Cooling system of marine diesel engine supercritical carbon dioxide combined cycle power plant

Abstract

The invention relates to the technical field of marine power plants, and discloses a marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system, comprising a supercritical carbon dioxide circulation loop and a diesel engine cooler, wherein the supercritical carbon dioxide circulation loop comprises a carbon dioxide turbine, a supercritical carbon dioxide cooler, a compressor and a first heat exchange side of a heat exchanger connected in sequence; the cooling medium inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler, and the cooling medium outlet of the diesel engine cooler is connected to the inlet of the compressor. The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system comprehensively utilizes ship diesel engine power generation and supercritical carbon dioxide Brayton cycle power generation, and also solves the problems of flow channel corrosion and cooler failure caused by direct application of existing seawater cooling technology to marine diesel engines, thereby increasing the reliability of diesel engine operation.

Description

Technical Field

[0001] The invention relates to the technical field of marine power devices, in particular to a cooling system for a marine diesel engine supercritical carbon dioxide combined cycle power device. Background Art

[0002] The technical level of ship propulsion is related to the development of the country's maritime economy. At present, diesel engines are the most commonly used ship propulsion devices; relatively expensive gas turbines have also gradually developed due to their outstanding power-to-weight ratio. In addition, electric propulsion devices or hybrid power devices have also received more and more attention. However, whether it is a diesel engine or a gas turbine, its energy utilization rate is only about 50%, and about 50% of the energy is still taken away by exhaust and cooling medium.

[0003] At present, the coolant of marine diesel engine coolers usually comes from seawater outside the ship. The corrosion of seawater, especially the silty seawater near the coast, on the cooler is an important cause of noise cooler failure. Moreover, the seawater flow rate exceeding 3m / s will significantly accelerate the scouring and corrosion of the seawater flow channel. In addition, for submersible diesel engines, the alternating seawater pressure generated by the change of diving depth will cause fatigue of the cooler structure and reduce the reliability of the diesel engine cooler. Summary of the invention

[0004] The embodiment of the present invention provides a cooling system for a supercritical carbon dioxide combined cycle power unit of a marine diesel engine, which is used to solve the problem that the existing seawater cooling technology applied to a marine diesel engine causes seawater flow channel corrosion, resulting in cooler failure, reduced reliability, and reduced service life, so as to improve the operating performance of the diesel engine.

[0005] An embodiment of the present invention provides a cooling system for a marine diesel engine supercritical carbon dioxide combined cycle power unit, comprising a supercritical carbon dioxide circulation loop and a diesel engine cooler, wherein the supercritical carbon dioxide circulation loop comprises a carbon dioxide turbine, a supercritical carbon dioxide cooler, a compressor and a first heat exchange side of a heat exchanger connected in sequence; a cooling medium inlet of the diesel engine cooler is connected to an outlet of the supercritical carbon dioxide cooler, and a cooling medium outlet of the diesel engine cooler is connected to an inlet of the compressor.

[0006] The inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler through a cooling pipeline, and a regulating valve is installed on the cooling pipeline.

[0007] Wherein, a pressure sensor is also installed on the cooling pipeline.

[0008] Wherein, a flow meter is also installed on the cooling pipeline.

[0009] Wherein, a diesel engine is also included, and the working fluid heat exchange side of the diesel engine cooler is connected in series to the working fluid circulation pipeline of the diesel engine.

[0010] Wherein, the exhaust port of the diesel engine is connected to the second heat exchange side of the heat exchanger.

[0011] It also includes a lubricating oil cooler, the inlet of the lubricating oil cooler is connected to the cooling medium inlet of the diesel engine cooler through a three-way plug valve, and the outlet of the lubricating oil cooler is connected to the cooling medium outlet of the diesel engine cooler.

[0012] The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system provided by the embodiment of the present invention comprises a supercritical carbon dioxide circulation loop and a diesel engine cooler, wherein the supercritical carbon dioxide circulation loop comprises a carbon dioxide turbine, a supercritical carbon dioxide cooler, a compressor and a first heat exchange side of a heat exchanger connected in sequence, the cooling medium inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler; and the cooling medium outlet of the diesel engine cooler is connected to the inlet of the compressor. The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system not only comprehensively utilizes the ship diesel engine power generation and the supercritical carbon dioxide Brayton cycle power generation, but also guides a part of the low-temperature and low-pressure supercritical carbon dioxide at the outlet of the supercritical carbon dioxide cooler to the diesel engine cooler to cool the internal circulating working fluid of the diesel engine, fundamentally solving the problems of flow channel corrosion and cooler failure caused by the direct application of the existing seawater cooling technology to marine diesel engines, and increasing the reliability of diesel engine operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 It is a structural schematic diagram of a cooling system of a supercritical carbon dioxide combined cycle power plant for a marine diesel engine in an embodiment of the present invention;

