Marine high-pressure water carbon capture method equipment

Abstract

The marine high-pressure water carbon capture device is characterized by comprising a waste heat engine, an air compressor, an air turbine, waterline absorption capture equipment, a tail gas treatment device, a high-pressure heat exchanger, a cooling device, a fan and a carbon dioxide desorption device, the waste heat engine comprises a waste heat boiler, a steam turbine, a condenser and a water feeding pump. The tail gas of the marine diesel engine sequentially passes through the turbine engine, the first-stage waste heat engine and the second-stage waste heat engine to release heat energy and kinetic energy, is treated by the tail gas treatment device, is cooled by the cooling device, enters the heat pipe air compressor and is compressed to a set high pressure value; then, the rich gas is subjected to heat exchange and cooling through a high-pressure heat exchanger, is further cooled to 0-2 DEG C through a heat pump cooling device and then enters waterline absorption and capture equipment, carbon dioxide in the rich gas is captured and decarbonized into lean gas, and the lean gas is subjected to heat exchange and temperature rise through the high-pressure heat exchanger and then enters a heat pipe air turbine to do work through expansion; the normal-pressure lean gas is conveyed to the diesel engine through a heat-insulating lean gas pipe, exchanges heat with the diesel engine, is heated and then is collected by a gas collector and is discharged into the atmosphere.

Description

Technical Field

[0001] The present invention relates to the technical field of marine high-pressure water carbon capture and marine engine waste heat power generation. Background Art

[0002] Chinese invention patent application 202510456726.4, "High-Pressure Water Absorption Carbon Capture Equipment Method and Business Model," discloses a high-pressure water carbon capture method and equipment. However, electricity prices on ships are high, and there is an urgent need for a large, low-cost power supply.

[0003] The implementation scenarios of the present invention differ from those of the aforementioned carbon capture equipment, including the following: 1) high-pressure water ship-mounted carbon capture devices require a large amount of high-grade energy; 2) high-grade energy on ships, including mechanical and electrical energy, is very expensive, with an average cost of around 5 yuan per kilowatt-hour; 3) the engine's exhaust compression at around 500°C further increases the demand for high-grade energy and reduces compression efficiency; 4) readily available seawater and river water can be used as a room-temperature cooling source; 4) some ships need to heat heavy fuel oil to around 120°C; and 5) there may not be ready-made space for installing carbon capture devices. Summary of the Invention

[0004] One of the objects of the present invention is to provide a method for capturing carbon dioxide from the exhaust gas of a marine engine using high-pressure water.

[0005] The method of the present invention for capturing carbon dioxide in exhaust gas from a marine engine using high-pressure water comprises: using a waste heat engine to convert the energy in the exhaust gas into mechanical energy, including using two cascaded sets of waste heat engines to obtain more energy; after the exhaust gas pressure and temperature are reduced and further cooled with seawater or river water, it is sent to an air compressor of a high-pressure water carbon capture system and compressed to a high pressure including but not limited to a range of 2 to 10 MPa, preferably 3 to 4 MPa; using a waterline absorption capture device to absorb the carbon dioxide, and utilizing an air turbine to expand the decarbonized lean gas to perform work and feed it back to the air compressor; the waste heat engine comprises a waste heat boiler, a steam turbine, a condenser and a water feed pump, and the relevant contents can be referred to in the prior art.

[0006] Using two sets of waste heat engines can coordinate heating temperatures including but not limited to one at 390℃ and one at 260℃.

[0007] Because the rich gas is isolated from the outside and needs to be compressed to above 3.5 MPa, in a possible design, the gas pressure entering the air compressor is kept higher than the atmospheric pressure in the range of 0.01 to 1 MPa, preferably in the range of 0.2 to 0.4 MPa.

[0008] One possible design involves placing a turbine engine between the marine diesel engine's exhaust and the waste heat boiler (HRSG), using the engine's exhaust to drive the turbine generator. This approach generates additional energy while mitigating the impact of exhaust gas on the HRSG. While this increases the back pressure on the marine diesel engine, a comprehensive design approach is expected to outweigh the disadvantages.

[0009] In one possible design, a heat pipe air compressor and a heat pipe air turbine are used, and two-phase flow heat exchange elements are used to achieve isothermal gas temperature in the heat pipe air compressor and air turbine. This includes using seawater or river water to cool the air in the air compressor to help achieve isothermal gas temperature within the range of 5 to 35°C. Furthermore, the low-temperature heat source of the waste heat engine is discarded to heat the heavy oil; including using the discarded heat of two-stage waste heat engines to relay heat the heavy oil.

