Pure oxygen combustion triple fluid gas turbine for power generation

Abstract

The application provides a pure oxygen combustion three-fluid gas turbine for power generation, a three-fluid combustor for controlling gas, oxygen and circulating gas respectively according to needs is arranged at the inlet of the combustion chamber, the outlet of the combustion chamber is uniformly distributed at the rear end of the turbine chamber and is respectively 0-90 degrees with the turbine chamber in the axial and radial directions; a rotating shaft is arranged in the turbine chamber along the central axis through a bearing, the rotating shaft is provided with 2-9 stages of turbine blades, the center of the rotating shaft is provided with a circulating gas cooling channel and is communicated with the circulating gas cooling channels in the interiors of the first 1-7 stages of turbine blades, the surfaces of the first 1-7 stages of turbine blades are provided with circulating gas cooling holes distributed according to a matrix; static blades are arranged in the inner wall of the turbine chamber and are arranged at intervals with the turbine blades, the interiors of the first 1-7 stages of static blades are provided with circulating gas cooling channels and are communicated with the circulating gas cooling channels in the turbine chamber, the surfaces of the static blades are provided with circulating gas cooling holes distributed according to a matrix; a diffuser and a heat exchanger are sequentially arranged at the front end of the turbine chamber, a circulating gas sealing box and a generator system are sequentially arranged on the rotating shaft outside the rear end of the turbine chamber.

Description

I. Technical Field

[0001] This invention relates to the field of gas turbine technology, and in particular to the structure of a gas turbine for power generation. II. Background Technology

[0002] Gas turbines, with their massive size, are widely recognized as the most difficult machines to manufacture in the world, often referred to as the "crown jewel of manufacturing." They require both high efficiency and economic benefits. The initial gas temperature and the compressor ratio are two major factors affecting gas turbine efficiency. Increasing the initial gas temperature and correspondingly increasing the compression ratio can significantly improve gas turbine efficiency, making it a key objective for gas turbine researchers.

[0003] In the late 1970s, the highest compression ratio reached 31; the initial gas temperature of industrial and marine gas turbines reached approximately 1200℃, while that of aviation gas turbines exceeded 1350℃. Gas turbines are generally classified into four classes: E-class (operating temperature approximately 1200℃), F-class (operating temperature approximately 1400℃), G / H-class (operating temperature approximately 1500℃), and J-class (operating temperature approximately 1600℃). The higher the inlet gas temperature, the higher the class and the higher the thermal efficiency. Currently, mainstream heavy-duty gas turbines are classified into E-class, F-class, and H-class, with internationally advanced gas turbines reaching the H-class with a rated output power of over 400MW. Currently, my country has made significant breakthroughs in core technologies such as improving turbine blade cooling technology and developing high-temperature materials capable of withstanding higher temperatures, placing it at an internationally leading level.

[0004] However, the traditional gas turbine operation involves a compressor continuously drawing in air from the atmosphere and compressing it. A portion of this compressed air enters the combustion chamber, mixes with injected fuel, and burns to become high-temperature gas. This gas then flows into the gas turbine, expands, and performs work, driving the turbine impeller and rotating the compressor impeller. The heated high-temperature gas significantly increases its work capacity, allowing the gas turbine to generate additional output work for the gas turbine while simultaneously driving the compressor. When starting a gas turbine from a standstill, a starter motor is required to rotate it; the starter motor disengages only after the turbine has accelerated to the point where it can operate independently. However, because high-compression air needs to be divided into three parts—combustion air, turbine blade cooling air, and stationary blade cooling air—through a complex airflow path with specific flow ratios and pressures, the high-precision and complex forward design technology and experience required for the compressor-combustion chamber-turbine chamber gas turbine system, which has fewer stages and a higher compression ratio, has become a core bottleneck problem hindered by foreign technology blockades. Between 2001 and 2007, China imported over 50 sets of F / E-class heavy-duty gas turbines from GE, Siemens, and Mitsubishi through three rounds of "bundled bidding for technology in exchange for market access." These were then manufactured domestically by four consortia: Harbin Turbine-GE, Dongfang Electric-Mitsubishi, SAIC-Siemens, and Nanjing Electric-GE. However, this "market-for-technology" approach over a decade failed to allow my country to master this core technology as desired. Consequently, Chinese companies could only manufacture and sell these turbines using OEM (Original Equipment Manufacturer) services based on provided drawings, unable to participate in joint R&D, let alone venture into the more lucrative gas turbine service sector.

