Gao Jingsheng (Beijing Beizhong Steam Turbine Motor Co., Ltd.) efficiency and output power.

1. The development of renewable energy requires energy storage power stations to adjust the balance between supply and demand, and improve energy efficiency. With the gradual maturity of wind power technology, China's wind power installed capacity has grown rapidly in recent years. In 2012, China's wind power installed capacity was 14.82 million kilowatts, and the cumulative grid connection reached 62.66 million kilowatts. The power generation capacity was 100.4 billion kilowatt hours, accounting for 2% of the country's total electricity consumption. After coal and hydropower, it became the third largest power source. However, in recent years, wind power in some areas has been repeatedly abandoned.

At present, China's "abandonment of wind and electricity" phenomenon is mainly concentrated in the northeast, northwest and north China. According to the statistics of the China Wind Energy Association, the power cut of wind power exceeded 20 billion degrees in 2012, and the power limit rate exceeded 20%. Wind power grid-connected operation and consumption problems are still the most important factors restricting the healthy and rapid development of wind power in China. This situation has led to a decline in the economics of wind farm operation. The direct economic losses caused by national wind power in 2012 were over 10 billion yuan.

The power storage system stores electrical energy through a certain medium, and releases the stored energy to generate electricity when needed. The development of electric energy storage systems is an urgent need for large-scale utilization of renewable energy, as well as an effective way to improve the efficiency, safety and economy of conventional power systems, as well as key technologies for smart grids and distributed energy systems. At present, existing energy storage technologies include pumped storage power stations, compressed air storage power stations, batteries, flow batteries, superconducting magnetic energy, flywheels, and capacitors/supercapacitors. - 2 compressed air system will be the most promising large-scale energy storage technology in addition to pumped storage, due to capacity, energy storage cycle, energy density, charge and discharge efficiency, life, operating costs, environmental protection, etc. (For example, above 100MW) The energy storage system operating in commercial systems is only pumped storage power station and compressed air. The pumping power station has the advantages of mature technology, high efficiency, large capacity and long energy storage period. It is a widely used power storage system. At present, there are about 200 pumping power storage systems in operation around the world, with a total installed capacity of more than 110 GW. However, the pumping station energy storage system requires special geographical conditions to build two reservoirs and dams, so the site selection is difficult and the construction period is very long. The initial investment is huge, and even a large area will inundate vegetation and even cities, leading to ecological and immigration problems. The compressed air energy storage system is another power storage system that enables large capacity and long-term energy storage. It stores excess electric energy through compressed air, releases high-pressure air when needed, and generates electricity through an expander. Since StalLaval proposed the use of underground caverns to achieve compressed air energy storage in 1949, domestic and foreign scholars have carried out a lot of research and practice work, and two large power plants have been put into commercial operation in Germany and the United States. The world's first commercial compressed air storage power station was the German Huntorf power station that was put into operation in 1978 and is still in operation. The unit's compressor power is 60MW and the output power is 290MW. The system stores compressed air in a 600m underground mine.

The unit can be continuously inflated for 8 hours and continuously generate electricity for 2 hours. The McIntosh compressed air energy storage power station in Alabama, USA, which was put into commercial operation in 1991, has an underground gas storage cavern 450 meters underground, a compressor unit power of 50 MW, and a power generation capacity of 110 MW, which can achieve 41 hours of air compression and 26 hours of power generation. In addition, Japan, Italy, Israel and other countries have compressed air storage power stations are under construction. Although China's R&D of compressed air energy storage system started late, with the rapid increase of peak-to-valley ratio of power load and the rapid development of renewable energy, especially wind power, it is urgent to develop a pumping power station. Large-scale long-term energy storage technology. Therefore, research on compressed air energy storage systems has been highly valued by relevant research institutes, power companies and government departments, and is currently a research and development hotspot for large-scale energy storage technologies.

