore, the NOx absorption section may include an SCR (Science Critical Regeneration Unit).

[0032] Here, the NOx absorption unit may further include a urea water storage tank for storing urea water and a urea water supply pump for pumping urea water from the urea water storage tank and supplying it to an injection nozzle drawn into the lower stage of the SCR.

[0033] Furthermore, the SOx absorption unit may include a passage through which exhaust gas passes, and a multi-stage seawater injection nozzle that, by opening and closing a seawater control valve, injects seawater supplied from the seawater supply unit downward to dissolve SOx, remove dust, and cool the exhaust gas.

[0034] Here, the SOx absorption unit includes a first temperature sensor and a second temperature sensor that measure the temperature before and after the exhaust gas passing through the seawater injection nozzle, respectively, and the amount of seawater injected by the seawater injection nozzle can be adjusted according to the amount of exhaust gas or the measured temperature.

[0035] Furthermore, the flow path may have alternatingly arranged holes through which exhaust gas passes, numerous laminated plates spaced apart vertically, structures forming a curved flow path, or absorbents filled with packing material, and partitions or umbrella-shaped barriers to prevent backflow of cleaning water may be formed.

[0036] Furthermore, the CO2 removal unit may include a first injection nozzle for injecting absorbent liquid supplied from the absorbent liquid regeneration unit, a first packing material formed below the first injection nozzle for causing a primary reaction between exhaust gas and absorbent liquid, a second injection nozzle for injecting circulating absorbent liquid provided from the absorbent liquid circulation supply unit, and a second packing material formed below the second injection nozzle for causing a secondary reaction between exhaust gas and absorbent liquid.

[0037] Here, the CO2 removal unit may further include a bent multi-plate mist removal plate formed above the second injection nozzle to block the discharge of the absorbent liquid, and a partition wall or umbrella-shaped blocking plate to prevent backflow of the absorbent liquid.

[0038] Furthermore, the CO2 removal unit may include a cooling jacket for cooling the heat generated in the first and second fillers.

[0039] Furthermore, the CO2 removal unit can adjust the amount of absorbent solution sprayed by monitoring the pH corresponding to the degree of reaction in the first and second packing materials.

[0040] Furthermore, the absorption liquid regeneration unit may include a regeneration reaction material storage tank for storing the regeneration reaction material, a transfer pump for pumping and transferring the carbonate aqueous solution, and a mixing tank for mixing and reacting the regeneration reaction material and the carbonate aqueous solution to regenerate the absorption liquid, generate solid-phase carbonate, and return the regenerated absorption liquid to the absorption tower.

[0041] Here, the regenerated reaction product may contain a divalent metal oxide or a divalent metal hydroxide.

[0042] Furthermore, the system may include a washing water tank for storing washing water discharged from the absorption tower, a water treatment device equipped with a filtering unit for adjusting the turbidity of the washing water transferred from the washing water tank to meet the conditions for overboard discharge, and a neutralizing agent injection unit for pH adjustment, and a washing water treatment unit that includes a sludge storage tank for separating and storing solid waste.

[0043] Furthermore, it may further include an EGE formed between the NOx absorption section and the SOx absorption section, which facilitates heat exchange between the waste heat of the ship's engine and the boiler water.

[0044] The steam generation unit may further include an auxiliary boiler that receives a mixture of heat-exchanged steam and saturated water, separates the steam, and supplies it to a steam consumption destination; a boiler water circulation pump that circulates boiler water from the auxiliary boiler to the EGE; a cascade tank that recovers condensed water from the steam consumption destination; and a supply pump and control valve that adjust and supply the amount of boiler water from the cascade tank to the auxiliary boiler.

[0045] Furthermore, the exhaust gas cooling unit branches off and cools at least a portion of the exhaust gas discharged from the ship's engine, and the CO2 removal unit reacts the cooled exhaust gas with the absorbent liquid to convert CO2 into the carbonate aqueous solution and collect the CO2.

[0046] Here, a blowing means can be provided to supply at least a portion of the branched exhaust gas to the exhaust gas cooling unit.

[0047] In this case, the blowing means may be a blower.

[0048] Furthermore, of the exhaust gas discharged from the ship's engine, the remaining exhaust gas that is not branched to the exhaust gas cooling unit is discharged through the main exhaust pipe, and at least a portion of the exhaust gas that is branched to the exhaust gas cooling unit can be discharged after CO2 has been collected and then merged into the main exhaust pipe, or discharged through another exhaust pipe.