[0005] Steam cooling was a revolutionary technology for H-class gas turbines, first proposed by GE in the 1990s. It involves using steam instead of air to cool the turbine's moving blades. This cooling technology is extremely efficient, increasing the inlet temperature of the first-stage moving blades by approximately 110°C under the same combustion chamber outlet temperature, while improvements to the metal materials themselves typically only increase the temperature by about 8°C. Unfortunately, due to the excessive complexity of steam cooling systems in actual commercial operation, and the slow start-up time affecting the peak-shaving performance of the gas turbine, major gas turbine manufacturers were ultimately forced to choose air cooling in their actual products. There is an urgent need to apply steam cooling technology in the development of next-generation heavy-duty gas turbines.

[0006] Furthermore, most current gas turbine designs are direct evolutions of aircraft jet engines, with the turbine chamber, combustion chamber, compressor, and generator arranged axially and horizontally. This places stringent requirements on the temperature resistance of the central shaft and the verticality of machining and use, necessitating a complex system comprised of rotating parts, bearings, seals, lubrication systems, and advanced electronic control equipment. Due to this technical complexity, most users rely on the original equipment manufacturer (OEM) for repairs, overhauls, and advanced maintenance. Since the airflow direction of the coaxially arranged compressor is not adjustable, and the high-temperature, high-speed direct-flow gas in the combustion chamber needs to be guided by fixed stationary blades to become a rotating airflow, energy consumption is required. Additionally, gas turbines used for power generation do not require the same compact spatial layout as aircraft jet engines. Therefore, developing efficient, simple, low-cost, easy-to-manufacture and assemble, and low-maintenance and replacement gas turbine structures based on fluid characteristics is one of the most pressing challenges in gas turbine structural design.

[0007] Given my country's reality of abundant coal, scarce oil, and limited natural gas resources, and the price ratio of coal, oil, and natural gas with equivalent calorific value (approximately 1:7:3), coal-fired power plays a crucial role in ensuring the safety and peak-shaving of my country's future low-carbon electrification energy system. It is also my country's safest and most economical energy source, and a key focus in building a safe, clean, efficient, and low-carbon new energy system. Integrated gasification combined cycle (IGCC) technology is considered a revolutionary and clean, efficient coal utilization technology. It overcomes the inherent shortcomings of direct coal combustion power generation in terms of resource utilization, technology, economics, conventional pollutant removal, and CO2 emission reduction, and is the main technology for future coal-fired power generation. A novel IGCC technology, characterized by pure oxygenation of pulverized coal, pure oxygen combustion power generation from gas, steam circulation temperature regulation, and liquid nitrogen expansion power generation, can achieve full carbon recovery, deep peak shaving, and water-saving efficiency. It is expected to achieve near-zero emissions from coal-fired power generation, power plant efficiency of over 75%, and significantly reduced coal consumption. Once a breakthrough is achieved, it will be a revolutionary clean coal power technology. However, there is an urgent need to develop three-fluid gas turbines suitable for pure oxygen combustion for power generation. III. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing gas turbine structural technologies by providing a pure oxygen combustion three-fluid gas turbine for power generation. The combustion chamber's gas, oxygen, and steam are controlled separately as needed, eliminating the need for complex airflow channel design and flow regulation. This results in a simple structure, low cost, and easy manufacturing and assembly, laying the foundation for low-energy CO2 recovery. For the first time, low-energy steam circulation is used to regulate combustion temperature, while both moving and stationary blades are cooled using low-cost steam. For materials of the same high temperature, the initial combustion temperature can be increased by more than 100°C (relative to a gas turbine class), solving the traditional steam cooling problem of gas turbines. The coaxial compressor is eliminated, significantly reducing the shaft length and allowing for vertical arrangement, lowering manufacturing and assembly difficulty and costs, and reducing maintenance and replacement costs. Low-energy pumping and pressurization of liquid pure oxygen and water, and low-energy compression of medium-pressure gas, significantly increase the gas turbine's compression ratio and work efficiency. High-temperature combustion flue gas is injected tangentially at high speed into the turbine chamber without flow direction conversion, fully utilizing the momentum of the high-speed gas to further improve power generation efficiency.

