Container ship carbon capture system and gas heater mutual utilization system and method

Abstract

The invention provides a container ship carbon capture system and gas heater mutual utilization system and method. The container ship carbon capture system and gas heater mutual utilization system comprises a cooling tower and a gas heater. An inlet of the cooling tower is communicated with main engine waste gas, a cooling spraying system is arranged in the cooling tower and used for cooling and cleaning the main engine waste gas, and a heat exchange system is arranged between the cooling tower and the gas heater and used for preheating gas in the gas heater through heat generated by the main engine waste gas. The waste gas cooling process in the carbon capture system and the heating process of the gas heater are organically combined, and complementary utilization of heat energy can be achieved, so that the energy utilization efficiency is improved, the overall energy consumption of a ship is reduced, and the purposes of energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The present invention relates to the field of ships, and particularly to a system and method for the mutual utilization of a carbon capture system and a gas heater on a container ship. Background Art

[0002] With the increasing global awareness of environmental protection and the growing urgency of the shipping industry's demand for carbon emission reduction, as an important tool for international logistics transportation, the environmental protection performance of the power system of container ships has received extensive attention. Traditional container ships usually use diesel as fuel, which can provide sufficient power, but a large amount of pollutants will be generated during the combustion process, including sulfur oxides (SO x ), nitrogen oxides (NO x ) and carbon dioxide (CO 2 ). These pollutants not only cause serious harm to the environment but also exacerbate the global warming problem. To address this challenge, dual-fuel main engines have gradually become the mainstream choice for the power systems of container ships. Dual-fuel main engines can switch between diesel mode and gas mode, where the gas mode uses liquefied natural gas (LNG) as the main fuel, which can significantly reduce the emissions of sulfur oxides and nitrogen oxides, thereby reducing environmental pollution.

[0003] However, although the dual-fuel main engine can effectively reduce the emissions of sulfur oxides and nitrogen oxides when operating in gas mode, a large amount of carbon dioxide (CO 2 ) will still be generated during its combustion process. As a major greenhouse gas, carbon dioxide has an important impact on global climate change. Therefore, how to further reduce the carbon dioxide emissions of container ships in gas mode has become one of the urgent problems to be solved in the current shipping industry. In recent years, the carbon capture system (Carbon Capture System, CCS) has gradually been introduced into the field of ships as an effective technical means to capture and store carbon dioxide in ship exhaust gas, thereby reducing its emissions into the atmosphere.

[0004] In the actual application of the carbon capture system, the exhaust gas of the main engine needs to be processed first. Usually, the exhaust gas temperature of the container ship main engine is relatively high, about 240 °C. To ensure the efficient operation of the carbon capture system, the exhaust gas must be cleaned and its temperature reduced to about 45 °C. This process not only consumes a large amount of energy but also requires dedicated cooling equipment, increasing the complexity and operating cost of the system. In addition, in the fuel gas supply system (Fuel Gas Supply System, FGSS) of container ships, the gas usually needs to be heated before entering the main engine. The gas heater uses thermal energy to heat the gas to improve its combustion efficiency. However, this heating process also consumes a large amount of thermal energy, resulting in waste of ship energy.

[0005] At present, in the existing technical solutions, the carbon capture system and the gas heater usually operate independently, lacking an effective mechanism for heat energy interaction and utilization between the two. This independent operation mode not only causes energy waste but also increases the system complexity and operating costs. Therefore, how to design a method for the mutual utilization of the carbon capture system and the gas heater of a container ship has become an urgent problem to be solved in the current technical field. Summary of the Invention

[0006] Aiming at the deficiencies in the existing technology, the present invention provides a system and method for the mutual utilization of the carbon capture system and the gas heater of a container ship. By organically combining the exhaust gas cooling process in the carbon capture system with the heating process of the gas heater, complementary utilization of heat energy can be achieved, thereby improving energy utilization efficiency, reducing the overall energy consumption of the ship, and achieving the goal of energy conservation and environmental protection.

[0007] The present invention achieves the above technical objectives through the following technical means.

[0008] A system for the mutual utilization of the carbon capture system and the gas heater of a container ship, comprising a cooling tower and a gas heater; the inlet of the cooling tower is connected to the main engine exhaust gas, and a cooling spray system is provided inside the cooling tower for cooling and cleaning the main engine exhaust gas: a heat exchange system is provided between the cooling tower and the gas heater for using the heat generated by the main engine exhaust gas to preheat the gas inside the gas heater.

