Thermodynamic Characteristics Of Polyphenyene Sulfide Fibers And The Application Of Activated Carbon Fiber Doped Filters In The Removal Of Zero-Valent Mercury

Coal-fired power plant air pollution control has become a major problem of China's environmental protection, In the combustion process, the environmental impact of the pollutants can not be ignored.Most of the heavy metal can be removed effectively in pollution control system, but most zero-valent mercury(Hg0)enters into the atmosphere with the flue gas.As activated carbon fiber(ACF) has high adsorption capacity for heavy metals, so it is of great significance to study the removal of zero-valent mercury with filters mixed activated carbon fibers and the chemical modifications of filters surfaces.Bag filter is highly efficient air pollution control dust equipment, which, as a filter medium bag is the key component, is made of woven fibers to trap the solid dust particles in flue gas. Polyphenylene sulfide (PPS) fibers are widely used as a bag filter.At the fitration of high temperature,the filter bag life and trapping efficiency are strongly dependent on the properties and structures of bag fiber materials and filter structure. This work studies the influences of heating rate on the pyrolyses of PPS fibers. The kinetic parameters were calculated using two kinds of kinetics models to study the thermal stability of PPS fibers. This is essential to the application of high temperature filters.ACF,PPS and modified PPS Fibers were studied by scanning electron microscope, elemental analyses, surface area measurements and infrared spectroscopy. It was found that the modifier was combined at the activated carbon doped fibers, resulting in the reduction of surface area. The modified fibers with strong oxidants such as nitrate increased the number of oxygen-bearing functional groups, which enhanced the removal of zero-valent mercury. A fixed bed was adopted to simulate the removal of zero-valent mercury (Hg0) in coal-fired flue gas, focusing on its performance and work stability. Seven kinds of single fiber, i.e. viscose-based activated carbon fiber, P84 fibers, PPS fibers, PSA fiber, PTFE fiber, glass fiber and Nomex fibers and composite fibers including ACF+ P84, ACF+PPS, ACF+PSA, ACF+PTFE, ACF+glass fiber, ACF+Nomex were used as adsorbents of zero-valent mercury. It was found that ACF+PPS composite filter was most effective for the removal of zero-valent mercury in these adsorbents.The performances of modifiers including KCl, KBr, KI, Na2S and HNO3 at different concentrations were also studied and the mechanisms were proposed based on the experimental results.