What Is a Combustion Turbine?

Gas Turbine is an internal combustion power machine that uses a continuously flowing gas as a working substance to drive the impeller to rotate at high speed and convert the energy of fuel into useful work.

Gas turbines in the main air and gas processes, only

In 1791, the British Barber first described

Gas turbines are rarely used in general automobiles and personal machines, and are related to their advantages and disadvantages. In fact, there were automobile companies that developed gas turbine family cars. For example, in 1950, JET 1.0 manufactured by Rover or Chrysler Turbine Car of Chrysler worked for decades until the 1980s, but finally abandoned the plan because of more disadvantages than benefits. ^[2]

Combustion chambers and turbines not only have high operating temperatures, but also withstand thermal shocks caused by drastic temperature changes during start-up and shutdown of gas turbines, and poor working conditions, so they are key components that determine the life of gas turbines. In order to ensure sufficient life, the parts with the worst working conditions in these two components, such as flame tubes and blades, must be made of high temperature materials such as nickel-based and cobalt-based alloys, and air cooling must be used to reduce the operating temperature.

For a gas turbine, in addition to the main components, there must be a complete regulation and security system. In addition, it needs to be equipped with good auxiliary systems and equipment, including: starter, fuel system, lubrication system, air filter, air intake and Exhaust muffler, etc.

There are two types of gas turbines, heavy and light. Heavy-duty parts are relatively heavy, with long overhaul periods and a life span of more than 100,000 hours. The lightweight structure is compact and light, and the materials used are generally better. Among them, the aircraft structure is the most compact and lightest, but has a short life.

Compared with piston internal combustion engines and steam power plants, the main advantages of gas turbines are small and light. Mass per unit of power, heavy gas turbines are generally 2 to 5 kg / kW, while aircraft are generally less than 0.2 kg / kW. Gas turbines have a small footprint. When used in transportation machinery such as cars and boats, they can save space and can be equipped with more powerful gas turbines to increase the speed of cars and boats. The main disadvantages of gas turbines are that they are not efficient enough, the efficiency decreases rapidly under part load, and the fuel consumption is high at no load.

Different application departments have different requirements and operating conditions for gas turbines. Most of the gas turbines with a power of more than 10 MW are used for power generation, and almost all of them are used for power generation.

The gas turbine generator set can start quickly without external power and has good maneuverability. It can be used to drive peak loads and serve as emergency backup in the power grid, which can better guarantee the safe operation of the power grid, so it is widely used. In mobile power stations such as automobile (or trailer) power stations and train power stations, gas turbines are also widely used due to their small size. In addition, there are many portable power sources that use gas turbines, with the minimum power below 10 kilowatts.

The future development trend of gas turbines is to improve efficiency, adopt high-temperature ceramic materials, use nuclear energy and develop coal combustion technology. The key to improving efficiency is to increase the initial temperature of the gas, that is, to improve the cooling technology of the turbine blades, and develop high-temperature materials that can withstand higher temperatures. The second is to increase the compression ratio and develop compressors with fewer stages and higher compression ratios. The third is to improve the efficiency of each component.

High-temperature ceramic materials can work at high temperatures above 1360 ° C. When it is used as high-temperature parts such as turbine blades and flame tubes of combustion chambers, the initial gas temperature can be greatly increased without air cooling, thereby greatly increasing the gas turbine. effectiveness. High-temperature ceramic materials suitable for gas turbines include silicon nitride and silicon carbide.

A device working in a closed cycle can utilize nuclear energy, and it uses a high-temperature gas-cooled reactor as a

Using high-temperature gas as the working medium, the chemical energy in the working fuel is converted into

Gas turbine advanced sealing technology is a branch field that has attracted great attention abroad in the past ten years.

Ship power units mainly include: steam power units,

Gas turbine is an advanced and complex complete set of power machinery and equipment, and is a typical high-tech intensive product. As a carrier of high technology, gas turbines represent the comprehensive level of development in multiple theoretical disciplines and multiple engineering fields, and are the leading technology of the 21st century. The development of a gas turbine industry combining new technologies, new materials and new technologies is one of the important signs of the country's high-tech level and scientific and technological strength, and has a very prominent strategic position. ^[6]

Due to various reasons, there is still a large gap between China's gas turbines and the international advanced level, and no real industry has yet formed. The state of backward power in many fields has become a "bottleneck" restricting the development of the national economy. Its technology is controlled by only a few developed countries in the world. Advanced gas turbines still restrict exports to China in Western countries.

Gas turbines are major core equipment. If they depend on imports for a long time, they will be restrained in key technologies, which is not conducive to the healthy and rapid development of China's gas turbine power industry and related industries. From the perspective of market capacity, China s four major projects in the new century, West-to-East Gas Transmission, West-to-East Power Transmission, and South-to-North Water Diversion, all require a large number of 30 MW industrial gas turbines. The rapid and healthy development of China requires a large number of 30 MW-class ship gas turbines, and China has become the world's largest potential market for gas turbines.

Facing the new situation of economic globalization, fierce competition in the international gas turbine market, and the high degree of foreign monopoly, the state attaches great importance to the development of the national gas turbine industry in China. In the Five-Year Plan and long-term development plan, heavy-duty gas turbines are one of the 10 major technical equipments that the country has prioritized for development. It is a key development area of the national equipment manufacturing industry, especially gas-steam combined cycle units and integrated gasification gas-steam combined cycle units. It is expected that with the rapid growth of China's energy demand and the large-scale development and utilization of natural gas resources, gas turbines are forming a "explosive growth" market. By 2020, the national gas turbine combined cycle installed capacity will reach 55 million kilowatts, which is 25 times that of the similar installed capacity in the 50 years before 2000. A conservative estimate is that the value of the gas turbines needed by PetroChina alone reached 3 billion yuan a year. By 2015, the market capacity of domestic gas turbines will reach 30 billion yuan, while the international market capacity will reach 270 billion yuan.