| Pulse—jet fabric filter is a kind of high-efficiency dust collect equipment. It has so many advantages such as good dust dislodgement effect, high collect efficiency, being able to treat large volume of flue gas and long life that it has been widely used in many industries. It is very significative to study and develop pulse-jet fabric filters with advanced technology and market competitiveness.Dust dislodgement in a pulse-jet fabric filter was studied by constructing a set of measuring system of the dust dislodgement process of pulse-jet fabric filters using a 1:1 scale pulse-jet fabric filter model with pressure transducers, accelerometers and the technology of controlling & measuring with computer to get the status of the pulse-jet fabric filter. The peak pressure P_p inside the filter bag and the pulse rise time t_R was selected to be the two main factors according to the equation about the dislodgement force between the dust cakes and the filters given by W Humphries and J J Madden. The distance between the nozzle and the top of the bag, the reservoir pressure, pulse time, location of the nozzle and the distance between the nozzle and the top of the bag was analyzed. It was found that the distance between the nozzle and the top of the bag and the reservoir pressure influenced the peak pressure P_p most remarkably and the distance between the nozzle and the top of the bag, the reservoir pressure, pulse time had conspicuous effects on the pulse rise time t_R. Then study the influence trend of the factors with significance influence to P_p and t_R. The influence trend of the factors was analyzed according to the data gained by altering the factor to be studied and keeping the other factors. Finally, the influence of the factors to the dislodgement force was studied synthetically using the data gained from the accelerometers.Results indicated that both the peak pressure and the pulse rise time varied down the length of the filter bag. And the dust dislodgement effect was different along the bag. The reservoir pressure was a very important factor to influence the dustdislodgement. The peak pressure of the bag increased with the reservoir pressure and the pulse rise time decreased with it slightly. The pulse rise time increased slightly with the pulse time but it didn't influence the peak pressure remarkably. Location of the nozzle and the distance between the nozzle and the top of the bag had little effect on both Pp and tR. The index that can reflect the dislodgement force directly, acceleration (a) changed markedly in different position of the bag. The reservoir pressure influenced the acceleration markedly, too. The other three factors didn't influenced a remarkably.The emphasis of the future research work will be developing the traditional filter cage to distribute the press inside of the filter bag more uniformly. The reduction of the peak pressures at the top of the bag may result in longer bag life due to less mechanical stress on the fabric. The increase in the peak pressures at the mid and bottom location should provide for increased dust cake removal during cleaning. And the filter bags can be lengthened to reduce the floor area, the weight and the cost of the fabric filters. |
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