Ship waste heat power generation system and ship
By designing a waste heat power generation system for ships, using the combination of evaporator, expansion generator and condenser, the problem of waste heat of low-grade diesel engines not being effectively recycled and utilized, achieving efficient waste heat generation and energy saving and emission reduction effects.
Patent Information
- Application Number
- CN202510117914.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-24
- Publication Date
- 2025-04-29
AI Technical Summary
Among existing ships, low-grade diesel engine waste heat has not been effectively recycled, resulting in low thermal energy utilization and room for energy conservation, emission reduction and carbon emission improvement.
A ship waste heat power generation system is designed, and the waste heat recovery and power generation of diesel engine exhaust heat heat oil is achieved by evaporating, expanding and condensing the organic medium by evaporating, expanding and condensing.
It improves the utilization rate of low-grade waste heat, achieves efficient power generation of waste heat, reduces fuel consumption, reduces carbon emissions, and has high thermal efficiency and reliability.
Smart Images
Figure CN119900623A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of ships, and in particular to a ship waste heat power generation system and a ship. Background Art
[0002] The main propulsion power of ships includes medium and low speed diesel engines, gas turbines, and nuclear power. Marine medium and low speed diesel engines are widely used in commercial transport ships because of their advantages such as good economy, high reliability, convenient maintenance, long service life, wide power range, good maneuverability, and the ability to burn low-quality fuel oil at low prices. At present, for medium and low speed marine diesel engines with excellent performance, only 45% to 55% of the heat energy released by fuel combustion is converted into the output power of the diesel engine, while the exhaust gas takes away 25% to 35% of the heat. Recovering this part of the waste heat from the exhaust gas of marine diesel engines can improve the utilization rate of fuel combustion energy and achieve a good effect of energy saving and emission reduction.
[0003] High-quality waste heat from ships mainly comes from diesel engine exhaust heat and cylinder liner heat, but diesel engine exhaust heat is mainly used to generate ship steam, and diesel engine cylinder liner heat is mainly used to make fresh water. It can be seen that the high-grade heat source of ships has been fully utilized; while there is still room for exploration of low-grade heat from ships. For example, before the ship's lubricating oil enters the oil separator, it needs to be heated by the exhaust steam of the diesel engine to ensure the purification effect of the lubricating oil. After the lubricating oil with a certain amount of heat flows back to the lubricating oil tank, the heat is dissipated in the engine room and wasted in the form of heat radiation.
[0004] The Rankine cycle used in the waste heat recovery system of traditional marine diesel engines uses water-steam as the working fluid, transfers heat to the circulating working fluid, and then uses the thermal energy of the circulating working fluid to perform a thermal cycle process of mechanical work. When recovering medium and low temperature waste heat, the temperature of low-grade waste heat resources is mostly below 400℃, and the waste heat resource temperature is relatively low, so the traditional thermal cycle system with water as the circulating working fluid is no longer applicable.
[0005] Therefore, there is an urgent need to provide a new type of ship waste heat power generation system and ship to solve the above technical problems. Summary of the invention
[0006] The purpose of the present invention is to provide a ship waste heat power generation system that can reuse the waste heat of lubricating oil, thereby recycling the low-grade waste heat generated by the diesel engine, achieving waste heat power generation, energy conservation and emission reduction, and reducing carbon emissions.
[0007] To achieve this object, the present invention adopts the following technical solutions:
[0008] The ship waste heat power generation system is used for recovering waste heat from diesel engines. The exhaust gas of the diesel engine can heat the ship's lubricating oil. The ship waste heat power generation system includes an evaporator, an expansion generator, and a condenser connected in sequence. The evaporator can be connected to the heated lubricating oil of the ship for heat exchange, so that the organic medium in the evaporator evaporates and generates organic saturated steam; the medium outlet of the evaporator is connected to the medium inlet of the expansion generator, so that the organic saturated steam drives the expansion generator to generate electricity, the medium outlet of the expansion generator is connected to the condenser, the organic saturated steam is liquefied in the condenser, and the medium outlet of the condenser is connected to the medium inlet of the evaporator.