[0049] On the other hand, in order to achieve the aforementioned objectives, another embodiment of the present invention provides a ship or offshore structure equipped with the aforementioned greenhouse gas emission reduction device for ships. [Effects of the Invention]

[0050] According to the present invention, the carbonate separated by the separator is discharged overboard using seawater, and the separator can be washed with fresh water to prevent corrosion by seawater. Furthermore, greenhouse gases can be mineralized to reduce environmental pollution. Since the material containing the collected greenhouse gases is discharged into the ocean, separate storage and handling facilities are unnecessary. NOx, SOx, and CO2 can be removed simultaneously, and the material can be stored in a solid state with few impurities such as Na2CO3, NaHCO3, (NH4)2CO3, and NH4HCO3. By removing CO2 after removing SOx and suppressing side reactions caused by SOx remaining in the exhaust gas, the solubility of CO2 and the efficiency of CO2 removal can be improved. [Brief explanation of the drawing]

[0051] [Figure 1] This diagram shows the configuration of a greenhouse gas emission reduction device for a ship according to an embodiment of the present invention. [Figure 2] This figure shows a system circuit diagram illustrating the greenhouse gas emission reduction device for the ship shown in Figure 1. [Figure 3] This diagram shows the seawater supply section and absorption tower separated from Figure 2. [Figure 4] This diagram shows the absorbent liquid circulation supply unit and absorbent liquid regeneration unit separated from Figure 2. [Figure 5] This diagram shows the overboard discharge section of Figure 2 separated from the main ship. [Figure 6] This diagram shows the washing water treatment section of Figure 2 in a separate view. [Figure 7] This diagram shows the steam generation section separated from Figure 2. [Figure 8] This is a diagram showing the CO2 removal section in Figure 3. [Figure 9] This figure shows the separation process, which is part of the process for the overboard discharge section of the ship. [Figure 10] This figure shows the discharge process, which is part of the process for the overboard discharge section of the ship. [Figure 11] Figure 5 shows the cleaning process, which is part of the process for the overboard discharge section. [Modes for carrying out the invention]

[0052] Hereinafter, embodiments of the present invention having the features described above will be described in more detail with reference to the attached drawings.

[0053] An embodiment of the present invention provides a greenhouse gas emission reduction device for a ship, comprising a seawater supply unit 110 for supplying seawater, an absorbent liquid circulation supply unit 120 for providing and circulating an absorbent liquid for absorbing CO2, an absorption tower 130 including a CO2 removal unit 131 that cools exhaust gas discharged from a ship's engine 10 by reacting it with seawater, and collects CO2 by reacting the cooled exhaust gas with the absorbent liquid to convert CO2 into a carbonate aqueous solution, an absorbent liquid regeneration unit 140 for regenerating the absorbent liquid and generating a precipitate by reacting the carbonate aqueous solution with a divalent metal oxide or divalent metal hydroxide, and an overboard discharge unit 150 for separating the precipitate, discharging it overboard with seawater, and washing it with fresh water. The aim is to mineralize CO2 and discharge it overboard, minimizing corrosion of the separator 152 by seawater.

[0054] Here, depending on the type and specifications of the marine engine used as the main engine or power generation engine (low-pressure engine or high-pressure engine) and the type of fuel supplied to the marine engine (HFO, MDO, LNG, MGO, LSMGO, ammonia, etc.), the absorption tower may be configured to selectively include a NOx absorption section or an SOx absorption section in addition to a CO2 removal section, or to include both.

[0055] In particular, when using LNG as fuel for a ship's engine, there is no SOx generation, so there is no need to provide a separate SOx absorption unit. However, when using low-sulfur fuel oil (LSMGO), a small amount of SOx may be generated, so it is possible to further equip the engine with an SOx absorption unit that can simultaneously cool the exhaust gas and absorb SOx by dissolving it.

[0056] The following describes an embodiment in which an absorption tower is sequentially layered with a NOx absorption section, an SOx absorption section for exhaust gas cooling, and a CO2 removal section, but is not limited to this embodiment.

[0057] In particular, the exhaust gas cooling section can cool the exhaust gas discharged from the ship's engine, lowering the temperature of the exhaust gas and facilitating the absorption of CO2 by the absorbent liquid. Alternatively, a SOx absorption section using seawater can perform this role, or the exhaust gas can be cooled using a fresh water heat exchange method. Specifically, fresh water supplied from an onboard cooling system (not shown) can be circulated through a heat exchange pipe (not shown) surrounding the exhaust gas discharge pipe through which the exhaust gas flows, thereby cooling the exhaust gas to a temperature of 27°C to 33°C through a heat exchange method with the fresh water.

[0058] In this case, a water-cooling system that directly cools the exhaust gas with fresh water may reduce the temperature of the absorbent solution due to the input of fresh water, potentially decreasing its greenhouse gas absorption performance. Therefore, it is preferable to cool the exhaust gas using a heat exchange system to prevent the concentration of the absorbent solution from decreasing and to maintain a constant greenhouse gas absorption performance.

[0059] The greenhouse gas emission reduction device for the ship with the above configuration will be described in detail below with reference to Figures 1 to 11.

