Analysis of the causes of black smoke in biomass boilers
Biomass particles are similar to bituminous coal, wood burning materials, etc., and their composition is not treated like anthracite. Therefore, the volatile matter yield is high, and if the combustion is insufficient, black smoke will be generated. However, high quality anthracite has the common characteristics with biomass particles, that is, high density, good hardness, and the like, although its volatile content will be more, as long as the combustion method is proper, it will greatly reduce or even not produce black smoke.
When choosing a biomass boiler, you must first understand the main components of the biomass particles. The carbon content is between about 75% and 85%, and the moisture content is between 1% and 3%. The ash content is about 3% to 6%. Although the fuel of biomass boilers is much less than that of ordinary coal boilers, there is even a saying that biomass boilers do not emit black smoke. However, when the fuel in the boiler is burning, it will produce a high temperature of 800-1000 degrees or higher. If the components in the biomass fuel are not fully burned, or the combustion control is not good, we will see black smoke. When the biomass particles are ignited and burned, the particles undergo strong physical and chemical reactions such as carbonization. When the combustion is incomplete or improper, the combustion produces a mixture of carbon monoxide, water vapor, hydrocarbons, and nitrogen oxides. At this time, if the power of the blower and the induced draft fan is too large, the mixed flue gas may be pumped away from the furnace body without being continuously burned, and then discharged into the atmosphere through the flue. If there is no dust removal process, we will see black smoke from the chimney of the boiler. Waste of fuel, reduce thermal efficiency, not to mention, it pollutes the atmosphere and produces a variety of pollutants.
In addition to the above-mentioned factors of black smoke from biomass boilers, the biomass pellets is poor, impurities, and ash are complicated, which causes the smoke components to be too complicated after combustion; when the boiler is burning, the power of the blower and the induced draft fan It is also to be properly controlled. If the power is too large, the combustion of biomass particles is not sufficient and complete, it will lead to black smoke; the boiler should be regularly inspected and maintained during use, if the biomass boiler is not used for a long time. In the case of cleaning the flue and ash, it will lead to blockage of the pipe and excessive ash, which will lead to black smoke. The boiler must be designed and installed in accordance with the distribution rules of the boiler heat island. If the chimney, flue, Unreasonable installation of equipment such as dust removal can also cause excessive flue resistance, resulting in black smoke.