Gas turbine methanol compound cycle power generation system based on expansion machine and methanol reforming reaction waste heat recovery

Abstract

The invention provides a gas turbine methanol compound cycle power generation system based on an expansion machine and methanol reforming reaction waste heat recovery. A methanol solution storage tank, a pump, a liquid methanol solution gasifier, a gaseous methanol-steam reforming reactor, the expansion machine and a gas turbine are integrated and circulated; exhaust smoke of a gas turbine sequentially passes through the gaseous methanol-steam reforming reactor unit and the liquid methanol solution gasifier unit for heat exchange and cooling and then enters an exhaust system; a liquid methanol solution is discharged from the liquid methanol solution storage tank, sequentially passes through the pressure pump, the liquid methanol solution gasifier unit and the gaseous methanol-steam reforming reactor unit, and then is converted into mixed gas of methanol, hydrogen, carbon dioxide and water; and after pressure reduction and temperature reduction, the gas enters a combustion chamber of the gas turbine to be mixed with air for combustion. The system has the advantages that the methanol reforming reaction hydrogen production technology, the expansion machine technology and the gas turbine cycle are integrated, and efficient power generation is achieved.

Description

Technical Field

[0001] This invention relates to the field of energy and power engineering technology, specifically to a gas turbine methanol combined cycle power generation system based on the waste heat recovery of expander and methanol reforming reaction. 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 in new power systems. Marine gas turbines are thermodynamic engines that use continuously flowing gas as the working fluid. Through a cyclical process of air compression by a compressor, combustion in a combustion chamber, and expansion and work by a gas turbine, they convert the chemical energy of fuel into mechanical work. Their core advantages are: ① Power density and lightweight: At the same power output, their volume is only 1 / 3 to 1 / 5 that of a diesel engine, resulting in significantly reduced weight. This makes them 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 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. Exhaust gas can be purified to meet increasingly stringent ship emission standards. ④ Compact structure and automation: The simplified transmission mechanism facilitates 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: Smooth operation with minimal low-frequency noise components, making it particularly suitable for ships sensitive to acoustic performance.

[0003] Despite their significant advantages, marine gas turbines currently 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 direct propeller driving unsuitable; gearbox reduction is necessary, increasing 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-methanol combined cycle power generation system based on expander and waste heat recovery from methanol reforming reaction. Its core lies in integrating methanol reforming reaction hydrogen production technology, expander technology and gas turbine cycle to achieve high-efficiency power generation.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: A gas turbine-methanol hybrid cycle power generation system based on expander and methanol reforming reaction waste heat recovery integrates methanol solution storage tank and pump, liquid methanol solution vaporizer, gaseous methanol-water vapor reforming reactor, expander and gas turbine into a single cycle to achieve efficient zero-carbon power generation. The system includes a liquid methanol solution storage tank and pump unit, a liquid methanol solution vaporizer unit, a gaseous methanol-water vapor reforming reactor unit, an expander power generation unit and a gas turbine power generation unit. The exhaust gas from the gas turbine passes through a gaseous methanol-water vapor reforming reactor unit and a liquid methanol solution vaporizer unit for heat exchange and cooling before entering the exhaust system. After the liquid methanol solution comes out of the liquid methanol solution storage tank, it passes through the pressurization pump, the liquid methanol solution vaporizer unit, and the gaseous methanol-water vapor reforming reactor unit in sequence, and is transformed into a mixture of methanol, hydrogen, carbon dioxide, and water. Then, it passes through the expander power generation unit to expand and generate electricity, and after depressurization and cooling, it enters the gas turbine combustion chamber to mix and burn with air. After passing through the intake system, the air enters the gas turbine compressor for compression, and then enters the gas turbine combustion chamber to mix and burn with the methanol, hydrogen, carbon dioxide, and water vapor produced by the gaseous methanol-water vapor reforming reaction. 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, "combined" refers to the simultaneous combined work of the expander power generation unit and the gas turbine power generation unit; "cycle" refers to the cycle mode formed by the methanol solution fuel flow path and the gas turbine side working fluid flow path, and the methanol solution fuel flow path and the gas turbine side working fluid flow path occur simultaneously.

[0007] Furthermore, in the liquid methanol solution, the molar ratio of water to methanol is 1.5:1 to 2.0:1.

[0008] Furthermore, the temperature of the mixed gas containing methanol, hydrogen, carbon dioxide, and water after the expander power generation unit expands and does work is maintained below 200°C, which is determined by the temperature resistance level of the existing gas turbine fuel control valve. The pressure of the mixed gas is maintained at a relatively high value that is not lower than the design pressure of the combustion chamber.

[0009] Furthermore, the high-temperature, high-pressure flue gas enters the gas turbine and expands, doing work for the gas turbine compressor to compress the gas, while the remainder is used to generate electricity for the generator.