[0060] First, the seawater supply unit 110 is configured to supply seawater to the absorption tower 130 and the overboard discharge unit 150. Specifically, as shown in Figures 2 and 3, it may include a seawater pump 112 that receives seawater from outside the ship via a sea chest 111 and pumps it to the SOx absorption unit 132, and a seawater control valve 113 that adjusts the amount of seawater injected from the seawater pump 112 to the SOx absorption unit 132 according to the amount of exhaust gas. In this case, the seawater pump 112 is preferably a quenching seawater pump.

[0061] Furthermore, depending on whether the vessel is docked or at sea, seawater can be selectively supplied to the seawater pump 112 from either a high-sea chest that draws in seawater from the upper part of the water or a low-sea chest that draws in seawater from the lower part of the water, depending on the water depth. That is, when the vessel is docked, the seawater from the upper part of the water is cleaner than the seawater from the lower part of the water, so the high-sea chest can be used, and when the vessel is at sea, the seawater from the lower part of the water is cleaner than the seawater from the upper part of the water, so the low-sea chest can be used.

[0062] Here, the seawater control valve 113 is a manually operated diaphragm valve or solenoid valve that adjusts the flow rate of seawater, and can adjust the amount of seawater injected via the seawater injection nozzle according to the amount of exhaust gas.

[0063] Next, the absorbent liquid circulation supply unit 120 is configured to provide an absorbent liquid that absorbs CO2 contained in the exhaust gas and circulate it to the absorption tower 130. Specifically, as shown in Figures 2 and 4, it may include an absorbent liquid storage tank 121 for storing the absorbent liquid, an absorbent liquid pump 122 for pumping the absorbent liquid from the absorbent liquid storage tank 121 and transferring it to the absorbent liquid circulation tank 123, an absorbent liquid circulation tank 123 for mixing and storing the carbonate aqueous solution discharged from the absorption tower 130 with the absorbent liquid supplied from the absorbent liquid pump 123, and an absorbent liquid circulation pump 124 for providing and circulating the absorbent liquid from the absorbent liquid circulation tank 123 to the upper stage of the CO2 removal unit 131.

[0064] In this case, the absorbent solution is a monovalent alkaline aqueous solution containing an aqueous solution of LiOH (lithium hydroxide), an aqueous solution of NaOH (sodium hydroxide), an aqueous solution of KOH (potassium hydroxide), or an aqueous solution of NH4OH (ammonia), and is preferably an aqueous solution of NaOH and / or an aqueous solution of NH4OH.

[0065] In this first step, where exhaust gas is reacted with an absorbent solution, which is a monovalent alkaline aqueous solution, to convert it into a carbonate aqueous solution, the CO2 in the exhaust gas reacts with water to produce H2CO3 (carbonic acid) according to Equation 1 below. At this time, the water that reacts with CO2 may be water that is present in the monovalent alkaline aqueous solution, which is the absorbent solution.

[0066] [ka]

[0067] After the first stage, if the absorbent monovalent alkaline aqueous solution is an NaOH aqueous solution, then the following equation 2 will produce a carbonate, either NaHCO3 (sodium bicarbonate) or Na2CO3 (sodium carbonate), and water, thus converting it into a carbonate aqueous solution.

[0068] [ka]

[0069] Alternatively, after the first step, if the absorbent monovalent alkaline aqueous solution is an NH4OH aqueous solution, then the following equation 3 will produce the carbonate NH4HCO3 (ammonium bicarbonate) or (NH4)2CO3 (ammonium carbonate) and water, converting it into a carbonate aqueous solution.

[0070] [ka]

[0071] Furthermore, when the carbonate of the solid phase CaCO3 is separated and discharged overboard by the overboard discharge section 150, a portion of the absorbent liquid is discharged overboard along with the carbonate. Therefore, the absorbent liquid pump 122 can supply a certain amount of absorbent liquid to the absorbent liquid circulation tank 123 to replenish the deficiency of the absorbent liquid.

[0072] On the other hand, the NaOH aqueous solution absorbent can be produced by electrolyzing seawater and freshwater, respectively, and stored in the absorbent solution storage tank 121. By producing electricity through the reduction and oxidation of Na and supplying a certain ratio of electricity applied for electrolysis, a portion of the electricity required for the production of NaOH(aq) can be reduced.

[0073] Furthermore, in the absorption tower 130, the absorbent liquid comes into contact with the exhaust gas and the CO2 is ionized into ions, and the ionized absorbent liquid flows into the absorbent liquid circulation tank 123, but the absorbent liquid discharged from the CO2 removal unit 131 contains CO3 2- If all CO2 absorption by iontophoresis is carried out, then HCO3 - The ion concentration is high, CO32- The concentration of HCO3 becomes relatively low, and the absorption solution is at a relatively high temperature, so the amount of precipitate is small, and it mostly exists in ionic form, with CO2 dissolving as HCO3 forms. - As the ion concentration increases, it can be continuously used for CO2 absorption until a certain concentration is reached.

[0074] Next, the absorption tower 130 includes a CO2 removal unit 131 that cools the exhaust gas discharged from the ship engine 10 by reacting it with seawater, and then reacts the cooled exhaust gas with an absorbent liquid to convert the CO2 into a carbonate aqueous solution and collect the CO2.