2013 Thermal Power Plant Pollutant Purification and Green Energy Technology Seminar and Environmental Protection Technology and Equipment Professional Committee (3rd) Conference 3. Compressed Air Energy Storage System Technical Features Traditional compressed air energy storage system is based on gas turbine technology. An energy storage system. During energy storage, the compressed air energy storage system consumes electric energy to compress and store the air in the gas storage device; when the energy is released, the high-pressure air is released from the gas storage device, enters the gas turbine combustion chamber and is mixed with the fuel to burn, and drives the turbine to generate electricity. The difference from conventional gas turbines is that the compressor and turbine are separate and operate separately. Due to the energy storage and energy release time-sharing work, in the process of energy release, there is no output power consumed by the compressor to consume the turbine. Therefore, the compressed air energy storage system can generate about three times more power than a gas turbine system that consumes the same fuel.

(1) Main components of compressed air energy storage system 1) Compressor: generally a multi-stage compressor that compresses air and stores it in a gas storage device to convert electrical energy into internal energy storage; 2) Turbine: generally Multi-stage turbine, which combines combustion of fuel and compressed air in combustion chamber to form high-temperature gas-driven turbine to work, release energy stored in compressed air and fuel; 3) Combustion chamber and heat exchanger: used for fuel combustion and recovery of waste heat 4) Gas storage devices: underground or above-ground caves or pressure vessels or underwater gas storage devices for storing compressed air; 5) motors and generators: respectively connected to compressors and turbines; 6) control systems and auxiliary equipment : Includes control systems, fuel tanks, mechanical transmission systems, piping and fittings.

(2) Characteristics and development trend of compressed air energy storage technology Compared with other energy storage technologies, compressed air energy storage system has the advantages of large capacity, long working time, good economic performance, long charge and discharge cycle life, etc. 1) second only to Pumping power stations, compressed air energy storage systems can last for hours or even days and work long hours.

2) The unit construction cost and operating cost of large compressed air energy storage systems are relatively low, which is lower than that of pumped storage power stations and has good economics.

3) The compressed air energy storage system has a long service life and can store and release energy for tens of thousands of times, and its efficiency can reach about 70%, which is close to the pumped storage power station.

(3) Disadvantages of compressed air energy storage system 1) The traditional compressed air energy storage system is not an independent technology, it must be used with gas turbine power plants; and the traditional compressed air energy storage system still relies on burning fossil fuel to provide heat source. On the other hand, it faces the threat of depletion of fossil fuels and rising prices. On the other hand, its combustion still produces pollutants such as nitrides, sulfides and carbon dioxide, which are not in line with green (zero emission) and renewable energy development requirements.

2) Compressed air energy storage systems are more suitable for large systems, and small compressed air energy storage systems are less efficient; large systems require specific geographical conditions to build large gas storage chambers, such as rock caves, salt caves, abandoned mines, etc. The application range of the compressed air energy storage system is greatly limited.

In order to solve the main problems faced by conventional compressed air energy storage systems, that is, the need for large gas storage devices and the problem of burning fossil fuels, there have been compressed air storage systems with heat storage, micro-miniature compressed air energy storage systems, and liquefied air. Energy storage systems, supercritical compressed air energy storage systems, compressed air energy storage systems coupled with renewable energy sources, etc.

The so-called compressed air storage system with heat storage is also known as the advanced adiabatic compressed air energy storage system. The compression process of air in a compressed air energy storage system is close to the adiabatic process and there is a large amount of heat of compression. The compressed air energy storage system with heat storage stores the heat of compression in the air compression process in the heat storage device, and in the process of releasing energy, uses the compressed heat of storage to heat the compressed air, and then drives the turbine to work, compared to combustion. The conventional compressed air energy storage system of fuel can greatly improve the energy storage efficiency of the system due to the recovery of the heat of compression in the air compression process. At the same time, the system removes the combustion chamber and achieves zero emissions due to the use of compressed heat instead of fuel combustion. Requirements. The main disadvantage of this system is that the initial investment cost of the system will increase compared to conventional compressed air energy storage plants due to the addition of heat storage devices.

The size of the small compressed air energy storage system is generally 10MW. It uses the above-ground high-pressure vessels to store compressed air, which breaks the dependence of large traditional compressed air power stations on gas storage caves, and has greater flexibility. Compared with large power plants, compressed air energy storage devices and systems - new applications for modified aircraft systems are more suitable for distributed energy supply in urban areas, small power grids, etc., for power demand side management, uninterrupted Power supply, etc.; it can also be built near renewable energy systems such as wind farms to regulate the supply of stable renewable energy.

