How to select fuel correctly for burner
Correct selection of fuel is an important part of burner operation. Therefore, it is necessary to master the characteristics of fuel, understand the combustion principle, and select fuel according to the fuel type required by boiler design to achieve the design requirements and expected results. The fuel used for burner can be divided into three categories according to physical state: solid fuel, liquid fuel and gas fuel.
1、 Solid fuel
Solid fuels include the following categories:
1. Bituminous coal: it is called long bituminous coal, which is gray black or black, and its surface is matte or oily.
2. Anthracite: it is called white coal or firewood coal, black, sometimes gray, hard and brittle, with shiny section.
3. Lean coal: between bituminous coal and anthracite, its volatile content is 10%~20%, which is easier to ignite.
4. Coal gangue: This is a kind of stone containing combustible in coal seam, with high ash content, more than 50%, low calorific value, and not suitable for ignition.
5. Oil-bearing shale is an oil-bearing mineral with ash content as high as 50% - 70% and volatile content as high as 80% - 90%. It is easy to catch fire.
6. Wood: Compared with coal, it has low ash content, high volatile content, fast combustion speed, but low calorific value.
2、 Liquid fuel
The liquid fuels commonly used in burners include heavy oil, residual oil and light diesel oil. Because the fuel contains a large amount of carbon and hydrogen and has a low water content, the heat generation is very high. Diesel oil is widely used for ignition and stable combustion of small and medium-sized thermal power plants, domestic boilers and large boilers, and heavy oil is mostly used for power station boilers.
1. Diesel fuel: diesel fuel has low density, is a kind of fuel with low viscosity, good fluidity, no need for preheating, and can be directly ignited for starting. It can be started by direct ignition. Diesel fuel has less sulfur content and little environmental pollution.
2. Heavy oil: heavy oil is the general name of light distillates extracted from petroleum refining process - heavy distillates after gasoline, kerosene and diesel. The main components of heavy oil are carbon and hydrogen, with little ash and moisture content, and high and stable calorific value.
3. Residual oil: residual oil is the residue from petroleum refining, and its main components are macromolecular alkanes and colloidal substances, which can be directly used as fuel. The residual oil has a high viscosity and can flow when heated to a certain temperature. Its storage, transportation and management are very convenient.
3、 Gaseous fuel
Gas fuel is a gaseous fuel at normal temperature. Compared with various solid fuels and liquid fuels, it has very prominent advantages: less pollution, high heat generation, easy operation, etc. It is an ideal high-quality boiler fuel. Gas fuel includes natural gas fuel and artificial gas fuel.
1. Natural gas fuel: There are two kinds of natural gas fuel: gas field gas and oil field associated gas. Gas field gas is a kind of combustible gas from the pure gas field, and the associated gas in the oil field is the combustible gas generated in the process of oil exploitation. The main components of the above two natural gaseous fuels are methane, and also contain a small amount of alkanes, olefins, carbon dioxide, hydrogen sulfide and nitrogen, both of which have high calorific value. Because natural gas is an important chemical raw material, only a few boilers near the production area can use natural gas as fuel.
2. Artificial gas fuel: There are many types of artificial gas fuel, including blast furnace gas, coke oven gas, producer gas and liquefied petroleum gas. Except for liquefied gas, the calorific value of other gases is very low. Although the calorific value of blast furnace gas and coke oven gas is low, they are mainly used as chemical raw materials and fuel for various heating furnaces, and only a small amount of them are used as boiler fuel locally. Producer gas and liquefied petroleum gas are generally not used as boiler fuel.