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When filtering high-temperature gas, what factors affect Nomex needle felt filter bag?

2022-07-29 Page view : 6 views

The mesh needle felt filter bag (Best Price Nomex Aramid Needle Felt Filter Bag) is a product that can be used continuously at 204 degrees, can withstand repeated 250 degrees instantaneous temperature fluctuations, has good dimensional stability (1% heat shrinkage at 250 degrees), and has good fire resistance. The filter bag has the advantages of temperature resistance, dimensional stability, fire resistance, chemical resistance and so on. It is understood that many people are very concerned about the service life of this product. Then, what are the factors that affect the metas needle felt filter bag (Nomex needle felt filter bag)? Next, let’s take a look at the relevant introduction in this article.

Generally speaking, the factors affecting the service life of filter bags mainly include the following:

1. Harm of high temperature to nomex filter bag
When the smoke exhaust temperature exceeds 204 ℃, the temperature has a significant impact on the life of the filter bag. With the increase of temperature, the life loss of the filter bag gradually increases, and the filter material may be burned when it reaches the first grade temperature. Moreover, because the coal is mixed with other chemical substances, when the smoke temperature is high, the reaction capacity of chemical substances will be accelerated, and the filter material is easy to be oxidized, making the strength weak, easy to crack, and the life loss will be more and more serious, Finally, the filter bag is corroded. Therefore, the smoke exhaust temperature should be strictly controlled during the operation of metas needle felt filter bag (Nomex needle felt filter bag) to prevent long-term over temperature operation and sudden temperature rise accidents in a short time.

2. Influence of low temperature condensation on nomex filter bag
When the boiler is operated at the initial stage of ignition or low load in winter, the temperature of flue gas is low, and the local temperature is easy to be lower than the dew point temperature due to local air leakage. In this way, dew will appear, and react with SO2 in the flue gas to form acid dew and acid mist, causing corrosion of the filter bag, reducing the characteristic index of the filter bag. In serious cases, it may cause large-area hardening of the filter bag, and reaching a certain weight will cause the filter bag to fall off, It seriously affects the service life of needle felt filter bag (Nomex needle felt filter bag). In addition, the northern region is cold in winter. If the heat preservation is not good, it is easy to cause ash accumulation on the inner wall of the ash hopper, resulting in ash blockage. And at the initial stage of ignition, the ash hopper is under negative pressure, and the moisture generated by the hydraulic ash removal at the lower part will also be brought into the ash hopper, which is also easy to cause ash accumulation and hanging on the inner wall of the ash hopper, causing serious consequences.

3. Influence of filtration wind speed on nomex filter bag
The filtration wind speed is an important factor that determines the performance of the dust collector. Too high will cause too much pressure loss, making the filter bag blocked and quickly damaged. Generally speaking, for dusty flue gas with high dust concentration, fine particles and high abrasiveness, the filtering wind speed should be smaller, otherwise, the one with larger wind speed should be selected. Because the filtration wind speed value of the bag filter will increase the resistance, the dust layer will reduce the porosity due to pressure, and the air flow will break through the weak place of the dust removal filter bag, resulting in the “perforation” phenomenon. The larger the filtration wind speed is, the more serious the “perforation” phenomenon of the dust removal filter bag is, so the filtration wind speed should be controlled well.

4. Influence of destructive ash removal on nomex filter bag
In order to keep the pressure difference of the filter bag running at the design value, the fly ash attached to the surface of the filter bag should be cleaned regularly, but the parameters of the ash removal method or ash removal system have a great impact on the service life of the needle felt filter bag (Nomex needle felt filter bag). The impact on the shaking, vibrating or high and medium pressure pulse back blowing ash cleaning system is not great, while the low-pressure pulse back blowing ash cleaning system is different. Its damage mechanism is mainly due to the use of external filtering and the bag cage in the filter bag, so the relative movement between the filter bag and the bag cage will cause wear, coupled with frequent soot blowing, close contact between the filter bag and the bag cage The change of amplitude with spacing and zigzag changes will directly affect the service life of the filter bag.

5. Influence of air inlet mode on needle felt nomex filter bag
The air inlet mode will also directly affect the service life of the filter bag. Try to ensure that the pressure difference between several chambers is relatively average. Once the pressure difference of one chamber increases, most of the flue gas enters other chambers to balance the pressure difference. However, if a part of the filter bag leaks in one chamber, the resistance of flue gas passing through the filter bag will be reduced, and the differential pressure of the chamber will be reduced, so most of the flue gas will enter the chamber, increasing the flow volume and aggravating the wear of the filter bag at the same time. Therefore, choosing a reasonable air inlet mode is also an aspect that affects the service life of the filter bag.

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