Pure oxygen combustion three-fluid gas turbine for power generation

Abstract

The invention provides a pure oxygen combustion three-fluid gas turbine for power generation, which is characterized in that a combustion chamber inlet is provided with a three-fluid combustor for respectively controlling fuel gas, oxygen and circulating gas as required, and combustion chamber outlets are uniformly distributed at the rear end of a turbine chamber and respectively form an angle of 0-90 degrees with the axial direction and the radial direction of the turbine chamber; a rotating shaft is mounted in the turbine chamber along the central axis through a bearing, the rotating shaft is provided with 2-9 stages of turbine blades, a circulating gas cooling channel is formed in the center of the rotating shaft and is communicated with circulating gas cooling channels in the turbine blades of the first 1-7 stages, and circulating gas cooling holes distributed in a matrix are formed in the surfaces of the turbine blades of the first 1-7 stages; stator blades are arranged on the inner wall of a turbine chamber, the stator blades and turbine blades are arranged at intervals, circulating gas cooling channels are formed in the first 1-7 stages of stator blades and communicated with the circulating gas cooling channel in the turbine chamber, and circulating gas cooling holes distributed in a matrix mode are formed in the surfaces of the stator blades. A diffuser and a heat exchanger are sequentially arranged at the front end of the turbine chamber, and a circulating air seal box and a generator system are sequentially arranged on the outer rotating shaft at the rear end of the turbine chamber.

Description

1. Technical Field

[0001] The present invention relates to the technical field of gas turbines, and in particular to a structure of a gas turbine for power generation. 2. Background Technology

[0002] The huge gas turbine is recognized as the most difficult mechanical equipment in the world to manufacture. It is known as the "crown jewel of the manufacturing industry". It requires both high efficiency and economic benefits. The initial temperature of the gas and the compression ratio of the compressor are the two main factors affecting the efficiency of the gas turbine. Increasing the initial temperature of the gas and the corresponding compression ratio can significantly improve the efficiency of the gas turbine.

[0003] In the late 1970s, the compression ratio reached a maximum of 31; the initial temperature of the gas in industrial and marine gas turbines reached a maximum of about 1200°C, and that of aviation gas turbines exceeded 1350°C. General gas turbines are divided into four grades: E-class, operating temperature is about 1200°C, F-class, operating temperature is about 1400°C, G / H-class, operating temperature is about 1500°C, J-class, operating temperature is about 1600°C. The higher the inlet temperature of the gas turbine, the higher the grade and the higher the thermal efficiency. At present, the mainstream heavy-duty gas turbines are divided into E-class, F-class, and H-class. The international advanced gas turbines have developed to the H-class with a rated output power of more than 400MW. At present, my country has made great breakthroughs in single core technologies such as improving the cooling technology of turbine blades and developing high-temperature materials that can withstand higher temperatures, and is at the international leading level.

[0004] However, the working process of a traditional gas turbine is that the compressor continuously inhales air from the atmosphere and compresses it; part of the compressed air enters the combustion chamber, mixes with the injected fuel and burns to become high-temperature combustion gas, which then flows into the gas turbine to expand and work, driving the turbine impeller to rotate with the compressor impeller; the working capacity of the heated high-temperature combustion gas is significantly improved, so while the gas turbine drives the compressor, there is still surplus work as the output mechanical work of the gas turbine. When the gas turbine starts from a standstill, it needs to be driven by the starter to rotate, and the starter is not disengaged until it is accelerated to be able to run independently. However, since the air with a high compression ratio needs to be divided into three parts of combustion air, turbine blade cooling air, and stationary blade cooling air through a complex air flow channel according to a specific flow ratio and pressure, the high-precision and high-difficulty system structure forward design technology and experience of the compressor with fewer stages and higher compression ratio, the compressor-combustion chamber-turbine chamber gas turbine has become the core problem of the technical blockade of foreign companies. Chinese companies can only use the processing method to complete manufacturing and sales, but cannot participate in joint research and development, let alone get involved in the more profitable gas turbine service link.

[0005] Steam cooling was a revolutionary technology for H-class gas turbines at the time. It was first proposed by GE in the United States in the 1990s, which is to use steam instead of air to cool the turbine rotor blades. This cooling technology is extremely efficient and can increase the inlet temperature of the first-stage turbine blades by about 110°C under the condition of the same combustion chamber outlet temperature, while the improvement of the metal material itself can generally only increase it by 8°C. Unfortunately, due to the overly complex structure of the steam cooling system in actual commercial operations, and the slow start-up of the steam system affecting the peak-shaving performance of the gas turbine, the major gas turbine manufacturers were forced to choose air cooling in actual products. There is an urgent need to apply steam cooling technology in the development of the next generation of heavy-duty gas turbines.

