Combustion gas turbine methanol compound cycle power generation system

Abstract

The invention provides a gas turbine methanol compound cycle power generation system. The gas turbine methanol compound cycle power generation system comprises a liquid methanol storage tank, a pump unit, a liquid methanol gasifier unit, a gaseous methanol cracker unit, an expansion machine power generation unit and a gas turbine power generation unit, exhaust smoke of the gas turbine sequentially passes through the gaseous methanol cracker unit and the liquid methanol gasifier unit to be subjected to heat exchange and cooling and then enters the exhaust system. Liquid methanol is discharged from a liquid methanol storage tank, sequentially passes through a booster pump, a liquid methanol gasifier unit and a gaseous methanol cracker unit and then is converted into mixed gas of methanol, hydrogen and carbon monoxide, and the mixed gas is expanded by an expansion machine power generation unit to do work and then enters a combustion chamber of a gas turbine to be mixed with air for combustion. The system has the advantages that the methanol cracking hydrogen production technology, the expansion machine technology and the gas turbine cycle are integrated, and efficient low-carbon power generation is achieved.

Description

Technical Field

[0001] This invention relates to the field of energy and power engineering technology, and specifically to a gas turbine methanol combined 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.

[0003] Marine gas turbines are thermal 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 by a gas turbine, they convert the chemical energy of fuel into mechanical work. Their core advantages are: ① Power density and lightweight: With the same power output, their volume is only 1 / 3 to 1 / 5 that of a diesel engine, resulting in significant weight reduction. 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. Short switching time from cold standby to full load makes them 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: Simplified transmission mechanisms facilitate 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 them particularly suitable for ships sensitive to acoustic performance.

[0004] 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

[0005] To overcome the limitations of current marine gas turbines in terms of insufficient fuel economy and low electrification, this invention proposes a gas turbine methanol combined cycle power generation system. Its core lies in integrating methanol cracking hydrogen production technology, expander technology and gas turbine cycle to achieve high-efficiency and low-carbon power generation.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A gas turbine-methanol combined cycle power generation system integrates a liquid methanol storage tank and pump, a liquid methanol vaporizer, a gaseous methanol cracker, an expander, and a gas turbine into a single cycle to achieve high-efficiency and low-carbon power generation. The system includes a liquid methanol storage tank and pump unit, a liquid methanol vaporizer unit, a gaseous methanol cracker 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 cracker unit and a liquid methanol vaporizer unit for heat exchange and cooling before entering the exhaust system. After liquid methanol comes out of the liquid methanol storage tank, it passes through the pressurization pump, the liquid methanol vaporizer unit, and the gaseous methanol cracker unit in sequence, and is transformed into a mixture of methanol, hydrogen and carbon monoxide. Then, it passes through the expander power generation unit to expand and generate electricity, and after depressurization and cooling, it enters the combustion chamber of the gas turbine 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 mixture of methanol, hydrogen and carbon monoxide generated by the thermal cracking of gaseous methanol. 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.

[0007] Furthermore, "compound" 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 fuel flow path and the gas turbine side working fluid flow path, and the methanol fuel flow path and the gas turbine side working fluid flow path occur simultaneously.

[0008] Furthermore, the temperature of the mixed gas containing methanol, hydrogen, and carbon monoxide after the expander power generation unit expands and performs 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 lower value 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 thermal cracking of the gaseous methanol cracker unit and the sensible heat absorption of the fuel, as well as the latent heat of vaporization and the sensible heat absorption of the fuel in the liquid methanol 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, which integrates methanol cracking hydrogen production technology, expander technology and gas turbine cycle to achieve high-efficiency and low-carbon 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. 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 formed by the methanol fuel flow path and the working fluid flow path on the gas turbine side, and the methanol fuel flow path and the working fluid flow path on the gas turbine side are carried out simultaneously. First, the waste heat from turbine exhaust is utilized for the thermal cracking and sensible heat absorption of the gaseous methanol cracker unit, as well as the latent heat of vaporization and sensible heat absorption of the fuel in the liquid methanol vaporizer unit. This allows the liquid methanol fuel to be converted into a mixture of methanol, hydrogen, and carbon monoxide with higher calorific value and greater sensible heat, resulting in more efficient recovery and utilization of the turbine exhaust waste heat. Furthermore, the hydrogen and carbon monoxide mixture produced after gaseous methanol cracking can mix better with air, forming a more uniform fuel gas, thereby improving combustion uniformity and efficiency. In addition, by having both the expander power generation unit and the gas turbine power generation unit generate electricity simultaneously, the entire system can save more fuel consumption for the same output power requirement. Under the limitations of current gas turbine technology, the overall system power generation efficiency reaches over 46.6%, far exceeding the power generation efficiency of other gas turbines of the same power class, second only to the efficiency of gas turbine-ammonia combined cycle power generation systems, demonstrating great potential for widespread application. 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 the system in 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-methanol combined cycle power generation system integrates a liquid methanol storage tank and pump, a liquid methanol vaporizer, a gaseous methanol cracker, an expander, and a gas turbine into a single cycle to achieve high-efficiency, low-carbon power generation. The system includes a liquid methanol storage tank and pump unit, a liquid methanol vaporizer unit, a gaseous methanol cracker unit, an expander power generation unit, and a gas turbine power generation unit. Gas turbine exhaust gas passes through the gaseous methanol cracker unit and the liquid methanol vaporizer unit for heat exchange and cooling before entering the exhaust system. Liquid methanol exiting the liquid methanol storage tank passes through a pressurization pump and a liquid methanol... After passing through the gasifier unit and the gaseous methanol cracker unit, the gas is converted into a mixture of methanol, hydrogen, and carbon monoxide. This mixture then passes through the expander power generation unit, where it expands 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, and carbon monoxide generated from the thermal cracking of gaseous methanol. The high-temperature, high-pressure flue gas then enters the gas turbine for expansion and to generate electricity. 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 proposed in this invention, a gas turbine-methanol combined cycle power generation system with a system power output of 2MW was designed, such as... Figure 2 As shown.

