Ammonia working medium cyclic compression acting power generation system

Abstract

The invention provides a novel system for efficiently carrying out heat-work conversion by taking liquid ammonia / water as a circulating working medium, low-grade sensible heat can be recovered, latent heat is recovered by using an ammonia compressor to compress and heat a circulating working medium gasification heat source, and the heat-work or thermoelectric conversion efficiency is greatly improved. According to the invention, the liquefied latent heat of the working medium is effectively utilized as an internal heat source for circulating gasification, the economic and technical bottleneck of low efficiency of implementing low-grade thermoelectricity or heat-work conversion in the existing combined heat and power generation or ammonia working medium is well broken, the energy consumption and the working medium circulation amount can be greatly reduced, and the method has wide popularization and application values and is worthy of popularization and application. And greater economic and social environmental protection benefits can be created, and energy conservation and emission reduction are greatly realized.

Description

Technical Field

[0001] This invention relates to an ammonia working fluid circulating compression power generation system. Background Technology

[0002] Resources and energy are the two fundamental material guarantees for the development of human society; in fact, they are two sides of the same coin. Apart from the Earth's rotation, the growth of life on Earth, wind, rain, lightning, and moving vehicles are all directly or indirectly driven by the energy of the sun, moon, or Earth. Biomass, coal, oil, and natural gas are all carriers of solar energy.

[0003] The clean, efficient, and low-cost conversion of coal, oil, natural gas, and biomass into clean energy sources such as fuel gas, oxygenated fuel oil, and fuel ethanol through chemical or biochemical processes forms the foundation of energy. Biomass energy, solar energy, and its derivatives such as wind, hydro, and geothermal power generation are the most worthwhile green energy sources to develop. Reducing energy consumption and investment / operating costs, and developing green and renewable energy should be the fundamental path to sustainable development.

[0004] Energy is the driving force of social development. Making good use of fossil fuels and developing solar and biomass energy have enormous potential for energy conservation and emission reduction. The low- and medium-grade heat below 200℃ in the flue gas from steam boilers or kilns in industries such as thermal power, steel, cement, and glass is not being well utilized. The sensible heat of flue gas and the latent heat of water vapor from the combustion of fuel oil, natural gas, and biomass are also largely untapped. The current energy utilization model results in enormous energy waste. It is particularly worth mentioning that rivers, lakes, seas, and the circulating water of various production enterprises contain vast amounts of energy, representing a valuable low-grade energy resource pool for development.

[0005] As can be seen, a thermal power boiler is a device that uses fuel combustion to generate heat energy to heat steam, and then uses the high-temperature, high-pressure steam to convert it into electrical energy through a steam turbine. Analysis of the power generation process of a thermal power boiler shows that most of the heat generated by the fuel is used for water vaporization to produce steam, which is then heated to over 485℃ and 100 atmospheres of pressure. Combustion heat loss and byproducts such as steam and flue gas carry away approximately 20% of the heat, while the remaining 80% is absorbed by the steam. Steam turbine power generation only utilizes a portion of the high-temperature sensible heat (1 kg of steam releases 1.84 × 300 = 552 kJ of heat that can do work when cooled from 485°C to 185°C; the latent heat of vaporization of water at 100°C is 2260 kJ / kg; the heat absorbed by 1 kg of steam when heated from 100°C to 185°C is 184 kJ / kg; the specific heat capacity of steam is 1.84 kJ / kg·K). The unutilized latent heat of steam and the sensible heat from the 180°C temperature increase total 2444 kJ / kg. Therefore, the actual sensible heat of the steam is only 552 kJ / hour, and its conversion efficiency into electrical energy accounts for only 18% of the total heat of 2996 kJ obtained by the steam, approximately half of the thermoelectric conversion efficiency. The other half of the work is done by the steam undergoing pressure reduction and volume increase through the Rankine cycle. The work done by utilizing (the increase in entropy).

[0006] It is evident that in power plants, the steam turbine generates electricity, but the boiler flue gas and steam carry away a significant amount of low- to medium-grade sensible heat, and the latent heat of liquefaction of the steam is also wasted during cooling. This portion of energy becomes ineffective energy in the thermoelectric conversion process. A 130-ton / hour thermal power boiler typically has a combustion heat output of around 30 million joules / hour, a steam heat output of around 25 million kilocalories / hour, and an electrical energy output of around 10 million kilowatt-hours / hour.

