Comparative analysis of dust removal methods

At present, there are four types of dust removal methods used in the market: mechanical dust removal, wet dust removal, filter dust removal and electric dust removal.

Mechanical dust removal: a device that separates dust and gas by mechanical force. It includes gravity settling chamber, inertia settling chamber and cyclone dust collector. The mechanical dust collector has the advantages of low dust removal efficiency, large floor area and low cost, but the equipment is rough and the service life is short. Mechanical dust collector is suitable for high-temperature, corrosion-resistant and high humidity flue gas dust, but the removal efficiency of particles with particle size less than 15m is low. Generally, it is only used as the primary dust collector of multi-stage dust removal system to reduce the load of secondary dust collector.

Wet dust removal: a device for washing the dusty air flow with liquid droplets or liquid film to separate and settle the dust from the air flow. It includes wet scrubber and high pressure spray. The high-pressure spray dust suppression device has simple structure and low price, and is suitable for purifying high temperature, inflammable, explosive and harmful gases. However, due to large water consumption, the nozzle is easy to be blocked, which is only suitable for humidifying materials. The wet scrubber covers a large area and needs to increase the workshop construction cost. It is easy to be corroded by acid-base dust substances (such as coal) and has short service life. Moreover, the sewage and sludge produced by the wet scrubber need to increase the difficulty and cost of later sewage treatment. The above two vacuum cleaners are only applicable to the workshops with thermal insulation measures in northern winter, and can not be used outdoors.

Filter: a device for filtering and separating dusty gas through fabric or packaging layer. Bag type dust collector and particle layer dust collector are applicable to the change of dust gas flow and have high dust removal efficiency in fixed pollution sources, However, the investment amount of bag type dust collector is high (taking the 200MW unit of Hohhot power plant as an example, the dust collector of each unit invests 20 million yuan to ensure that the emission concentration is only 50mg / Nm3. The boiler emission comes from fixed pollution sources, the investment in unorganized emission will be greater, and the emission concentration will increase or double accordingly). It is characterized by high maintenance cost, large floor area, complex ash cleaning device, high energy consumption The allowable temperature is low, high temperature, viscous and corrosive dust, which is difficult to handle. For example, when the capacity of the dust collector is large, a large amount of money needs to be invested in the construction of ash storage yard or ash warehouse. The dust in the ash storage yard will produce secondary dust pollution in the later loading, unloading and transportation process.

Electrostatic precipitator: charge the dust particles with high-voltage electric field. Under the action of Coulomb force, the dust and air flow are separated and settled. At the fixed pollution source, the dust removal efficiency is high, the pressure loss is small, but the power consumption is large, The investment amount is high (taking the 200MW unit of Hohhot power plant as an example, according to four electric fields, the specific dust removal area is 130m2 / m3 / s, reaching the standard of 250mg / Nm3, the investment of each dust collector is about 25 million yuan, and the boiler emission is a fixed pollution source, so the investment will be greater in the case of unorganized emission, and the emission concentration will increase correspondingly or multiply). For example, when the dust collector capacity is large, A lot of money needs to be invested in the construction of ash storage yard or ash warehouse. The dust in the ash storage yard will produce secondary dust pollution in the later loading, unloading and transportation process. Compared with the above four types of general dust collectors, it can be seen that a dust removal device with small investment, small floor area, low operation cost, convenient operation and maintenance, normal use in winter, high dust removal efficiency and complete control of unorganized dust emission is needed. The dry fog dust suppression system can fully realize the above characteristics, and can well control the dust below 10m. The maintenance cost of the dry fog dust suppression system is low (once every half a year), and the maintenance cost is only 2000-3000 yuan (the sewage discharge fee of the bag filter is at least 100-millions yuan per furnace / year).

Original link address: http://www.aotua.com/NewsDetail/3063568.html