[0075] For example, the absorption tower 130 further includes an SOx absorption unit 132 that cools the exhaust gas by reacting it with seawater supplied from the seawater supply unit 110, dissolving and removing SOx. The CO2 removal unit 131 cools the exhaust gas from which SOx has been removed by reacting it with seawater supplied from the seawater supply unit 110, and then reacts the cooled exhaust gas with the absorbent liquid from the absorbent liquid circulation supply unit 120 to convert it into a carbonate aqueous solution, thereby capturing CO2.

[0076] Alternatively, the absorption tower 130 further includes a NOx absorption section 133 that absorbs and removes NOx from the exhaust gas, and the CO2 removal section 131 cools the exhaust gas from which NOx has been removed by reacting it with seawater supplied from the seawater supply section 110, and then reacts the cooled exhaust gas with the absorbent liquid from the absorbent liquid circulation supply section 120 to convert it into a carbonate aqueous solution and capture CO2.

[0077] Alternatively, the absorption tower 130 can be constructed by sequentially stacking a NOx absorption section 133 that absorbs and removes NOx from exhaust gas, an SOx absorption section 132 that cools the exhaust gas from which NOx has been removed by reacting it with seawater supplied from the seawater supply section 110 to dissolve and remove SOx, and a CO2 removal section 131 that reacts the exhaust gas from which SOx has been removed with an absorbent liquid from the absorbent liquid circulation supply section 120 to convert it into a carbonate aqueous solution, which is then collected and used to remove CO2.

[0078] Specifically, referring to Figure 3, the CO2 removal unit 131 may include a first injection nozzle 131a that injects absorbent liquid supplied from the absorbent liquid regeneration unit 140, a first packing material 131b formed below the first injection nozzle 131a to cause a primary reaction between the exhaust gas and the absorbent liquid, a second injection nozzle 131c that injects circulating absorbent liquid provided from the absorbent liquid circulation supply unit 120, and a second packing material 131d formed below the second injection nozzle 131c to cause a secondary reaction between the exhaust gas and the absorbent liquid.

[0079] Here, the second injection nozzle 131c can be formed to branch off to the upper sections of the first packing material 131b and the second packing material 131d, respectively, and inject the absorbent liquid downwards.

[0080] Furthermore, as shown in Figure 8, the CO2 removal section 131 may further include a bent multi-plate mist removal plate 131e formed above the second injection nozzle 131c to form droplets that block the external discharge of the absorbent liquid, and a partition wall 131f or an umbrella-shaped barrier plate 131g to prevent backflow of the absorbent liquid into the exhaust gas piping.

[0081] Furthermore, the CO2 removal unit 131 includes a cooling jacket (not shown) for cooling the heat generated in the first packing material 131b and the second packing material 131d, thereby maintaining the exhaust gas temperature at 80°C to 100°C, or lowering the temperature of the absorbent liquid supplied from the first injection nozzle 131a and the second injection nozzle 131c by 10°C to 20°C, thereby increasing the absorption rate during the heat-generating process in which CO2 is absorbed into the absorbent liquid while minimizing the loss of H2O due to vaporization.

[0082] Furthermore, the first packing material 131b and the second packing material 131d can be formed in a shape consisting of multiple stages of distilling column packing designed to increase the contact area per unit volume. The appropriate distilling column packing can be selected considering the contact area per unit area, the pressure drop of the gas, and the flooding velocity. A solution redistributor can be formed between the multiple stages of distilling column packing to prevent the channeling phenomenon of the solution.

[0083] Furthermore, the CO2 removal unit 131 can monitor the pH corresponding to the degree of reaction in the first packing material 131b and the second packing material 131d via the pH sensor P and adjust the amount of absorbent liquid injected via the first injection nozzle 131a and the second injection nozzle 131c.

[0084] Specifically, referring to Figure 3, the SOx absorption unit 132 may include a flow path 132a through which exhaust gas passes, and a multi-stage seawater injection nozzle 132b that, by opening and closing the seawater control valve 113, injects seawater supplied from the seawater supply unit 110 downwards to dissolve SOx, remove dust such as soot, and cool the exhaust gas.

[0085] Furthermore, the SOx absorption unit 132 includes a first temperature sensor T1 and a second temperature sensor T2 that measure the temperature before and after the exhaust gas passing through the seawater injection nozzle 132b, respectively, and the amount of seawater injected by the seawater injection nozzle 132b can be adjusted according to the amount of exhaust gas or the measured temperature.

[0086] Furthermore, the flow path 132a may have alternating holes through which exhaust gas passes, a number of laminated plates spaced apart vertically, a structure forming a curved flow path, or an absorbent filled with packing material to increase the contact area between seawater and exhaust gas, thereby facilitating smooth cooling and absorption, and a partition wall 132c or umbrella-shaped barrier plate 132d may be formed to prevent backflow of wash water.