[0006] In addition, the design structure of most gas turbines is a direct evolution of aircraft jet engines. The turbine chamber, combustion chamber, compressor, generator, etc. are arranged axially and horizontally, which has strict requirements on the temperature resistance of the central axis and the verticality of processing and use. It requires a complex device consisting of rotating parts, bearings, seals, lubricating oil systems and cutting-edge electronic control equipment. Due to the technical complexity, most users have to rely on the original equipment manufacturer to complete repairs, overhauls and advanced maintenance. Since the airflow direction of the coaxial compressor cannot be adjusted, the high-temperature and high-speed direct current gas in the combustion chamber needs to be guided by fixed static blades to become a rotating airflow, which consumes energy. At the same time, the gas turbine used for power generation does not require compact space layout like aircraft jet engines. Therefore, based on the fluid characteristics, developing a gas turbine structure with high efficiency, simple structure, low cost, easy manufacturing and assembly, and low maintenance and replacement costs is one of the problems that need to be solved in the current gas turbine structure design.

[0007] Due to the reality of my country's fossil energy endowment of "rich in coal, less oil and poor gas" and the price ratio of coal, oil and natural gas of the same calorific value of about 1:7:3, coal-fired power has determined the bottom-line guarantee and peak-shaving role in my country's future low-carbon electrification energy system. It is also the safest and most economical energy in my country, and the key and focus of building a safe, clean, efficient and low-carbon new energy system. Integrated coal gasification combined cycle power generation (IGCC) technology is regarded as a subversive and transformative technology for clean and efficient utilization of coal. It has the potential to break through the resource utilization, technology, economy, conventional pollutant removal and CO2 removal of coal direct combustion power generation technology. 2 Congenital defects in emission reduction and other aspects are the main technologies of coal-fired power generation in the future. The new IGCC technology, characterized by pure oxygen gasification of pulverized coal, pure oxygen combustion power generation with gas, steam cycle temperature control, and liquid nitrogen expansion power generation, can achieve full carbon recovery, deep peak regulation, and water-saving and high efficiency. It is expected to achieve near-zero emissions of coal-fired power generation, power plant efficiency of more than 75%, and greatly reduce coal consumption for power generation. Once a breakthrough is achieved, it will be a clean coal-fired power technology with revolutionary significance, but it is urgently necessary to develop a three-fluid gas turbine suitable for pure oxygen combustion for power generation. III. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the existing gas turbine structure technology and provide a pure oxygen combustion three-fluid gas turbine for power generation. The gas, oxygen and water vapor in the combustion chamber are controlled separately on demand, and no complicated air flow channel design and flow control are required. The structure is simple, the cost is low, and the manufacturing and assembly are easy. 2 It lays the foundation for low-energy recovery; for the first time, low-energy water vapor circulation is used to control the combustion temperature, while the cooling of the dynamic and static blades is also low-cost water vapor cooling. The same high-temperature material can increase the initial combustion temperature by more than 100°C (relative to a gas turbine level), solving the problem of water vapor cooling of traditional gas turbines; the coaxially arranged compressor is cancelled, the length of the rotating shaft is greatly reduced and can be arranged vertically, which reduces the difficulty and cost of manufacturing and assembly, and the maintenance and replacement costs are low; liquid pure oxygen and water are used for low-energy pumping and pressurization, and medium-pressure fuel gas is used for low-energy compression, which greatly improves the compression ratio of the gas turbine and greatly improves the work efficiency; the high-temperature flue gas is sprayed into the turbine chamber at high speed in a tangential direction without the need for flow direction conversion, making full use of the momentum of high-speed fuel gas to further improve the power generation efficiency.