[0018] The gas turbine compressor is an axial-flow compressor with a design pressure ratio of 17 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 565.2℃, pressure 1.05259 bar) passes sequentially through a gaseous methanol cracker unit (using a Cu-based catalyst, achieving a methanol cracking conversion rate of over 75%) and a liquid methanol 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 thermal cracking of the gaseous methanol cracker unit and the absorption of sensible heat from the fuel, as well as the latent heat of vaporization and the absorption of sensible heat from the fuel in the liquid methanol vaporizer unit. The remaining waste heat from the gas turbine exhaust can either be used for further heat exchange in the heat exchanger before entering the exhaust system or can be directly discharged into the exhaust system. After liquid methanol exits the liquid methanol storage tank (methanol mass flow rate 0.2033 kg / s), it is pressurized by a pressurization pump (temperature 20℃, pressure 100 bar), then passes through a liquid methanol vaporizer unit and a gaseous methanol cracker unit, and is transformed into a mixture of methanol, hydrogen and carbon monoxide (temperature 547.2℃, pressure approximately 100 bar). After passing through an expander power generation unit, it expands to generate electricity and is depressurized and cooled (temperature 200℃, pressure approximately 20 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 4.6475 kg / s, pressure 1.013 bar), atmospheric air enters the gas turbine compressor for compression (compressed air temperature 409.9℃, pressure 17.0544 bar). Then, it enters the gas turbine combustion chamber and is mixed with and combusted with a mixture of methanol, hydrogen, and carbon monoxide generated from the thermal decomposition of gaseous methanol. The high-temperature, high-pressure flue gas (temperature 1200℃, pressure 16.52886 bar) then enters the gas turbine for expansion and power generation. The power generated by turbine expansion (output power 3800.5 kW) is used for compression in the gas turbine compressor (power consumption 1912.88 kW), while the remainder is used for power generation by the gas turbine generator. The total power output of the system is 2MW, 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 46.6%, 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) = 2MW / (0.2033kg / s × 21.1MJ / kg) = 46.6%. This efficiency is significantly higher than that of other gas turbines of the same power rating and is second only to 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, characterized in that: The system integrates a liquid methanol storage tank and pump, a liquid methanol vaporizer, a gaseous methanol cracker, an expander, and a gas turbine into a single cycle. The system includes a liquid methanol storage tank and pump unit, a liquid methanol vaporizer unit, a gaseous methanol cracker 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 cracker unit and a liquid methanol vaporizer unit for heat exchange and cooling before entering the exhaust system. After liquid methanol comes out of the liquid methanol storage tank, it passes through the pressurization pump, the liquid methanol vaporizer unit, and the gaseous methanol cracker unit in sequence, and is transformed into a mixture of methanol, hydrogen and carbon monoxide. Then, it passes through the expander power generation unit to expand and generate electricity, and after depressurization and cooling, it enters the combustion chamber of the gas turbine 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 mixture of methanol, hydrogen and carbon monoxide generated by the thermal cracking of gaseous methanol. 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 according to claim 1, characterized in that: The temperature of the mixed gas containing methanol, hydrogen, and carbon monoxide after the expander power generation unit expands and does work is maintained below 200°C.

3. The gas turbine-methanol combined cycle power generation system according to 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.

4. The gas turbine-methanol combined 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 of the gaseous methanol cracker unit and the sensible heat absorption of the fuel, as well as the latent heat of vaporization and the sensible heat absorption of the fuel in the liquid methanol vaporizer 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.

Images