Saltworks Technologies has successfully concluded a 60-day on site pilot to selectively remove chlorides at a major US coal fired power plant.
Chlorides are a by-product of coal combustion and accumulate in wet scrubbers, reducing sulphur absorption and causing corrosion. The project, which was a collaboration with the US Department of Energy, the Electric Power Research Institute and Southern Company, treated challenging flue gas desulfurization (FGD) wastewater to selectively remove chlorides for recycle and re-use inside the coal stack scrubber system. By targeting chlorides, which are a key concern, this selective removal method provides an alternative to expensive complex treatments for discharge.
The pilot included a full scale Saltworks’ Flex EDR Selective Stack, which acts as a “chloride kidney”, removing only chlorides and allowing sulphate-rich water to be recycled back to the scrubber. Within the stack, Saltworks’ monovalent selective anion exchange membranes pull chlorides out of the FGD wastewater under a DC electric field. Outside of the stack, a robotised plant enables the process while adjusting to variable water quality and providing valuable data to the operator. Full details of the process can be seen in the Saltworks' video here.