Nuclear power generation: Nuclear energy is converted into the internal energy of water and water vapor, the mechanical energy of the generator rotor, and electrical energy.
Nuclear power generation is a method of producing electricity using thermal energy released by nuclear fission in a nuclear reactor. It is very similar to thermal energy production. It simply uses nuclear reactors and steam generators to replace thermal boilers, and uses nuclear fission energy to replace the chemical energy of fossil fuels. Except boiling water reactors, other types of power reactors heat the coolant in the primary loop through the reactor core, transfer the heat to the water in the secondary or tertiary loop of the generator steam, then form steam to drive the turbogenerator. In a reactorr boiling water, the coolant of the primary circuit is heated through the reactor core and transformed into saturated steam with a pressure of approximately 70 atmospheres. After the steam and water are separated and dried, the steam turbine generator is directly driven.
Workflow:
1. Coal Burning:
Use a coal conveyor belt to transport coal from the coal yard to the coal hopper. In order to improve the efficiency of large thermal power plants, coal combustion efficiency is to burn pulverized coal. Therefore, the raw coal in the coal hopper must first be sent to the coal crusher to be crushed into pulverized coal. The crushed pulverized coal is transported by hot air and sent to the boiler furnace via the pulverizer fan for combustion. The hot flue gases formed after the combustion of pulverized coalized flow along the horizontal duct and boiler tail duct, release heat and finally enter the dust collector.
Separate the burned coal ash. The clean combustion gases are evacuated to the atmosphere through the chimney under the action of the induced draft fan. The combustion air is sent by the fan into the air preheater installed on the flue, and the hot combustion gases are used to heat the air. In this way, on the one hand, in addition to increasing the temperature of the air entering the boiler, which facilitates the ignition and combustion of the pulverized coal, on the other hand, it can also reduce the temperature of the exhaust fumes and improve the utilization rate. thermal energy.
The hot air discharged from the air preheater is divided into two streams: one stream goes to the coal crusher to dry and transport the pulverized coal, and the other stream is sent directly to the coal crusher.t in the oven to maintain combustion. The ashes from the burned coal fall into the slag hopper below the kiln and are washed with water in the mortar pump room with the fine ash separated from the dust collector, then the mortar is pumped to the ash pond.
2. Thermal energy is converted into mechanical energy:
The water in the deaerator tank is boosted by the water feed pump and then sent to the economizer via the high pressure heater. In the economizer, the water is heated by the hot flue gases then enters the steam drum located at the top of the boiler. There are water pipes densely distributed around the boiler, called water-cooled walls.
The upper and lower ends of the water pipes of the water-cooled wall are connected to the steam drum through the collector. Water in the steam drum continuously circulates through the water-cooled wall, absorbing heatr. released during the combustion of coal. Some of the water is heated and boiled in the cold wall and then vaporized into water vapor. Saturated steam flows from the top of the drum to the superheater.
The saturated steam continues to absorb heat in the superheater and becomes superheated steam. Superheated steam has very high pressure and temperature, so it has high thermal potential energy. After the superheated steam containing thermal potential energy is fed into the steam turbine through the pipeline, the thermal potential energy is converted into kinetic energy. The steam flowing at high speed causes the turbine rotor to rotate, thereby forming mechanical energy.
3. Conversion of mechanical energy into electrical energy:
The steam turbine rotor and the generator rotor are connected together by a coupling. When the steamboatWhene the rotor of the machine rotates, it causes the rotation of the generator rotor. There is a small DC generator called an exciter at the other end of the generator rotor. The DC power generated by the exciter is sent to the generator rotor coil, making the rotor an electromagnet and creating a magnetic field around it.
As the generator rotor rotates, the magnetic field also rotates and the generator stator wires intersect the magnetic lines of force to induce current. In this way, the generator converts the mechanical energy of the turbine into electrical energy. Once the electrical energy is increased by the voltage passing through the transformer, it is sent to the electricity users via the transmission lines.
4. Water cycle:
The steam that releases thermal potential energy is discharged through the exhaust port located in the lower part of the turbine, called vapeur worn. The spent steam is cooled by the cooling water sent into the condenser by the circulating water pump in the condenser, and condenses into water again, and this water becomes condensed water. The condensate water is sent to the low pressure heater by the condensate water pump and finally returns to the deaerator, thus completing a cycle.
During the circulation process, it is inevitable that there will be leakage of carbonated water, that is, loss of carbonated water. Therefore, an appropriate amount of water must be supplied to the circulation system to ensure normal operation. operation of the cycle. High and low pressure heaters are devices used to improve the thermal efficiency of the cycle, and degassers are used to remove oxygen from water to reduce corrosion of equipment and pipelines.
Detailed information:
Energy conversion process of a thermal power plant:
1. The chemical energy of the fuel is converted into thermal energy in the boiler equipment.
2. The conversion of thermal energy into mechanical energy is carried out in the steam turbine.
3. The conversion of mechanical energy into electrical energy is carried out in the generator.
Main parameters and indicators of thermal power plants:
Classifications of fuels used in thermal power plants:
1. Coal-fired power plants: Coal includes anthracite, semi- There are five categories of bituminous coal, bituminous coal, lignite and low-grade coal.
2. Fuel-Fired Power Plants: Fuels include heavy oil, diesel, and crude oil. In general, fuel-fired power plants are not developed.
3. Gas-fired power plant : gas includes natural gas, artificial gas and underground gasification gas.