[0087] This allows for the removal of SOx first via the SOx absorption section 132, followed by the removal of CO2 via the CO2 removal section 131. This solves the problem that CO2 removal is difficult until all SOx has dissolved, as SOx has high solubility and is converted first into compounds such as Na2SO4, thus improving the efficiency of CO2 removal.

[0088] Furthermore, the washing water drained from the lower part of the SOx absorption section 132 contains SO3 - SO4 2- Soot, NaSO3, Na2SO4, MgCO3, MgSO4, and other ionic compounds may be included together.

[0089] On the other hand, the NOx absorption unit 133 includes an SCR (Selective Catalyst Reduction) 133c and can include a urea water storage tank 133a for storing urea water and a urea water supply pump 133b for pumping urea water from the urea water storage tank 133a and supplying it to an injection nozzle drawn into the lower stage of the SCR 133c.

[0090] Furthermore, it may further include an EGE 134 formed between the NOx absorption section 133 and the SOx absorption section 132, which exchanges heat between the waste heat of the ship's engine 10 and the boiler water.

[0091] Furthermore, as shown in Figure 3, the absorption tower 130 can divert (branch) at least a portion of the exhaust gas discharged from the ship's engine 10, cool it by reacting it with seawater, and then react the cooled exhaust gas with an absorbent liquid to convert CO2 into a carbonate aqueous solution, thereby capturing the CO2.

[0092] In other words, by providing a blowing means (not shown) that branches off at least a portion of the exhaust gas and supplies it to the SOx absorption section 132, and by minimizing the back pressure generated by the piping system of the absorption tower 130, the diameter of the absorption tower 130 can be minimized and its height increased, thereby overcoming constraints on installation space.

[0093] Here, the blowing means can be configured as a blower, and if a SOx absorption section 132 is provided, the blower is preferably designed to blow or pressurize exhaust gas at 40°C to 50°C, and if a SOx absorption section 132 is not provided, it is preferably designed to blow or pressurize exhaust gas at around 300°C.

[0094] In this configuration, the remaining exhaust gas from the ship's engine that is not branched to the absorption tower 130 is discharged through the main exhaust pipe, while at least a portion of the exhaust gas that is branched to the absorption tower 130 can be discharged after CO2 has been collected by joining the main exhaust pipe, or it can be discharged through another exhaust pipe.

[0095] Next, the absorbent solution regeneration unit 140 regenerates the absorbent solution by reacting an aqueous carbonate solution with a divalent metal oxide or divalent metal hydroxide, thereby generating a precipitate.

[0096] Specifically, referring to Figure 4, the absorbent liquid regeneration unit 140 may include a regeneration reaction product storage tank 141 for storing regeneration reaction products of divalent metal oxide (CaO) or divalent metal hydroxide (Ca(OH)2), a transfer pump 142 for pumping carbonate aqueous solution from the absorbent liquid circulation tank 123 to the mixing tank 143, and a mixing tank 143 for mixing and reacting the regeneration reaction products with the carbonate aqueous solution to regenerate the absorbent liquid, generating solid-phase carbonate (CaCO3(s)), and returning the regenerated absorbent liquid to the absorption tower 130 for reuse.

[0097] First, when NaOH and CO2 react to produce the carbonate NaHCO3 (sodium bicarbonate) or Na2CO3 (sodium carbonate), the carbonate NaHCO3 (sodium bicarbonate) or Na2CO3 (sodium carbonate) reacts with CaO (calcium oxide) according to equation 4 below to produce the carbonate CaCO3 while regenerating NaOH, or reacts with Ca(OH)2 (calcium hydroxide) according to equation 5 below to produce the carbonate CaCO3 while regenerating NaOH.

[0098] [Chem.]

[0099] [Chem.]

[0100] Alternatively, when NH4OH and CO2 react to form NH4HCO3 (ammonium bicarbonate) or (NH4)2CO3 (ammonium carbonate), the carbonate NH4HCO_{3} (ammonium bicarbonate) or (NH4)2CO3 (ammonium carbonate) reacts with CaO (calcium oxide) according to Equation 6 to produce CaCO3 as a carbonate while regenerating NH4OH, or reacts with Ca(OH)2 (calcium hydroxide) according to Equation 7 to produce CaCO3 as a carbonate while regenerating NH4OH.

[0101] [Chem.]

[0102] [Chem.]

[0103] Here, when the HCO3 ion concentration in the absorption liquid circulation tank 123 increases, the absorption liquid is transferred to the mixing tank 143 through the transfer pump 142, and the absorption liquid can be transferred at a concentration that allows continuous absorption of CO2 during the progress of the mineralization process in the subsequent steps. - [ion concentration]

[0104] [[ID=4 Also, the mixing tank 143 reacts the absorption liquid in which CO2 is ionized with CaO or Ca(OH)2 to regenerate the absorption liquid, converts CO2 into the form of CaCO3, and supplies OH ions from CaO or Ca(OH)2 through the reactions of [Chemical Equation 4] to [Chemical Equation 7]. - [OH ion] 2- [CO3 ion] 2+It can combine with ions to produce CaCO3, which is insoluble in the solid phase.