[0009] The technical solution of the present invention:

[0010] The present invention provides a pure oxygen combustion three-fluid gas turbine for power generation, which is composed of a turbine chamber, a combustion chamber, a rotating shaft, turbine blades, bearings, a heat exchanger, a circulating gas sealing box, a generator system, stationary blades, insulation materials, a holding ring, a three-fluid nozzle, a diffuser, and a flue gas outlet. The inlet of the combustion chamber is provided with a three-fluid burner for controlling the fuel gas, oxygen and circulating gas respectively as required, and the outlet of the combustion chamber is evenly arranged on the circumference of the rear end of the turbine chamber, and is 0-90 degrees with the axial direction and radial direction of the turbine chamber respectively; a rotating shaft is installed inside the turbine chamber along the central axis through a bearing, and the rotating shaft is provided with 2-9 stages of turbine blades, and a circulating gas cooling channel is provided at the center of the rotating shaft and is connected with the turbine blades of the first 1-7 stages. The circulating air cooling channels inside the turbine blades are interconnected, and the surfaces of the first 1-7 stages of turbine blades are provided with circulating air cooling holes distributed in a matrix; stationary blades are provided on the inner wall of the turbine chamber and are arranged at intervals with the turbine blades, and the insides of the first 1-7 stages of stationary blades are provided with circulating air cooling channels and are connected to the circulating air cooling channels in the turbine chamber, and the surfaces of the stationary blades are provided with circulating air cooling holes distributed in a matrix; a diffuser, a heat exchanger and a flue gas exhaust port are sequentially provided at the front end of the turbine chamber to diffuse and decelerate the flue gas to reduce the outlet speed loss; a circulating air sealing box and a generator system are sequentially provided on the outer rotating shaft at the rear end of the turbine chamber, and the circulating air sealing box is connected to the circulating air cooling channel at the center of the rotating shaft.

[0011] The rotating shaft of the pure oxygen combustion three-fluid gas turbine for power generation is arranged vertically or horizontally, preferably vertically.

[0012] The circulating gas is water vapor or CO 2 , preferably water vapor.

[0013] The combustion chamber outlet is rectangular or circular, preferably a flat rectangular outlet.

[0014] The bearing is one of a sliding bearing, a rolling bearing, an air bearing and a magnetic bearing, and is preferably an air bearing.

[0015] The stationary blades are mounted on a holding ring, which is in turn mounted on the inner wall of the turbine chamber. Insulating materials and circulating air cooling channels are arranged in sequence between the inner wall of the turbine chamber and the holding ring to ensure that the operating temperature of the turbine chamber is low.

[0016] The heat exchanger is one of a braided packing heat exchanger, a tube-sheet heat exchanger, a spiral plate heat exchanger, a flat plate heat exchanger and a plate-fin heat exchanger, preferably a braided packing heat exchanger. IV. Description of the drawings

[0017] Figure 1 It is a schematic diagram of the pure oxygen combustion three-fluid gas turbine for power generation according to the present invention.

[0018] Attached Figure 1 The drawings are as follows: 1. turbine chamber, 2. combustion chamber, 3. rotating shaft, 4. turbine blades, 5. bearings, 6. heat exchanger, 7. circulating gas sealing box, 8. generator system, 9. stationary blades, 10. insulation material, 11. holding ring, 12. three-fluid nozzle, 13. diffuser, A. circulating gas inlet, B. oxygen inlet, C. fuel gas inlet V. Specific implementation methods

[0019] The present invention is described in detail below in conjunction with the accompanying drawings:

[0020] The present invention provides a pure oxygen combustion three-fluid gas turbine for power generation, which comprises a turbine chamber (1), a combustion chamber (2), a rotating shaft (3), turbine blades (4), bearings (5), a heat exchanger (6), a circulating gas sealing box (7), a generator system (8), stationary blades (9), a heat insulation material (10), a holding ring (11), a three-fluid nozzle (12), a diffuser (13), and a smoke exhaust port (14). The inlet of the combustion chamber (2) is provided with a three-fluid burner (12) for controlling the fuel gas, oxygen and circulating gas respectively as required. The outlet of the combustion chamber (2) is evenly arranged along the circumference of the rear end of the turbine chamber (1) and is 0-90 degrees with the axial and radial directions of the turbine chamber (1). A rotating shaft (3) is installed inside the turbine chamber (1) along the central axis through a bearing (5). The rotating shaft (3) is provided with 2-9 stage turbine blades (4). The center of the rotating shaft (3) is provided with a circulating gas outlet (14). The ring air cooling channel is connected to the circulating air cooling channel inside the turbine blades (4) of the first 1-7 stages, and the surfaces of the turbine blades (4) of the first 1-7 stages are provided with circulating air cooling holes distributed in a matrix; stationary blades (9) are provided on the inner wall of the turbine chamber (1) and are arranged at intervals with the turbine blades (4), and the circulating air cooling channel is provided inside the stationary blades of the first 1-7 stages and is connected to the circulating air cooling channel inside the turbine chamber, and the surfaces of the stationary blades (9) are provided with circulating air cooling holes distributed in a matrix; a diffuser (13), a heat exchanger (6) and a flue gas outlet (14) are provided in sequence at the front end of the turbine chamber (1) to reduce the speed of the flue gas by pressure expansion and reduction to reduce the outlet speed loss; a circulating air sealing box (7) and a generator system (8) are provided in sequence on the outer rotating shaft (3) at the rear end of the turbine chamber (1), and the circulating air sealing box (7) is connected to the circulating air cooling channel at the center of the rotating shaft (3).

