Experiment Investigation Absorption of Mercury by Modified Fly Ash Dust Layer Attaching on Filter

Abstract

As to figure out the effect that modified fly ash, which is prepared by fly ash –CaO, and modified fly ash dust layer attached on the surface of the filter material adsorbed elemental mercury, experimental studies are administrated in a laboratory-scale fixed bed reactor system with gaseous elemental mercury produced by a mercury vapor generator and simulated flue gas composition. The experimental results indicated that the adsorption performance of fly ash and CaO relatively poor. The proportion of CaO in the modified fly ash will affected the mercury removal efficiency of the absorbent which prepared by fly ash and CaO. It will be an optimal effect when the blend ratio of the flying ash and CaO is 2 to 1, and the maximum removal efficiency is up to 34%.As the adsorption temperature increases the removal efficiency of the modified fly ash deteriorates. The efficiency of dust layer attaching on the surface of the filter material is getting higher with the larger porosity of dust layer and smaller particle material size.

Effect of Mechanical–Chemical Modification Process on Mercury Removal of Bromine Modified Fly Ash

“…Fly ash, as a byproduct of a coal-fired power plant, is also has wide sources and low cost. It is able to be a very effective adsorbent after physical and chemical modification. , The late research results showed that the physical structure and chemical composition of fly ash featured crucial influence on mercury removal, such as particle size, specific surface area, unburned carbon, , mineral composition, , and surface functional groups. , The raw fly ash has poor mercury removal performance because it is in stable physical and chemical states, while its mercury removal capability can be significantly improved after halogen modification. , Zhou et al found that the NH 4 Br chemical impregnation modified fly ash can improve its oxidation ability and promote the adsorption to Hg 0 . Zhang et al used two kinds of fly ash modified by CaCl 2 , CaBr 2 , and HBr impregnation to investigate the removal effect of mercury in an air flow reactor.…”

“…It is able to be a very effective adsorbent after physical and chemical modification. 8,9 The late research results showed that the physical structure and chemical composition of fly ash featured crucial influence on mercury removal, such as particle size, 10 specific surface area, 11 unburned carbon, 12,13 mineral composition, 14,15 and surface functional groups. 16,17 The raw fly ash has poor mercury removal performance because it is in stable physical and chemical states, while its mercury removal capability can be significantly improved after halogen modification.…”