[0105] Next, the overboard discharge section 150 separates the CaCO3(s) precipitate and discharges it overboard with seawater in the form of precipitate that is basically present in the marine environment, and then washes it with fresh water.

[0106] In other words, the overboard discharge section 150 can sequentially perform the following steps: a separation process of sediment and absorbent liquid along the path P1 shown in Figure 9, a discharge process of sediment with seawater along the path P2 shown in Figure 10, and a cleaning process with fresh water along the path P3 shown in Figure 11.

[0107] Meanwhile, the overboard discharge unit 150 sucks in and separates the sediment and absorbent liquid from the absorbent liquid regeneration unit 140, dilutes the sediment with seawater to meet the overboard discharge conditions, and discharges it overboard. If the sediment does not meet the overboard discharge conditions, the sediment can be temporarily stored in another storage tank (not shown).

[0108] For example, the overboard discharge section 150 includes sensors (not shown) for measuring the turbidity, pH, and oil content of the sediment separated from the separator 152, and can be used to either discharge the sediment overboard or temporarily store it depending on whether the overboard discharge conditions corresponding to the values ​​measured by the sensors are met.

[0109] Specifically, referring to Figure 5, the overboard discharge section 150 may include a separation pump 151 that sucks in sediment and absorbent liquid from the absorbent liquid regeneration section 140, a separator 152 that separates the sediment and absorbent liquid transferred from the separation pump 151, discharging the sediment overboard and returning the absorbent liquid to the absorbent liquid circulation supply section 120, a discharge seawater pump 153 that supplies cooled seawater to the separator 152 to dilute the sediment before discharging it overboard, and a cooling seawater pump 154 ​​that supplies cooling seawater from the sea chest 111 to the discharge seawater pump 153.

[0110] Here, the separator 152 may be a filter-shaped separator or a centrifuge-shaped separator that separates the precipitate and the absorbent from each other.

[0111] Furthermore, the overboard discharge section 150 may further include a freshwater supply valve 155 that supplies freshwater to the separator 152 to clean it, thereby preventing corrosion by seawater and preventing seawater from mixing with the regenerated absorbent.

[0112] Furthermore, the overboard discharge section 150 further includes a freshwater cooler 156 that cools the seawater supplied to the discharge seawater pump 153 into cooling freshwater, and the cooled seawater from the freshwater cooler 156 can be supplied to the sediment discharged from the separator 152 to dilute it before it is discharged overboard.

[0113] Next, as shown in Figure 6, the washing water treatment unit 160 includes a washing water tank 161 for storing washing water discharged from the absorption tower 130, a water treatment device 162 equipped with a filtering unit for adjusting the turbidity of the washing water transferred from the washing water tank 161 to meet the conditions for overboard discharge and a neutralizing agent injection unit for pH adjustment, and a sludge storage tank 163 for separating and storing solid waste.

[0114] Next, as shown in Figure 3, the steam generation unit 170 may further include an EGE 134 formed between the NOx absorption unit 133 and the SOx absorption unit 132, which exchanges heat between the waste heat of the ship's engine and the boiler water. Specifically, as shown in Figure 7, the steam generation unit 170 consists of an auxiliary boiler 171 that receives a mixture of steam and saturated water that has passed through the EGE 134 and separates the steam using a steam drum (not shown) and supplies it to steam consumption points on board; a boiler water circulation pump 172 that circulates boiler water from the auxiliary boiler 171 to the EGE 134; a cascade tank 173 that recovers condensed water that has been consumed and has undergone a phase change; and a supply pump 174 and control valve 175 that adjust and supply the amount of boiler water from the cascade tank 173 to the auxiliary boiler 171, thereby generating and supplying the steam necessary for heating devices on board.

[0115] Here, if the load on the ship's engine 10 is high, the amount of heat that can be supplied from the exhaust gas is high, and the required amount of steam on board can be sufficiently produced via the EGE 134. Otherwise, the auxiliary boiler 171 itself can burn fuel to produce the necessary steam.

[0116] On the other hand, another embodiment of the present invention provides a ship or offshore structure equipped with the aforementioned greenhouse gas emission reduction device for ships.

[0117] Therefore, with the configuration of the embodiment of the present invention, the carbonate separated by the separator is discharged overboard using seawater, and the separator can be washed with fresh water to prevent corrosion by seawater. Furthermore, greenhouse gases can be mineralized to reduce environmental pollution. Since the material containing the collected greenhouse gases is discharged into the ocean, separate storage and handling facilities are unnecessary. NOx, SOx, and CO2 can be removed simultaneously, and the material can be stored in a solid state with few impurities such as Na2CO3, NaHCO3, (NH4)2CO3, and NH4HCO3. By removing CO2 after removing SOx and suppressing side reactions caused by SOx remaining in the exhaust gas, the solubility of CO2 and the efficiency of CO2 removal can be improved.

