Onboard CO2 capture system

Abstract

To provide an onboard CO2 recovery system that separates and recovers CO2 contained in exhaust gas from a ship's main engine using a separation membrane, and that can suppress a decrease in the overall CO2 recovery efficiency of the ship. [Solution] An onboard CO2 recovery system equipped with a CO2 separation membrane module 6 for separating CO2 from exhaust gas sent via an exhaust gas pipe directly or indirectly connected to the ship's main engine 1, characterized in that a condensation mist catcher 5 for removing condensed mist generated in the exhaust gas is provided upstream of the CO2 separation membrane module 6, and a pipe for supplying liquefied CO2 is connected upstream of the condensation mist catcher 5.

Description

Technical Field

[0001] The present invention relates to an on-board CO2 recovery device that separates and recovers carbon dioxide (hereinafter referred to as "CO2") contained in exhaust gas from a ship's main engine by means of a separation membrane. More specifically, the present invention relates to an on-board CO2 recovery device that can improve the CO2 recovery efficiency of the entire ship.

Background Art

[0002] In recent years, from the perspective of suppressing global warming, the reduction of greenhouse gas (GHG) emissions from various combustion engines has been demanded, and ship main engines are no exception. Patent Document 1 describes a CO2 emission reduction ship that separates CO2 contained in exhaust gas from a ship's main engine using a separation filter having a cylindrical separation membrane, and liquefies or solidifies it for landfall.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, it is a technology for discharging CO2 into the sea or pressurizing and liquefying or solidifying it for landfall, and the CO2 separated by membrane separation is not utilized. As a result, for example, when performing membrane separation, depending on the exhaust gas sent to the separation membrane, there is a problem that the life of the membrane is shortened, and there is a risk that the CO2 recovery efficiency of the entire ship will be reduced.

[0005] Therefore, an object of the present invention is to provide an on-board CO2 recovery device that can suppress a decrease in the CO2 recovery efficiency of the entire ship in an on-board CO2 recovery device that separates and recovers CO2 contained in exhaust gas from a ship's main engine by means of a separation membrane.

[0006] Furthermore, other problems of the present invention will become clear from the following description. [Means for solving the problem]

[0007] The above problems are solved by the following inventions.

[0008] 1. In a shipboard CO2 recovery system equipped with a CO2 separation membrane module that separates CO2 from exhaust gas delivered via an exhaust gas pipe directly or indirectly connected to the ship's main engine, A condensation mist catcher is provided upstream of the CO2 separation membrane module to remove condensation mist generated in the exhaust gas from the exhaust gas. A shipboard CO2 recovery system characterized in that a pipe for supplying liquefied CO2 is connected to the upstream of the condensing mist catcher. 2. The piping connected to the upstream of the aforementioned condensing mist catcher is The shipboard CO2 recovery apparatus according to claim 1, characterized in that it has a mist nucleus purification function which cools the exhaust gas by supplying and injecting the liquefied CO2, thereby removing the heat of vaporization when the liquefied CO2 vaporizes, and atomizing water vapor using at least soot and / or oil in the exhaust gas as nuclei. 3. At least a portion of the exhaust gas from the ship's main engine is sent to a CO2 separation membrane module having a CO2 separation membrane. The CO2 separation membrane module separates CO2 from the exhaust gas. A shipboard CO2 recovery device according to claim 1 or 2, characterized in that it is a shipboard CO2 recovery device. 4. In the preceding CO2 separation membrane module, the exhaust gas is passed through a scrubber that brings the exhaust gas into contact with water to remove soot and other particles from the exhaust gas. A shipboard CO2 recovery device according to claim 1 or 2, characterized in that it is a shipboard CO2 recovery device. 5. In the preceding stage of the CO2 separation membrane module, an EGR unit removes soot and dust from the exhaust gas and cools the exhaust gas. Send at least a part of the exhaust gas returned from the EGR unit to the main engine of the ship to the CO2 separation membrane module. The on-ship CO2 recovery device according to claim 1 or 2, characterized in that. 6. Send the CO2 separated from the exhaust gas in the CO2 separation membrane module to a CO2 liquefaction unit that compresses and cools it to liquefy it. In the CO2 liquefaction unit, liquefy the CO2. The on-ship CO2 recovery device according to claim 1 or 2, characterized in that.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide an on-ship CO2 recovery device that can increase the CO2 recovery efficiency of the entire ship in an on-ship CO2 recovery device that separates and recovers CO2 contained in the exhaust gas from the main engine of the ship by a separation membrane.

