Water-In-Oil Emulsion as Boiler Fuel for Reduced NOx Emissions and Improved Energy Saving

• Published in: Energies (Basel) Vol. 12; no. 6; p. 1002
• Main Authors: Hsuan, Chung-Yao, Hou, Shuhn-Shyurng, Wang, Yun-Li, Lin, Ta-Hui
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 14-03-2019
• Subjects: Ambient temperature; Atomizing; boiler efficiency; Boiler tubes; Cleaning; Combustion; Comparative studies; Diesel engines; Diesel fuels; droplets evaporation; Efficiency; Energy; Energy conservation; energy saving; Evaporation; Firing; Flame temperature; Fuel consumption; Fuel oils; Heat; Heat transfer; High temperature; Latent heat; Mechanical engineering; microexplosion; Nitrogen oxides; NOx emissions; Oil; Pollutants; Studies; Surfactants; water-emulsified fuel; Taiwan
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en12061002

An experimental system for observing the drop vaporization and microexplosion characteristics of emulsified droplets in high-temperature environments was conducted to analyze the effects of environmental temperature, droplet size, and water content on droplet behavior. In addition, emulsified low-sulfur heavy fuel oil (HFO) with a 20 vol% water content and pure low-sulfur HFO were used as fuels for burning in an industrial boiler under normal operating conditions. The results showed that by using an emulsified HFO with a 20 vol% water content, the boiler efficiency can be improved by 2%, and that a reduction of 35 ppm in NOx emissions (corresponding to a NOx reduction rate of 18%) can be achieved. These advantages are due to the occurrence of a microexplosion during the combustion of the emulsified droplets. It was observed that when emulsified HFO with a 20 vol% water content was used, the fuel (HFO) consumption rate was 252 l/h. On the other hand, the fuel consumption rate was 271 l/h when pure low-sulfur HFO was used. Therefore, a reduction of 19 l/h in the fuel (HFO) consumption rate was achieved when using the water-in-oil emulsion, corresponding to fuel savings of 7%.