Study On Dust Removal Characteristics Of Dust Preloaded Electrostatic Synergistic Particle Layer

High temperature precipitation technology not only plays important roles in the high efficient and clean utilization of the coal energy, but has deep impact on the energy-saving and emission mitigation in the fields of oil refining, chemical industry and metallurgy. Nowadays, the related techniques remain to be improved for their drawbacks and limitations.In order to find a technique for efficient and stable operation in the atmosphere of high temperature, the fixed granular bed filter was combined with thermionic emission electrostatic precipitation (TEESP) to be a new system. Experiments were conducted on charge of particles with thermionic emission, electrostatic precipitation and the granular bed filtration system with the electrostatic field enhancement. And results show that,(1) The efficiencies of the TEESP and new system were significantly increased with the improvement of the temperature, reasons for which may be explained as follows, firstly, the emission ability of the cathode would be enhanced as the temperature increased, then more and more particles in the air flow were successfully charged. Meanwhile, the diffusion and deposition ability of the particles were also reinforced in the filtration bed owing to the rising temperature. In accordance with the traditional electrostatic precipitation, the efficiency of the TEESP system was decreased as the concentration of the particle increased and the velocity of the air flow rose up.(2) The performance of the TEESP improved a lot for the rising voltage in charge and collection area when other conditions being equal; and the filtration capability increased once the height of the filtration bed was raised or the size of the filtration media was lowered; the ability of the filtration bed improved smoothly as time went by, then reached the maximum value, and after which the ability would decrease gradually. The maximum efficiency was achieved at the filtration time of lOmin, and the pressure drop was just 40Pa.(3) The grade efficiency of the fine particles was proved to be a great improvement in the new system. When the diameter of the media is 5mm, temperatures of the charge and collection area are 300℃ and 900℃, and the voltages of two areas are respectively 5000 V and 8000V, the air flow is 1.5Nm3/h, the removal efficiency of the particles below 1μm reaches up to 94.5%, and that of particles below 2μm is 89%. In comparison, the efficiency of the tested single granular filtration system only arrives about 65%.