[0009] Further, the cooling spray system includes a second water pump and a spray pipeline; the spray pipeline is located in the middle of the cooling tower, and the second water pump pumps seawater to the spray pipeline to form a water curtain inside the cooling tower, thereby cooling and cleaning the main engine exhaust gas from top to bottom.

[0010] Further, the cooling tower is vertically installed, and the inlet of the cooling tower is located at the bottom of the cooling tower, allowing the main engine exhaust gas to enter from the bottom; the flow direction of the main engine exhaust gas is opposite to the flow direction of the cooling spray system.

[0011] Further, the heat exchange system includes a first coil, a second coil, and a first water pump; the first coil is located inside the cooling tower and above the cooling spray system; the second coil is located inside the gas heater, and the first water pump connects the first coil and the second coil for transporting a heat exchange medium to form a circulation system.

[0012] Further, the heat exchange system further includes a temperature control valve, the temperature control valve is installed between the inlet of the second coil and the first water pump, and the bypass of the temperature control valve is connected to the outlet of the second coil; a temperature sensor is provided at the gas outlet of the gas heater for measuring the temperature of the gas outlet; the temperature control valve controls the flow rate of the bypass according to the temperature measured by the temperature sensor.

[0013] Further, when the temperature measured by the temperature sensor exceeds the set temperature, the temperature control valve is controlled to open the bypass, so that part of the heat exchange medium directly flows into the outlet of the second coil;

[0014] When the temperature measured by the temperature sensor is less than or equal to the set temperature, the temperature control valve is controlled to close the bypass, so that all the heat exchange medium enters the inlet of the second coil, and at the same time, the flow rate output by the first water pump is increased.

[0015] Further, the heat exchange system further includes a pressure maintaining tank, which contains a gas-liquid two-phase medium. The gas phase in the pressure maintaining tank has a preset pressure, and the liquid phase in the pressure maintaining tank is communicated with the heat exchange medium in the heat exchange system for maintaining the pressure of the heat exchange system.

[0016] Further, a gas probe is provided in the gas phase of the pressure maintaining tank for detecting whether there is gas in the heat exchange system; when the gas probe detects the existence of gas, an alarm is given and the machine is stopped to check the second coil in the gas heater.

[0017] A method for mutual utilization of a container ship carbon capture system and a gas heater includes the following steps:

[0018] Construct the system for mutual utilization of the container ship carbon capture system and the gas heater described above;

[0019] The cooling spray system sucks seawater from outside the ship and sprays the seawater in the cooling tower through the first water pump; the main engine exhaust gas enters from the bottom of the cooling tower, and the sprayed seawater and the main engine exhaust gas flow in opposite directions and fully contact in the cooling tower to cool and clean the main engine exhaust gas, so that the temperature of the main engine exhaust gas is reduced to T 1 ;

[0020] During the upward movement of the main engine exhaust gas after being cooled by spraying, heat exchange occurs with the cold end of the heat exchange system, so that the temperature of the main engine exhaust gas is reduced to T 1 -10°, and is transported to the carbon capture system;

[0021] The liquefied gas is input into the gas heater at a temperature of T 2 and heat exchange occurs with the hot end of the heat exchange system, so that the temperature of the gas does not exceed the set temperature; and the preheated gas is input into the main engine.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. For the system and method for mutual utilization of the container ship carbon capture system and the gas heater described in the present invention, by organically combining the exhaust gas cooling process in the carbon capture system with the heating process of the gas heater, complementary utilization of heat energy can be achieved, thereby improving the energy utilization efficiency, reducing the overall energy consumption of the ship, and achieving the goal of energy conservation and environmental protection.

[0024] 2. The system and method for the mutual utilization of the container ship carbon capture system and the gas heater of the present invention heat the water in the first coil in the cooling tower, and the hot water enters the gas heater through the pipeline to heat the relatively low-temperature gas. The heated gas meets the requirements of the main engine for the required gas, fully utilizes the heat energy of the main engine exhaust gas, and at the same time utilizes the cold energy of the gas. The main engine exhaust gas is cooled in the cooling tower, fully utilizing the heat energy and cold energy of the ship system, achieving the purpose of energy conservation and environmental protection and reducing environmental pollution.

[0025] 3. The system and method for the mutual utilization of the container ship carbon capture system and the gas heater of the present invention. The pressure maintaining tank can provide pressure for the heat exchange system and keep the pipeline of the heat exchange system full of water; in addition, the pipeline at the high point of the pressure maintaining tank is provided with a gas probe through the gas phase for detecting whether there is gas in the heat exchange system.