[0007] In summary, thermoelectric conversion efficiency refers to the efficiency of converting heat energy into electrical energy. The thermoelectric efficiency of ordinary coal-fired power generating units is only about one-third because steam turbines only utilize a portion of the high-temperature sensible heat and expansion work. A large amount of low- and medium-grade sensible heat is carried away by flue gas and steam. In particular, the latent heat of liquefaction of the circulating working fluid, steam, is wasted through cooling towers or air-cooled towers, and the cooling process also consumes a significant amount of water and energy. Therefore, the potential for developing technologies to recover and utilize waste heat and innovating processes to improve thermoelectric conversion efficiency is enormous.

[0008] Appendix Figure 1 The Rankine cycle shown refers to an ideal cycle process using water vapor as the working fluid, which mainly includes the following four indispensable processes: 1) isentropic compression, 2) isobaric heating, 3) isentropic expansion, and 4) isobaric condensation.

[0009] A heat pump is a device system that can convert low-temperature heat energy into high-temperature heat energy. Its principle is based on the thermodynamic cycle principle. By inputting external energy (such as electrical energy), low-temperature heat energy is extracted from a low-temperature source and released into a high-temperature source to achieve the effect of raising the temperature.

[0010] The working process of a heat pump can be divided into four steps: evaporation, compression, condensation, and expansion.

[0011] First, during evaporation in the evaporator, the solvent absorbs heat from the heat source, evaporating into low-temperature vapor. This vapor then absorbs heat energy from the low-temperature heat source (such as low-grade heat in industry, geothermal energy, air, or circulating water). Next, the low-temperature vapor is compressed by the compressor, the core power unit of the heat pump, increasing both its temperature and pressure. This process requires a small amount of external energy (such as electricity). Then, the high-temperature, high-pressure compressed gas enters the evaporator as a heat source, releasing heat to drive the continuous evaporation of the circulating solvent, which then condenses into a high-temperature liquid. Finally, the high-temperature liquid is depressurized by an expander, becoming a low-temperature, high-pressure liquid, which can be continuously pumped into the evaporator to absorb heat of vaporization, either from external sources or its own supply.

[0012] Heat pump systems have the following characteristics:

[0013] 1. High-efficiency energy upgrading and utilization technology: Heat pump systems can upgrade and utilize low- and medium-grade industrial waste heat, geothermal energy, ambient air, and water sources, promoting efficient energy transfer and being more energy-efficient than traditional heating methods. This reduces energy and resource consumption and dependence on fossil fuels, aligning with green, environmentally friendly, and sustainable development strategies.

[0014] 2. Simple installation and wide range of applications: Currently, heat pump systems are used in many aspects such as heating, cooling and hot water supply, with great flexibility and adaptability, and can be developed into a wide range of application scenarios.

[0015] 3. Environmental protection: The refrigerant used in heat pump systems can be liquid ammonia or water-based environmentally friendly refrigerants, which have less impact on the ozone layer.

[0016] In conclusion, heat pump systems are a highly efficient heat energy conversion technology worthy of development and expanded application. In particular, utilizing the latent heat of steam through heat pump compression is a technological route with enormous development potential, which will be valuable for heating and cooling, as well as heat-power and thermoelectric conversion. Preliminary research results indicate that a 1000 kW heat pump centrifugal compressor can compress 7 tons of steam, consuming only about one-quarter of the energy gained from the steam, demonstrating high energy efficiency. Therefore, by rationally designing processes, heat pump systems can be widely applied to power generation, and the development of industrial and transportation waste heat. The liquefaction of natural gas or biomass boiler flue gas through heat pump compression not only enables waste heat reuse or power generation, but also produces a carbon dioxide solution as a byproduct that can be used as gaseous fertilizer for crops, potentially doubling crop yields, resulting in even more significant overall benefits. Summary of the Invention

[0017] Existing research indicates that using liquid ammonia instead of water as the circulating working fluid can utilize most of the sensible heat above room temperature, and the liquid ammonia / water system can significantly improve thermoelectric conversion efficiency, reducing irreversible heat loss in the evaporator and condenser. However, the thermoelectric conversion efficiency of existing ammonia or ammonia / water circulating working fluids remains low; even using 135°C hot water, the efficiency is only around 12%. Utilizing the low boiling point of ammonia as the working fluid, using low-pressure ammonia gas discharged from a steam turbine as a refrigerant can achieve combined power generation and cooling. Similarly, at an absorption temperature of 135°C and a release temperature of 7°C, the combined power generation and cooling efficiency can be increased to 22.5%. However, the utilization and matching of the cold source still face limitations imposed by application scenarios. In particular, the use of liquid ammonia or liquid ammonia / water circulating working fluids to replace water suffers from the same unresolved constraint affecting thermoelectric efficiency improvement—the latent heat of liquefaction of the working fluid is carried away by the cooling medium and cannot be utilized.