[0009] The technical solution of the present invention:

[0010] This invention provides a pure oxygen combustion three-fluid gas turbine for power generation, comprising a turbine chamber, a combustion chamber, a rotating shaft, turbine blades, bearings, a heat exchanger, a recirculating gas sealing box, a generator system, stationary blades, insulation material, retaining rings, three-fluid nozzles, a diffuser, and a flue gas outlet. The combustion chamber inlet is equipped with three-fluid nozzles for controlling the combustion gas, oxygen, and recirculating gas as needed. The combustion chamber outlet is evenly distributed along the circumference of the rear end of the turbine chamber, forming angles of 0-90° with both the axial and radial directions of the turbine chamber. Inside the turbine chamber, a rotating shaft is mounted along the central axis via bearings. The rotating shaft has 2-9 stages of turbine blades, and a recirculating gas cooling channel is located at the center of the rotating shaft, connecting with the turbine blades of the first 1-7 stages. The internal circulating air cooling channels of 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. The internal circulating air cooling channels of the first 1-7 stages of stationary blades are provided and are connected to the circulating air cooling channels in the turbine chamber. 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 outlet are provided in sequence at the front end of the turbine chamber to diffuse and reduce the speed of the flue gas and reduce the outlet velocity loss. A circulating air sealing box and a generator system are provided in sequence on the outer rotating shaft at the rear end of the turbine chamber. 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 can be arranged vertically or horizontally, with vertical arrangement being preferred.

[0012] The circulating gas is either water vapor or CO2, with water vapor being preferred.

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

[0014] The bearing is one of the following: sliding bearing, rolling bearing, air bearing, and magnetic levitation bearing, with air bearing being preferred.

[0015] The stationary blades are mounted on the retaining ring, which is then mounted on the inner wall of the turbine chamber. Insulation material and circulating air cooling channels are sequentially provided between the inner wall of the turbine chamber and the stationary blades to ensure that the operating temperature of the turbine chamber is low.

[0016] The heat exchanger is one of the following: braided packing heat exchanger, tube sheet heat exchanger, spiral plate heat exchanger, flat plate heat exchanger, and plate-fin heat exchanger, with braided packing heat exchanger being preferred. IV. Description of the attached drawings

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

[0018] Appendix Figure 1 The drawing is shown as follows: 1. Turbine chamber, 2. Combustion chamber, 3. Rotating shaft, 4. Turbine blades, 5. Bearing, 6. Heat exchanger, 7. Recirculating gas seal box, 8. Generator system, 9. Stationary blades, 10. Insulation material, 11. Holding ring, 12. Three-fluid nozzle, 13. Diffuser, A. Recirculating gas inlet, B. Oxygen inlet, C. Fuel gas inlet. V. Detailed Implementation Methods

[0019] The present invention will now be described in detail with reference to the accompanying drawings:

