Elemental mercury (Hg 0 ) is predominant constituent of flue gas emitted from coal-fired power plants. Adsorption has been considered the best available technology for removal of Hg 0 from flue gas. However, adsorbent injection increases the amount of ash generated. In the present study, powdered activated carbon (PAC) was coated on polytetrafluoroethylene/glass fiber filters to increase Hg 0 removal while concurrently reducing the amount of ash generated. The optimal PAC coating rate was determined in laboratory experiments to ensure better Hg 0 removal with low pressure drop. When PAC of particle size less than 45 μm was used, and the areal density was 50 g/m 2 , the pressure drop remained under 30 Pa while the Hg 0 removal efficiency increased to 15.8% from 4.3%. The Hg 0 removal efficiency also increased with decrease in filtration velocity. The optimal PAC coating rate was applied on a hybrid filter (HF), which was combined with a bag filter and an electrostatic precipitator in a single chamber. Originally designed to remove fine particulates matter, it was retrofitted to the flue gas control device for simultaneous Hg 0 removal. By employing the PAC coating, the Hg removal efficiency of the HF increased to 79.79% from 66.35%. Also, a temporary reduction in Hg removal was seen but this was resolved following a cleaning cycle in which the dust layer was removed.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Environmental Chemistry
- Environmental Science(all)