Combustion gas turbine and water vapor mixed ammonia compound cycle power generation system

Abstract

The invention provides a gas turbine and water vapor mixed ammonia compound cycle power generation system which integrates a liquid ammonia storage tank, a pressure pump, a liquid ammonia gasifier, an ammonia cracker, a seawater desalination device, a pressure pump, a water evaporator, a water vapor superheater, an expansion machine and a gas turbine into an integral cycle. Liquid ammonia flows out of the liquid ammonia storage tank and the pump unit and then sequentially passes through the liquid ammonia gasifier unit and the ammonia cracker unit to be converted into mixed gas of ammonia gas, hydrogen gas and nitrogen gas, the mixed gas of the ammonia gas, the hydrogen gas and the nitrogen gas is mixed with superheated steam, and the mixed gas is expanded by the expansion machine power generation unit to do work and then enters the combustion chamber of the gas turbine to be mixed with air to be combusted. The expansion machine power generation unit and the gas turbine power generation unit act at the same time to generate power, under the limitation of the technical level of an existing gas turbine, the overall output power and the power generation efficiency of a whole machine system are greatly improved, and more fuel consumption can be saved.

Description

Technical Field

[0001] This invention relates to the field of energy and power engineering technology, specifically to a gas turbine combined with steam and ammonia hybrid cycle power generation system. Background Technology

[0002] As the cornerstone of efficient energy conversion and clean utilization infrastructure, gas turbines play a crucial role in modern power generation. They have become key equipment supporting flexible peak shaving and low-carbon transformation of new power systems. A gas turbine is a thermodynamic engine that uses a continuously flowing gas as its working fluid. Through a cyclical process of air compression by a compressor, combustion of fuel and air in a combustion chamber, and expansion and work done by a gas turbine, it converts the chemical energy of fuel into mechanical work. Its core advantages are: ① Power density and lightweight: With the same power, its volume is only 1 / 3 to 1 / 5 of that of a diesel internal combustion engine, and its weight is significantly reduced, making it particularly suitable for space-constrained ship designs, improving the ship's maneuverability and carrying capacity; ② Rapid response and flexibility: Excellent low-temperature start-up performance, reaching full load status within 1-2 minutes, and short switching time from cold standby to full load, suitable for emergency peak shaving or high-dynamic scenarios; ③ Environmental protection and low emissions: Using gaseous or liquid fuels, combustion is complete and ash-free, and exhaust gas can be purified to meet increasingly stringent ship emission standards; ④ Compact structure and automation: Simplified transmission mechanism, facilitating monitoring, remote control, and full automation, significantly improving the engine room working environment, and supporting the integration of intelligent technologies such as digital twins; ⑤ Low vibration and low noise: Stable operation with very low-frequency noise components, particularly suitable for ships sensitive to acoustic performance, and friendly to marine life.

[0003] Despite its significant advantages, traditional marine gas turbines still face the following challenges: ① Insufficient fuel economy: High fuel consumption, especially with a significant drop in efficiency at low loads, leading to increased operating costs, and requiring the use of high-quality, low-viscosity fuels; ② Torque and drive limitations: High operating speed but low output torque, making it unsuitable for directly driving propellers, requiring gearbox reduction, which increases system complexity; ③ Low level of electrification. Summary of the Invention

[0004] To overcome the limitations of current marine gas turbines in terms of fuel economy and low electrification, this invention proposes a gas turbine-steam-ammonia hybrid cycle power generation system. Its core lies in integrating ammonia cracking hydrogen production technology, expander technology, seawater desalination technology, water evaporation and superheating technology with the gas turbine cycle to achieve efficient zero-carbon power generation.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: A gas turbine combined with steam and ammonia hybrid cycle power generation system integrates a liquid ammonia storage tank and pressurization pump, a liquid ammonia vaporizer, an ammonia cracker, a seawater desalination unit and pressurization pump, a water evaporator, a steam superheater, an expander, and a gas turbine into a single cycle. The system includes a liquid ammonia storage tank and pump unit, a liquid ammonia vaporizer unit, an ammonia cracker unit, a seawater desalination unit and pump unit, a water evaporator unit, a steam superheater unit, an expander power generation unit, and a gas turbine power generation unit. The exhaust gas from the gas turbine is split into two streams. One stream passes through the ammonia cracker unit, and the other stream passes through the steam superheater unit. The two streams are then mixed and passed through the liquid ammonia vaporizer unit and the water evaporator unit for heat exchange and cooling before entering the exhaust system. After exiting the liquid ammonia storage tank and pump unit, the liquid ammonia passes through the liquid ammonia vaporizer unit and the ammonia cracker unit in sequence, and is then transformed into a mixed gas of ammonia, hydrogen and nitrogen. After passing through the seawater desalination unit and pump unit, the water is converted into superheated steam after passing through the water evaporator unit and the water steam superheater unit. A mixture of ammonia, hydrogen, and nitrogen is mixed with superheated steam and then expanded by the expander power generation unit before entering the gas turbine combustion chamber to mix and burn with air. The pressure of the mixture is maintained at a relatively high value that is not lower than the design pressure of the combustion chamber. After passing through the intake filtration system, the air enters the gas turbine compressor for compression, and then enters the gas turbine combustion chamber to mix and burn with a mixture of ammonia, hydrogen, nitrogen and water vapor. The high-temperature and high-pressure flue gas then enters the gas turbine for expansion and does work. The total power output of the system is the sum of the power outputs of the expander power generation unit and the gas turbine power generation unit.