[0020] This invention provides a pure oxygen combustion three-fluid gas turbine for power generation, comprising 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, insulation material 10, a retaining ring 11, three-fluid nozzles 12, a diffuser 13, and a flue gas outlet 14. The combustion chamber 2 inlet is equipped with three-fluid nozzles 12, each controlling the combustion gas, oxygen, and circulating gas as needed. The combustion chamber 2 outlet is evenly distributed along the circumference of the rear end of the turbine chamber 1, forming 0-90° angles with the axial and radial directions of the turbine chamber 1, respectively. Inside the turbine chamber 1, a rotating shaft 3 is mounted along its central axis via bearings 5. The rotating shaft 3 has 2-9 stages of turbine blades 4, and a circulating gas cooling channel is located at the center of the rotating shaft 3, connecting to the front... The circulating air cooling channels inside the turbine blades 4 of stages 1-7 are connected. The surface of the turbine blades 4 of stages 1-7 is 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. The interior of the stationary blades of stages 1-7 is provided with circulating air cooling channels and is connected to the circulating air cooling channels inside the turbine chamber. The surface of the stationary blades 9 is 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 diffuse and reduce the speed of the flue gas and 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. 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 can be arranged vertically or horizontally, with vertical arrangement being preferred.

[0022] The circulating gas is either water vapor or CO2, with water vapor being preferred.

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

[0024] Bearing 5 is one of sliding bearings, rolling bearings, air bearings and magnetic levitation bearings, with air bearings being preferred.

[0025] The stationary blade 9 is mounted on the retaining ring 11, which is then mounted on the inner wall of the turbine chamber 1. Between the inner wall of the turbine chamber 1 and the stationary blade 9, thermal insulation material 10 and a circulating air cooling channel are sequentially provided to ensure that the operating temperature of the turbine chamber 1 is low.

[0026] The heat exchanger 6 is one of the following: braided packing heat exchanger, tube sheet heat exchanger, spiral plate heat exchanger, flat plate heat exchanger, and plate fin heat exchanger, with braided packing heat exchanger being preferred.

[0027] In actual operation, when the pure oxygen combustion three-fluid gas turbine for power generation is working, high-pressure circulating gas from the circulating gas inlet A, high-pressure oxygen from the oxygen inlet B, and pressurized gas from the gas inlet C are respectively controlled to be introduced into the three-fluid nozzle 12 for mixing and combustion as needed. This solves the problems of difficult control of the gas-combustion air mixing ratio in traditional two-fluid gas turbines, as well as the high-precision and high-difficulty system design of air flow channel design and manufacturing. It avoids the problems of using compressors and starters and their disengagement during startup. The flow rate of each fluid in the three-fluid nozzle 12 is simple and easy to adjust. The generated high-temperature and high-speed gas is injected into the turbine chamber 1 tangentially along the circumference of the rear end of the turbine chamber 1, directly driving the turbine blades 4 to drive the rotating shaft to rotate at high speed. The high-frequency current generated by the coaxial high-speed rotating generator system 8 is converted into 50HZ or 60HZ current and output through the frequency conversion system. The high-temperature flue gas flowing out from the center of the turbine chamber 1 first exchanges heat with water or supercritical CO2 in the heat exchanger to recover energy and use it for waste heat power generation. Then the flue gas is discharged to recover CO2. The high-pressure circulating gas is divided into three parts as needed, which are then fed into the three-fluid nozzle 12 for temperature regulation, the turbine blade 4 for cooling and protection, and the stationary blade 9 for cooling and temperature reduction. This avoids the problem of traditional gas turbines using complex flow channels to regulate compressed air flow, and the temperature adjustment of each component is simple and convenient. After selecting steam as the high-pressure circulating gas, the steam circulation regulates the combustion temperature, and the cooling of both the moving and stationary blades is also done with steam. This solves the problem of the difficulty of adopting revolutionary steam cooling technology in traditional two-fluid gas turbines. Using the same high-temperature materials, the initial combustion temperature can be increased by more than 100°C, allowing my country to improve gas turbines by 1 to 3 levels based on the existing breakthroughs in high-temperature materials. It is easy to develop J-class or higher-level gas turbines. The low compression ratio of cryogenic air separation and the low-energy-consumption high-pressure pumping of liquid oxygen eliminate the need for compressors with fewer stages and higher compression ratios. In addition, the medium-pressure gas can be further compressed with low energy consumption, which can easily enable my country's gas turbines to overcome the difficulty of raising the compression ratio to 31. It is easy to double the compression ratio of gas turbines, and it is expected to reach 60-100, with a power efficiency increase of more than 40%. For power generation using pure oxygen combustion, cryogenic air separation is required. It is more reasonable to separate the compressor and gas turbine. The length of the rotating shaft is shortened by more than 60% and can be arranged vertically. This further reduces the difficulty of gas turbine design, manufacturing and assembly, reduces gas turbine manufacturing cost by 50%, and lowers maintenance and replacement costs.

