Characteristics of flue gas emission from cement industry
The pollutants in the flue gas from cement production mainly include dust, sulfur dioxide, nitrogen oxides, etc. When the emission exceeds the standard, it will have adverse effects on the environment and human health.
1. Dust. Every production link in the cement plant will produce a large amount of dust
1、 Dust emission in raw material preparation procedure. Including limestone crushing, raw meal grinding and some dust emission of coal mill system;
2、 Dust emission during clinker burning;
3、 Dust emission from cement mill and cement packaging during cement production;
The gas discharged from the raw material preparation and cement grinding process is generally normal temperature dusty gas. The dusty gas discharged from the raw material drying and kiln head and kiln tail belongs to high-temperature dusty gas.
The main components of dust include CaCO3, CaO, SiO2, Fe2O3, Al2O3, MgO, Na2O, K2O, etc.
2. Sulfur dioxide. Sulfur dioxide in waste gas of cement industry is derived from sulfur compounds in cement raw materials or fuels. More than 80% of sulfur oxides generated under high temperature oxidation conditions react with calcium, potassium and sodium in rotary kiln to form sulfate residues in clinker.
3. Nitrogen oxides. The nitrogen oxides emitted during the burning of cement clinker mainly come from the combination of nitrogen and oxygen in the air when the fuel is burning at high temperature. The amount of nitrogen generated depends on the combustion flame temperature. The higher the flame temperature is, the more nitrogen oxides will be generated from nitrogen oxidation.
Selection ofdust filter bag in cement industry
The production process of cement can be simply divided into three links: raw material preparation, clinker burning and cement grinding. Each link requires the use of filter bags of dust collectors. The following four positions have a large amount of filter bags:
Cement mill: normal temperature flue gas, no special working conditions. Polyester filter bag is the standard filter material in this environment. Water and oil resistant, PTFE coated, ultra-fine fiber and other filter materials can be selected according to special conditions.
Coal mill: polyester anti-static filter material can be used when the temperature is below 80 ℃. If the working condition contains water vapor, consider adding acrylic fiber.
Kiln head: the temperature is about 180 ℃, which can reach 200-220 ℃ when it is high, and the dust concentration is high. Aramid is a suitable filter material.
Kiln tail: temperature up to 260 ℃, containing acid gas and nitrogen oxides. The working conditions at the kiln end are relatively complex, so there are many choices of filter materials, such as glass fiber composite filter materials, glass fiber membrane filter materials, P84 filter materials, etc.
SFFITECH filter bagsfocus on providing a variety of micron filter materials, including dust filter bag series, liquid filter bag series, and various customized filter bags. The products are widely used in fine chemical industry, food and beverage, metal processing, automobile industry, water treatment, paint and ink, biological pharmacy, electronic industry, electroplating and coating, etc.