CN102900529B - Method for cooling and efficiency improvement of double-working-medium combined cycle turbine - Google Patents

Abstract

The invention relates to the technical fields of gas turbines and steam turbines, namely a method for cooling and improving efficiency of a duplex combined cycle turbine. Gas and water (steam) are used as the working medium, the gas is generated in the combustion chamber, and the water is phase-transformed in the phase-change chamber; the two potential energies are generated separately and work together. The wet steam generated in the phase change chamber is mixed with the gas to perform work, and the total amount of solid-line working medium is adjustable. The second working medium, water, is fed into the phase change chamber at the temperature of the vapor-liquid interface, and the phase change occurs while cooling the parts. Realize the strong utilization of potential energy. The two turbine engines with different combustion methods are simplified into one turbine, and two different working fluids are connected in series in one turbine to complete the Brayden cycle and the Rankine cycle. A large amount of water vapor is used to replace the gas, so that the fuel consumption rate is reduced, and the carbon dioxide emission is also reduced in the same proportion. It is low-carbon and environmentally friendly. The engine temperature is regulated with a new concept, and the thermal power conversion capacity of the single machine is greatly improved. The thermal efficiency is ≥ 60%. Eliminate harmful gas emissions.

Description

Cooling and Efficiency Improvement Method for Duplex Combined Cycle Turbine

technical field

The invention relates to the technical fields of gas turbines and steam turbines, and aims at a method for eliminating thermal damage, improving thermal efficiency, and reducing self-consumption work of gas turbines, that is, a method for cooling and improving efficiency of a duplex combined cycle turbine. It is suitable for the power source of large and small walking machines and table machines on land and water.

Background technique

Thermodynamics believes: "'heat' cannot be directly converted into mechanical work, but must be aided by working fluid."

In the existing technology, "heat~working medium-mechanical work", the source of "heat" is the calorific value of fuel, which is a fixed value; The structure is precisely fixed, which is also a fixed value; "mechanical work" is the conversion of fixed "heat" with a fixed "working medium", and the result of "mechanical work" must also be a fixed value.

Therefore, the result obtained by converting a fixed value into a fixed value must be a fixed value, which is the fundamental reason why the thermal efficiency of thermomechanical machinery cannot be improved.

The engine of the closed combustion mode can only utilize the chemical energy of the first step, and the energy after the second step can only be discharged into the atmosphere as "residual heat" to do useless work.

The open combustion engine does not have the equipment conditions to utilize and transform the energy of the first step, and can only use the physical energy of the second step to discharge the heat energy after the first step and the third step for free, doing useless work.

The thermal efficiency of the gas turbine (simple) cycle is 18%, and the thermal efficiency can reach 38% when the working temperature is increased to 1430°C. The high temperature and high speed working medium will seriously damage the impeller blades.

Gas turbine: low thermal efficiency, serious thermal damage, large self-consumption, high material selection requirements, high manufacturing cost, and limited practical application. A. Thermal efficiency: 18~38%. B. Working temperature: 1340~1430℃ (gas index). C. The concept of improving thermal efficiency is: to increase the working temperature as much as possible, and to increase the flow rate of the working medium by increasing the "specific volume" of the working medium. D. In order to reduce the damage of high temperature to the combustion chamber and impeller, a large amount of air is needed to cool the gas turbine. 2/3 of the air entering the compressor is used as cooling medium, and only 1/3 is used to supply oxygen for fuel. The burden on the compressor Very heavy. E. The impeller and combustion chamber must be made of advanced high temperature resistant materials.

Cheng's cycle: Brayden cycle and Rankine cycle are completed in parallel in a gas turbine.

A. Thermal efficiency: ≈53%. B. The second working fluid completes the phase change in the waste heat boiler. C. The steam (and gas) is added into the combustion chamber in the state of equal pressure. D. The potential energy of phase change can only be utilized after storage and transport decay. E. The waste heat boiler and supporting facilities take up a huge space. F, waste heat recovery and reuse.

Two-machine combined cycle thermal unit: the gas turbine and the steam turbine share a fuel energy and use two different working fluids. Complete the Brayden cycle and the Rankine cycle respectively, and make output work respectively. Dual machine thermal efficiency: ≈55%. Not suitable for small machinery and walking machinery.