[0015] Description of reference numerals:

[0016] 1: Diesel engine cooler; 2: CO2 turbine; 3: Supercritical CO2 cooler;

[0017] 4: compressor; 5: heat exchanger; 6: diesel engine. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "first" and "second" are for the purpose of clearly describing the numbering of product components and do not represent any substantial difference. The directions of "up", "down", "left" and "right" are all based on the directions shown in the accompanying drawings. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0020] It should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the invention can be understood in specific circumstances.

[0021] Figure 1 FIG. 1 is a schematic diagram of a cooling system for a supercritical carbon dioxide combined cycle power plant for a marine diesel engine according to an embodiment of the present invention. Figure 1 As shown, a marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system provided by an embodiment of the present invention comprises a supercritical carbon dioxide circulation loop and a diesel engine cooler 1, wherein the supercritical carbon dioxide circulation loop comprises a carbon dioxide turbine 2, a supercritical carbon dioxide cooler 3, a compressor 4 and a first heat exchange side of a heat exchanger 5 connected in sequence. The cooling medium inlet of the diesel engine cooler 1 is connected to the outlet of the supercritical carbon dioxide cooler 3, and the cooling medium outlet of the diesel engine cooler 1 is connected to the inlet of the compressor 4.

[0022] Specifically, the circulating medium of the supercritical carbon dioxide circulation loop and the cooling medium of the diesel engine cooler 1 are both supercritical carbon dioxide. The normal temperature supercritical carbon dioxide has the characteristics of high density (about 30%-50% of the density of liquid water at normal temperature), high specific heat ratio (about 1.5 times the specific heat ratio of liquid water at normal temperature), and low viscosity (about 1 / 30 of liquid water at normal temperature). Due to the low viscosity, supercritical carbon dioxide will not cause erosion and corrosion to the cooling flow channel due to excessive viscosity at high flow rate. After entering the compressor 4 for compression, the supercritical carbon dioxide enters the heat exchanger 5 to absorb heat, and then enters the carbon dioxide turbine 2 to expand and do work. The carbon dioxide turbine 2 is connected to the generator through the shaft system, and then connected to the power generation system of the ship. Finally, the supercritical carbon dioxide enters the supercritical carbon dioxide cooler 3 and is cooled to the exit state point, and re-enters the compressor 4 to complete a cycle. At the same time, the outlet of the supercritical carbon dioxide cooler 3 leads to a cooling medium inlet connected to the diesel engine cooler 1, providing a part of the supercritical carbon dioxide for cooling the diesel engine.

[0023] The present embodiment provides a marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system, including a supercritical carbon dioxide circulation loop and a diesel engine cooler, wherein the supercritical carbon dioxide circulation loop includes a carbon dioxide turbine, a supercritical carbon dioxide cooler, a compressor, and a first heat exchange side of a heat exchanger connected in sequence, wherein the cooling medium inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler; and the cooling medium outlet of the diesel engine cooler is connected to the inlet of the compressor. The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system not only comprehensively utilizes the ship diesel engine power generation and the supercritical carbon dioxide Brayton cycle power generation, but also guides a part of the low-temperature and low-pressure supercritical carbon dioxide at the outlet of the supercritical carbon dioxide cooler to the diesel engine cooler to cool the internal circulating working fluid of the diesel engine, fundamentally solving the problems of flow channel corrosion and cooler failure caused by the direct application of existing seawater cooling technology to marine diesel engines, and increasing the reliability of diesel engine operation.

[0024] Furthermore, the inlet of the diesel engine cooler 1 is connected to the outlet of the supercritical carbon dioxide cooler 3 through a cooling pipeline, and a regulating valve (not shown in the figure) is installed on the cooling pipeline. Specifically, an electric regulating valve or a manual regulating valve can be used to adjust the pressure and flow of the supercritical carbon dioxide to the diesel engine cooler 1 by adjusting the opening of the regulating valve.