[0006] Furthermore, the waste heat from the gas turbine exhaust is mainly used for the thermal cracking and sensible heat absorption of fuel in the ammonia cracker unit, as well as the latent heat of vaporization and sensible heat absorption of fuel in the liquid ammonia vaporizer unit, and the latent heat of water vaporization and superheat absorption of water in the water evaporator unit and the steam superheater unit. Afterwards, the remaining waste heat from the gas turbine exhaust can be used for heat exchange in the heat exchanger before entering the exhaust system for exhaust, or it can be directly entered into the exhaust system for exhaust.

[0007] Furthermore, besides the power consumed by the turbine expansion during gas turbine compressor compression, the remainder is used for power generation by the generator.

[0008] In this invention, "composite" refers to the simultaneous combined work of the expander power generation unit and the gas turbine power generation unit. "Cycle" refers to the circulation mode composed of the liquid ammonia fuel flow path, the water evaporation and superheating flow path, and the gas turbine-side working fluid flow path, and the liquid ammonia fuel flow path, the water evaporation and superheating flow path, and the gas turbine-side working fluid flow path are carried out simultaneously.

[0009] Compared with the prior art, the present invention has the following advantages: This invention discloses a gas turbine combined with steam and ammonia hybrid cycle power generation system, which aims to solve the limitations of existing gas turbines in terms of insufficient fuel economy and low electrification. The "composite" refers to the simultaneous combined work of the expander power generation unit and the gas turbine power generation unit. The "cycle" refers to the circulation mode composed of the liquid ammonia fuel flow path, the water evaporation and superheating flow path, and the working fluid flow path on the gas turbine side, and the liquid ammonia fuel flow path, the water evaporation and superheating flow path, and the working fluid flow path on the gas turbine side are all carried out simultaneously.

[0010] Specifically, this invention utilizes the waste heat from turbine exhaust for thermal cracking and sensible heat absorption of fuel in the ammonia cracker unit, as well as the latent heat of vaporization and sensible heat absorption of fuel in the liquid ammonia vaporizer unit, and the latent heat of vaporization and superheat absorption of water in the water evaporator unit and the steam superheater unit. This allows liquid ammonia fuel to be converted into a mixed gas of ammonia / hydrogen / nitrogen with higher calorific value and greater sensible heat. Furthermore, the mixing of the mixed gas of ammonia, hydrogen, and nitrogen with superheated steam enables more complete recovery and utilization of the waste heat from turbine exhaust. This not only reduces NOx emissions and unburned ammonia emissions, but also allows the mixed gas of ammonia, hydrogen, nitrogen, and superheated steam to mix better with air, forming a more uniform fuel gas, thereby improving the uniformity and efficiency of combustion.

[0011] Furthermore, by generating electricity through the simultaneous operation of the expander power generation unit and the gas turbine power generation unit, the overall output power and power generation efficiency of the entire system are greatly improved under the current limitations of gas turbine technology, which can save more fuel consumption. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the system module framework of the present invention.

[0013] Figure 2 This is a schematic diagram of the single-unit power generation efficiency of the small gas turbine in Embodiment 1 of the present invention.

