Working principle of coal-fired boiler dust collector

The maintenance and maintenance of coal-fired boilers is inseparable from the dust collector. At present, there are many types of coal-fired boiler dust collectors. The following is a brief introduction by Zhongchuang Boiler Network to introduce the types and working principles of coal-fired boiler dust collectors.

First, mechanical dust collector

A mechanical dust collector is a device that separates dust particles from a gas stream by the action of mass forces such as gravity, inertial force, and centrifugal force. Such as gravity dust collectors, inertial dust collectors and cyclone dust collectors. The mechanical dust collector is characterized by simple structure, low cost and convenient maintenance, but the dust removal efficiency is low.

Gravity dust collectors and inertial force precipitators have low dust removal efficiency and can not meet the current environmental requirements, so they are gradually being eliminated. Although the dust removal efficiency of the cyclone dust collector is relatively high compared with the first two, the dust particle resistance is large and it is difficult to separate the dust particles with the particle size less than 5 tim. Therefore, the pulverized coal furnace should not be used, and the chain furnace is used more.

Second, the filter dust collector

The filter dust collector is a device that separates and collects dust from the dust-containing gas stream through the filter material. Such as granular layer dust collector, bag filter, etc. The filter type dust collector has the advantages of high dust removal efficiency (high dust removal efficiency under low dust concentration), simple operation and reliable operation, but high resistance and high energy consumption, and is not suitable for treating wet gas and sticky dust.

Due to the large investment in the filter dust collector, the resistance is large, the operating cost is high, and it is currently used less on the boiler.

Third, wet dust collector

Wet dust collectors use dusty air streams to contact dust or other liquids to capture dust particles. Such as venturi dust collector, cyclone water film dust collector. The scrubber has high efficiency, simple structure, low cost, and also has the function of absorbing harmful gases, but it will produce sewage and sludge, which needs to be treated.

The wet type dust collector has a simple structure, a small metal consumption and a small land occupation, so the dust removal efficiency can reach more than 90%, so that medium and small boilers are used more. The disadvantage of the wet dust collector is that the water consumption is large, and the acid-containing wastewater needs to be treated to meet the discharge standard. The flue gas brings water to cause dust accumulation in the flue and the induced draft fan impeller, causing corrosion and imbalance of the impeller fan mass.

Fourth, the electrostatic precipitator

The electrostatic precipitator is a device that uses a strong electric field corona discharge to ionize the gas, charge the dust particles, and separate the dust particles from the gas flow under the action of Coulomb force. The electrostatic precipitator is characterized by high dust removal efficiency, high temperature gas treatment, low resistance and low operating cost, but high steel consumption, high cost and high technical requirements.

Due to the large amount of flue gas treatment and low resistance, the electrostatic precipitator has good adaptability to soot concentration and can collect dust particles of various particle sizes. The dust removal efficiency is over 95%, the operating cost is low and the environmental emission standards are improved. Can meet the requirements of the new environmental emission standards after the improvement. Therefore, although the initial investment is high and the land occupation is high, the quality of manufacturing, installation and maintenance is high. Most of the large and medium-sized pulverized coal furnaces use electrostatic precipitators.