Anthropogenic emissions from the combustion of composite coal-based fuels

Composite fuels made of waste from coal, petroleum and wood processing industries have a high environmental and economic potential. In this research, we experimentally studied the concentrations of the most hazardous gaseous anthropogenic emissions (CO2, SO2, NO) from waste-based fuel combustion. Using two techniques operating in complementary temperature ranges, we obtained data on SO2 and NO emissions in the temperature range from 300 degrees C to 1000 degrees C, including all the stages of thermochemical conversion of fuels. A quasi-stationary technique was used, based on a setup of thermogravimetric analysis with mass spectrometry, to obtain information in a low-temperature range (300-600 degrees C). This technique allows the conversion at a low controlled rate of heating a sample together with the fumace.To obtain data in a high-temperature range (700-1000 degrees C), a non-stationary technique was used, where the sample was introduced into a pre-heated furnace. The conditions were established in which it was possible to reduce the concentration of flue gases from the combustion of the compositions under study (replacement of the coal part with water, injection of water vapor, addition of biomass, selection of the temperature range). The impact of water vapors was determined when they were injected into the chemical reaction zone together with air and when they were formed naturally by evaporation from the fuel sample. Unlike biomass that reduces the emissions of sulfur oxides from composite fuels due to the mechanical dilution of the mixture, water vapor present in the heterogeneous reaction zone decreases the gaseous anthropogenic emissions through chemical reactions and conversion of a part of fuel sulfur and nitrogen to an inactive form (neutral to the environment). (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Composite fuels made of waste from coal, petroleum and wood processing industries have high potential for reducing hazardous gaseous anthropogenic emissions like SO2 and NO during combustion. Different techniques were used to study these emissions at different temperature ranges, with results showing the positive impact of water vapor on reducing emissions.