[0018] Therefore, the key to overcoming the technical bottleneck of low heat-to-power or heat-to-work conversion efficiency in cogeneration lies in fully utilizing the latent heat of liquefaction of the working fluid as the internal heat source for its vaporization.

[0019] Ammonia is a commonly used low-toxicity chemical. Liquid ammonia has a boiling point of -33.5℃, which is 133.5℃ lower than water. If liquid ammonia is used instead of water as the working medium, the boiling temperature can be lowered by 133.5℃, allowing for the conversion of low-grade heat energy into usable pressure energy using a medium- or low-temperature heat source to vaporize the liquid ammonia. The latent heat of vaporization of liquid ammonia is 1374 kJ / kg, only 60% of that of the same mass of water. This means that the same amount of heat energy can vaporize ammonia into 1.65 times the volume of water vapor, making it more conducive to expansion and work. The maximum permissible concentration of ammonia in air is 30 mg / m³. 3 Concentration exceeding 360 mg / m³ 3 It may cause an explosion. Ammonia has an auto-ignition point of 651℃, making it relatively safe; its density at room temperature and saturated vapor pressure is 0.59 kg / m³. 3With water vapor 0.6-0.59 kg / m 3 Ammonia is readily compressible; at 20°C and 1 atmosphere, 1 volume of water can dissolve 703 volumes of ammonia gas. This property allows for water injection during compression to aid dissolution and reduce compression energy consumption. Ammonia is also easily compressible; it liquefies at 20°C under pressure of 0.871 MPa, and can be vaporized by reducing pressure and increasing temperature, absorbing heat. These properties make ammonia a commonly used refrigerant in industry and it has the potential to become the preferred refrigerant for low-temperature heat sources in heat-work or thermoelectric conversion. Consulting the pressure table for liquid ammonia at different temperatures, we find that the saturated vapor pressure of liquid ammonia is 0.1 MPa at -33.5℃; 0.4244 MPa at 0℃; 0.8466 MPa at 20℃; 1.152 MPa at 30℃; 1.534 MPa at 40℃; 2.006 MPa at 50℃; 2.578 MPa at 60℃; 3.264 MPa at 70℃; and [the pressure is missing from the original text]. The vapor pressure is 4.078 MPa; at 90℃, the saturated vapor pressure of liquid ammonia is 5.034 MPa; at 100℃, it is 5.151 MPa; at 110℃, it is 7.447 MPa; at 120℃, it is 8.924 MPa; and at 160℃, it is 10.669 MPa. It can be seen that the saturated vapor pressure of liquid ammonia reaches 1.152 MPa at 30℃, rises to 2.006 MPa at 50℃, and is as high as 5.15 MPa at 100℃. If the pressure of liquid ammonia after work is 0.4 MPa, the temperature will drop to around 0℃. Using an ammonia compressor at a compression ratio of 6, the pressure rises to 2.4 MPa, corresponding to a temperature of 50°C. This vaporizes to obtain ammonia gas at 2 MPa. Further heating with a high-temperature gas at constant pressure yields a high-temperature, high-pressure gas exceeding 100°C and 2 MPa, which can then be used for work. Clearly, by balancing and controlling pressure, temperature, and the ammonia circulation rate, it is possible to achieve the heat-to-work conversion between the low-grade sensible heat and the latent heat of the working fluid.

[0020] As early as 2001, Liu Qishou et al. reported in Modern Electric Power 18(4): "High-efficiency new power cycle" that the efficiency of direct geothermal power generation using liquid ammonia as working fluid at a heat absorption temperature of 135℃ and a heat release temperature of 7℃ was about 12%. They also used the low boiling point of ammonia working fluid and the low-pressure ammonia gas discharged from the steam turbine as refrigerant to achieve combined power generation and cooling. Similarly, at a heat absorption temperature of 135℃ and a heat release temperature of 7℃, the combined power generation and cooling efficiency was 22.5%.

[0021] In 2009, Liu Weimin et al. reported at the Second National Symposium on Seawater Energy a systematic study of seawater temperature difference power generation using ammonia-water non-azeotropic mixtures as the working fluid in the Rankine cycle. Figure 2 The study found that the physical properties of the ammonia-water non-azeotropic working fluid system, which involves temperature-dependent evaporation and condensation, can effectively adapt to the temperature changes of seawater, minimizing irreversible heat loss in the evaporator and condenser. When the warm seawater is 27°C, the low-temperature seawater is 5°C, and the turbine inlet pressure is 0.8 MPa, the circulation efficiency of pure liquid ammonia is only 1.764%. Similarly, when the warm seawater is 27°C, the low-temperature seawater is 5°C, the turbine inlet pressure is 0.73 MPa, and the mass fraction of ammonia in the circulating liquid is 0.92% (i.e., 8% water content), the circulation efficiency can be increased to 2.452%. It is evident that the circulation efficiency of the ammonia / water non-azeotropic working fluid in the entire circulation system is superior to that of pure liquid ammonia.