Brief Description of the Drawings

[0010] [Figure 1] Explanatory drawing showing the configuration of the on-ship CO2 recovery device of the first embodiment of the present invention [Figure 2] Block diagram showing the operation of the on-ship CO2 recovery device shown in FIG. 1 [Figure 3] Explanatory drawing showing the configuration for returning the liquefied CO2 of the on-ship CO2 recovery device of the first embodiment [Figure 4] Block diagram showing the operation of the on-ship CO2 recovery device shown in FIG. 3 [Figure 5] Explanatory drawing showing the configuration of the on-ship CO2 recovery device of the second embodiment of the present invention [Figure 6] Block diagram showing the operation of the on-ship CO2 recovery device shown in FIG. 5 [Figure 7] Explanatory drawing showing the configuration for returning the liquefied CO2 of the on-ship CO2 recovery device of the second embodiment [Figure 8] Block diagram showing the operation of the on-ship CO2 recovery device shown in FIG. 7

Modes for Carrying Out the Invention

[0011] Hereinafter, preferred embodiments of the present invention will be described. [First Embodiment] FIG. 1 is an explanatory diagram showing the configuration of a shipboard CO2 recovery device according to a first embodiment of the present invention, and FIG. 2 is a block diagram showing the operation of the shipboard CO2 recovery device shown in FIG. 1.

[0012] This shipboard CO2 recovery device is a device provided with a CO2 separation membrane module that separates CO2 from exhaust gas sent through an exhaust gas pipe directly or indirectly connected to a ship's main engine. The ship's main engine includes, for example, a marine diesel engine. In the present embodiment, the introduced exhaust gas is passed through a scrubber and a condensate mist catcher in the front stage of the CO2 separation membrane module.

[0013] As shown in FIG. 1, in the shipboard CO2 recovery device, at least a part of the exhaust gas branches from the middle of the pipe from the exhaust receiver 1a of the ship's main engine 1 through the economizer 2 to the flue 3 and is introduced into the exhaust gas treatment unit 4. The exhaust gas treatment unit 4 includes a scrubber 40, a blower 41, a cooler 42, and a condensate mist catcher 5. The temperature of the exhaust gas introduced into the exhaust gas treatment unit 4 is about 180°C. This introduction is made by the suction force of the blower 41 provided in the exhaust gas treatment unit 4.

[0014] In this shipboard CO2 recovery device, as shown in FIGS. 1 and 2, the introduced exhaust gas is introduced into the lower part of the scrubber 40 of the exhaust gas treatment unit 4. Water is supplied to the upper part of the scrubber 40. The scrubber 40 can wash the exhaust gas by bringing water into gas-liquid contact with the exhaust gas and removing dust and oil content, including the removal of SOx in the exhaust gas. In the CO2 separation membrane module 6 described later, if the CO2 separation membrane 60 that separates CO2 performs membrane separation without washing the exhaust gas, the separation function deteriorates due to clogging by dust and cylinder oil. Therefore, by washing the exhaust gas with the scrubber 40, deterioration of the membrane separation function can be prevented.

[0015] In this embodiment, soot and oil in the exhaust gas can also be removed by a dust collector using a porous filter. However, exhaust gas from a ship's main engine contains a very large amount of soot, as well as oil such as cylinder oil, so porous filters may become clogged in a short time. In this embodiment, by using the scrubber 40, it is possible to remove soot and oil from the exhaust gas over a long period of time and prevent deterioration of the membrane's separation function.

[0016] The water that has absorbed soot and oil in the scrubber 40 is drained downwards from the scrubber 40. The exhaust gas from which soot and oil have been removed in the scrubber 40 is pulled by a blower 41 located on the upper outlet side of the scrubber and exhausted upwards from the scrubber 40.

[0017] The exhaust gas, which is discharged above the scrubber 40 by the blower 41, is passed through the cooler 42. Cooling water is supplied to the cooler 42, and this cooling water cools the exhaust gas. In the cooler 42, the temperature of the exhaust gas is cooled to 40°C to 80°C or lower, and the water vapor in the exhaust gas absorbs any remaining soot and oil and condenses into a liquid. The liquid that has absorbed and condensed soot and oil is drained from a drain outlet located below the cooler 42.