[0010] Furthermore, the waste heat from the gas turbine exhaust is mainly used for the reaction endothermic heat and sensible heat of the fuel in the gaseous methanol-water vapor reforming reactor unit, as well as the latent heat of vaporization and sensible heat of the fuel in the liquid methanol solution vaporizer unit. Afterward, 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.

[0011] Compared with the prior art, the present invention has the following advantages: This invention discloses a gas turbine methanol combined cycle power generation system based on expander and methanol reforming waste heat recovery, which integrates methanol reforming hydrogen production technology, expander technology and gas turbine cycle to achieve high-efficiency power generation.

[0012] Specifically, this invention aims to address the limitations of existing marine gas turbines, such as insufficient fuel economy and low electrification. It proposes a gas turbine-methanol combined cycle power generation system based on the waste heat recovery of the expander and methanol reforming reaction. The combined cycle 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 jointly formed by the methanol solution fuel flow path and the gas turbine side working fluid flow path, and the methanol solution fuel flow path and the gas turbine side working fluid flow path are carried out simultaneously. First, the waste heat from the turbine exhaust is utilized for the reaction endothermic and fuel sensible heat endothermic of the gaseous methanol-water vapor reforming reactor unit, as well as the latent heat of vaporization and fuel sensible heat endothermic of the liquid methanol solution vaporizer unit. This allows the liquid methanol solution fuel to be converted into a mixture of methanol, hydrogen, carbon dioxide, and water vapor, which have higher calorific value and greater sensible heat. This ensures that the waste heat from the turbine exhaust is fully recovered and utilized. Moreover, the hydrogen and carbon dioxide mixture produced after the gaseous methanol-water vapor reforming reaction can be better mixed with air to form a more uniform fuel gas, thereby improving the uniformity and efficiency of combustion. In addition, by generating electricity simultaneously through the expander power generation unit and the gas turbine power generation unit, the entire system can save more fuel consumption under the same output power demand. Under the limitations of current gas turbine technology, the power generation efficiency of the entire system reaches over 50.20%, which is far higher than the power generation efficiency of other gas turbines of the same power class and higher than the efficiency of gas turbine ammonia combined cycle power generation systems. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the system module framework of the present invention.

[0014] Figure 2 This is a schematic diagram of the power generation efficiency of 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 1 As shown, a gas turbine-methanol hybrid cycle power generation system based on expander and methanol reforming reaction waste heat recovery integrates a methanol solution storage tank and pump, a liquid methanol solution vaporizer, a gaseous methanol-water vapor reforming reactor, an expander, and a gas turbine into a single cycle, achieving efficient zero-carbon power generation. The system includes a liquid methanol solution storage tank and pump unit, a liquid methanol solution vaporizer unit, a gaseous methanol-water vapor reforming reactor unit, an expander power generation unit, and a gas turbine power generation unit. The gas turbine exhaust gas passes through the gaseous methanol-water vapor reforming reactor unit and the liquid methanol solution vaporizer unit for heat exchange and cooling before entering the exhaust system. The liquid methanol solution exits from the liquid methanol solution storage tank. After passing through a pressurization pump, a liquid methanol solution vaporizer unit, and a gaseous methanol-water vapor reforming reactor unit, the gas is transformed into a mixture of methanol, hydrogen, carbon dioxide, and water. This mixture then passes through an expander power generation unit to generate electricity and is depressurized and cooled before entering the gas turbine combustion chamber to mix and burn with air. The air passes through the intake system and enters the gas turbine compressor for compression. It then enters the gas turbine combustion chamber to mix and burn with the mixture of methanol, hydrogen, carbon dioxide, and water vapor generated from the gaseous methanol-water vapor reforming reaction. The high-temperature, 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-methanol combined cycle power generation system based on expander and methanol reforming waste heat recovery proposed in this invention, a gas turbine-methanol combined cycle power generation system with a system power output of 2.4355MW based on expander and methanol reforming waste heat recovery was designed, as follows: Figure 2 As shown.