[0022] This process uses liquid ammonia and a liquid ammonia / water system as the heat carrier. The liquid ammonia absorbs heat energy from a high-temperature heat source (surface seawater at 27°C) through evaporation. The resulting gas-liquid mixture is separated into liquid (mainly water) by a separator. The pressurized ammonia gas drives an ammonia turbine to generate electricity. The ammonia gas, having released its pressure energy and cooled, is then absorbed by water and liquefied by cooling with deep, low-temperature seawater (5°C). The highest thermoelectric efficiency is only 2.452%. Therefore, the thermoelectric conversion efficiency is very low. Clearly, due to design flaws and the limitation of small seawater temperature differences, seawater power generation has not yet been realized due to a lack of economic viability.

[0023] However, while this process demonstrates the feasibility of using a liquid ammonia / water system as a heat transfer medium instead of water, its fatal weaknesses must be overcome: First, the process fails to utilize the latent heat of vaporization of liquid ammonia, which accounts for 93% of the absorbed heat, ultimately releasing it to the low-temperature water, effectively using only the sensible heat from the 22°C temperature difference between the high and low heat sources for work. Second, an unnecessary separator is installed to separate the liquid water from the high-temperature ammonia gas, reducing the power of the working fluid. Since a significant drop in the temperature and pressure of the working fluid is conducive to condensation and absorption, 1 volume of water can absorb approximately 700 volumes of ammonia gas and significantly reduce the internal pressure. Therefore, the separator, lean ammonia solution pump, return heat exchanger, absorber, and corresponding branch lines can be eliminated, simplifying the process. Allowing the water / ammonia mixture to simultaneously enter the ammonia turbine increases the positive and negative pressure difference, improving the heat-to-work conversion efficiency.

[0024] One objective of this invention is to provide a system using liquid ammonia / water as the circulating working fluid, comprising:

[0025] Ammonia pressure pump, primary evaporator, secondary evaporator, expander, power or electricity conversion device;

[0026] Condenser, high-pressure liquid ammonia pump, chilled water pump or air cooler;

[0027] The heat of condensation of the ammonia / water vapor working medium after compression and expansion by the ammonia pressure pump is used as a heat source to vaporize part of the ammonia / water mixture in the first-stage evaporator and enter the second-stage evaporator. Hot water or hot gas is then pumped or blowed into the second-stage evaporator to provide a heat source for further vaporization and temperature increase of the circulating ammonia. The high-temperature and high-pressure ammonia gas heated in the second stage enters the expander to do work or directly generate electricity. Part of the kinetic energy generated ensures the energy consumption of the ammonia pressure pump, and the rest is output in the form of electricity.

[0028] After the low-temperature and low-pressure ammonia gas is cooled by the work, it is pressurized and heated by the ammonia pressure pump and then circulated into the first-stage evaporator as a heat source for vaporizing liquid ammonia. It heats the liquid ammonia in the heat exchanger so that it can be partially vaporized. Then it enters the second-stage evaporator to absorb heat and be further heated. The high-temperature and high-pressure ammonia gas produced enters the expander to do work or directly generate electricity.

[0029] The pressurized heat circulation material, after being fully heat-exchanged in the first-stage evaporator, enters the condenser cooled by already heated cold water or cold air, where it is completely condensed and transformed into a liquid ammonia / water mixture. Then, a liquid ammonia pump is used to quantitatively pump it into the first-stage evaporator, realizing the complete internal circulation of the working fluid and the conversion of absorbed energy.

[0030] Another object of the present invention is to provide a system using liquid ammonia / water as the circulating working fluid, comprising:

[0031] Ammonia pressure pump, primary evaporator, secondary evaporator, expander, power or electricity conversion device;

[0032] Condenser, high-pressure liquid ammonia pump, chilled water pump or air cooler;

[0033] Hot water or hot gas is pumped or blowed into the first-stage evaporator, where part of the ammonia / water mixture in the evaporator is vaporized and enters the second-stage evaporator for further heating. The high-temperature and high-pressure ammonia gas heated in the second stage enters the expander to do work or directly generate electricity. Part of the kinetic energy generated is used to ensure the energy consumption of the ammonia compressor, and the rest is output in the form of electricity.

[0034] After cooling down by doing work, the low-temperature, low-pressure ammonia gas is pressurized and heated by an ammonia pressure pump and enters the secondary evaporator to circulate as a heat source for vaporizing liquid ammonia, providing a heat source for further vaporization and temperature increase of the circulating liquid ammonia working fluid.