[0010] A second object of the present invention is to provide a special device for capturing high-pressure water carbon dioxide from the exhaust gas of a marine engine.

[0011] This object of the present invention is achieved by manufacturing a marine high-pressure water carbon capture device, including a waste heat engine, an air compressor, an air turbine, a waterline absorption and capture device, an engine exhaust treatment device, a high-pressure heat exchanger, a cooling device including a cooling device using seawater or river water as cooling water, a fan, a carbon dioxide desorption device and a carbon dioxide liquefaction device; the waste heat engine includes a waste heat boiler, a steam turbine, a condenser and a feed water pump.

[0012] In a possible design, the waste heat engine is connected to the air compressor of the carbon capture device through a shaft transmission.

[0013] Because the rich gas is isolated from the outside and needs to be compressed to above 3.5 MPa, in a possible design, the gas pressure entering the air compressor is kept higher than the atmospheric pressure in the range of 0.01 to 1 MPa, preferably in the range of 0.2 to 0.4 MPa.

[0014] In one possible design, two-phase flow heat exchange elements are used to achieve isothermalization of the gas in the heat pipe air compressor and the air turbine; including using seawater and river water to cool the air in the heat pipe air compressor to help achieve isothermalization of the gas in the air compressor and air turbine at each temperature within the range of 5 to 35°C.

[0015] In one possible design, the low-temperature heat source of the waste heat engine is discarded to heat the heavy oil, including using the discarded heat of two-stage waste heat engines to relay heat the heavy oil.

[0016] In a possible design, the ship-mounted high-pressure water carbon capture device is integrated into several containers to facilitate skid-mounting of the carbon capture device.

[0017] Beneficial effects: The present invention provides a ship-mounted high-pressure water carbon capture device, which can capture carbon dioxide emitted by ships at low cost and high efficiency; the waste heat engine efficiently utilizes the energy in the exhaust gas of the ship engine, and is expected to obtain energy equivalent to about 3% of the output of the ship engine to drive the heat pipe air compressor of the carbon capture device, greatly reducing the power supply load of the ship engine, and can use the low-temperature heat source of the waste heat engine to discard heat to heat the heavy oil of the ship engine.

[0018] The pressure of the rich gas entering the air compressor of the carbon capture device is maintained at 0.01 to 1 MPa higher than the atmospheric pressure. This can not only reduce the expansion and cooling amplitude of the gas in the waste heat boiler, but also reduce the total energy of the compressed air, and reduce the temperature rise of the compressed air and the total heat generated. Reducing the temperature rise can reduce the excessive increase in the isothermal temperature between the heat pipe air compressor and the air turbine caused by the reduction in the quality of the lean gas.

[0019] The prior art does not address the positive effects of "maintaining the pressure of the rich gas entering the carbon capture unit's air compressor at 0.01 to 1 MPa above atmospheric pressure, thereby reducing the expansion and cooling of the gas in the waste heat boiler, the total energy of the compressed air, and the temperature rise and total heat production of the compressed air; reducing the temperature rise can also reduce the excessive increase in the isothermal temperature between the heat pipe air compressor and the air turbine caused by the reduction in lean gas mass." These positive effects cannot be reasonably expected from the prior art. This demonstrates the non-obviousness of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a system block diagram of a marine high-pressure water carbon capture device.

[0021] Figure 2 It is a structural diagram of a turbine engine that uses exhaust gas from a marine diesel engine to drive a turbine.

[0022] In the figure, 1 is a marine diesel engine; 2 is a turbine engine; 3 is a waste heat engine; 4 is an exhaust gas treatment device; 5 is a cooling device; 6 is a heat pipe air compressor; 7 is a high-pressure heat exchanger; 8 is a heat pump cooling device; 9 is a waterline absorption and capture device; 10 is a heat pipe air turbine; 11 is an insulated lean gas pipe; 12 is a gas collector; 13 is a desorption device; 14 is a waste heat boiler; 15 is a steam turbine; 16 is a condenser; 17 is a feed water pump; 18 is a transmission shaft; 19 is an output shaft; 20 is a motor; 21 is a heavy oil tank; 31 is a casing; 32 is a rotating shaft; 33 is an impeller; and 34 is a stator. DETAILED DESCRIPTION

[0023] Figure 1Example 1 is provided. In Example 1, a marine high-pressure water carbon capture device is manufactured, comprising a waste heat engine, an exhaust gas treatment device, a heat pipe air compressor, a heat pipe air turbine, a waterline absorption capture device, a high-pressure heat exchanger, a cooling device (including but not limited to a cooling device using seawater or river water as cooling water), a fan, a carbon dioxide desorption device, and a carbon dioxide liquefaction device. The waste heat engine includes a waste heat boiler, a steam turbine, a condenser, and a feedwater pump.