[0018] The exhaust gas that has passed through the cooler 42 is sent to the condensed mist catcher 5. The condensed mist catcher 5 removes condensed mist (fine water droplets) that have formed in the exhaust gas due to the condensation of water vapor in the exhaust gas, and discharges it. Condensed mist is generated when water vapor remaining in the exhaust gas condenses around remaining soot and oil particles.

[0019] The exhaust gas that has passed through the condensation mist catcher 5 is sent to the CO2 separation membrane module 6. The exhaust gas that has passed through the condensation mist catcher 5 may, but is not limited to, be sent to the CO2 separation membrane module 6 by the blower 41.

[0020] The CO2 separation membrane module 6 is equipped with a CO2 separation membrane 60, through which CO2 from the exhaust gas passes. The CO2 that has passed through the CO2 separation membrane 60 is passed downstream of the CO2 separation membrane and sent to the CO2 liquefaction unit 7. Meanwhile, the remaining exhaust gas (processed gas) that did not pass through the CO2 separation membrane 60 is sent from the exhaust gas return line 62 to the flue 3.

[0021] The CO2 separation membrane 60 can be any membrane that can permeate CO2, such as a non-porous membrane. Non-porous membranes are generally made of polymer materials and are sometimes referred to as organic membranes.

[0022] The supplied CO2 is liquefied by compression by the compressor 70 and cooling by the cooler 71 of the CO2 liquefaction unit 7. The liquefied CO2 produced in the CO2 liquefaction unit 7 is stored in the tank 72.

[0023] Figure 3 is an explanatory diagram showing the configuration for returning liquefied CO2 in the onboard CO2 recovery device of the first embodiment, and Figure 4 is a block diagram showing the operation of the onboard CO2 recovery device shown in Figure 3.

[0024] In this embodiment, the onboard CO2 recovery device may be configured to supply (inject) the liquefied CO2 in the CO2 liquefaction unit 7 into the exhaust gas upstream of the condensation mist catcher 5, as shown in Figures 3 and 4.

[0025] The exhaust gas, cooled to below 40°C via the cooler 42, is in a saturated vapor state. By injecting liquefied CO2 into it, the exhaust gas is immediately further cooled by the heat of vaporization of the CO2. This exhibits a mist nucleus purification function in which water vapor condenses (mistes) around soot and oil, or soot and oil, and this mist can be captured by the condensed mist catcher 5.

[0026] When using the internal pressure of tank 72 (i.e., when tank 72 is a pressurized tank), the injection of liquefied CO2 can be controlled by adjusting the supply flow rate using a flow control valve (not shown). If tank 72 is not a pressurized tank, the liquefied CO2 can be supplied by installing a supply pump (not shown) in the liquefied CO2 supply line 73.

[0027] In this embodiment, the cooler 42 does not need to be provided. In this case, the liquefied CO2 supplied from the supply line 73 is injected upstream of the condensing mist catcher 5, thereby performing a mist nucleus purification function. The exhaust gas is immediately further cooled by the heat of vaporization caused by the vaporization of CO2, so water vapor condenses (mistes) around oil and dust in the exhaust gas, and this mist can be captured by the condensing mist catcher 5. In the condensing mist catcher 5, the dust and oil in the misted exhaust gas are captured and discharged.

[0028] By injecting liquefied CO2, the amount of soot and oil flowing into the CO2 separation membrane module 6 can be reduced, preventing clogging of the separation membrane due to soot and oil, and extending the service life (replacement life) of the separation membrane.

[0029] Instead of using liquefied CO2 injected before the condensing mist catcher 5, the exhaust gas can also be cooled using liquefied nitrogen (N2). In this case as well, the mist nucleus purification function can be achieved by atomizing soot or oil in the exhaust gas, or by using soot and oil as nuclei, but liquefied nitrogen must be prepared separately. In contrast, in this embodiment, since the exhaust gas can be purified by utilizing CO2 separated from the exhaust gas, it has the effect of eliminating the need to install unnecessary equipment.

[0030] [Second Embodiment] The onboard CO2 recovery system in this embodiment is a device that sends at least a portion of the exhaust gas returned from the EGR to the ship's main engine to a CO2 separation membrane module, and separates CO2 from the exhaust gas in the CO2 separation membrane module.

