Utilization of pyrolytic wastewater in oil shale fired CFBC boiler

The current paper presents the results of incineration of pyrolytic wastewater (WW) in an oil shale fired 250 MW thermal (MWth) circulating fluidized bed combustion (CFBC) boiler. The measurements in the industrial-scale oil shale fired CFBC unit show that WW incineration did not cause the plant to exceed the gaseous pollutant or particulate matter (PM) emission limits set for large combustion plants. The data obtained is compared to previous results from a pilot-scale 60 kW(th) CFB combustor. In pulverized combustion (PC) units, incineration of pyrolytic WW was carried out a long time ago as it reduced SO2 emissions and improved PM removal from flue gases in an electrostatic precipitator (ESP). Regarding PM emissions, a similar result was achieved in a CFBC unit; however, a high nitrogen content in WW results in increased NOx emissions. From the practical point of view, pyrolytic WW incineration (ca 13 t/h) increases fuel (oil shale) consumption by up to 6% for the same thermal output, which consequently reduces a unit's efficiency. (C) 2019 Elsevier Ltd. All rights reserved.