The selection of burners for oil-fired and gas-fired boilers shall be based on the structural characteristics and performance requirements of the boiler body and the user's service conditions. Generally, they can be selected according to the following principles:
1) According to the types of fuels used by users, liquid fuels include kerosene, diesel, heavy oil, residue and waste oil, and gaseous fuels include city gas, natural gas, liquefied petroleum gas and biogas. The fuels used shall have necessary analysis data:
① Kerosene and diesel oil shall have calorific value and density.
② Heavy oil, residue and waste oil shall have viscosity, calorific value, moisture, flash point, mechanical impurities, ash, freezing point, density and oil supply temperature.
③ The fuel gas shall have calorific value, gas supply pressure and density.
2) The atomization mode of fuel injection nozzle or the type of gas burner in the burner shall be selected according to the boiler performance and furnace structure.
3) The output power of the burner shall match the rated output of the boiler, and the shape of the flame, such as length and diameter, shall be selected to adapt to the furnace structure. The air required for fuel combustion is supplied from the root of the flare to quickly and evenly mix the oil mist or gas with the air to ensure complete combustion.
The fuel consumption is calculated according to the rated output and boiler efficiency determined by the boiler transformation, and then the configuration number of burners is determined according to the power of the selected single burner. Increasing the number of burners is conducive to the atomization quality and ensure the mixing of air and oil. However, too many burners are not convenient for operation and maintenance, which will also bring difficulties to the layout of burners.
4) The adjustment range of burner shall be large, which can meet the needs of boiler load change and ensure complete and stable combustion under different working conditions.
5) Fuel atomization consumes less energy and the resistance of air regulating device is small.
6) The impact of flue gas emission and noise must meet the requirements of environmental protection standards, mainly the emissions of S02, CO and NOx must be lower than the national regulations, and the burner with low NOx and low noise shall be selected.
7) The burner can be assembled in two ways: integral type and split type. Integral type, that is, the burner body, burner fan and combustion system (including oil pump, solenoid valve, servo motor, etc.) are integrated; Split type, i.e. burner body (including combustion head, fuel oil or gas system), burner fan and burner control system (including control box, fan thermal relay, AC contactor, etc.) are independent systems, which shall be selected according to the specific conditions of boiler and user requirements.
8) Burners with simple structure, reliable operation, easy adjustment, control and repair, and easy to realize automatic control of combustion process shall be selected.
9) The brand, performance, price, service life and after-sales service of burner shall be comprehensively compared.
10) In addition to overcoming the resistance of boiler body, the air pressure of burner shall also overcome the resistance of economizer and flue gas system.