[0028] The combined adoption of the above measures significantly reduces the difficulty of forward design and manufacturing of pure oxygen combustion three-fluid gas turbine systems for power generation, allows for flexible control of the flow and pressure of each fluid, enables rational utilization of heat and momentum, results in higher power generation efficiency, simpler structure, reduces equipment volume by more than 50%, lowers cost, facilitates manufacturing and assembly, reduces maintenance and replacement costs, avoids NOx generation in flue gas, and reduces CO2 recovery energy consumption and costs by more than 80%. This enables my country to achieve a leapfrog development and take the lead in the design and manufacturing level of gas turbines for power generation.

Claims

1. A pure oxygen combustion triple 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 seal cartridge, a generator system, stationary blades, heat insulation materials, a retaining ring, a triple fluid nozzle, a diffuser, and a flue gas exhaust port, characterized in that The combustion chamber inlet is provided with a three-fluid nozzle for controlling gas, oxygen and circulating gas as needed, the combustion chamber outlet is uniformly arranged along the circumference of the rear end of the turbine chamber, and is respectively 0-90° to the turbine chamber in the axial and radial directions; a rotating shaft is installed in the turbine chamber along the central axis through a bearing, the rotating shaft is provided with 2-9 turbine blades, the rotating shaft is provided with a circulating gas cooling channel in the center and is communicated with the circulating gas cooling channel in the inside of the front 1-7 turbine blades, the surface of the front 1-7 turbine blades is provided with a matrix-distributed circulating gas cooling hole; the turbine chamber is provided with a stationary blade and is arranged in the turbine chamber, the inside of the front 1-7 stationary blades is provided with a circulating gas cooling channel and is communicated with the circulating gas cooling channel in the turbine chamber, the surface of the stationary blade is provided with a matrix-distributed circulating gas cooling hole; the front end of the turbine chamber is provided with an expander, a heat exchanger and a flue gas outlet in sequence, so that the flue gas is expanded and reduced in speed to reduce the outlet velocity loss; the outside of the rear end of the turbine chamber is provided with a circulating gas sealing box and a generator system in sequence on the rotating shaft, and the circulating gas sealing box is communicated with the circulating gas cooling channel in the center of the rotating shaft.

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

3. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The rotating shaft of the pure oxygen combustion three-fluid gas turbine for power generation is vertically arranged.

4. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The circulating gas is water vapor or CO2.

5. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The circulating gas is water vapor.

6. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The combustion chamber outlet is rectangular or circular.

7. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The combustion chamber outlet is a flat rectangular outlet.

8. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The bearing is one of a sliding bearing, a rolling bearing, an air bearing and a magnetic suspension bearing.

9. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The stationary blade is mounted on a holder, and the holder is mounted on the inner wall of the turbine chamber, and the inner wall of the turbine chamber and the stationary blade are sequentially provided with thermal insulation material and a circulating gas cooling channel.

10. The pure oxygen combustion triple fluid gas turbine for power generation according to claim 1, characterized by The heat exchanger is one of a woven packing type heat exchanger, a tube plate type heat exchanger, a spiral plate type heat exchanger, a flat plate type heat exchanger and a plate-fin type heat exchanger.

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