Internal combustion engine: "gas-fuel ratio" is to ensure the precise ratio of oxygen supply requirements for complete oxidation of hydrocarbons, rather than to ensure precise "working fluid requirements" for "thermal power conversion". A. Thermal efficiency of gasoline engine: 27~30%, thermal efficiency of diesel engine: 37~42%. B. A single working substance completes a single cycle. C. The inertia of the piston connecting rod group is large, the operation vibration is large, the noise is large, the failure rate is high, and the maintenance cycle is short. D. The forced cooling system loses 30% of the heat, and the exhaust gas carries away 30% of the heat, making useless work. How to realize the regulation of the total amount of working fluid is the key to eliminate thermal damage and improve thermal efficiency.

Contents of the invention

The object of the present invention is to provide a dual-mass combined cycle turbine in which gas and water are used as working fluids, and two different working fluids are connected in series in a turbine to complete the Brayden cycle and the Rankine cycle. Cooling method.

The technical solution of the present invention is: a method for cooling and improving the efficiency of a double working medium combined cycle turbine, which is characterized in that a turbine uses gas working medium and water as the second working medium at the same time to create a reasonable "working medium heat ratio ", using a variable working medium to convert a fixed value of fuel internal energy to improve the utilization rate of fuel energy; the second working medium is heated to complete the phase change in the phase change chamber with equal pressure in the combustion chamber, and does not directly absorb heat from the gas, and does not Affect the normal combustion of fuel; the phase change potential energy of the second working fluid is connected with the combustion potential energy of the first working fluid to do work, so as to adjust the total amount of working fluid to control the engine temperature and thermal efficiency.

The annular combustor and the phase change chamber are complementary equipment conditions for the dual-mass turbine to convert the chemical energy of the first step and the physical energy of the second step and beyond in the fuel energy simultaneously. The annular combustion chamber is a circular conical longitudinal corrugated space, and an inverted cone-shaped isolation plate is arranged between the inner wall of the annular combustion chamber and the outer wall of the phase change chamber, and the isolation plate is a corrugated plate.

The second working fluid is fed into the phase change chamber at the temperature of the vapor-liquid interface to shorten the phase change lag time, avoid attenuation, and embody strong utilization.

The turbine engines with different combustion methods are simplified into one turbine, and the second working fluid supply system is added on the basis of the gas turbine structure, so that two different working fluids can be connected in series in one turbine to complete the Brayden cycle and the Rankine cycle .

The gas working medium and water are used as the second working medium, the gas is burned in the combustion chamber, the second working medium is phase changed in the phase change chamber, and then the wet steam and the gas are mixed for heat exchange and work, so as to realize the regulation of the total amount of working medium.

The second working fluid is fed into the phase change chamber at the temperature of the vapor-liquid interface to cool the parts and undergo phase change at the same time.

The two turbine engines with different combustion methods are simplified into one turbine, and two different working fluids are connected in series in one turbine to complete the Brayden cycle and the Rankine cycle.

"Combustion potential energy" is the irreversible potential energy in the chemical reaction process of fuel combustion. The energy absorbed and transformed in this chemical reaction process is set as the chemical energy of the "first step". "Phase change potential energy" uses the remaining heat of "combustion potential energy" to perform thermal work conversion, which is the "second step" reversible physical energy. The "heat" in the exhaust gas is set as "third step energy", and the emitted The energy in the dual qi is set to "fourth step energy"...

The heat energy with low heat density is gradually carried back (rather than transferred) by the second working fluid from the low-temperature heat source to the high-temperature heat source, and then absorbs the heat of the high-temperature heat source on the outer wall of the combustion chamber (corrugated partition), completes the phase change, generates phase change potential energy, and directly acts as Useful work.

The annular combustor and the phase change chamber are the complementary equipment conditions for the dual-mass turbine to convert the chemical energy of the first step and the physical energy of the second step and beyond in the fuel energy simultaneously. The fuels are all hydrocarbons, and "combustion" is an oxidation process that "absorbs" and "releases" heat, rather than a purely exothermic process. This oxidation process is an irreversible chemical reaction process, and the heat energy consumed by the oxidation process is converted It becomes "burning potential energy". If you use "burning potential energy", it will do useful work. If you don't use it, it will do useless work. It no longer needs the rest of the thermal energy as a surplus, free discharge, and wasted. The external combustion engine uses its "residual heat" and then uses "water" as the working medium to complete the conversion of heat and work. The phase transition of water to steam is reversible. So: what is irreversible is chemical energy, and what is reversible is physical energy.