[0031] Figure 5 is an explanatory diagram showing the configuration of a shipboard CO2 capture device according to a second embodiment of the present invention, and Figure 6 is a block diagram showing the operation of the shipboard CO2 capture device shown in Figure 5.

[0032] In this embodiment, as shown in Figures 5 and 6, an EGR unit 8 removes soot from the exhaust gas and cools it in front of the CO2 separation membrane module 6, and at least a portion of the exhaust gas that is returned from the EGR unit 8 to the ship's main engine 1 is sent to the CO2 separation membrane module 6. Furthermore, by recirculating the exhaust gas from the EGR unit 8 to the ship's main engine 1 and lowering the oxygen concentration in the scavenging air of the ship's main engine 1, the peak value of the combustion temperature is reduced, and nitrogen oxides (NOx) generated during combustion are suppressed.

[0033] A portion of the exhaust gas from the exhaust receiver 1a of the ship's main engine 1 is introduced into the EGR unit 8. The remaining exhaust gas from the exhaust receiver 1a is discharged through the flue 3. In the EGR unit 8, exhaust gas is sent to the EGR scrubber 81 via the On-off control valve 80. The flow rate of exhaust gas sent to the EGR scrubber 81 can be adjusted by the EGR blower 84.

[0034] In the EGR scrubber 81, the exhaust gas sent to the scrubber 81 comes into gas-liquid contact with water supplied to the EGR wastewater treatment device 10, removing soot and oil and cleaning the exhaust gas. The water that has taken in the soot and oil from the exhaust gas is discharged into the tank 11. The water discharged into the tank 11 is sent to the EGR wastewater treatment device 10, where sludge is separated. The water from which the sludge has been separated in the EGR wastewater treatment device 10 is supplied to the EGR scrubber 81.

[0035] The exhaust gas, from which soot and oil have been removed by the EGR scrubber 81, is sent to the EGR cooler 82 for cooling, and then passes through the WMC (Water Mist Catcher) 83 to remove condensed mist generated in the exhaust gas before being sent out from the EGR unit 8 by the EGR blower 84.

[0036] The exhaust gas sent from the EGR unit 8 is returned to the ship's main engine 1 via the On-off valve (blower throttle valve) 12, but at least a portion of it is branched off before reaching the blower throttle valve 12 and sent to the condensed mist catcher 5.

[0037] In the condensed mist catcher 5, as in the first embodiment, condensed mist (fine water droplets) formed in the exhaust gas by the condensation of water vapor in the exhaust gas is removed from the exhaust gas and discharged. This discharged water is sent to the tank 11.

[0038] The exhaust gas that has passed through the condensation mist catcher 5 is sent to the CO2 separation membrane module 6. The means for sending the exhaust gas to the CO2 separation membrane module 6 is the same as in the first embodiment, and the CO2 separation membrane module 6 is also the same as in the first embodiment. The CO2 separated from the exhaust gas in the CO2 separation membrane module 6 is passed downstream of the CO2 separation membrane and sent to the CO2 liquefaction unit 7. The CO2 liquefaction unit 7 is the same as that in the first embodiment.

[0039] The remaining exhaust gas, after CO2 has been separated in the CO2 separation membrane module 6, is returned to the scavenging (AIRINTAKE) of the ship's main engine 1 via the exhaust gas return line 62. This is done to reduce the oxygen concentration in the scavenging of the ship's main engine 1, thereby lowering the peak combustion temperature and suppressing nitrogen oxides (NOx) generated during combustion of the ship's main engine 1.

[0040] Figure 7 is an explanatory diagram showing the configuration for returning liquefied CO2 in the onboard CO2 recovery device of the second embodiment, and Figure 8 is a block diagram showing the operation of the onboard CO2 recovery device shown in Figure 7.

[0041] In this onboard CO2 recovery system, as shown in Figures 7 and 8, the liquefied CO2 liquefied in the CO2 liquefaction unit 7 may be supplied (injected) into the exhaust gas upstream of the condensation mist catcher 5.

[0042] The exhaust gas, cooled to below 40°C via the EGR unit 8, is in a saturated vapor state. By injecting liquefied CO2 into it, the exhaust gas is immediately further cooled by the heat of vaporization of the CO2. This causes water vapor to condense (mist) around soot and oil, or both soot and oil, and this mist can be captured by the condensation mist catcher 5.

