How do we purify polluted gases produced during calcination in an internal heat rotary kiln?
How do we purify polluted gases produced during calcination in an internal heat rotary kiln?
We know that when roasting materials, rotary kiln equipment unavoidably produces some harmful gases, causing certain environmental pollution. So how do we solve this atmospheric pollution caused by calcination? Are there any good solutions to improve gas purification while not affecting production? Strengthening environmental protection is also essential. This article will give a brief introduction on how to handle polluted gases:
Air pollution from an internal heat rotary kiln has always been an important issue in the production process. Dust pollution, which is more obvious, often receives attention, but harmful gases like sulfur dioxide that are produced can easily be overlooked.
During material drying, flue gas is generated. The hot flue gas exchanges heat with the material inside the dryer cylinder, so the temperature of the material rises, and its moisture evaporates as the flue gas gradually cools down. It is then discharged through the tail end of the double cylinder internal heat rotary kiln and either recovered by dust removal equipment or directly released into the atmosphere.
The content of dust in the flue gas varies depending on the type, characteristics, and degree of dryness of the material. Since SO2 exists in the flue gas, along with a humid environment that may cause corrosion to the equipment and filter material, the SO2 mainly comes from burning coal with a high sulfur content. As the flue gas contains harmful components to the air, dust removal equipment should be added to the tail end of the double cylinder internal heat rotary kiln to avoid direct discharge into the atmosphere, thereby reducing air pollution.
If the moisture content of the dried material is large and fluctuates between 5% – 20%, the corresponding humidity of the flue gas will also be large, with dew points reaching 60°C – 70°C, leading to condensation and clogging in pipes and dust collectors. Additionally, the temperature is high and the range of fluctuations is large. In general, even if the moisture content of the material is higher, it can still be sufficiently dried at an outlet temperature of 120°C, but if a situation occurs where there is no material feeding, the flue gas temperature will rapidly rise above 200°C. When the moisture content of the material is low, normal drying can occur at an outlet temperature of 60°C – 80°C.