The working fluid of the dual-mass combined cycle turbine adopts gas and water (only water, economical, pollution-free, and low calorific value, but not absolutely limited to water, and can also be other working fluids, such as: Freon, liquid ammonia, etc. Liquid materials.), gas and water enter separately in the combustion chamber; the second working medium, water, is combined with the gas as wet steam after a phase change in the phase change chamber, temperature control, and work, so that the total amount of working medium can be adjusted. The second working medium, water, is fed into the phase change chamber at the temperature of the vapor-liquid interface, and the phase change occurs while cooling the parts.

The dual-mass combined cycle turbine (abbreviation: dual-mass turbine) completes the Brayden cycle based on the structure and working principle of the gas turbine, and completes the Rankine cycle in the turbine of the gas turbine based on the working principle of the steam turbine. The two turbine engines with different combustion methods are simplified into one turbine, and two different working fluids are used in series in one turbine to complete the Brayden cycle and the Rankine cycle. In the dual-mass turbine: the adiabatic compression process and the constant pressure heating and constant pressure heat absorption process are completed separately; the adiabatic expansion process and the constant pressure heat release process are completed together in the same turbine.

"Adjustable total amount of working fluid" is a new idea to control "thermal power conversion capacity". The Brayden cycle and the Rankine cycle are completed in series in a turbine. Using a variable working fluid to convert a fixed value of fuel internal energy and controlling the utilization rate of heat energy can make the thermal efficiency ≥ 60% (because: "'heat' cannot be directly converted into mechanical work, it must be used with the help of working fluid" to improve the total energy consumption of the working fluid. Quantity instead of increasing the specific volume of working medium.). Working temperature: the lowest can be adjusted to 480°C (water is a low-heat substance, the latent heat of phase change is very large, and the potential energy of phase change is very strong.). The impeller and combustion chamber are made of common high temperature and acid resistant materials. The second working fluid is fed into the phase change chamber at the temperature of the vapor-liquid interface. The phase change is completed in the phase change chamber with the pressure peak of the gas potential energy as its pressure starting point. No piston inertia, high speed, low failure rate, long maintenance cycle, good continuous operation characteristics.

The advantages of the present invention are:

1. Compared with gas turbines, dual-mass turbines: high thermal efficiency, eliminate thermal damage, meet the highest emission standards, easy material selection, and low manufacturing costs. Duplexes are available in Ultra Micro, Micro, Small, Neutral, Heavy, Super Heavy, Super Super Heavy. Thermal efficiency: ≥60%. Working temperature: the lowest can be adjusted to 480°C (dual gas balance index). The impeller and combustion chamber can be made of ordinary high temperature and acid resistant materials.

2. Comparison between dual-mass turbine and "Cheng's cycle": Brayden cycle and Rankine cycle are completed in series in one turbine. Thermal efficiency: ≥60%. The second working fluid is fed into the phase change chamber at the temperature of the vapor-liquid interface, and the phase change is completed in the phase change chamber. The peak of gas pressure is the starting point of phase change potential energy pressure, which reflects the strong utilization. The second working fluid supply system takes up little space. A combination of direct and recovery uses waste heat.

3. Comparison between dual-mass turbine and "two-machine combined cycle thermal unit": in one turbine, the combustion potential energy is used to complete the Brayden cycle, and the phase change potential energy is used to complete the Rankine cycle. Single machine output mechanical work. Stand-alone thermal efficiency: ≥60%. It is suitable for the power source of large and small walking machines and table machines on land and water.

4. Comparison between dual-mass turbine and internal combustion engine: the total amount of working medium can be adjusted. Thermal efficiency: ≥60%. "Dual mass" combined cycle in one turbine. No piston inertia, high speed, low failure rate, long maintenance cycle, good continuous operation characteristics. The second working fluid is the phase change that occurs while the components are cooling. There is no forced cooling system, and the exhaust gas is not directly discharged, so that useless work becomes useful work.

