With the development of frequency control technology and the improvement of localization rate, the equipment price has been greatly reduced, so the frequency conversion operation of vacuum system is a development direction of energy saving and consumption reduction in gas power plant. Vacuum system is an important auxiliary system of power plant. As the main energy consumption equipment of the circulating water system, the vacuum system is the key link of energy saving in the operation of the circulating water system. The application of vacuum system in gas power plant is analyzed according to the product characteristics and working principle of vacuum system.
Vacuum system characteristics:
1. High vacuum, stable performance and long service life
2. Flow: 4-1300m3 / HR (single pump)
3. Vacuum service range: 0.5-500mbar (absolute pressure)
4. No need to connect to water source
5. Compact structure, less floor space
6. Simple operation, convenient maintenance and low noise
7. PLC joint control of multiple units can be realized
8. GDMS system can be connected
The working principle of the vacuum system is to start the main vacuum pump group of the system to work until the vacuum degree in the vacuum tank reaches the set upper limit value, the vacuum pump will automatically stop running, and the vacuum in the central vacuum system will be maintained automatically by the vacuum check valve on the pipeline. If the vacuum degree in the vacuum tank drops and is lower than the set lower limit value due to work demand, the standby vacuum pump group will start automatically. Thus, the vacuum degree of the vacuum system can maintain a stable vacuum source and meet the production requirements.
Thermal power plants need a large number of cooling water supply continuously because of the supply of heat engine cooling source and various cooling needs. A million kilowatt thermal power plant of condensing unit needs 30m3 / s cold water. Such a large amount of cooling water is pumped into the condenser by vacuum pump to exchange heat with the superheated steam after work. Therefore, the energy consumption of vacuum pump in gas power plant is very high. How to reduce the energy consumption of vacuum pump operation, reduce the cost of power generation, the transformation and optimization of the cold end of gas power plant in the design become the key link.
Gas power plant is a cycle system composed of gas turbine and generator, waste heat boiler and steam turbine. It converts the high-temperature exhaust gas discharged by gas turbine into steam through waste heat boiler recovery, and then inject the steam into steam turbine for power generation. With the development of gas turbine technology, the change of national energy structure and the improvement of environmental protection requirements, the development of gas turbine power plant is bound to be greatly accelerated.
After the application of vacuum system in gas power plant, its advantages are mainly reflected in the following aspects:
1. The overall cycle efficiency of the power plant is high;
2. Little environmental pollution;
3. The unit (ratio) investment is low; under the same conditions, the unit (ratio) investment is low.
4. Good peak regulation performance; fast start and stop. The gas turbine is generally less than 20 minutes from Startup to full load operation, and the time can be shorter when it is started quickly.
5. Less land occupation; since there is no need for coal yard, coal conveying system, ash and slag removal system, as well as dust removal, desulfurization, system, etc., the plant area is much smaller than that of coal-fired power plant.
6. Low water consumption; gas turbine power plants do not need a large amount of cooling water, which can reduce the supply of cooling water, which is particularly important for the construction of power plants in dry and water deficient areas.
7. The construction period of the plant is short; the automation degree is high, and the advanced vacuum system is adopted, so the control personnel can be greatly reduced.
8. The auxiliary power consumption rate is low.
Vacuum system in gas power plant