[0026] 4. The system and method for the mutual utilization of the container ship carbon capture system and the gas heater of the present invention. The carbon capture system will generate a large amount of low-temperature heat energy when cooling the exhaust gas, while the gas heater requires high-temperature heat energy to heat the gas. By organically combining these two systems to achieve complementary utilization of heat energy, the energy utilization efficiency can be improved, and the overall energy consumption of the ship can also be reduced, thereby achieving a more energy-saving, more economical and environmentally friendly operation goal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, it is obvious that other drawings can also be obtained according to these drawings.

[0028] Figure 1 It is the system schematic diagram of the mutual utilization of the container ship carbon capture system and the gas heater of the present invention.

[0029] In the figure:

[0030] 1 - Cooling tower, 2 - Gas heater, 3 - First water pump, 4 - Temperature control valve, 5 - First coil, 6 - Second coil, 7 - Pressure maintaining tank, 8 - Gas probe, 9 - Temperature sensor, 10 - Second water pump, 11 - Spray pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following details the embodiments of the present invention. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation of the present invention.

[0032] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "connection", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] As Figure 1 shown, the carbon capture system of the container ship described in the present invention and the gas heater are mutually utilized systems, including a cooling tower 1 and a gas heater 2;

[0035] The cooling tower 1 is vertically installed, and its bottom is provided with a cooling tower inlet, which is communicated with the exhaust gas pipeline of the ship's main engine. High-temperature exhaust gas (about 240 °C) enters the cooling tower 1 from the bottom, and the flow direction of the main engine exhaust gas is opposite to that of the cooling spray system. A cooling spray system is provided inside the cooling tower 1 for cooling and cleaning the main engine exhaust gas:

[0036] The cooling spray system includes a second water pump 10 and a spray pipeline 11; the spray pipeline 11 is located in the middle of the cooling tower 1 and forms a water curtain from top to bottom through nozzles. The second water pump 10 is used to pump seawater from outside the ship and pump the seawater to the spray pipeline 11, and by forming a water curtain inside the cooling tower 1, the main engine exhaust gas is cooled and cleaned from top to bottom. When the high-temperature main engine exhaust gas flows from bottom to top, the sprayed seawater contacts it in the opposite direction to achieve the cooling and cleaning effect. During this process, particulate matter and some acidic gases (such as SOx) in the exhaust gas are absorbed by the seawater, and at the same time, the exhaust gas temperature drops from 240 °C to about 60 °C.

[0037] A heat exchange system is provided between the cooling tower 1 and the gas heater 2 for preheating the gas LNG in the gas heater 2 by using the heat generated by the main engine exhaust gas. The heat exchange system includes a first coil 5, a second coil 6 and a first water pump 3; the first coil 5 is located in the cooling tower 1 and above the cooling spray system; the preliminarily cooled exhaust gas exchanges heat with the first coil 5 during the rising process, further reducing the exhaust gas temperature to about 50°C, and then being transported to the carbon capture system.

[0038] The second coil 6 is located inside the gas heater 2, and the first water pump 3 is connected to the first coil 5 and the second coil 6 for transporting the heat exchange medium to form a circulation system. The heat exchange medium can be water or ethylene glycol solution. The first water pump 3 circulates the heat exchange medium between the first coil 5 and the second coil 6 to achieve heat transfer.

[0039] The heat exchange system further includes a temperature control valve 4, which is installed between the inlet of the second coil 6 and the first water pump 3, and the bypass of the temperature control valve 4 is connected to the outlet of the second coil 6; a temperature sensor 9 is provided at the gas outlet of the gas heater 2 for measuring the temperature of the gas outlet; the temperature control valve 4 controls the flow rate of the bypass according to the temperature measured by the temperature sensor 9. When the temperature of the gas outlet measured by the temperature sensor 9 exceeds 45°C, the temperature control valve 4 is controlled to open the bypass, so that part of the heat exchange medium directly flows into the outlet of the second coil 6, and part of the heat exchange medium directly returns, reducing the heat input to prevent the gas from overheating; when the temperature of the gas outlet measured by the temperature sensor 9 is less than or equal to 45°C, the temperature control valve 4 is controlled to close the bypass, so that all the heat exchange medium enters the inlet of the second coil 6, and at the same time, the flow rate output by the first water pump 3 is increased to improve the heat exchange efficiency.