[0024] The operating principle of the marine high-pressure water carbon capture device is as follows: Exhaust gas from a marine diesel engine 1, carrying a large amount of heat and kinetic energy, sequentially passes through a turbine engine 2, a first-stage waste heat engine 3 (demarcated by the dashed box), and a second-stage waste heat engine. After releasing this heat and kinetic energy, it is treated by an exhaust gas treatment device 4, including but not limited to desulfurization and denitrification, and cooled by a cooling device 5. It then enters a heat pipe air compressor 6 and is compressed to a set high pressure value, including 3.5 MPa. It then passes through a high-pressure heat exchanger 7 for heat exchange and cooling, and further cools to 0.2°C by a heat pump cooling device 8. It then enters a waterline absorption capture device 9. Carbon dioxide in the rich gas is captured and decarbonized, becoming lean gas. This gas is then heated by the high-pressure heat exchanger 7 and heated before entering a heat pipe air turbine 10, where it expands and generates work. The atmospheric-pressure lean gas is then delivered to the diesel engine 1 via an insulated lean gas pipe 11. After heat exchange and heating with the diesel engine, it is collected by a gas collector 12 and discharged into the atmosphere. The insulated lean gas pipe refers to a gas transmission pipeline with an insulation layer. The cooling of the diesel engine can improve the efficiency of the heat engine and optimize its operating conditions.

[0025] While the rich gas is decarbonized and becomes lean gas, the lean liquid in the waterline absorption capture equipment absorbs carbon dioxide to become rich liquid, and the carbon dioxide is desorbed by the desorption device 13, including liquefaction by the liquefaction device; the waste heat engine includes a waste heat boiler 14, a steam turbine 15, a condenser 16 and a feed water pump 17.

[0026] Water supplied by the feedwater pump evaporates into steam in the waste heat boiler. This steam drives the steam turbine, converting waste heat into mechanical energy. Exhaust gas, after performing work, exchanges heat with the outside world in the condenser, where it condenses into water. This water is then transported by the feedwater pump to the waste heat boiler, where it is heated and converted into steam. This continuous process converts thermal energy into mechanical energy. The mechanical energy output by the air turbine is fed back to the heat pipe compressor via drive shaft 18.

[0027] The waste heat engine outputs mechanical energy through its output shaft 19. The heat pipe air compressor is driven by a motor 20 or a combined drive. Figure 1 In the figure, the output shaft 19 is connected to the heat pipe air compressor shaft by a double line with an arrow. This can reduce the use of generators and motors and improve the total heat engine efficiency of the system.

[0028] The cold air output by the air turbine can also be used for other purposes.

[0029] For the waterline absorption and capture equipment, desorption device, air compressor and air turbine in Example 1, please refer to Chinese invention patent application 202510456726.4 "High-pressure water absorption and carbon capture equipment method and business model".

[0030] In one possible design, a two-phase flow heat exchange element is used to achieve isothermalization of the gas in the air compressor and air turbine; including using seawater and river water to cool the air in the air compressor to help achieve an isothermal temperature of the gas in the heat pipe air compressor and air turbine at an average temperature value within the range of 5 to 35°C.

[0031] In one possible design, the waste heat from the low-temperature heat source of the waste heat engine is used to heat the heavy oil in the heavy oil tank 21, including using the waste heat from two stages of waste heat engines to heat the heavy oil in relay mode. For details on heating heavy oil, refer to the prior art.

[0032] In a possible design, the ship-based high-pressure water carbon capture device is integrated into one or more containers to facilitate skid-mounting of the carbon capture device.

[0033] The waste heat power generation in Example 1 may employ a number of units other than two.

[0034] The turbine engine of embodiment 1 may not be used. The heat pipe air compressor and air turbine of embodiment 1 may also be replaced by ordinary air compressors and air turbines.

