|Abstract Title:||Reducing the Mercury Emissions From Coal-Fired Power Plants by Means of Membrane Electrolysis|
|Presenter Name:||Boleslav Zach|
|Company/Institution:||Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, v. v. i.|
|Session:||Energy/ Fossil Fuels|
|Day and Session:||Thursday 28th July - Session Three|
|Start Time:||12:00 UTC|
Abstract Information :
There are several options for mercury emission control at coal-fired power plants. Some are based on adsorption in the dedusting part of the flue gas treatment system, others use the wet flue gas treatment system to capture mercury. The first is usually realized by the injection of activated carbon. The latter is typically based on the precipitation of mercury dissolved in the absorber of the wet desulfurization system by various agents.
These agents prevent reemission, but a significant part of mercury in flue gas is often in its metallic form, which is almost insoluble in water. To achieve low concentrations of mercury in flue gas, it might be necessary to first oxidize metallic mercury in the flue gas to an oxidized form to increase the amount of mercury captured in the wet desulfurization system.
Membrane electrolysis can be used to achieve both oxidization of metallic mercury and its removal from a wet desulfurization system. Membrane electrolysis allows the production of a sorbent that can capture mercury compounds. This sorbent is based on hydroxides of metals present in the absorber. Simultaneously, at the other electrode, the formation of sodium hypochlorite takes place. The method, therefore, produces both the sorbent as well as the oxidizing agent. Moreover, a relatively small amount of waste is produced and no consumption of chemicals is associated with the process. Therefore, the only consumed commodity is electrical power, which is plentiful and cheap at power plants. These advantages are the cause for the low expected operating costs.
The aim of the paper is to present the method, results of laboratory verification experiments, compare the method with its alternatives in terms of estimated costs and produced waste stream. Moreover, a critical summary of crucial issues associated with its realization will be presented.