[0040] The control system adjusts the opening degree of the temperature control valve 4 according to the temperature value exceeding the set temperature. The opening degree of the temperature control valve 4 can be determined by the ratio of the flow rate entering the bypass to the flow rate entering the second coil 6.

[0041] Let the temperature of the gas outlet measured by the temperature sensor 9 be T 3 , greater than T 1 , then T 3 -T 1 is the temperature increment ΔT; let the heat capacity of the heat exchange medium be c and the flow rate at the outlet of the first water pump 3 be Q;

[0042] According to the heat balance principle, when the gas outlet temperature exceeds the set value T 1 and reaches T 3 , it is necessary to adjust the flow rate of the heat exchange medium through the bypass to control the heat transfer.

[0043] The heat balance equation is established:

[0044] Heat absorbed on the gas side:

[0045] Q 燃气 =q·c 燃气 ·(T 3 -T 2 )

[0046] Among them, T 2 is the initial temperature of the fuel gas input to the fuel gas heater 2, c 燃气 is the specific heat capacity of gas; the natural gas flow rate in the gas heater is q.

[0047] Heat released by heat transfer medium:

[0048] Q 介质 =Q 2 ·c·ΔT'

[0049] Among them, Q 2 is the flow rate entering the second coil, and ΔT' is the temperature difference of the medium at the inlet and outlet of the second coil.

[0050] In steady state, the heat absorbed by the gas is equal to the heat released by the medium: Q 燃气 =Q 介质 ;

[0051] Bypass flow expression:

[0052] The total flow Q is divided into bypass flow Q b and the flow rate Q entering the second coil 2 ,Right now:

[0053] Q=Qb+Q 2

[0054] Combined with the heat balance equation, the bypass flow rate is:

[0055]

[0056] When T 3 = set temperature T 1 When there is no bypass, Q2 = Q, then we get

[0057] Q·c·ΔT'=q·c 燃气 (T1-T2)

[0058] Then the simplified bypass flow expression is:

[0059]

[0060] Then the ratio i of the flow rate entering the bypass to the flow rate entering the second coil 6 is expressed as:

[0061]

[0062] The ratio of the flow rate entering the bypass to the flow rate entering the second coil 6 can be used to control the opening degree of the temperature control valve 4.

[0063] The heat exchange system further includes a pressure maintaining tank 7. There is a gas-liquid two-phase medium (such as nitrogen + ethylene glycol solution) in the pressure maintaining tank 7. The gas phase in the pressure maintaining tank 7 has a preset pressure. The liquid phase in the pressure maintaining tank 7 is communicated with the heat exchange medium in the heat exchange system for maintaining the pressure of the heat exchange system. A gas probe 8 is provided in the gas phase in the pressure maintaining tank 7 for detecting whether there is gas in the heat exchange system; when the gas probe 8 detects the existence of gas, an alarm is given and the machine is stopped to check the second coil 6 in the gas heater 2 to ensure safety.

[0064] The method for mutual utilization of the container ship carbon capture system and the gas heater according to the present invention includes the following steps:

[0065] Build a system for mutual utilization of the container ship carbon capture system and the gas heater;

[0066] The cooling spray system sucks seawater from outside the ship and sprays the seawater in the cooling tower 1 through the first water pump 3; the main engine exhaust gas enters from the bottom of the cooling tower 1. The sprayed seawater and the main engine exhaust gas flow in opposite directions and fully contact in the cooling tower 1 to cool and clean the main engine exhaust gas, reducing the temperature of the main engine exhaust gas to 60°C;

[0067] During the upward movement of the main engine exhaust gas after being cooled by spraying, heat exchange occurs with the cold end of the heat exchange system, reducing the temperature of the main engine exhaust gas to 50°C and transporting it to the carbon capture system;

[0068] In the container, the liquefied gas at -160°C becomes -20°C after gasification. Therefore, the gas inlet temperature of the gas heater 2 is about -20°C. Heat exchange occurs with the hot end of the heat exchange system, increasing the gas temperature by no more than 45°C; and the preheated gas is input into the main engine. The temperature sensor 9 monitors the gas temperature in real time, and adjusts the flow rate of the heat exchange medium through the temperature control valve 4 to ensure the stability of the gas temperature.

[0069] By integrating the carbon capture system and the gas heater, the present invention realizes the efficient utilization of waste heat of exhaust gas, not only reducing the energy consumption of the ship, but also improving the environmental protection performance. The system has a compact structure and intelligent control, is applicable to various dual-fuel container ships, and has broad application prospects.