[0018] The gas turbine compressor is an axial-flow compressor with a design pressure ratio of 15.56 and an isentropic thermal efficiency of 88%. The turbine is also an axial-flow turbine with a design isentropic thermal efficiency of 90%. The combustion chamber has a design combustion efficiency of 99.8%. The turbine exhaust (temperature 605.0℃, pressure 1.05259 bar) passes sequentially through a gaseous methanol-steam reforming reactor unit (using a Cu-based catalyst, achieving a methanol conversion rate of over 75%) and a liquid methanol solution vaporizer unit for heat exchange and cooling before entering the exhaust system. The waste heat from the gas turbine exhaust is mainly used for the reaction endothermic heat and fuel sensible heat endothermic heat of the gaseous methanol-steam reforming reactor unit, as well as the vaporization latent heat and fuel sensible heat endothermic heat of the liquid methanol solution vaporizer unit. The remaining waste heat from the gas turbine exhaust can be used for further heat exchange in the heat exchanger before entering the exhaust system, or it can be directly discharged into the exhaust system. After the liquid methanol solution (molar ratio of water to methanol is 1.5:1) comes out of the liquid methanol solution storage tank (methanol solution mass flow rate 0.4239 kg / s), it is pressurized by a pressurization pump (temperature 20℃, pressure 100 bar), then passes through a liquid methanol solution vaporizer unit, and a gaseous methanol-water vapor reforming reactor unit, and is transformed into a mixture of methanol, hydrogen, carbon dioxide, and water vapor (temperature 587.1℃, pressure approximately 100 bar). After passing through an expander power generation unit to expand and generate electricity, and after depressurization and cooling (temperature 200℃, pressure approximately 20 bar), it enters the gas turbine combustion chamber to mix and burn with air. After passing through the intake system (temperature 15℃, mass flow rate 4.090 kg / s, pressure 1.013 bar), atmospheric air enters the gas turbine compressor for compression (compressed air temperature 392.9℃, pressure 15.60979 bar). Then, it enters the gas turbine combustion chamber and is mixed with and combusted with a mixture of methanol, hydrogen, carbon dioxide, and water vapor produced by the gaseous methanol-water vapor reforming reaction. The high-temperature, high-pressure flue gas (temperature 1200℃, pressure 15.12877 bar) then enters the gas turbine for expansion and work. The turbine expansion work (output power 3656.7 kW) is used for compression in the gas turbine compressor (power consumption 1608.40 kW), with the remainder used for power generation by the gas turbine generator. The total power output of the system is 2.4355MW, consisting of the power output of the expander generator unit (expander efficiency of 85%) and the gas turbine generator unit (gas turbine generator efficiency of 0.982 and mechanical transmission efficiency of 0.995). At this point, the overall system power generation efficiency reaches 50.20%, which is calculated as follows: Overall system power generation efficiency = (expander power generation + gas turbine power generation) / (fuel mass flow rate × fuel lower heating value) = 2.4355MW / (0.4239kg / s × 21.10 * 0.5424MJ / kg) = 50.20%. This is significantly higher than the power generation efficiency of other gas turbines of the same power rating and also higher than the efficiency of the gas turbine ammonia combined cycle power generation system.

[0019] 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-methanol combined cycle power generation system based on waste heat recovery from expander and methanol reforming reaction, characterized in that: The system integrates a methanol solution storage tank and pump, a liquid methanol solution vaporizer, a gaseous methanol-water vapor reforming reactor, an expander, and a gas turbine into a single cycle. The system includes a liquid methanol solution storage tank and pump unit, a liquid methanol solution vaporizer unit, a gaseous methanol-water vapor reforming reactor unit, an expander power generation unit, and a gas turbine power generation unit. The exhaust gas from the gas turbine passes through a gaseous methanol-water vapor reforming reactor unit and a liquid methanol solution vaporizer unit for heat exchange and cooling before entering the exhaust system. After the liquid methanol solution comes out of the liquid methanol solution storage tank, it passes through the pressurization pump, the liquid methanol solution vaporizer unit, and the gaseous methanol-water vapor reforming reactor unit in sequence, and is transformed into a mixture of methanol, hydrogen, carbon dioxide, and water. Then, it passes through the expander power generation unit to expand and generate electricity, and after depressurization and cooling, it enters the gas turbine combustion chamber to mix and burn with air. After passing through the intake system, the air enters the gas turbine compressor for compression, and then enters the gas turbine combustion chamber to mix and burn with the methanol, hydrogen, carbon dioxide, and water vapor produced by the gaseous methanol-water vapor reforming reaction. 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-methanol combined cycle power generation system based on expander and methanol reforming reaction waste heat recovery as described in claim 1, characterized in that: In a liquid methanol solution, the molar ratio of water to methanol is 1.5:1 to 2.0:

1.

3. The gas turbine-methanol combined cycle power generation system based on expander and methanol reforming reaction waste heat recovery according to claim 1, characterized in that: The temperature of the mixed gas containing methanol, hydrogen, carbon dioxide, and water after the expander power generation unit expands and does work is maintained below 200°C.

4. The gas turbine-methanol combined cycle power generation system based on expander and methanol reforming reaction waste heat recovery as described in claim 1, characterized in that: The high-temperature, high-pressure flue gas enters the gas turbine and expands, doing work for the gas turbine compressor. The remaining power is used to generate electricity for the generator.

5. A gas turbine-methanol combined cycle power generation system based on waste heat recovery from expander and methanol reforming reaction as described in claim 1, characterized in that: The waste heat from the gas turbine exhaust is mainly used for the reaction endothermic heat and fuel sensible heat absorption of the gaseous methanol-water vapor reforming reactor unit, as well as the latent heat of vaporization and fuel sensible heat absorption of the liquid methanol solution vaporizer unit. The remaining waste heat from the gas turbine exhaust can then 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.

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