Through the compressed air energy storage system with heat storage, the solar thermal energy can be stored in the heat storage device, the compressed air is heated when needed, and then the turbine power is driven to solve the problem of intermittent and unstable solar energy. In addition to solar thermal energy, waste heat and waste heat in power, chemical, cement and other industries can be used as external heat sources for compressed air energy storage systems. The compressed air energy storage system with heat storage has broad application prospects.

On the whole, the compressed air energy storage technology is generally mature. Although its energy conversion efficiency is not as high as that of the battery, the system has large energy storage capacity and lower average cost than other energy storage batteries. It is an intermittent energy source such as wind power generation and photovoltaic power generation. In the context of a large number of developments, it has gained wide recognition worldwide. Currently in the world, the United States and Germany are in a leading position, followed by Japan and Europe, and China has made important progress in the field of new compressed air energy storage.

Compressed air energy storage technology based on gas turbine is difficult to promote in China, and there are three major constraints. First of all, China's gas turbine industry is relatively backward, and the core technology of gas turbines has not yet been fully grasped. The large-scale gas turbines produced by foreign technology have not obtained design technology, and the varieties are single and expensive. Secondly, gas turbines must burn oil and gas, and China is a country that lacks oil and gas. Third, a large capacity gas storage device is required. With the increase in the demand for energy storage in the market, with the improvement of the level of China's machinery manufacturing industry, with the increase in the proportion of natural gas use and the use of alternative energy sources, these difficulties will be gradually resolved with the attention of people on the resources of large-scale gas storage devices. .

4. Several schemes for realizing compressed air energy storage by aircraft modification As mentioned above, China has not yet fully grasped the core technology of gas turbine design. The manufacture of power plant gas turbines relies on the introduction of foreign technology, with few varieties and specifications, and the price is expensive. The space chosen is limited. However, China's aviation industry has produced a variety of aero engines in various batches for many years. Although many of them are imitations, they have been manufacturing and operating for many years. Among them, the turboprop engine is used to drive the aircraft propeller, it can directly output mechanical power, and it was transformed into a ground gas turbine for power generation as early as the 1970s. Since the aircraft land engine can be refurbished with a retired engine, the price is lower. Beizhong Plant and Aero Engine Factory have cooperated in the production of more than 20 sets of 2000kW aircraft mobile power station YD2000. According to our national conditions, as a starting point, this engine can be used to transform into a 7600kW compressed air energy storage power station. In addition to burning oil, the turboprop modified engine can burn natural gas, oil with gas, coke oven gas and other gas fuels. Of course, China's aviation industry can currently provide other types of aircraft land products, such as QD-128. In fact, you can have many choices for compressors and expanders for compressed air storage, such as piston compressors and expanders, screw compressors and expanders, but comparable compressors and turbines for gas turbines. Large capacity, high efficiency and more advantages. In the following, only a few solutions are proposed to realize the compressed air energy storage by using the modification of the domestic turbo engine.

See the schematic diagram of the YD2000 unit for turboelectric engine ground power generation.

(1) Performance parameters Compressor pressure ratio: 7.45 Compressor flow: 19.54kg/s Turbine exhaust flow: 20.3kg/s Exhaust temperature: <450°C Rated output power: 2000kW YD2000 principle 013 years thermal power plant pollutant purification The Green Energy Technology Seminar and the Environmental Technology and Equipment Professional Committee (3rd) Conference (2) The traditional gas turbine technology-based compressed air energy storage power generation system is modified for the compressed air energy storage system () In comparison, it can be seen that the original engine turbine is directly connected to the compressor and operates synchronously, while the middle turbine and the compressor are separated, and are respectively connected to the synchronous generator and the synchronous motor through the gear box. They each operate separately. It is estimated that the synchronous generator power is about 7600 kW. The synchronous motor power is about 5600 kW. Of course, it is also possible to use a double-output shaft motor as both an electric motor and a generator. But it must be connected by a clutch and a compressor and a generator. Which plan to choose is good, it should be decided after the technical and economic analysis and comparison.