[0070] It should be understood that although this specification is described according to each embodiment, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0071] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included within the protection scope of the present invention.

Claims

1. A system in which a container ship carbon capture system and a gas heater are mutually utilized, characterized in that: It comprises a cooling tower (1) and a gas heater (2); The inlet of the cooling tower is connected to the main engine exhaust gas, and a cooling spray system is provided in the cooling tower (1) for cooling and cleaning the main engine exhaust gas. A heat exchange system is provided between the cooling tower (1) and the gas heater (2) for preheating the gas in the gas heater (2) by utilizing the heat generated by the main engine exhaust gas.

2. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 1, characterized in that: The cooling spray system comprises a second water pump (10) and a spray pipeline (11); the spray pipeline (11) is located in the middle of the cooling tower (1); the second water pump (10) pumps seawater to the spray pipeline (11), and forms a water curtain in the cooling tower (1), thereby cooling and cleaning the main engine exhaust gas from top to bottom.

3. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 2, characterized in that: The cooling tower (1) is installed vertically, and the cooling tower inlet is located at the bottom of the cooling tower (1), so that the main engine exhaust gas enters from the bottom; the flow direction of the main engine exhaust gas is opposite to the flow direction of the cooling spray system.

4. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 1, characterized in that: The heat exchange system comprises a first coil (5), a second coil (6) and a first water pump (3); the first coil (5) is located in a cooling tower (1) and above a cooling spray system; the second coil (6) is located inside a gas heater (2); the first water pump (3) is connected to the first coil (5) and the second coil (6) to transport a heat exchange medium to form a circulation system.

5. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 4, characterized in that: The heat exchange system further comprises a temperature control valve (4), the temperature control valve (4) being installed between the inlet of the second coil (6) and the first water pump (3), and the bypass of the temperature control valve (4) being connected to the outlet of the second coil (6); the gas outlet of the gas heater (2) is provided with a temperature sensor (9) for measuring the temperature of the gas outlet; the temperature control valve (4) controls the flow of the bypass according to the temperature measured by the temperature sensor (9).

6. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 5, characterized in that: When the temperature measured by the temperature sensor (9) exceeds the set temperature, the temperature control valve (4) is controlled to open the bypass so that part of the heat exchange medium is directly introduced into the outlet of the second coil (6); When the temperature measured by the temperature sensor (9) is less than or equal to the set temperature, the temperature control valve (4) is controlled to close the bypass, so that the heat exchange medium completely enters the inlet of the second coil (6), and at the same time the flow rate output by the first water pump (3) is increased.

7. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 4, characterized in that: The heat exchange system further comprises a pressure-maintaining tank (7), wherein the pressure-maintaining tank (7) contains a gas-liquid two-phase medium, the gas phase in the pressure-maintaining tank (7) has a preset pressure, and the liquid phase in the pressure-maintaining tank (7) is connected to the heat exchange medium in the heat exchange system, so as to maintain the pressure of the heat exchange system.

8. The system of container ship carbon capture system and gas heater mutually utilizing each other according to claim 7, characterized in that: The gas phase in the pressure-maintaining tank (7) is provided with a gas probe (8) for detecting whether there is gas in the heat exchange system; when the gas probe (8) detects the presence of gas, an alarm is sounded and the system is shut down to check the second coil (6) in the gas heater (2).

9. A method for mutual utilization of a container ship carbon capture system and a gas heater, characterized in that: The steps include: Construct a system in which the container ship carbon capture system and the gas heater are mutually utilized as described in any one of claims 1 to 8; The cooling spray system sucks seawater from outside the ship and sprays the seawater into the cooling tower (1) through a first water pump (3); the main engine exhaust gas enters from the bottom of the cooling tower (1), and the sprayed seawater and the main engine exhaust gas flow in opposite directions, and are fully in contact with each other in the cooling tower (1), thereby cooling and cleaning the main engine exhaust gas, and reducing the temperature of the main engine exhaust gas to T1; During the rising process of the main engine exhaust gas after spray cooling, heat exchange occurs with the cold end of the heat exchange system, so that the temperature of the main engine exhaust gas drops to T1-10° and is transported to the carbon capture system; The liquefied gas is input into the gas heater (2) at a temperature of T2, and heat is exchanged with the hot end of the heat exchange system so that the gas temperature rises to a value not exceeding the set temperature; and the preheated gas is input into the main engine.

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