[0021] The pure oxygen combustion three-fluid gas turbine for power generation is arranged vertically or horizontally, preferably vertically.

[0022] The circulating gas is water vapor or CO 2 , preferably water vapor.

[0023] The outlet of the combustion chamber (2) is rectangular or circular, preferably a flat rectangular outlet.

[0024] The bearing (5) is one of a sliding bearing, a rolling bearing, an air bearing and a magnetic suspension bearing, preferably an air bearing.

[0025] The stationary blades (9) are mounted on a holding ring (11), which is in turn mounted on the inner wall of a turbine chamber (1). A heat insulating material (10) and a circulating air cooling channel are arranged in sequence between the inner wall of the turbine chamber (1) and the holding ring (9), thereby ensuring that the operating temperature of the turbine chamber (1) is relatively low.

[0026] The heat exchanger (6) is one of a braided packing type heat exchanger, a tube-sheet type heat exchanger, a spiral plate type heat exchanger, a flat plate type heat exchanger and a plate-fin type heat exchanger, preferably a braided packing type heat exchanger.

[0027] In specific operation, when the pure oxygen combustion three-fluid gas turbine for power generation is working, high-pressure circulating gas is controlled from circulating gas inlet A, high-pressure oxygen is controlled from oxygen inlet B, and pressurized fuel gas is controlled from fuel gas inlet C to be respectively introduced into the three-fluid burner (12) for mixed combustion as required, thereby solving the problem of difficult control of the mixing ratio of fuel gas and combustion-supporting air in traditional two-fluid gas turbines, high-precision and high-difficulty system design of air flow channel design and manufacturing, avoiding the problem of using compressors and starters and their starting and disconnection problems, and the flow rate of each fluid in the three-fluid burner (12) is easy to adjust; the high-temperature and high-speed fuel gas generated is sprayed into the turbine chamber (1) along the circumference of the rear end of the turbine chamber (1) in a tangential direction, directly pushing the turbine blades (4) to drive the rotating shaft to rotate at high speed, and the high-frequency current generated by the coaxial high-speed rotating generator system (8) is converted into 50HZ or 60HZ current for external transmission through the frequency conversion system; the high-temperature flue gas flowing out from the center of the turbine chamber (1) is first mixed with water or supercritical CO in a heat exchanger. 2 Heat exchange is used to recover energy and use it for waste heat power generation, and then the flue gas is discharged to recover CO 2 The high-pressure circulating gas is divided into three parts as needed, and respectively introduced into the three-fluid nozzle (12) for temperature adjustment, the turbine blade (4) for cooling and protection, and the stationary blade (9) for cooling and cooling, thus avoiding the difficulty of using complex flow channels to control the flow of compressed air in traditional gas turbines, and the temperature of each component can be easily adjusted. After the high-pressure circulating gas is preferably water vapor, the water vapor circulation controls the combustion temperature while the dynamic and static blades are cooled by water vapor, which solves the difficulty of traditional two-fluid gas turbines to adopt revolutionary water vapor cooling technology. The same high-temperature material is used to increase the initial combustion temperature by more than 100°C, allowing my country to improve the gas turbine by 1 to 3 levels on the basis of the existing high-temperature material breakthrough, and it is very easy to develop J-class or higher gas turbines; low-compression ratio deep-cold air separation, low-energy high-pressure pumping of liquid oxygen, no need to use compressors with fewer stages and higher compression ratios, and the medium-pressure fuel gas can be further compressed with low energy consumption, which can easily make my country's gas turbines break through the dilemma of the compression ratio being difficult to reach 31, and easily double the compression ratio of the gas turbine, which is expected to reach 60-100, and the work efficiency is increased by more than 40%. For power generation using pure oxygen combustion, deep-cold air separation is required. It is more reasonable to separate the compressor and the gas turbine. The length of the rotating shaft is shortened by more than 60% and can be arranged vertically, which further reduces the difficulty of gas turbine design, manufacturing and assembly. The manufacturing cost of the gas turbine is reduced by 50%, and the maintenance and replacement costs are lower.