5. Emissions: The combustion temperature of any heat engine is very high, and the hot spots are all above 2000°C. In a high-heat hot environment, carbon dioxide may be pyrolyzed for the second time to generate carbon monoxide and oxygen, and nitrogen can be oxidized to generate nitrogen Oxygen compounds. The dual-mass machine adopts low-temperature combustion technology, and there is always no hot spot, which is conducive to environmental protection.

6. A large amount of water vapor in the dual-mass machine replaces the gas (which needs to consume fuel), so that the fuel consumption rate is reduced, and the emission of carbon dioxide is also reduced in the same proportion, which is low-carbon and environmentally friendly.

7. The dual-mass turbine greatly increases the total quality of the working medium, and the second working medium cools down the parts and undergoes a phase change at the same time. The gas temperature is suitable for regulation at 1300±50°C. Not only eliminate heat damage, but also prevent the generation of harmful gases.

Embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Description of drawings

Figure 1 is a schematic diagram of the main structure of a dual-mass combined cycle turbine.

Fig. 2 is a schematic diagram of the cross-sectional structure of the longitudinal corrugated insulation board.

Detailed ways

See Figures 1 and 2, the names of the components are as follows: Turbine and shaft 1, compressor impeller 2, compressor blade 3, compressor housing 4, lubricating oil inlet 5, fuel inlet 6, infrared grill 7, oil and water nozzle Middle body 8, fuel injection nozzle 9, exhaust port 10, water nozzle 11, water nozzle gland 12, annular combustion chamber 13, longitudinal corrugated isolation plate 14, combustion inner wall 15, swirl guide plate 16, turbine blade 17, Stator guide plate 18, invisible heat exchanger 19, warm water outlet 20, exhaust pipe 21, slow-decay bushing 22, fuel oil backup inlet 23, second working fluid inlet 24, phase change outer wall 25, cold water inlet 26, phase change Room 27.

The dual working medium combined cycle turbine includes a moving part, a fuel supply system, a second working medium supply system, an electrical system, a lubrication system, and a load. The concrete experimental structure is: it comprises turbine and shaft 1, turbine blade 17; There are compressor impeller 2, compressor blade 3, compressor housing 4 on left turbine and shaft 1; Annular combustion chamber 13, phase change chamber 27; There is a separation plate 14 between the combustion chamber and the phase change chamber, which is divided into a combustion chamber 13 and a phase change chamber 27; one end of the annular chamber has an annular fuel injector 9 and an annular water nozzle 11, and the annular injector 9 communicates with the combustion chamber 13 The annular water nozzle 11 communicates with the phase change chamber 27; the other end of the annular chamber steam and gas merge and blow to the turbine blades 17 through the deflector.

The isolation plate 14 is a corrugated plate (inverted cone shape) with a large contact area. The fuel injector 9 has a cone angle of 45°. An infrared grill 7 is arranged between the fuel injectors 9 at the entrance of the combustion chamber 13 . The combustion chamber 13 is an annular conical longitudinal corrugated space. The phase change chamber 27 is an inverted cone longitudinal corrugated space between the combustion chamber wall separation plate 14 and the phase change chamber wall 25 .

Referring to FIG. 2 , the combustion chamber 13 and the phase change chamber 27 are separated by a longitudinal corrugated isolation plate 14 , and the isolation plate 14 is both the outer wall of the combustion chamber 13 and the inner wall of the phase change chamber 27 .

The compressor delivers air around the circumference. The fuel injectors are annular, with a 45° cone angle and a circular spray. The narrow annular compressed air channel is connected to the narrow annular inlet of the annular combustion chamber 13 . The combustion chamber 13 can be divided into two types: direct combustion type and infrared type. Direct combustion type: the fuel is sprayed to the narrow annular inlet of the combustion chamber 13 at a close distance with a cone angle of 45o, and the fuel starts to burn at the inlet; between burning. Combustion chamber 13 is "annulus conical longitudinal corrugation space". The phase change chamber 27 is an "inverted cone longitudinal corrugated space" between the corrugated plate on the outer wall of the combustion chamber 13 and the outer wall 25 of the cylindrical phase change chamber.