[0009] Optionally, a working fluid pump is further provided between the medium outlet of the condenser and the medium inlet of the evaporator.
[0010] Optionally, a preheating device is further provided between the working fluid pump and the medium inlet of the evaporator, and the preheating device is used to preheat the organic medium entering the evaporator.
[0011] Optionally, a gas-liquid separator is further provided between the medium outlet of the evaporator and the medium inlet of the expansion generator.
[0012] Optionally, the expansion generator comprises an expander and a generator, the organic saturated steam is used to drive the rotor of the expander to rotate, and the rotor drives the main shaft of the motor connected to the generator.
[0013] Optionally, the expander includes any one of a screw expander, a centrifugal turbine expander or a turbo expander.
[0014] Optionally, the condenser is connected to a cooling medium for heat exchange, and the cooling medium is used to cool the organic medium entering the condenser.
[0015] Optionally, the cooling medium is cooling water of the diesel engine.
[0016] Optionally, the organic medium is one of R11, R113, R123, R141B, R245CA, R245FA, R365MFC, n-pentane and isopentane.
[0017] Another object of the present invention is to provide a ship, comprising a ship waste heat power generation system as described in any of the above schemes.
[0018] Beneficial effects:
[0019] The ship waste heat power generation system in the present invention can be used for waste heat recovery of diesel engines on ships, specifically to recover the waste heat of lubricating oil after diesel engine exhaust heating. The waste heat of lubricating oil heats the organic medium in the evaporator and converts it into organic supersaturated steam. The organic supersaturated steam enters the expansion generator to do work and generate electricity. After the work is done, the organic exhaust steam enters the condenser and is cooled into a liquid organic solvent. The organic solvent enters the evaporator for the next cycle. The organic medium used in the ship waste heat power generation system has good thermodynamic properties, and its latent heat of vaporization is much lower than that of water. Not only can the organic medium be converted from a liquid state to a saturated or superheated state after absorbing less heat, but the evaporation temperature of the organic medium is relatively low compared to water. Therefore, the ship waste heat power generation system has a higher thermal efficiency than the ship diesel engine waste heat power generation system based on the Rankine cycle, and the utilization rate of the waste heat of the ship diesel engine exhaust gas at a lower temperature is higher. It can recycle the low-grade waste heat generated by the diesel engine, and achieve the effects of waste heat power generation, energy saving and emission reduction, and carbon emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a system schematic diagram of a ship waste heat power generation system provided by a specific embodiment of the present invention.
[0021] In the figure:
[0022] 100. Evaporator; 200. Expansion generator; 300. Condenser; 400. Working fluid pump. DETAILED DESCRIPTION
[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0024] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0025] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0026] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.
[0027] Please refer to Figure 1 The ship waste heat power generation system is used for waste heat recovery of diesel engines. The exhaust gas of the diesel engine can heat the lubricating oil of the ship. The ship waste heat power generation system includes an evaporator 100, an expansion generator 200, and a condenser 300 which are connected in sequence. The evaporator 100 can be connected to the heated lubricating oil of the ship for heat exchange, so that the organic medium in the evaporator 100 evaporates and generates organic saturated steam; the medium outlet of the evaporator 100 is connected to the medium inlet of the expansion generator 200, so that the organic saturated steam drives the expansion generator 200 to generate electricity, the medium outlet of the expansion generator 200 is connected to the condenser 300, the organic saturated steam is liquefied in the condenser 300, and the medium outlet of the condenser 300 is connected to the medium inlet of the evaporator 100.
[0028] The ship waste heat power generation system in this embodiment can be used for waste heat recovery of diesel engines on ships, specifically, to recover waste heat of lubricating oil after diesel engine exhaust heating. The waste heat of lubricating oil heats the organic medium in the evaporator 100 and converts it into organic supersaturated steam. The organic supersaturated steam enters the expansion generator 200 to do work and generate electricity. After the work is done, the organic exhaust steam enters the condenser 300 and is cooled into a liquid organic solvent. The organic solvent enters the evaporator 100 for the next cycle. The organic medium used in the ship waste heat power generation system has good thermodynamic properties, and its latent heat of vaporization is much lower than that of water. Not only can the organic medium be converted from a liquid state to a saturated or superheated state after absorbing less heat, but the evaporation temperature of the organic medium is relatively low compared to water. Therefore, the ship waste heat power generation system has higher thermal efficiency than the ship diesel engine waste heat power generation system based on the Rankine cycle, and has a higher utilization rate of waste heat of ship diesel engine exhaust gas at a lower temperature. It can recycle the low-grade waste heat generated by the diesel engine, and achieve waste heat power generation, energy saving and emission reduction, and carbon emission reduction.