[0014] Figure 3 This is a schematic diagram of the power generation efficiency of the small gas turbine composite cycle system according to Embodiment 1 of the present invention. Detailed Implementation

[0015] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0016] like Figure 1As shown, a gas turbine-steam-ammonia hybrid cycle power generation system integrates a liquid ammonia storage tank and pressurization pump, a liquid ammonia vaporizer, an ammonia cracker, a seawater desalination unit and pressurization pump, a water evaporator, a steam superheater, an expander, and a gas turbine into a single cycle. The system includes a liquid ammonia storage tank and pump unit, a liquid ammonia vaporizer unit, an ammonia cracker unit, a seawater desalination unit and pump unit, a water evaporator unit, a steam superheater unit, an expander power generation unit, and a gas turbine power generation unit. The gas turbine exhaust is split into two streams: one stream passes through the ammonia cracker unit, and the other passes through the steam superheater unit. The two streams are then mixed and sequentially pass through the liquid ammonia vaporizer unit and the water evaporator unit for heat exchange and cooling before entering the exhaust system. Liquid ammonia exiting the liquid ammonia storage tank and pump unit passes through the liquid ammonia steam superheater unit. After passing through the ammonia vaporizer and ammonia cracker units, the gas is converted into a mixture of ammonia, hydrogen, and nitrogen. Water, after passing through the seawater desalination unit and pump unit, is converted into superheated steam after passing through the water evaporator and steam superheater units. The mixture of ammonia, hydrogen, and nitrogen is mixed with the superheated steam and then expanded and worked by the expander power generation unit before entering the gas turbine combustion chamber to mix and burn with air. The pressure of the mixture is maintained at a relatively high value not lower than the design pressure of the combustion chamber. Air passes through the intake filtration system and then enters the gas turbine compressor for compression. It then enters the gas turbine combustion chamber to mix and burn with the mixture of ammonia, hydrogen, nitrogen, and steam. The high-temperature and high-pressure flue gas then enters the gas turbine for expansion and work. The total power output of the entire system is the sum of the power outputs of the expander power generation unit and the gas turbine power generation unit. Example 1

[0017] To test the effectiveness of the gas turbine-steam-ammonia hybrid cycle power generation system proposed in this invention, a 1.85MW small gas turbine was selected for gas turbine-steam-ammonia hybrid cycle retrofit and upgrade. Figure 3 As shown.

[0018] like Figure 2 As shown, the gas turbine has a compressor design pressure ratio of 7.5, an isentropic thermal efficiency of 77.1%, a turbine design isentropic thermal efficiency of 91.2%, a generator efficiency of 96.5%, a rotor drive mechanical efficiency of 98%, and a system power generation of 1.852MW. The system power generation efficiency is (gas turbine power generation) / (fuel mass flow rate × fuel lower heating value) = 1.852MW / (0.173kg / s × 47880.7kJ / kg) = 22.4%.

[0019] While maintaining the same component efficiency, the gas turbine plus steam-ammonia hybrid cycle power generation system can be upgraded, such as... Figure 3As shown, the gas turbine exhaust (536℃) is split into two streams. One stream passes through an ammonia cracker unit (ammonia cracking conversion rate can reach over 80%), and the other stream passes through a steam superheater unit. The two streams then mix and successively pass through a liquid ammonia vaporizer unit and a water evaporator unit for heat exchange and cooling before entering the exhaust system. The waste heat from the gas turbine exhaust is mainly used for the thermal cracking and sensible heat absorption of fuel in the ammonia cracker unit, the latent heat of vaporization and sensible heat absorption of fuel in the liquid ammonia vaporizer unit, and the latent heat of water vaporization and superheat absorption of water in the water evaporator and steam superheater units. The remaining waste heat from the gas turbine exhaust can be used for further heat exchange in the heat exchangers before entering the exhaust system, or it can be directly discharged into the exhaust system. After liquid ammonia exits the storage tank (liquid ammonia mass flow rate of 0.46 kg / s, calculated to maintain a constant gas turbine compressor pressure ratio and essentially constant pre-turbine pressure), it is sequentially pressurized by a booster pump (temperature 21℃, pressure 50 bar), passes through a liquid ammonia vaporizer unit, and then an ammonia cracker unit, transforming into a mixture of ammonia, hydrogen, and nitrogen (temperature 518℃, pressure approximately 50 bar). Water exiting the seawater desalination unit is pressurized by a booster pump (water mass flow rate 0.66 kg / s). The mass flow rate of water is 1.12 kg / s, the temperature is 20℃, and the pressure is 50 bar. The water mass flow rate is calculated based on keeping the gas turbine compressor pressure ratio constant and the pressure before turbine operation basically unchanged. After passing through the water evaporator unit and the water steam superheater unit, it is converted into superheated steam (temperature 518℃, pressure approximately 50 bar). The mixture of ammonia, hydrogen, and nitrogen is mixed with the superheated steam and then expanded and does work in the expander power generation unit (total mass flow rate = liquid ammonia mass flow rate + water mass flow rate = 1.12 kg / s, temperature 302℃, pressure 50 bar) before entering the gas turbine combustion chamber to mix and burn with air. After passing through the intake system (temperature 15℃, mass flow rate 10.5 kg / s, pressure 1.013 bar), atmospheric air enters the gas turbine compressor for compression (compressed air temperature 300℃, pressure 7.5 bar). Then, it enters the gas turbine combustion chamber to mix and burn with a mixture of ammonia, hydrogen, nitrogen, and water vapor. The high-temperature, high-pressure flue gas (temperature 953℃, pressure 7.3 bar) then enters the gas turbine for expansion and work. The power output from this expansion (increasing from 5258 kW to 6133 kW, based on the product of the actual inlet and outlet enthalpy drop of the turbine and the flue gas mass flow rate) is used for the gas turbine compressor's compression power consumption (power consumption remains unchanged at 3137 kW, based on the product of the actual inlet and outlet enthalpy drop of the compressor and the air mass flow rate). The remainder is used for power generation by the gas turbine generator.The total power output of the system is the sum of the power of the expander power generation unit (expander efficiency is 85%, output power is 614kW, the output power is obtained by multiplying the product of the actual inlet and outlet enthalpy drop of the expander and the mass flow rate of the working fluid by the generator efficiency) and the gas turbine power generation unit, minus the power consumption of the booster pump and the power consumption of the seawater desalination unit. The total output power is 3.49MW. At this time, the power generation efficiency of the whole system reaches 40.8%, that is, the power generation efficiency of the whole system = (expander power generation + gas turbine power generation - booster pump power consumption - seawater desalination unit power consumption) / (fuel mass flow rate × fuel lower heating value) = 3.49MW / (0.46kg / s × 18.6MJ / kg) = 40.8%, which is much higher than the power generation and efficiency of the gas turbine before the modification.

