Today, most environmental engineers agree that filter cloth filtration technology is superior to electrostatic dust removal technology.
Therefore, most of the new dust collectors installed in the world are bag filter dust collectors (bag filter dust collectors). Bag filters and electrostatic precipitators have the following main advantages: higher efficiency ( Lower emissions); reduced maintenance (components, manpower); online maintenance (when the bag filter is segregated); there are no too precise restrictions on the nature of the inlet dust; it can handle increased ventilation; The filter media can be changed when the condition changes.
The main advantage of the bag filter is to reduce the emission concentration. As the global air quality standards become more and more strict, the dust emission of the chimney becomes an increasingly important factor in determining the dust collection system. Many ESP designs cannot simply achieve the very low emission levels required, and ESP retrofits can effectively reduce dust emission concentrations and are considered a viable option.
However, the retrofit of the electrostatic precipitator is not suitable for some. Because the dust is too fine, the electrostatic precipitator is not easy to collect, the dust is too high in electrical resistance or the conductivity is too good, so the dust is not easy to maintain a good charge, so that the electrostatic precipitator can not be very good. Where the dust is collected. For these conditions, the use of bag filtration technology is a better choice.
Second, the characteristics of pulse jet bag filter
After the dust-containing gas enters the bag filter, it is distributed to the filter element through the deflector. The function of the inlet portion is to reduce the operating speed of entering the dust and to use the gravity principle to directly settle the dust of the large particles, thereby generating a gas flow that reaches a balanced distribution of the filter elements. This allows the dust flow to not cause excessive wear on the filter element. When the dust-containing gas is directed through the filter element, the purified gas penetrates the filter element and enters the clean room (the upper portion of the flower plate), and the dust is trapped outside the filter element. Clean gas is discharged from the clean room from the clean room through the fan.
When collecting dust, the filter element needs to periodically clean the surface of the filter to maintain the desired level of running resistance of the dust collector. When the compressed air is directly directed downward into the interior of the filter element during the cleaning process, the surface of the filter element can be immediately applied. The dust cake is dialed away. The clean compressed air is regulated by a pulse injection valve and directly introduced into the filter element through the injection pipe. The cleaning of the filter element of the pulse bag filter can be carried out online. The dust cake is peeled off from the outer surface of the filter element through the cleaning process, and gradually enters the ash hopper. The rapid pulsed cleaning of compressed air is the only way to keep the outer surface of the filter element clean and working properly.
The pulse bag filter has the following advantages over other bag cleaning methods: the pulse bag filter can be made very compact and can be various in size. The equipment includes a small number of moving parts, and the pulse blowing valves in these parts may need to be maintained or replaced. Since these moving parts are mostly located outside the baghouse, it is very convenient for maintenance and replacement. The filter element can be installed either in the clean air chamber (loading it from above into the dust collector) or in a dust chamber (installed in the lower part of the dust collector). The traditional pulse jet bag filter uses a filter bag and a skeleton with a metal venturi (used to guide clean compressed air from the blow pipe). The modern new bag filter combines a traditional filter bag and skeleton into a traditional filter bag and skeleton. The filter material and the skeleton-integrated pleated filter element replace the traditional filter bag, and the pleated filter element can be used to increase the total filter area and further shorten the component installation time.
Pulse bag filter design is being chosen as the main bag dust removal method in the world. Many factories have modified their mechanical vibrating and pulse bag type dust collectors into pulsed cleaning. Most baghouse manufacturers now offer pulsed cleaning technology as an important part of their product line.
One of the most common concerns in the history of bag filters is their ability to handle very high temperature dust gases, which is one of the reasons why electrostatic precipitators have become so popular in power plants, cement plants and other industries. In addition, it is more concerned that high-wear dust is likely to cause premature damage to the filter element (this problem is rarely found in electrostatic dust removal technology). When formulating the electric bag change plan, this issue should be fully considered and a feasible corresponding solution can be proposed.