[0029] In this embodiment, the ship's lubricating oil is heated using the exhaust gas of the diesel engine. Specifically, the exhaust gas of the diesel engine first heats water to form high-temperature steam, which then heats the ship's lubricating oil, thereby achieving indirect heating of the ship's lubricating oil by the diesel engine.
[0030] Furthermore, a working fluid pump 400 is provided between the medium outlet of the condenser 300 and the medium inlet of the evaporator 100. The working fluid pump 400 is used to drive the organic medium to circulate in the ship waste heat power generation system. Specifically, the working fluid pump 400 can be selected as a centrifugal pump, a gear pump, a screw pump, an axial flow pump or a vortex pump, which should be selected according to the medium type, flow rate, head range and temperature of the organic medium, and will not be described in detail here.
[0031] In this embodiment, a preheating device is further provided between the working fluid pump 400 and the medium inlet of the evaporator 100, and the preheating device is used to preheat the organic medium entering the evaporator 100. The heat source of the preheating device can be other waste heat sources on board, such as main engine cylinder jacket cooling water, high-temperature pressurized air, etc. By preheating the organic medium entering the evaporator 100, the organic medium can be completely vaporized in the evaporator 100, thereby improving thermal efficiency.
[0032] Furthermore, a gas-liquid separator is provided between the medium outlet of the evaporator 100 and the medium inlet of the expansion generator 200. The gas-liquid separator is used to separate the liquid in the organic medium flowing out of the evaporator 100, to prevent the liquid from entering the expansion generator 200 and causing liquid hammer, etc., to reduce the probability of equipment failure and to improve the reliability of system operation.
[0033] The expansion generator 200 in this embodiment includes an expander and a generator. The organic saturated steam is used to drive the rotor of the expander to rotate, and the rotor is driven to connect to the main shaft of the motor of the generator. The expander is a machine that uses the principle of outputting mechanical work to reduce the temperature of the gas when the compressed gas expands and depressurizes to obtain cooling capacity. The expander is divided into two categories according to the movement form and structure: a piston expander and a turbine expander. In this embodiment, a turbine expander is selected to drive the main shaft of the generator to rotate so as to generate electricity, realize the conversion of diesel engine waste heat into electrical energy, and realize the recovery of waste heat.
[0034] Specifically, the above-mentioned expander includes any one of a screw expander, a centrifugal turbine expander and a turbine expander. The centrifugal turbine expander occupies a small volume, has a simple and compact structure, and has a low maintenance cost, but has a narrow stable operating range and poor economy; the turbine expander has a high efficiency, low vibration and noise of the whole machine, and a long service life, but has a high manufacturing cost and is inconvenient to maintain and repair; the screw expander has fewer parts, low maintenance and manufacturing costs, and stable operation, and can also be automatically adjusted, but its rotor tooth surface machining accuracy requirements are high, the process cost is high, and the noise is high during operation. In this embodiment, a screw expander is specifically selected. When used for waste heat recovery of ships, it can reduce maintenance costs, achieve long-term reliable operation, and ensure that it does not require maintenance for more than 10 years.
[0035] In this embodiment, the condenser 300 is connected to a cooling medium for heat exchange, and the cooling medium is used to cool the organic medium entering the condenser 300. Such a setting can use the cooling medium to completely liquefy the organic medium in the condenser 300, thereby preventing gas from entering the working fluid pump 400 and causing damage to the working fluid pump 400.