[0020] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A gas turbine combined with steam and ammonia hybrid cycle power generation system, characterized in that: The system integrates a liquid ammonia storage tank and pressurization pump, liquid ammonia vaporizer, ammonia cracker, seawater desalination unit and pressurization pump, water evaporator, steam superheater, expander and gas turbine into a single cycle. The system includes a liquid ammonia storage tank and pump unit, a liquid ammonia vaporizer unit, an ammonia cracker unit, a seawater desalination unit and pump unit, a water evaporator unit, a steam superheater unit, an expander power generation unit and a gas turbine power generation unit. The exhaust gas from the gas turbine is split into two streams. One stream passes through the ammonia cracker unit, and the other stream passes through the steam superheater unit. The two streams are then mixed and passed through the liquid ammonia vaporizer unit and the water evaporator unit for heat exchange and cooling before entering the exhaust system. After exiting the liquid ammonia storage tank and pump unit, the liquid ammonia passes through the liquid ammonia vaporizer unit and the ammonia cracker unit in sequence, and is then transformed into a mixed gas of ammonia, hydrogen and nitrogen. After passing through the seawater desalination unit and pump unit, the water is converted into superheated steam after passing through the water evaporator unit and the water steam superheater unit. A mixture of ammonia, hydrogen, and nitrogen is mixed with superheated steam, then expanded and does work in the expander power generation unit before entering the gas turbine combustion chamber to mix and burn with air. After passing through the intake filtration system, the air enters the gas turbine compressor for compression, and then enters the gas turbine combustion chamber to mix and burn with a mixture of ammonia, hydrogen, nitrogen and water vapor. The high-temperature and high-pressure flue gas then enters the gas turbine for expansion and does work. The total power output of the system is the sum of the power outputs of the expander power generation unit and the gas turbine power generation unit.

2. The gas turbine plus steam-ammonia hybrid cycle power generation system according to claim 1, characterized in that: The waste heat from the gas turbine exhaust is mainly used for the thermal cracking and sensible heat absorption of fuel in the ammonia cracker unit, as well as the latent heat of vaporization and sensible heat absorption of fuel in the liquid ammonia vaporizer unit, and the latent heat of water vaporization and superheat absorption of water in the water evaporator unit and the steam superheater unit. The remaining waste heat from the gas turbine exhaust can be used for heat exchange in the heat exchanger before entering the exhaust system for exhaust, or it can be directly entered into the exhaust system for exhaust.

3. The gas turbine plus steam-ammonia hybrid cycle power generation system according to claim 1, characterized in that: The work done by turbine expansion is used for the compression work of the gas turbine compressor, and the remainder is used for the power generation of the generator.

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