[0118] The embodiments and configurations shown in the drawings described herein represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that there are various equivalents and modifications available at the time of filing.

Claims

1. CO ２ An absorbent liquid circulation supply unit provides and circulates an absorbent liquid, which is a monovalent alkaline aqueous solution that absorbs the substance, An exhaust gas cooling unit that cools the exhaust gas discharged from a ship's engine, The cooled exhaust gas and the absorbent liquid react to form CO ２ Replace it with a carbonate solution and CO ２ CO2 is collected ２ An absorption tower including a removal section, The absorption liquid regeneration unit regenerates the absorption liquid by reacting the carbonate aqueous solution with a regeneration reaction product containing a divalent metal oxide or divalent metal hydroxide, and generates a precipitate containing a solid-phase carbonate. An overboard discharge unit separates the aforementioned sediment, dilutes the sediment with seawater, and discharges it overboard; Includes, The offshore discharge unit includes a separator that separates the sediment and the absorbent liquid, discharging the sediment overboard and returning the absorbent liquid to the absorbent liquid circulation supply unit; a freshwater supply valve that supplies fresh water to the separator; and a sensor for measuring one or more of the turbidity, pH, and oil content of the sediment. The unit is configured to perform a separation step of the sediment and the absorbent liquid, and if the measurement value from the sensor satisfies the offshore discharge conditions, a discharge step is performed in which the sediment is diluted with seawater and discharged overboard from the separator; if the offshore discharge conditions are not met, a storage step is performed in which the sediment is temporarily stored; and a cleaning step is performed in which the freshwater supply valve is used to supply fresh water to the separator and clean the separator. A device for reducing greenhouse gas emissions from ships.

2. The aforementioned discharge section for the ship is A separation pump that sucks up the precipitate and the absorbent liquid from the absorbent liquid regeneration unit and transfers them to the separator, A discharge seawater pump that supplies seawater to the separator to dilute the sediment and discharge it overboard the ship, A greenhouse gas emission reduction device for a ship according to claim 1, characterized by including the following.

3. The separator is, The greenhouse gas emission reduction device for a ship according to claim 1, characterized in that it is a filter-type separator or centrifuge for separating the precipitate and the absorbent liquid from each other.

4. The aforementioned discharge section for the ship is The greenhouse gas emission reduction device for a ship according to claim 2, further comprising a freshwater cooler that cools the seawater supplied to the discharge seawater pump by heat exchange with cooling freshwater.

5. The greenhouse gas emission reduction device for a ship according to claim 4, characterized in that seawater cooled via the freshwater cooler is supplied to the sediment discharged from the separator, diluted, and discharged overboard.

6. The absorbent solution is an aqueous solution of LiOH, an aqueous solution of NaOH, an aqueous solution of KOH, and NH ４ The greenhouse gas emission reduction device for a ship according to claim 1, characterized by containing any one of the OH aqueous solutions.

7. It further includes a seawater supply unit that supplies seawater from outside the vessel, The aforementioned seawater supply unit is A seawater pump that receives the seawater from outside the ship via a sea chest and pumps it to the absorption tower, A seawater control valve adjusts the amount of seawater injected from the seawater pump to the absorption tower according to the amount of exhaust gas, A greenhouse gas emission reduction device for a ship according to claim 1, characterized by including the following.

8. The exhaust gas cooling unit is The greenhouse gas emission reduction device for a ship according to claim 7, characterized in that it cools the exhaust gas discharged from the ship's engine by reacting it with the seawater supplied from the seawater supply unit.

9. The exhaust gas cooling unit is The greenhouse gas emission reduction device for a ship according to claim 1, characterized in that it cools the exhaust gas discharged from the ship's engine by reacting it with fresh water.

10. The exhaust gas cooling unit is A greenhouse gas emission reduction device for a ship according to claim 1, characterized in that fresh water supplied from an onboard cooling system is circulated through heat exchange piping surrounding the exhaust gas discharge pipe to cool the exhaust gas.

11. The greenhouse gas emission reduction device for a ship according to claim 1, characterized in that the exhaust gas cooling unit is provided inside the absorption tower.

12. The absorbent liquid circulation supply unit is, An absorbent liquid storage tank for storing the absorbent liquid, An absorbent liquid pump for pumping and transferring the absorbent liquid from the absorbent liquid storage tank, An absorbent liquid circulation tank that mixes and stores the carbonate aqueous solution discharged from the absorption tower and the absorbent liquid supplied from the absorbent liquid pump, The absorbent liquid is supplied from the absorbent liquid circulation tank to the CO ２ An absorption liquid circulation pump is provided to the upper part of the removal section for circulation, A greenhouse gas emission reduction device for a ship according to claim 1, characterized by including the following.