[0028] The comprehensive adoption of the above measures has greatly reduced the difficulty of the forward design and manufacturing of the structure of the pure oxygen combustion three-fluid gas turbine system for power generation, and the flow and pressure of each fluid can be freely regulated, the heat and momentum can be reasonably utilized, the power generation efficiency is higher, the structure is simpler, the equipment volume is reduced by more than 50%, the cost is low, the manufacturing and assembly are easy, the maintenance and replacement costs are low, and the generation of NOx and CO in the flue gas is avoided. 2The recovered energy consumption and cost are reduced by more than 80%, thus enabling my country to overtake and take the lead in the design and manufacturing of gas turbines for power generation.

Claims

1. A pure oxygen combustion three-fluid gas turbine for power generation, which is composed of a turbine chamber, a combustion chamber, a rotating shaft, turbine blades, bearings, a heat exchanger, a circulating gas sealing box, a generator system, stationary blades, insulation materials, a holding ring, a three-fluid nozzle, a diffuser, and a flue gas outlet, and is characterized in that A three-fluid burner for controlling the fuel gas, oxygen and circulating gas as required is arranged at the inlet of the combustion chamber, and the outlet of the combustion chamber is evenly arranged on the circumference of the rear end of the turbine chamber, and is 0-90 degrees with the axial and radial directions of the turbine chamber respectively; a rotating shaft is installed inside the turbine chamber along the central axis through a bearing, and the rotating shaft is provided with 2-9 stages of turbine blades, and a circulating gas cooling channel is provided at the center of the rotating shaft and is connected with the circulating gas cooling channel inside the turbine blades of the first 1-7 stages, and the surfaces of the turbine blades of the first 1-7 stages are provided with circulating gas cooling holes distributed in a matrix; stationary blades are provided on the inner wall of the turbine chamber and are arranged at intervals with the turbine blades, and the inside of the stationary blades of the first 1-7 stages is provided with circulating gas cooling channels and is connected with the circulating gas cooling channels in the turbine chamber, and the surfaces of the stationary blades are provided with circulating gas cooling holes distributed in a matrix; a diffuser, a heat exchanger and a flue gas outlet are arranged in sequence at the front end of the turbine chamber, so that the flue gas is diffused and decelerated to reduce the outlet speed loss; a circulating gas sealing box and a generator system are arranged in sequence on the outer rotating shaft at the rear end of the turbine chamber, and the circulating gas sealing box is connected with the circulating gas cooling channel at the center of the rotating shaft.

2. The pure oxygen combustion three-fluid gas turbine for power generation according to claim 1, characterized in that The rotating shaft of the pure oxygen combustion three-fluid gas turbine for power generation is arranged vertically or horizontally, preferably vertically.

3. The pure oxygen combustion three-fluid gas turbine for power generation according to claim 1, characterized in that The circulating gas is water vapor or CO2, preferably water vapor.

4. The pure oxygen combustion three-fluid gas turbine for power generation according to claim 1, characterized in that The combustion chamber outlet is rectangular or circular, preferably a flat rectangular outlet.

5. The pure oxygen combustion three-fluid gas turbine for power generation according to claim 1, characterized in that The bearing is one of a sliding bearing, a rolling bearing, an air bearing and a magnetic bearing, and is preferably an air bearing.

6. The pure oxygen combustion three-fluid gas turbine for power generation according to claim 1, characterized in that The stationary blades are mounted on a holding ring, which is in turn mounted on the inner wall of the turbine chamber. Insulating material and circulating air cooling channels are arranged in sequence between the inner wall of the turbine chamber and the holding ring.

7. The pure oxygen combustion three-fluid gas turbine for power generation according to claim 1, characterized in that The heat exchanger is one of a braided packing heat exchanger, a tube-sheet heat exchanger, a spiral plate heat exchanger, a flat plate heat exchanger and a plate-fin heat exchanger, preferably a braided packing heat exchanger.

Images