[0035] The marine diesel engine of the present invention can also be replaced with other engines including Stirling engines.

[0036] Figure 2 In Example 2, a turbine engine utilizing exhaust gas from a marine diesel engine to drive a turbine is manufactured. The turbine engine comprises a housing 31, a rotating shaft 32, an impeller 33, and a stator 34. The turbine engine's inlet is connected to the marine engine's exhaust pipe, and its outlet is connected to a waste heat engine.

[0037] Working principle of Example 2: The kinetic energy of the rich gas drives the impeller to convert the potential energy into mechanical energy which is output through the rotating shaft.

[0038] Figure 2 The two turbines can also be replaced with one or more.

Claims

1. A method for capturing carbon dioxide from marine engine exhaust using high-pressure water: The waste heat engine is used to convert the energy in the exhaust gas into mechanical energy, including the use of two cascaded waste heat engines to obtain more energy. After the exhaust gas pressure and temperature are reduced and further cooled with seawater or river water, it is sent to the air compressor of the high-pressure water carbon capture system and compressed to a high pressure range including but not limited to 2-10 MPa. The water line absorption capture equipment absorbs the carbon dioxide, and the decarbonized lean gas is expanded by the air turbine to produce work and fed back to the air compressor. The waste heat engine includes a waste heat boiler, a steam turbine, a condenser, and a feed water pump. Keep the gas pressure entering the air compressor higher than the normal pressure by 0.01~1MPa.

2. A marine high-pressure water carbon capture device, characterized in that It includes waste heat engine, air compressor, air turbine, waterline absorption and capture equipment, engine exhaust treatment device, high-pressure heat exchanger, cooling device, fan and carbon dioxide desorption device; the waste heat engine includes waste heat boiler, steam turbine, condenser and feed water pump.

3. The marine high-pressure water carbon capture device according to claim 2, characterized in that The exhaust gas from the marine diesel engine passes through the turbine engine, the first-stage and second-stage waste heat engines in sequence to release heat and kinetic energy. After being treated by the exhaust gas treatment device and cooled by the cooling device, it enters the heat pipe air compressor and is compressed to the set high pressure value. It then passes through the high-pressure heat exchanger for heat exchange and further cools to 0.~2℃ by the heat pump cooling device before entering the waterline absorption and capture equipment. The carbon dioxide in the rich gas is captured and decarbonized to become lean gas. After heat exchange and temperature increase through the high-pressure heat exchanger, it enters the heat pipe air turbine to expand and perform work. The atmospheric pressure lean gas is sent to the diesel engine through an insulated lean gas pipe. After heat exchange and temperature increase by the diesel engine, it is collected by the gas collector and discharged into the atmosphere. The waste heat engine includes a waste heat boiler, a steam turbine, a condenser and a feed water pump.

4. The marine high-pressure water carbon capture device according to claim 2, characterized in that The low-temperature heat source of the waste heat engine is discarded to heat the heavy oil in the heavy oil tank 21; including using the discarded heat of two-stage waste heat engines to relay heat the heavy oil.

5. The marine high-pressure water carbon capture device according to claim 2, characterized in that Keep the gas pressure entering the air compressor higher than the normal pressure by 0.01~1MPa.

6. The marine high-pressure water carbon capture device according to claim 2, characterized in that Two-phase flow heat exchange elements are used to achieve isothermal control of the gas inside the heat pipe air compressor and the air turbine.

7. The marine high-pressure water carbon capture device according to claim 2, characterized in that The low-temperature heat source of the waste heat engine is discarded to heat the heavy oil; including using the discarded heat of the two-stage waste heat engine to relay heat the heavy oil.

8. The marine high-pressure water carbon capture device according to claim 2, characterized in that The marine high-pressure water carbon capture device is integrated into a plurality of containers, which facilitates the skid-mounting of the carbon capture device.

9. The marine high-pressure water carbon capture device according to claim 2, characterized in that The invention comprises a turbine engine which utilizes exhaust gas from a marine diesel engine to drive a turbine, and is characterized by comprising a casing 31 , a rotating shaft 32 , an impeller 33 and a stator 34 .

10. A turbine engine that uses exhaust gas from a marine diesel engine to drive a turbine, characterized in that It includes a housing 31, a rotating shaft 32, an impeller 33 and a stator 34; the inlet of the turbine engine is connected to the exhaust pipe of the marine engine; and the outlet of the turbine engine is connected to the waste heat engine.

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