The gas turbine output delivered by the original engine gearbox is much less than the power of the compressor and turbine, so the original gearbox cannot be used. The speed of the generator and motor can be selected to be 3000r/min. The newly selected gearbox has a large power, but the speed is relatively small. After the turbine and compressor are separated, the respective rotor and casing are modified.

The compressor outlet is equipped with a check valve to prevent the compressed air from being lost during shutdown. A quick closing valve and a regulating valve are added to the air line in front of the combustion chamber. The regulator valve is used to adjust the amount of air required to initiate the speed increase. After the turbine and the compressor are separated, the moment of inertia and damping of the shafting system are greatly reduced, and the unit is easy to overspeed when the load is unloaded. When the machine is stopped, the fuel is first turned off, and then the regulating valve and the quick closing valve are closed in time. Conventional gas turbines do not require these two valves because they have a compressor load during shutdown. As soon as the fuel is shut off, the speed drops, the air pressure drops, and the turbine's power source disappears, naturally shutting down.

Because of the gas storage device as the power source, the turbine starts very quickly, and he no longer starts up with the starter motor like a conventional gas turbine. When the air storage device is depleted, the shut-off valve to the gas storage device can be closed, the valve to the combustion chamber can be opened, the compressor can be turned on, and the gas turbine can be operated like a conventional gas turbine. Although the power is only 2000 kW, it can also be adjusted. Peak effect.

After the engine has been decomposed in this way, the efficiency is definitely low due to the temperature, pressure loss, and other additional losses after the compressor. In order to improve efficiency, the exhaust heat of nearly 450*C can be utilized to preheat the air entering the combustion chamber through the regenerator. As shown.

Compressed air energy storage power generation unit and system - new use of modified aircraft system with regenerator system (3) fuel-free compressed air energy storage system with heat storage can cancel the combustion chamber without fuel directly The energy of the compressed air lets the turbine work, let's do a simple calculation. Assume that the compressed air temperature is 20*C and the pressure is 0.7 MPa. The turbine exhaust pressure is O.IMPa. Its isentropic adiabatic enthalpy is 125kJ/Kg. If the air flow rate is 19.54kg/s, the volume flow is equal to 2.3m 3 / s, much lower than the rated volume flow of gas turbine 7.5m3 / s, that is, a lot of deviation from the design point, assuming that the turbine efficiency is reduced to 0.8, the mechanical efficiency is 0.98, the generator efficiency is 0.97, the turbine power is 1857kW... ...compressed lkg air consumption 200.7kJ work, release lkg air production 95kJ work, energy storage power generation efficiency is 0.473. Turbine exhaust temperature is about -80*C, the temperature is extremely low, turbine exhaust can be used for refrigeration. The condition is to check the turbine for low temperature strength to see if it can operate normally.

From the perspective of energy storage, the above scheme is too inefficient. Whether the efficiency can be improved, the reason for the low efficiency of the scheme is that the air will generate heat of compression after being compressed by the compressor, but this part of the heat is lost after entering the gas storage device. Secondly, if the turbine operating point deviates too much from the design point, especially if the volume flow drops too much, the turbine efficiency will decrease. The calculation shows that when the intake air temperature is 2 (TC, the pressure ratio reaches 7.45. The compressor outlet air temperature will rise to about 287*C. If we store this part of the heat in the heat storage, the compressed air is released for work. At the same time, the heat is heated by the heat storage device, and then the turbine is expanded to work, so that the heat generated by the compressor can be recycled. The filled heat storage device shown in the present invention needs sufficient volume, and the filler can be stone, Ceramics, concrete, etc., filled type heat storage device is simple in structure, common in materials, easy to operate and maintain. If the temperature before the turbine reaches 220*C, the pressure is 0.7MPa, the exhaust pressure is O.IMPa, and its isentropic adiabatic enthalpy is 212kJ/Kg. If the intake air flow rate is 7.5m3/s when the rated flow rate of the turbine is 20.3kg/s, according to experience, the flow efficiency of the turbine is constant, the flow efficiency is basically the same, that is, the turbine efficiency can be taken as the rated value, and the actual enthalpy drop is 192kJ. /Kg, if the mechanical efficiency is 0.98, the generator efficiency is 0.97. When the volume flow rate is 7.5m3/s, the mass flow rate of the turbine is 36.2kg/s, the turbine power is 6609kW, and the energy consumption of the compressed lkg air is 287kJ. Lkg The work performed by the air is 156kJ, and the energy storage efficiency is 0.575. The turbine exhaust temperature is about 30.7*C. From the above calculations, after adding the heat storage device and maintaining the rated volume flow, the energy storage efficiency is 0.473. Increased to 0.575, the efficiency is significantly improved.

