Introduction to Thermal Power Generation
Input and Output of Thermal Power Generation Units
Thermal Power generation is the main way to generate electricity of the current power system. Take the large-capacity steam power generation as an example, it based on the steam cycle method.
Heat produced by burning fossil fuels. The water flowing through the boiler is transferred by heat and turns into high-temperature, high-pressure steam. The driving or impelling force of steam turbine can be converted into mechanical energy. The generator then converts the mechanical energy into electrical energy (or electric power) that can be transmitted to homes and buildings through transmission lines.
In the Combustion Process of fossil fuels and oxygen, it forms many associated products including fly ash, bottom ash, oxides of nitrogen, sulfur, carbon dioxide and particulate matter and so on. Since it has a lot of impact on the environment, we also set up many environmental protection equipment to improve the emission from power generation to fulfill the environmental standards.
The Methods of Thermal Power Generation
The methods of thermal power generation in Taipower can be generally divided into the following four types：
Steam Units
In combustion reaction, chemical energy is transformed to heat energy. Heat produced by burning fossil fuels. The water flowing through the boiler is transferred by heat and turns into high-temperature, high-pressure steam. The driving or impelling force of steam turbine can be converted into mechanical energy. The generator then converts the mechanical energy into electrical energy (or electric power) that can be transmitted to homes and buildings through transmission lines. This type of power generation has the advantages of low fuel cost and large power generating capacity. However, it has the disadvantages of high installation cost and lack of quick start capability. Since the fossil fuel includes coal, heavy oil, and liquid nature gas (LNG) etc., steam units can be divided into coal-fired steam unit, oil-fired steam unit and gas-fired steam unit depending on the type of fuel.
Combined-cycle Units
Combined-cycle power generation is the power generation method that combines gas turbine and steam turbine. The high-temperature exhaust gases from the gas turbine can be transferred to the heat recovery steam generator (HRSG) that captures heat to produce steam, which is then supplied to a steam turbine to generate additional electric power. This type of power generation has the advantages of a high heat efficiency, quick start capability, and low air pollutant emissions. Recently, Taipower also increases power supply from this type of units.
Gas Turbines
Gas turbines are a type of internal combustion (IC) engine. In burning process, the fuel (i.e. natural gas or diesel oil) is injected into the combustion cylinder and mixed with the high-pressure air passing through the air compressor to produces hot gases that impel a turbine to generate electric power. This type of power generation has the advantages of quick start capability but has the disadvantages of high fuel cost and low efficiency.
Diesel Engines
In the cylinder of the diesel engine, air is compressed by a piston to such a high temperature above the ignition point of diesel fuel (i.e. heavy oil or diesel oil) to ignite the fuel directly injected into the cylinder before combustion. The high-temperature and high-pressure air gas generated by the combustion will push the piston to work. Next, the driving or impelling force acted on piston rotates the crankshaft synchronously connected by the generator to produce electrical energy. This type of power generation has the advantages of quick start capability, but has the disadvantages of high fuel cost, low efficiency and low generating capacity.