[0043] When using the internal pressure of tank 72 (i.e., when tank 72 is a pressurized tank), the injection of liquefied CO2 can be controlled by adjusting the supply flow rate using a flow control valve (not shown). If tank 72 is not a pressurized tank, the liquefied CO2 can be supplied by installing a supply pump (not shown) in the liquefied CO2 supply line 73.

[0044] By injecting liquefied CO2, the amount of soot and oil flowing into the CO2 separation membrane module 6 can be reduced, preventing clogging of the separation membrane due to soot and oil, and extending the service life (replacement life) of the separation membrane.

[0045] In this embodiment, even when using the EGR unit 8 shown in Figures 5 to 8, the exhaust gas may be branched before the flue 3 as shown in Figures 1 to 4, and the CO2 from the cleaned exhaust gas may be separated and recovered using the exhaust gas treatment unit 4. In this case, it is preferable to separate and recover the CO2 from the branched exhaust gas using the same configuration and method as in the first embodiment. For example, as explained in Figures 5 and 6, a portion of the exhaust gas from the exhaust receiver 1a of the ship's main engine 1 is introduced into the EGR unit 8, and the remaining exhaust gas from the exhaust receiver 1a goes to the flue 3. However, a portion of the exhaust gas may be branched before reaching the flue 3, and the CO2 from the cleaned exhaust gas may be separated and recovered using the exhaust gas treatment unit 4 shown in Figures 1 to 4. [Explanation of Symbols]

[0046] 1: Ship main engine 1a: Exhaust receiver 2: Economizer 3: Flue 4: Exhaust gas treatment unit 40: Scrubber 41: Blower 42: Kura 5: Condensed Mist Catcher 6: CO2 separation membrane module 60:CO2 separation membrane 62: Exhaust gas return line 7: CO2 liquefaction unit 70: Compressor 71: Cooler 72: Tank 73: Supply Line 8: EGR unit 80: On-off valve 81: EGR Scrubber 82: EGR cooler 84: EGR blower 10: EGR wastewater treatment equipment 11: Tank 12: On-off valve (blower throttle valve)

Claims

1. CO2 is released from exhaust gases delivered through exhaust pipes directly or indirectly connected to the ship's main engine. ２ CO2 separation ２ Shipboard CO2 equipped with a separation membrane module ２ In the recovery device, The aforementioned CO ２ A condensation mist catcher is provided upstream of the separation membrane module to remove condensation mist generated in the exhaust gas from the exhaust gas. Prior to the aforementioned condensing mist catcher, liquefied CO ２ A feature of onboard CO2 is that it is connected to a piping for supplying CO2. ２ Recovery device.

2. The piping connected to the upstream of the aforementioned condensing mist catcher is The liquefied CO ２ is fed and injected, and by doing so, the heat of vaporization when the liquefied CO ２ vaporizes is taken away to cool the exhaust gas, and a mist nucleation purification function is provided to atomize water vapor around at least dust and / or oil content in the exhaust gas. The onboard CO ２ recovery device according to claim 1, characterized in that it has such a function.

3. At least a portion of the exhaust gas from the ship's main engine is CO ２ CO2 with separation membrane ２ Send to the separation membrane module. The aforementioned CO ２ In the separation membrane module, CO is separated from the exhaust gas. ２ Separate Onboard CO2 according to claim 1 or 2 as described above. ２ Recovery device.

4. The aforementioned CO ２ In the preceding stage of the separation membrane module, the exhaust gas is passed through a scrubber that brings the exhaust gas into contact with water to remove soot and other particles from the exhaust gas. Onboard CO2 according to claim 1 or 2 as described above. ２ Recovery device.

5. The aforementioned CO ２ In the preceding stage of the separation membrane module, an EGR unit removes soot and dust from the exhaust gas and cools the exhaust gas. At least a portion of the exhaust gas returned from the EGR unit to the ship's main engine is the CO ２ Send to the separation membrane module Onboard CO2 according to claim 1 or 2 as described above. ２ Recovery device.

6. The aforementioned CO ２ CO separated from the exhaust gas in the separation membrane module ２ CO2 is compressed and cooled to liquefy it. ２ Send to the liquefaction unit, The aforementioned CO ２ In the liquefaction unit, the CO ２ Liquefy Onboard CO2 according to claim 1 or 2 as described above. ２ Recovery device.

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