By taking full advantage of the turbine's flow capacity, the mass flow is increased and the turbine output is close to the level of the gas turbine.

2013 Thermal Power Plant Pollutant Purification and Green Energy Technology Seminar and Environmental Protection Technology and Equipment Professional Committee (3rd) Conference (4) The use of solar energy compressed air energy storage power generation system from the above calculation and analysis, the expansion ratio is Timing, the higher the temperature before the turbine, the stronger the unit mass air is. Usually, the nighttime electrical load is low, the power consumption is low, the system absorbs the electric energy, and the compressor compresses the air to store energy. During the day, the peak of electricity consumption, the sun rises, the light is getting stronger, just use solar energy to heat the heat storage device, improve the air temperature before the turbine, thereby increasing the turbine output and increasing the peaking effect. Solar collectors are slotted, disc, tower, etc. The trough solar collector is relatively mature, and the collector temperature can reach 300400*C. The power of the disc is small. The temperature of the tower solar collector can be made very high, the power can be made larger, the heating part is fixed, easy to design, technically superior, but the price is high. As shown, the water and steam are heated by solar energy, and the endothermic section includes an evaporator and a superheater, and the steam is separated by a steam drum. The saturated water and superheated steam produced by the solar boiler are respectively introduced into the heat storage device, the regenerative section of the heat storage is provided with a saturated water exothermic section and the superheated steam exothermic section, and the superheated steam exothermic section is placed at the high temperature end of the heat storage device, that is, the turbine side The saturated water exothermic section is placed at the low temperature end of the heat storage device, that is, the gas storage device side. After the superheated steam and saturated water are cooled by the heat storage device, the condensed water is heated by the water pump into the evaporator, and the generated wet steam enters the steam drum, the steam and water are separated, and the saturated water is introduced into the low temperature heating section of the heat storage device, and the steam in the steam drum Enter the superheater and then introduce the high temperature section of the heat reservoir. Water is closed in the system and acts only as a heat transfer medium for heating the air and does not work directly.

Assume that the turbine front temperature is 400*C, the pressure is 0.7MPa, the exhaust pressure is O.IMPa, and its isentropic adiabatic enthalpy is 291.6kJ/Kg. The actual enthalpy drop is 251kJ/Kg. When the mechanical efficiency is 0.98, the generator efficiency At 0.97, a power of 1 degree can be used to deliver 0.8742 kWh. The mass flow rate at a nominal volume flow rate of 7.522m3/s is 27.2kg/s. At this flow rate, the turbine power is a new use of the compressed air energy storage power generation unit and system-modified aircraft system. 5. Summary The use of aviation engines is described above. The basic set constitutes several schemes for the compressed air energy storage power generation system, and the energy storage efficiency and output power are preliminarily calculated, each having its own characteristics.

The fuel-filled system has a high temperature before the turbine, and the turbine has a large output, which requires the smallest volume of the gas storage device.

A system with a heat accumulator can combine different systems. It does not require a combustion chamber, it can recover the heat of the compressor, and it can also accept the heat of the solar energy and other waste heat.

In general, the higher the air temperature before the turbine, the stronger the function of the turbine, the less the amount of air consumed by the same power, and the lower the volume requirement for the gas storage device. With the implementation of the grid price difference between China's power grids and the opening of sufficient grades, it will certainly promote the development of compressed air energy storage.

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