A, burner classification
Biomass pellet fuel burner has many forms and classification methods. According to different charging methods, burners can be divided into three types: upper charging type, lower charging type and horizontal charging type.
1, ignition
There are two main ignition methods: one is to use electronic ignition device, and the other is to use pilot flame. Electronic ignition has lower pollutant emission and simpler control than ignition flame.
Step 2 operate
In order to ensure the clean emission of the burner, it is necessary to avoid starting or using the pilot flame many times as much as possible, and at the same time, to ensure stable combustion conditions. A well-designed burner can output rated heat with an efficiency of over 90%. When it runs under low load or the load changes, the efficiency will decrease, but it is generally above 86%.
The burner can accurately control the feed rate according to the heat demand, and control the combustion process by adjusting the amount of combustion-supporting air. According to the heat demand, the particle burner is usually set to several different fixed heat output gears. When the output heat is lower than the set value, the burner will automatically start running until the set heat output value is reached. Temperature sensors are usually used to monitor heat output, and combustion air is provided by blowers. λ sensor is used to monitor and control the supply of combustion air to ensure efficient and clean combustion. Small combustion equipment usually controls the heat output by opening and closing the thermostat, while large combustion equipment uses complex control methods to control the heat output.
The operation mode of burner is mainly divided into two categories: one is represented by Sweden, and the burner is an independent unit, often equipped with a standard boiler. Feeding, ignition and combustion are all automatic, but its heat output is uncontrollable or there are only two options, namely, full output (100%) and half output (50%); The other, represented by Austria, has the functions of automatic feeding, ignition, combustion and ash removal, and its calorific value can be adjusted within a certain range (such as 30%~ 100%), which is very convenient to use, but its price is relatively high, about 50% higher than the former.
3. Ash cleaning device
Ash cleaning devices can be divided into mechanical scraping type and mechanical vibration type, and there are other ways. Some burners are also equipped with ash presses to meet the needs of long-term automatic operation. A well-designed burner requires little maintenance. At present, the ash cleaning devices of most burners can meet the requirement of cleaning once a week.
4. Pollutant discharge
The pollutants in the flue gas of biomass particle burner mainly include incomplete combustion particles CxHy and harmful gas CO, which are mainly produced by incomplete combustion of fuel and also related to the composition of particle fuel. The flue gas emission of the burner is very low, especially the burner with air inlet and exhaust device. Because the content of nitrogen and sulfur in biomass pellet fuel is relatively low, the emission of nitrogen oxides and SOx is much lower than that of coal.