There are many types of coal used in power plants. They mix different types of coal to achieve low cost and high yield. So it is not possible to specifically answer the question you asked. Please refer to the following to understand. You can also visit the coal website to check supply and demand information, many of which relate to thermal coal.
Quality requirements for coal used in power generation: ?
Pulverized coal furnaces in power plants have a wide range of applications for coal types. It can be designed to burn high volatility lignite or low volatility anthracite. However, for an installed boiler, it is impossible to burn coal containing various volatile components as this is limited by the type of burner and the structure of the furnace. The indicatorss of coal quality for power generation include: ?
①Volatile content. It is the main indicator for determining the ignition characteristics of coal. The higher the volatile content, the easier it is to catch fire. According to the design requirements of the boiler, the value of volatile materials present in the coal supply should not change too much, otherwise it will affect the normal operation of the boiler. If the original design uses low volatile coal and switches to high volatile coal, the center of the flame is close to the burner outlet, which can cause the burner to go out and the furnace to shut down if the original design uses low volatile coal. highly volatile coal; , If you switch to burning low volatile coal, the combustion will be incomplete due to too late ignition, and even cause extinguishing accidents. Therefore, when you provideez coal, try to supply it according to the type of volatile coal originally designed or a similar type of coal. ?
②Contents in ashes. The ash content will reduce the flame propagation speed, delay the ignition time, make combustion unstable and reduce the oven temperature. ?
③Humidity. Moisture is one of the harmful substances in the combustion process. It absorbs a large amount of heat during the combustion process and has a much greater impact on combustion than ash. ?
④ Calories. The calorific value constitutes an important basis for the design of a boiler. Since the coal pulverized in power plants has strong adaptability to coal types, it is sufficient as long as the calorific value of the coal generally conforms to the design requirements of the boiler. ?
⑤Melting point of ashes. Since the temperature at the center ofthe flame of pulverized coal furnace is generally above 1500°C, at such a high temperature, most of the coal ash is in a softened or fluid state. ?
⑥The sulfur content of coal. Sulfur is a harmful impurity in coal. Although it has no effect on the combustion itself, its content is too high, which may cause serious equipment corrosion and environmental pollution. Therefore, the sulfur content of coal burned in power plants cannot be too high, and the general requirement is that it cannot exceed 2.5%.