Review of water/steam addition in liquid-fuel combustion systems for NOx reduction: Waste-to-energy trends.

This paper reports on the latest advances regarding water/steam addition to liquid-fuel combustion systems for the development of sustainable energy through NOx reduction. The review focuses on applications of steam injection to achieve environmentally safe recycling of liquid combustible waste in conjunction with energy production. The basic information regarding the theory of combustion and gasification with steam is presented. A brief overview of current NOx control methods is included. Steam supply in liquid-fuel combustion systems (diesel engines, water-fuel emulsions, burners) is considered in detail, with a particular focus on reducing toxic emissions and improving efficiency. The main mechanisms of NOx reduction upon steam injection in liquid-fuel burners are analysed. The benefits of using steam to create low-NOx waste-to-energy conversion technologies, as well as the knowledge gaps in this area, are discussed. Further research requirements are discussed for the environmentally safe use of substandard fuels and waste as alternative fuels, for the development of new sustainable energy technologies. Image 1 • Water/steam addition to liquid-fuel combustion systems is reviewed. • Current NOx control methods are briefly reviewed. • Mechanisms of NOx reduction upon steam injection in liquid-fuel combustion systems are analysed. • The benefits of using steam for prospective waste-to-energy technologies are presented. [ABSTRACT FROM AUTHOR]