The largest consumption of water in the production process of thermal power plants is the cooling process.
A thermal power plant is a factory that uses coal, oil and natural gas as fuel to produce electrical energy. Its basic production process is as follows: fuel is burned in the boiler and heated water is heated. transformed into steam and the fuel is steamed. Chemical energy is converted into thermal energy, the steam pressure drives the rotation of the steam turbine, the thermal energy is converted into mechanical energy, then the steam turbine drives the rotation of the generator, converting the energy mechanical energy is transformed into electrical energy.
Thermal power plants are classified according to their fuel: coal-fired power plants, oil-fired power plants, gas-fired power plants, hp power plantswastewater and power plants using garbage and industrial waste as fuel. . Depending on the pressure and temperature of the steam: the working fluid in the boiler is water. The critical water parameters are: 22.064 MPa, 373.99 ℃. At this pressure and temperature, the density of water and steam is the same, which is called the critical value. water point.
If the pressure of the working fluid in the furnace is lower than this pressure, it is called a subcritical boiler. If the pressure is higher than this, it is called a supercritical boiler. The steam temperature in the oven is. not lower than 593℃ or the vapor pressure is not lower than 31MPa. It is called supercritical boiler.
According to the installed capacity of power plants
Small capacity power plants (less than 100 MW), medium capacity power plants (100-250 MW ), power stationslarge and medium capacity plants (250-1,000 MW), large capacity power plants (above 1,000 MW); Thermal power plants produce wastewater in several categories: industrial wastewater, domestic wastewater, coal-containing wastewater, and acid-base wastewater. The processing method is chosen depending on the classification, the process is also different.
Thermal power plant boilers have different levels of pressure and temperatures depending on the size of the unit. They can be divided into low pressure, medium pressure, high pressure and ultra high. -pressure units, subcritical and supercritical.
For boilers with a low pressure boiler outlet steam pressure of 2.45 MPa or less, the steam temperature is mainly the saturation temperature or does not exceed 400 °C.
The steam pressure at the boiler outlet meansThe pressure is specified as 3.83MPa and the steam temperature is 450°C.
The steam outlet pressure of the ultra high pressure boiler is specified as 13.7 MPa, and the steam outlet temperature is 540°C, and some are 555°C .
The outlet steam pressure of subcritical pressure boilers is specified as 16.7 MPa and the outlet steam temperature is 540°C or 555°C, some being 570 °C.
The pressure of supercritical boilers is generally between 25 and 27 MPa.