13. The aforementioned absorbent liquid pump is The greenhouse gas emission reduction device for a ship according to claim 12, characterized in that the absorbent liquid is supplied to the absorbent liquid circulation tank in order to replenish the amount of absorbent liquid that is discharged overboard by the overboard discharge section.

14. The absorbent solution is an aqueous NaOH solution. The greenhouse gas emission reduction device for a ship according to claim 12, characterized in that the NaOH aqueous solution is produced by electrolyzing seawater and freshwater, respectively, and stored in the absorbent storage tank.

15. The system further includes a seawater supply unit that supplies seawater from outside the vessel, and the exhaust gas cooling unit is provided inside the absorption tower. The aforementioned absorption tower is The exhaust gas cooling unit further includes an SOx absorption unit that cools the exhaust gas by reacting it with seawater supplied from the seawater supply unit, while dissolving and removing SOx. The aforementioned CO ２ The removed part is, The cooled exhaust gas, from which SOx has been removed, reacts with the absorbent liquid from the absorbent liquid circulation supply unit to convert it into a carbonate aqueous solution, which then reacts with CO2. ２ A greenhouse gas emission reduction device for a ship according to claim 1, characterized by collecting [unclear].

16. It further includes a seawater supply unit that supplies seawater from outside the vessel, The aforementioned absorption tower is The system further includes a NOx absorption unit that absorbs and removes NOx from the exhaust gas, The exhaust gas cooling unit is located inside the absorption tower and cools the exhaust gas from which NOx has been removed by reacting it with seawater supplied from the seawater supply unit. The aforementioned CO ２ removal unit is The cooled exhaust gas reacts with the absorbent liquid from the absorbent liquid circulation supply unit to convert it into a carbonate aqueous solution, which is then converted to CO2. ２ A greenhouse gas emission reduction device for a ship according to claim 1, characterized by collecting [unclear].

17. It further includes a seawater supply unit that supplies seawater from outside the vessel, The exhaust gas cooling unit is provided inside the absorption tower. The aforementioned absorption tower is The NOx absorption unit absorbs and removes NOx from the exhaust gas, The exhaust gas cooling unit includes an SOx absorption unit that cools the exhaust gas from which NOx has been removed by reacting it with seawater supplied from the seawater supply unit, while dissolving and removing SOx, The cooled exhaust gas, from which SOx has been removed, reacts with the absorbent liquid from the absorbent liquid circulation supply unit to convert it into a carbonate aqueous solution, which is then collected as CO2. ２ The CO2 that removes ２ The greenhouse gas emission reduction device for a ship according to claim 1, characterized in that the removal sections are sequentially stacked.

18. The greenhouse gas emission reduction device for a ship according to claim 16 or 17, characterized in that the NOx absorption section includes an SCR.

19. The absorbent liquid regeneration unit is, A regenerated reaction material storage tank for storing the aforementioned regenerated reaction material, A transfer pump for pumping and transferring the carbonate aqueous solution, A mixing tank that mixes the regenerated reaction product and the carbonate aqueous solution to regenerate the absorption solution, generates the solid-phase carbonate, and returns the regenerated absorption solution to the absorption tower, A greenhouse gas emission reduction device for a ship according to claim 1, characterized by including the following.

20. A washing water tank for storing washing water discharged from the aforementioned absorption tower, A water treatment apparatus comprising a filtering unit that adjusts the turbidity of the wash water transferred from the wash water tank to meet the conditions for discharge of the wash water overboard, and a neutralizing agent injection unit for pH adjustment, A washing water treatment section includes a sludge storage tank for separating and storing solid waste, A greenhouse gas emission reduction device for a ship according to claim 1, further comprising the following:

21. The exhaust gas cooling unit is At least a portion of the exhaust gas discharged from the aforementioned ship engine is diverted and cooled. The aforementioned CO ２ The removed part is, The cooled exhaust gas and the absorbent liquid react to form CO ２ Replace CO with the aforementioned carbonate aqueous solution. ２ A greenhouse gas emission reduction device for a ship according to claim 1, characterized by collecting [unclear].

22. The greenhouse gas emission reduction device for a ship according to claim 21, further comprising a blowing means for supplying at least a portion of the branched exhaust gas to the exhaust gas cooling section.

23. The greenhouse gas emission reduction device for a ship according to claim 22, characterized in that the blowing means is a blower.

24. Of the exhaust gas discharged from the aforementioned ship engine, the residual exhaust gas that is not branched off to the exhaust gas cooling section is discharged through the main exhaust pipe. At least a portion of the exhaust gas that is branched to the exhaust gas cooling section is CO ２ The greenhouse gas emission reduction device for a ship according to claim 21, characterized in that the collected gases are then merged into the main exhaust pipe and discharged, or discharged through another discharge pipe.

25. A ship or offshore structure equipped with a greenhouse gas emission reduction device for ships according to any one of claims 1 to 17.

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