[0035] The pressurized heat circulation material, after being fully heat-exchanged in the first-stage evaporator, enters the condenser cooled by already heated cold water or cold air, where it is completely condensed into a liquid ammonia / water mixture. The liquid ammonia is then pumped quantitatively into the first-stage evaporator, achieving complete circulation of the working fluid and conversion of absorbed energy.

[0036] Preferably, seawater, lake water or river water at room temperature is used as a heat source and is pumped into the first-stage evaporator to vaporize part of the ammonia / water mixture and enter the second-stage evaporator; the high-temperature and high-pressure ammonia gas heated in the second stage enters the expander to do work or directly generate electricity, and part of the kinetic energy generated is used to ensure the energy consumption of the ammonia pressure pump, while the rest is output in the form of electricity.

[0037] After cooling down by doing work, the low-temperature and low-pressure ammonia gas is pressurized and heated by an ammonia pressure pump and enters the secondary evaporator to circulate as a heat source for vaporizing liquid ammonia, providing a heat source for further vaporization and temperature increase of the circulating ammonia gas;

[0038] The pressurized heat circulation material, which releases latent heat of liquefaction through condensation in the first-stage evaporator, then enters the condenser of the crop cooling heat exchange medium, which has already extracted heat from cold water or cold air, to fully condense it into a liquid ammonia / water mixture. The liquid ammonia is then pumped quantitatively into the first-stage evaporator to achieve complete internal circulation of the working fluid and conversion of absorbed energy.

[0039] Preferably, ambient temperature seawater enters the first-stage evaporator to provide part of the heat source for the vaporization of liquid ammonia. The heated low-temperature seawater is used directly as a cold source or enters the condenser. The high-temperature and high-pressure gaseous ammonia compressed by the ammonia compressor is further condensed into liquid ammonia / water by the second-stage high-temperature condenser after sufficient heat exchange. The low-temperature water after heat exchange becomes medium-temperature water and is discharged into the water body or used as a cold source.

[0040] Preferably, the hot water is selected from one or more of seawater, river water, large body water, geothermal water, circulating cooling water, waste steam, condensate, and solar hot water; the hot gas is selected from the hot gas from the three furnaces of a steel plant, boiler exhaust gas, and flue gas.

[0041] Preferably, the cold source is selected from cooling water or cold air.

[0042] Preferably, the cold source is selected from cold seawater or any other cooling medium.

[0043] Another object of the present invention is to provide a water propulsion system comprising the above-described system using liquid ammonia / water as the circulating working fluid, wherein the water propulsion system is capable of generating energy in water for navigation.

[0044] This invention uses liquid ammonia and water as heat transfer media, which can utilize most of the sensible heat above room temperature; the latent heat can also be utilized by compressing the ammonia with a compressor. This is of great value for heating and cooling, as well as for heat work and thermoelectric conversion. The cost is that about a quarter of the energy obtained is electricity, which has a significant price advantage, especially in mobile vehicles.

[0045] The latent heat of vaporization of liquid ammonia is 1374 kJ / kg. 1 kg of liquid ammonia has a volume of 1318 liters under standard conditions. At 27°C, the ammonia pressure is 1 MPa, and at 5°C, it is 0.5 MPa, with a pressure difference of 0.5 MPa. Within this temperature range, the heat capacity of ammonia is 4.676 kJ / kg·°C. Based on a 22°C temperature difference, 1 kg of liquid ammonia can perform 103 kJ of work. 1 kg of liquid ammonia absorbs 1477 kJ of heat from 27°C seawater and releases 1374 kJ of latent heat into 5°C water. Even with the highest quantitative conversion cycle efficiency, it is only 7%. Currently, the utilization level is close to 2.452%. Based on the highest cycle efficiency of 7%, the thermoelectric conversion efficiency is 35%, which should be close to the normal level.

[0046] At 30℃, the saturated vapor pressure of liquid ammonia is 1.152 MPa; at 50℃, it rises to 2.006 MPa; and at 100℃, it reaches a staggering 5.15 MPa. If the pressure of the liquid ammonia after work is 0.4 MPa, the temperature drops to around 0℃. Using an ammonia compressor at a compression ratio of more than 3 times, the temperature of the compressed gas can be raised to 50℃. Ammonia gas at approximately 2 MPa acts as a heat source in the secondary evaporator, completely vaporizing most (about 90%) of the unvaporized ammonia to perform work. Clearly, by adjusting and controlling the ammonia circulation rate, pressure, temperature, and heat source quantity, this process can fully realize the heat-work conversion between low-grade sensible heat and latent heat of the working fluid, without any equipment or technical obstacles.

