Influencing factors of mercury removal by pure powdered activated carbon on a bag filter

Abstract

In order to improve the Hg0 removal efficiency and utilization of powdered activated carbon (PAC) of the traditional mercury removal technology which applies activated carbon injection based on a bag filter, a new mercury removal technology with pure PAC on a bag filter was put forward in the present study. Mercury removal experiments were conducted on a small-scale bag filter test bed with pure PAC as the absorbent. The results indicated that the average mercury removal efficiency (AMRE) within the first 65 min decreased from 99.6% to 43.2% when the adsorption temperature increased from 80°C to 170ଌ and increased from 75.5% to 84.6% when the volume fraction of H 2 O (g) increased from 0% to 8% at 100°C, but it decreased when the H 2 O (g) content further increased to 12%. The AMRE increased with the increase of the pure PAC load and decrease of the filtration velocity of the bag filter. When the adsorption temperature was 80°C, the AMRE with pure PAC and that with a mixture of 5% PAC and 95% fly ash within the first 85 minutes were respectively 99.1% and 59.6%. When the mercury removal efficiency was above 75%, the accumulated mercury adsorption amount with pure PAC and that with a mixture of 5% PAC and 95% fly ash were respectively 196.1 and 21.7 µg Hg/g AC, indicating that mixing with fly ash had a very significant effect, and the mercury removal technology with pure PAC on a bag filter had obvious advantages as to mercury removal efficiency and utilization of PAC.