The combustion process of the fuel and the phase change process of the second working substance are independently completed in the same pressure space, without directly absorbing the heat of vaporization from the gas, and not affecting the normal combustion of the fuel.

The heat energy with low heat density is gradually recovered by the second working fluid and brought back (rather than transferred) to the high-temperature heat source, and then absorbs the heat from the corrugated insulation plate 14 on the outer wall of the combustor to complete the phase change, generate phase change potential energy, and directly perform useful work.

The engine of the closed combustion mode can only utilize the chemical energy of the first step, and the energy after the second step can only be discharged into the atmosphere as "residual heat" to do useless work.

The open combustion engine does not have the equipment conditions to utilize and transform the energy of the first step, and can only use the physical energy of the second step to do useless work for the free discharge of heat energy after the first step and the third step.

The annular combustor and the phase change chamber are the complementary equipment conditions for the dual-mass turbine to convert the chemical energy of the first step and the physical energy of the second step and beyond in the fuel energy at the same time.

Working process: 1. Start: When starting, first disconnect the load, turn on the power of the igniter, and start the turbine rotor with compressed air (or electric motor). When the rotation speed reaches 8,000~10,000 rpm, quickly open 40% of the liquefied gas valve, preheat the operation, and fully open the liquefied gas valve at the right time. The liquefied gas enters the annular fuel injector 9 from the fuel inlet 6; the compressed air is supplied by the compressor, mixed at the annular injector 9, (ignited by electric spark) directly enters the annular combustion chamber 13 for combustion, and the gas burns the longitudinal corrugated isolation plate 14 2. After 30 to 40 seconds of preheating, start the second working fluid supply system, open the valve slightly, let a small amount of water enter the phase change chamber 27, and cool the combustion chamber isolation plate 14 to undergo a phase change at the same time; 3. Wet steam Mixed heat exchange with the gas at the outlet of the longitudinal corrugated isolation plate 14 into the double gas channel: 4. The cold water previously filled in the water storage tank (heat exchanger) enters the invisible heat exchanger 19 through the cold water inlet 26 to absorb the heat of the exhaust gas , to further heat up, enter the cooling water jacket of the combustion chamber from the warm water outlet 20, absorb the heat of the inner wall of the combustion chamber, and reach the temperature of the vapor-liquid interface. Isolation plate 14 is used for the cooling of annular combustion chamber 13 and phase change occurs simultaneously. The water vapor in phase change enters the double gas channel from exhaust port 10 through steam-water separator; Heat, superheated steam and gas are mixed and exchanged by the turbulent flow of the swirl guide plate 16, and after being accelerated, they are blown to the turbine blades 17 together; The blade 17 is a reaction force; 7. The turbine work drives the compressor impeller 2 to provide compression work for the compressor through the turbine, turbine and shaft 1, and at the same time drives the load to perform shaft work.

Claims (1)

1. A method for cooling and improving the efficiency of a double working medium combined cycle turbine, characterized in that in a turbine, gas working fluid is adopted as the first working medium and water is the second working medium; The internal energy of the fuel with a fixed value improves the utilization rate of the fuel energy; the second working medium is heated to complete the phase change in the phase change chamber with equal pressure in the combustion chamber, and the phase change potential energy of the second working medium is the same as the combustion potential energy of the first working medium. Work to adjust the total amount of working fluid to control the engine temperature and thermal efficiency; the annular combustion chamber and the phase change chamber are dual-mass turbines that can control the chemical energy of the first step in the fuel energy and the physical energy of the second step and beyond Complementary equipment conditions for thermal power conversion at the same time, the annular combustion chamber (13) is a circular conical longitudinal corrugated space, and an inverted cone cylindrical separation plate (14) is provided between the inner wall of the annular combustion chamber (13) and the outer wall of the phase change chamber (27). ), the isolation plate (14) is a corrugated plate; the second working fluid is filled into the phase change chamber with the temperature of the vapor-liquid interface, and the turbine engines with different combustion methods are simplified into one turbine, and the phase change chamber (27) is the isolation plate (14) and the inverted cone longitudinal corrugated space between the phase change outer wall (25); on the basis of the gas turbine structure, a second working fluid supply system is added to realize two different working fluids connected in series in one turbine to complete Braden cycle and Rankine cycle.