[0047] For the utilization of low- and medium-grade waste heat for power generation, a primary and secondary evaporator can be installed, and the heat can be introduced into an ammonia compressor to fully utilize both heat sources. Figure 3 and attached Figure 4 The innovative process shown cleverly utilizes the ammonia compressor to pressurize and heat the internal circulation to the evaporator for heating. This allows for the use of both low-grade waste heat and the latent heat of ammonia liquefaction as heat sources for liquid ammonia vaporization, significantly reducing the mass of the circulating working fluid, greatly improving the heat-work conversion efficiency, and co-producing a large amount of low-temperature cold source water.

[0048] Clearly, the biggest highlight of this invention is the introduction of ammonia compressor technology and the new process of setting up dual evaporators. This invention not only makes full use of the latent heat of the working fluid, but also can smoothly convert medium and low temperature heat sources, greatly improve the heat-work conversion efficiency, significantly reduce the circulation volume of the working fluid, reduce equipment investment, and has very significant economic, social and environmental benefits.

[0049] Ammonia compressors using ammonia-water mixtures as working fluids for power generation have significant applications in a wide range of low- and medium-temperature heat sources, including solar energy, geothermal energy, power plant waste heat, and waste heat from generator and engine flue gas. Therefore, developing low-grade heat utilization technologies to directly convert pressure energy into mechanical or electrical energy is of great significance for energy conservation and emission reduction across various industries.

[0050] The technical approach and basic process of high-efficiency energy-saving equipment proposed in this invention are of great significance for reducing energy consumption, improving the atmospheric environment, mitigating global warming, and promoting the development of the economy, society, and ecological industries. Attached Figure Description

[0051] Figure 1 This is a Rankine cycle diagram for a conventional water / water vapor working medium.

[0052] Figure 2 Flowchart of a seawater temperature difference power generation device using liquid ammonia / water as the working medium

[0053] Figure 3 This is a flow chart of a low-grade waste heat recovery and power generation system for liquid ammonia / water-based ammonia compressors.

[0054] Figure 4 The process of liquid ammonia / water-based seawater ammonia compressor power generation equipment Detailed Implementation

[0055] To fully illustrate the content of this invention and better understand the value of this process, the following three embodiments are provided to aid understanding. It should be noted that the above embodiments do not encompass the entirety of the invention, nor are they intended to limit it. Any improvements using ammonia compressors and dual evaporators for power generation fall within the scope of this invention.

[0056] Example 1: Low-grade waste heat is used to generate electricity.

[0057] As attached Figure 3 The process shown is a new process and equipment combination system that uses liquid ammonia / water as the circulating working fluid to recover low-grade sensible heat, and then uses the gaseous working fluid compressed, heated and expanded by the ammonia compressor as the main vaporization heat source to recover latent heat, which greatly improves the efficiency of heat-work or thermoelectric conversion. The material circulation process is described as follows: the gaseous working fluid after being compressed and expanded by the ammonia compressor serves as a heat source to vaporize part of the ammonia / water mixture in the first-stage evaporator and enter the second-stage evaporator. Hot water or hot gas is then used to enter the second-stage evaporator to provide a heat source for further vaporization and temperature increase of the circulating ammonia gas. The high-temperature and high-pressure ammonia gas after secondary heating enters the expander (or ammonia turbine) to do work or directly generate electricity. The kinetic energy generated is partially used to ensure the energy consumption of the ammonia compressor, and most of the rest is output in the form of electricity. After being cooled by work, the low-temperature, low-pressure ammonia gas is pressurized and heated by an ammonia compressor and enters the primary evaporator as a heat source for vaporizing liquid ammonia. The liquid ammonia is partially vaporized and then enters the secondary evaporator for further heating. The resulting high-temperature, high-pressure ammonia gas enters an expander (or ammonia turbine) to perform work or generate electricity directly. The pressurized heat circulation material, after sufficient heat exchange in the primary evaporator, then enters a condenser cooled by cold water or cold air to completely condense it into a liquid ammonia / water mixture. This mixture is then metered into the primary evaporator using a liquid ammonia pump, thus achieving complete circulation of the working fluid and the conversion of most of the absorbed energy.

[0058] Example 2: Seawater Power Generation Ship Propulsion System

[0059] Adopting attachment Figure 4 The innovative process flow cleverly utilizes the ammonia compressor to pressurize and heat the seawater, enabling it to function as both a low-temperature and high-temperature heat source. By fully utilizing the sensible heat of seawater and the latent heat of ammonia liquefaction as the internal heat source for circulating liquid ammonia, the heat-work conversion efficiency can be significantly improved.

