Composition of a gas and ash mixture formed during the pyrolysis and combustion of coal-water slurries containing petrochemicals

Highlights: • NO_x and SO₂ in coal combustion products are 1.4–2.6 times higher relative to slurry. • Adding biomass made it possible to reduce the NO_x and SO₂ emissions by 5–33%. • C₂ from the slurries combustion are lower by a factor of 2.4–4.5 as compared to coal. • The values of from the slurries combustion are 37–58% higher relative to coal. • The relative performance indicator of slurries exceeds that of coal by 28–56%. This paper presents the results of experimental research into the component composition of gases and ash residue from the combustion of a set of high-potential coal-water slurries containing petrochemicals. We have established that the use of slurry fuels provides a decrease in the CO₂, CH₄, SO₂, and NO_x concentrations as compared to those from coal combustion. The content of carbon monoxide and hydrogen in the gas environment from the combustion of slurries is higher due to the intense water evaporation. It is shown that adding biomass allows a further 5–33% reduction in the emissions of nitrogen and sulfur oxides as compared to the coal-water slurry and the composition with added waste turbine oil and a 23–68% decrease as compared to coal (per unit mass of the fuel burnt). The mechanisms and stages of CO₂, SO₂, and NO_x formation are explained with a view to controlling gaseous anthropogenic emissions and ash buildup. The values of the relative environmental performance indicator are calculated for slurry fuels. It is shown to exceed the same indicator of bituminous coal by 28–56%.