The Principle Of The EP-Bag Comprehensive Filter And System Design

Electrostatic precipitation (ESP) and bag fitler are air cleaning equipmentwidely used in collecting contamination. While, separately using ESP or bagfilter will be very hard to comply with the new requitemens in theenvironmental protection from international society. ESP collection efficiency isaffected by dust character character and equipment condition, which will makeits structure increased. In the same way, its body weight, running cost andinvestment will be increased a lot. Bag filter also have high de-dustingeffect(reaching to 99.99%). But the outlet emission density of filter is15～20mg/m~3 which still can not meet the requirement of new State rules ofless than 10mg/m~3, if the inlet dust density is very high such as150g/m~3～200g/m~3. And in this way bags numbers and bags length will beincreased much more, and inlet density is much high which will increase therunning cost and make more running resistance. Therefore, it's not only the needfor power production to study and develop new-type dust collecting equipmentthat adapts to the coal-fired power plant, but also the need for environmentprotection. So in order to use their advantages and overcome their disadvantage,we will have a comprehensive consideration of EP and bag filter. So it is veryimportant to study the comprehensive de-dusting technology with EP and bagfilter.EP advantages are that air processing quantity is very large, its resistanceis low, and running cost is small. Bag filter have more advantages such as lowenergy consumption besides of EP advantages. Inthis thesis we will considerboth advantages of EP and filter to study the EP-Bagfilter Technology andmake structure design. At first the dust gas will go into theelectrostatic-dedusting part of EP-Bagfilter, under the electro field action, thedust density will be decreased greatly. And then the gas will go into thebag-dedusting part of EP-bagfilter, and then the dust contents will be lower, so the bag resistance will be lower, and the bag cleaning time will be prolongedgreatly. In this thesis, the electro field airspeed in the electrostatic-dedustingpart will reach to 1m/s, so the gas processing quantity will be increased.Under the condition of inlet density is 50g/m~3 and dedusting effect is 85% inthe electro-dedusting part, its outlet dust density will be 7.5g/m~3. In the bagdedusting part, the inlet dust density is very low, so some pressure of them willonly be 175～1200Pa, its dedusting effect will be 99.87%, the outlet dust densitywill be 9.98mg/m~3.