The Effect of CaBr2 on Mercury Speciation in Flue Gas: An Experimental and DFT Study

Background: Additives affect the formation of different mercury speciation in coal-fired derived flue gas. Objective: In order to study the effect of the additive CaBr2 content, the Ontario Hydro Method (OHM) method has been applied to analyze the mercury speciation at the entrance and export of denitration (SCR). Method: Density Functional Theory (DFT) has been used to study the adsorption of mercury halide on unburned carbon surface. Result: The results show that along with the increasing amount of additive CaBr2, there is an increasing trend of the ratio of Hg2+ in flue gas. Conclusion: CaBr2 addition contributes to oxidize Hg 0 to Hg2+ and increase the mercury concentration through SCR. DFT results indicate that the adsorption of HgBr and HgBr2 on unburned carbon surface is chemisorption, and Br-C bond is stronger than Hg-C bond, both these bonds are covalent interaction.

How Hydro Ontario Went Local: The Creation of Local Districts and the Ontario Central System

When Ontario Hydro was created, its task was to distribute electricity to local hydro commissions across Ontario. By the 1920s, however, it had become a local distributor itself, providing direct service to thousands of customers across the province. This essay examines the two major events that brought Ontario Hydro into local distribution during this period: the creation of the Central Ontario System in 1916 and the Rural Power District in 1920. This essay draws on previously unexplored archival sources to argue that the two processes were quite separate from one another, and that only one – the Rural Power District – left a lasting institutional legacy in Ontario’s electricity sector. Both developments, however, reveal the “flexibility” of local political autonomy in Ontario – the cultural and political limits of appeals to local autonomy in the face of economic risk and opportunity and technological change.

Research Progress of Pollution Control for Mercury in the Flue Gas from the Coal-Fired Industrial Boilers

Mercury is one of harmful pollutants during the coal-burning process that can not be ignored. The Ontario-Hydro method, Method 30B and Method 29 are mainly used for sampling the mercury in the flue gas from the coal-fired industrial boilers. This article studied the control ability of the mercury by the electrostatic precipitator (ESP), wet flue gas device (WFGD) and the dust removal and desulfurization integration at home and abroad.

Full Scale Evaluation and Suppression of Mercury Re-Emission in Wet Flue Gas Desulfurization System

The full-scale of PC/Cyclone Boilers with common wet flue gas desulfurization (WFGD) with limestone forced oxidation (LSFO) was studied. Ontario Hydro Method (OHM) recommended by the United States Environmental Protection Agency (USEPA) was used to determine mercury emission and speciation at these two full-scale WFGD systems, and OHM quality assurance/quality control (QA/QC) was followed during the field testing. WFGD re-emission problems were repeatedly observed at this unit. Selective catalytic reduction (SCR) had significant effects on mercury removal and Hg0 re-emission rates across WFGD. Effects of injection of continuous chemicals additive containing HS-, S2- or I- on mercury re-emission control were also conducted at this unit.