[0060] Appendix Figure 4 This invention relates to a novel process and equipment combination for generating electricity from sensible heat in water to power waterborne navigation. The material flow is as follows: At room temperature, seawater first enters a primary evaporator, providing partial heat for the vaporization of liquid ammonia. The heated, low-temperature seawater can be used directly as a cold source or enters a condenser. The high-temperature, high-pressure gaseous ammonia, compressed by an ammonia compressor and having undergone sufficient heat exchange in a secondary high-temperature condenser, is largely condensed into ammonia / water mixture, which is then further condensed into liquid ammonia / water. This low-temperature water, after heat exchange, becomes medium-temperature water and is discharged into the water body or used as a cold source. Approximately 10% of the liquid ammonia, which has obtained energy from the room-temperature seawater in the primary evaporator, vaporizes. The resulting liquid ammonia-ammonia-water mixture enters a secondary evaporator. Hot ammonia gas at 50°C and 2MPa, pressurized and heated by an ammonia compressor, serves as a secondary heat source to further vaporize and heat the approximately 10% vaporized liquid ammonia-ammonia-water mixture. After secondary heating and sufficient vaporization, the ammonia-ammonia-water mixture at approximately 50°C and below 2MPa enters an expander to perform work or directly generate electricity. The generated kinetic energy... Alternatively, a portion of the electrical energy is used to power the ammonia compressor, with the remainder being output as electricity. The ammonia gas, after being cooled and depressurized, enters the ammonia compressor for compression, heating, and pressurization, generating a high-temperature heat source (approximately 50°C, 20-30°C higher than seawater). This heat source then enters the secondary evaporator as a heat source, circulating and heating a mixture of pressurized liquid ammonia, ammonia gas, and water from the primary evaporator. This mixture further absorbs heat, vaporizes, and heats up before entering the expander to generate electricity. Using an ammonia compressor fully utilizes the enormous potential of ammonia liquefaction, increasing the amount of liquid ammonia vaporization and ammonia temperature to improve internal energy and work efficiency, significantly reducing the amount of ammonia circulating and the size of the equipment. The pressurized hot material, after sufficient heat exchange, enters a condenser using low-temperature water as the cooling medium for further condensation into a liquid ammonia / water mixture. This mixture is then pumped quantitatively into the primary evaporator using a liquid ammonia pump, completing the circulation of the working fluid and the efficient utilization of the sensible heat of the water. This provides power for mobile vehicles, enabling green navigation powered by underwater energy extraction.

[0061] Example 31: Analysis of the heat-work conversion efficiency of 1 kmol ammonia as the circulating working fluid and water as the heat source

[0062] The volume of ammonia gas at standard conditions is 22.4 cubic meters (1 kmol molecule, or 17 kg of liquid ammonia). At 2 MPa pressure, the volume is only 2.24 cubic meters, and at 0.8 MPa, it is 2.8 cubic meters. 17 kg of liquid ammonia can circulate 300 times per hour, assuming a 12-second cycle time. Based on a 0.8 MPa pressure, the hourly circulation volume of pressurized ammonia is 840 cubic meters, or 5100 kg of ammonia per hour. Assuming the heat absorption during the vaporization of liquid ammonia is 1500 kJ / kg, and the heat exchanger's thermal conductivity is 10000 kJ / m², this translates to a total heat transfer rate of 5100 kg / kg. 2 Based on a 20°C water temperature drop, the heat exchanger area is 765 square meters, indicating a relatively small equipment size. With a calculated heat-to-work conversion efficiency of 85% (approximately 90% contributed by ammonia liquefaction), the power output can reach 1806 kWh. Assuming an ammonia compressor energy consumption of 200 kWh, it can output approximately 1600 kWh of electricity per hour. With a 20°C water temperature drop, the hourly water intake is 383 cubic meters, simultaneously providing low-temperature water with a 20°C temperature reduction. Since the heat source is virtually cost-free, the efficiency and benefits are very high, and there is potential to further increase the heat-to-work output by increasing the number of cycles and enhancing heat transfer.

[0063] In practical applications, the water volume and circulation process quality for providing the heat source can be adjusted proportionally according to the above embodiments as needed.