[0036] Optionally, the cooling medium is cooling water of the diesel engine. Thus, after the cooling medium flows through the condenser 300, it is first preheated by the organic medium in the condenser 300, and then used to cool the diesel engine. This part of the cooling water can be completely vaporized into supersaturated steam, which can be used for steam power generation, steam heating, heating and hot water supply, etc., thereby improving the heat recovery efficiency of the diesel engine.
[0037] It should be noted that the above organic medium is one of R11, R113, R123, R141B, R245CA, R245FA, R365MFC, n-pentane and isopentane. It is understandable that the organic medium can be selected as an organic substance with a low evaporation temperature and a low latent heat of vaporization, so that the ship waste heat power generation system forms an organic Rankine cycle, and no specific restrictions are made here. Compared with water vapor, due to the low sound velocity of the organic medium, at low blade speeds, favorable aerodynamic coordination can be obtained, and a higher turbine efficiency can be generated at 50Hz, and no gearbox is required. In addition, the condensation pressure of the organic medium is high, and the entire system works at a pressure close to and slightly above atmospheric pressure, which greatly reduces the leakage of the organic medium. In addition, the freezing point of the organic medium is very low (below -73°C), which allows it to release energy at a lower temperature, increase output in cold weather, and the condenser 300 does not need to add antifreeze facilities.
[0038] This embodiment also provides a ship, which includes a ship waste heat power generation system as described in any of the above schemes. The ship has all the beneficial effects of the ship waste heat recovery power generation system described in any of the above schemes, which will not be repeated here. The ship has a higher utilization rate of the waste heat of the exhaust gas of the marine diesel engine with a lower temperature, and can recycle the low-grade waste heat generated by the diesel engine to achieve waste heat power generation, energy saving and emission reduction, and reduce carbon emissions.
[0039] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.
Claims
1. A ship waste heat power generation system, comprising a diesel engine, the exhaust of which can heat the lubricating oil of the ship, characterized in that: The invention comprises an evaporator (100), an expansion generator (200), and a condenser (300) which are connected in sequence. The evaporator (100) can be connected to the lubricating oil heated by the ship for heat exchange, so that the organic medium in the evaporator (100) evaporates and generates organic saturated steam. The medium outlet of the evaporator (100) is connected to the medium inlet of the expansion generator (200), so that the organic saturated steam drives the expansion generator (200) to generate electricity. The medium outlet of the expansion generator (200) is connected to the condenser (300), and the organic saturated steam is liquefied in the condenser (300). The medium outlet of the condenser (300) is connected to the medium inlet of the evaporator (100).
2. The ship waste heat power generation system according to claim 1, characterized in that: A working fluid pump (400) is also provided between the medium outlet of the condenser (300) and the medium inlet of the evaporator (100).
3. The ship waste heat power generation system according to claim 2, characterized in that: A preheating device is also provided between the working fluid pump (400) and the medium inlet of the evaporator (100), and the preheating device is used to preheat the organic medium entering the evaporator (100).
4. The ship waste heat power generation system according to claim 2, characterized in that: A gas-liquid separator is also provided between the medium outlet of the evaporator (100) and the medium inlet of the expansion generator (200).
5. The ship waste heat power generation system according to claim 1, characterized in that: The expansion generator (200) comprises an expander and a generator, the organic saturated steam is used to drive the rotor of the expander to rotate, and the rotor drives the main shaft of the motor connected to the generator.
6. The ship waste heat power generation system according to claim 5, characterized in that: The expander includes any one of a screw expander, a centrifugal turbine expander or a turbo expander.
7. The ship waste heat power generation system according to claim 1, characterized in that: The condenser (300) is connected to a cooling medium for heat exchange, and the cooling medium is used to cool the organic medium entering the condenser (300).
8. The ship waste heat power generation system according to claim 7, characterized in that: The cooling medium is cooling water of the diesel engine.
9. The ship waste heat power generation system according to any one of claims 1 to 8, characterized in that: The organic medium is one of R11, R113, R123, R141B, R245CA, R245FA, R365MFC, n-pentane and isopentane.
10. A vessel, characterized in that It comprises the ship waste heat power generation system as claimed in any one of claims 1 to 9.