Fuel additive technology is based on the use of a solid, fuel additive (iron, aluminium, calcium and silicon based oxides), to reduce NOx emission, improve the quality of fly ash and result in 1-3% coal savings for pulverised coal combustion. The findings in this study have been mainly based on extensive experimentation on 100 kWth down fired-combustion test facility (CTF) and partially on a commercial 260 tons/h steam producing water tube pf boiler. International Innovative Technologies (IIT) developed this additive based technology for the combined effect of reducing NOx from the combustion of hydrocarbon fuels (mainly coal) and more specifically to improve the combustion process of fossil fuels resulting in an ash by product with improved loss on ignition and lower carbon content. The improvement in the combustion thermal efficiency of the commercial 260 tons/h steam producing boiler has been calculated as per the direct calculation method of EN BS12952-15:2003 standard. (C) 2014 Elsevier Ltd. All rights reserved.