Claims

1. An ammonia working fluid circulating compression power generation system, comprising: Ammonia pressure pump, primary evaporator, secondary evaporator, expander, power or electricity conversion device; Condenser, high-pressure liquid ammonia pump, chilled water pump or air cooler; The heat of condensation of the ammonia / water vapor working medium after compression and expansion by the ammonia pressure pump is used as a heat source to vaporize part of the ammonia / water mixture in the first-stage evaporator and enter the second-stage evaporator. Hot water or hot gas is then pumped or blowed into the second-stage evaporator to provide a heat source for further vaporization and temperature increase of the circulating ammonia. The high-temperature and high-pressure ammonia gas heated in the second stage enters the expander to do work or directly generate electricity. Part of the kinetic energy generated ensures the energy consumption of the ammonia pressure pump, and the rest is output in the form of electricity. After the low-temperature and low-pressure ammonia gas is cooled by the work, it is pressurized and heated by the ammonia pressure pump and then circulated into the first-stage evaporator as a heat source for vaporizing liquid ammonia. It heats the liquid ammonia in the heat exchanger so that it can be partially vaporized. Then it enters the second-stage evaporator to absorb heat and be further heated. The high-temperature and high-pressure ammonia gas produced enters the expander to do work or directly generate electricity. The pressurized heat circulation material, after being fully heat-exchanged in the first-stage evaporator, enters the condenser cooled by already heated cold water or cold air, where it is completely condensed and transformed into a liquid ammonia / water mixture. Then, a liquid ammonia pump is used to quantitatively pump it into the first-stage evaporator, realizing the complete internal circulation of the working fluid and the conversion of absorbed energy.

2. An ammonia working fluid circulating compression power generation system, comprising: Ammonia pressure pump, primary evaporator, secondary evaporator, expander, power or electricity conversion device; Condenser, high-pressure liquid ammonia pump, chilled water pump or air cooler; in, Hot water or hot air is pumped or blowed into the first-stage evaporator, causing part of the ammonia / water mixture in the evaporator to be vaporized and enter the second-stage evaporator for further heating; the high-temperature and high-pressure ammonia gas heated in the second stage enters the expander to do work or directly generate electricity, and part of the kinetic energy generated guarantees the energy consumption of the ammonia compressor, while the rest is output in the form of electricity. After cooling down by doing work, the low-temperature, low-pressure ammonia gas is pressurized and heated by an ammonia pressure pump and enters the secondary evaporator to circulate as a heat source for vaporizing liquid ammonia, providing a heat source for further vaporization and temperature increase of the circulating liquid ammonia working fluid. The pressurized heat circulation material, after being fully heat-exchanged in the first-stage evaporator, enters the condenser cooled by already heated cold water or cold air, where it is completely condensed into a liquid ammonia / water mixture. The liquid ammonia is then pumped quantitatively into the first-stage evaporator, achieving complete circulation of the working fluid and conversion of absorbed energy.

3. The system according to claim 2, wherein, Normal temperature seawater, lake water or river water is used as a heat source and is pumped into the first-stage evaporator to vaporize part of the ammonia / water mixture and enter the second-stage evaporator; the high temperature and high pressure ammonia gas heated in the second stage enters the expander to do work or directly generate electricity. Part of the kinetic energy generated is used to ensure the energy consumption of the ammonia pressure pump, and the rest is output in the form of electricity. After cooling down by doing work, the low-temperature and low-pressure ammonia gas is pressurized and heated by an ammonia pressure pump and enters the secondary evaporator to circulate as a heat source for vaporizing liquid ammonia, providing a heat source for further vaporization and temperature increase of the circulating ammonia gas; The pressurized heat circulation material, which releases latent heat of liquefaction through condensation in the first-stage evaporator, then enters the condenser of the crop cooling heat exchange medium, which has already extracted heat from cold water or cold air, to fully condense it into a liquid ammonia / water mixture. The liquid ammonia is then pumped quantitatively into the first-stage evaporator to achieve complete internal circulation of the working fluid and conversion of absorbed energy.

4. The system according to claim 2, wherein, At room temperature, seawater enters the first-stage evaporator to provide part of the heat source for the vaporization of liquid ammonia. The heated, low-temperature seawater is used directly as a cold source or enters the condenser. The high-temperature, high-pressure gaseous ammonia compressed by the ammonia compressor is further condensed into liquid ammonia / water through the second-stage high-temperature condenser after sufficient heat exchange. The low-temperature water after heat exchange becomes medium-temperature water and is discharged into water bodies or used as a cold source.

5. The system according to any one of claims 1-2, wherein, The hot water is selected from one or more of the following: seawater, river water, large body of water, geothermal water, circulating cooling water, waste steam, condensate, and solar hot water; the hot gas is selected from the hot gas from the three furnaces of a steel plant, boiler exhaust gas, and flue gas.

6. The system according to any one of claims 1-4, wherein, The cold source is selected from cooling water or cold air.

7. The system according to any one of claims 1-4, wherein, The cold source is selected from cold seawater or any other cooling medium.

8. A hydrodynamic system comprising the system of claim 3, wherein the hydrodynamic system is capable of powering a boat by harvesting energy from water.

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