[0025] Furthermore, a pressure sensor (not shown in the figure) is installed on the cooling pipeline, and a flow meter (not shown in the figure) is installed on the cooling pipeline, and specifically a vortex flow meter can be used. The state of the supercritical carbon dioxide in the cooling pipeline can be monitored in real time through the pressure sensor and the flow meter, and the opening of the regulating valve can be adjusted in time to meet the cooling requirements of the diesel engine.

[0026] Furthermore, a diesel engine 6 is included, and the working fluid heat exchange side of the diesel engine cooler 1 is connected in series to the working fluid circulation pipeline of the diesel engine 6. The working fluid circulation pipeline of the diesel engine 6 can be a circulating cooling water pipeline in the diesel engine 6.

[0027] Furthermore, if Figure 1 As shown, the exhaust port of the diesel engine 6 is connected to the second heat exchange side of the heat exchanger 5. The heat source of the supercritical carbon dioxide circulation loop can come from the exhaust of the diesel engine 6, thereby fully utilizing the energy of the diesel engine 6 and improving the power generation efficiency.

[0028] Furthermore, a lubricating oil cooler (not shown in the figure) is included, the inlet of the lubricating oil cooler is connected to the cooling medium inlet of the diesel engine cooler 1 through a three-way plug valve, and the outlet of the lubricating oil cooler is connected to the cooling medium outlet of the diesel engine cooler 1. A portion of the low-temperature and low-pressure supercritical carbon dioxide enters the lubricating oil cooler through the three-way plug valve. The three-way plug valve is used to control the flow of supercritical carbon dioxide flowing through the lubricating oil cooler to control the temperature of the lubricating oil. When the lubricating oil does not need to be cooled, the three-way plug valve can be used to switch the passage, and the supercritical carbon dioxide will bypass the lubricating oil cooler and directly enter the diesel engine cooler 1.

[0029] It can be seen from the above embodiments that the marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system provided by the present invention includes a supercritical carbon dioxide circulation loop and a diesel engine cooler, the supercritical carbon dioxide circulation loop includes a carbon dioxide turbine, a supercritical carbon dioxide cooler, a compressor and a first heat exchange side of a heat exchanger connected in sequence, the cooling medium inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler; the cooling medium outlet of the diesel engine cooler is connected to the inlet of the compressor. The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system not only comprehensively utilizes the ship diesel engine power generation and the supercritical carbon dioxide Brayton cycle power generation, but also guides a part of the low-temperature and low-pressure supercritical carbon dioxide at the outlet of the supercritical carbon dioxide cooler to the diesel engine cooler to cool the internal circulating working fluid of the diesel engine, fundamentally solving the problems of flow channel corrosion and cooler failure caused by the direct application of existing seawater cooling technology to marine diesel engines, and increasing the reliability of diesel engine operation.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system, characterized in that: It comprises a supercritical carbon dioxide circulation loop and a diesel engine cooler, wherein the supercritical carbon dioxide circulation loop comprises a carbon dioxide turbine, a supercritical carbon dioxide cooler, a compressor and a first heat exchange side of a heat exchanger which are connected in sequence; the cooling medium inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler, and the cooling medium outlet of the diesel engine cooler is connected to the inlet of the compressor; The inlet of the diesel engine cooler is connected to the outlet of the supercritical carbon dioxide cooler through a cooling pipeline, and a regulating valve is installed on the cooling pipeline; The carbon dioxide turbine is connected to a generator through a shaft system and then connected to a power generation system of the ship; It also includes a lubricating oil cooler, the inlet of which is connected to the cooling medium inlet of the diesel engine cooler through a three-way plug valve, and the outlet of which is connected to the cooling medium outlet of the diesel engine cooler; it also includes a diesel engine, the working fluid heat exchange side of the diesel engine cooler is connected in series to the working fluid circulation pipeline of the diesel engine, and the working fluid circulation pipeline of the diesel engine is a circulating cooling water pipeline in the diesel engine; a part of the low-temperature and low-pressure supercritical carbon dioxide at the outlet of the supercritical carbon dioxide cooler is guided to the diesel engine cooler to cool the circulating working fluid inside the diesel engine; The exhaust port of the diesel engine is connected to the second heat exchange side of the heat exchanger.

2. The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system according to claim 1, characterized in that: A pressure sensor is also installed on the cooling pipeline.

3. The marine diesel engine supercritical carbon dioxide combined cycle power plant cooling system according to claim 1, characterized in that: A flow meter is also installed on the cooling pipeline.

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