Hydrogen production by direct injection of ethanol microdroplets into nitrogen microwave plasma flame

• Published in: International journal of hydrogen energy Vol. 43; no. 46; pp. 21196 - 21208
• Main Authors: Czylkowski, Dariusz, Hrycak, Bartosz, Jasiński, Mariusz, Dors, Mirosław, Mizeraczyk, Jerzy
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.11.2018
• Subjects: Atmospheric pressure plasma; Ethanol conversion; Hydrogen production; Liquid microdroplets injection into plasma; Microwave plasma; Microwave plasma; Atmospheric pressure plasma; Liquid microdroplets injection into plasma; Hydrogen production; Ethanol conversion
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.09.143

Liquid ethanol introduced as microdroplets into the tip of microwave nitrogen plasma, operating at 2.45 GHz under atmospheric pressure, has been investigated. Injection of ethanol outside the region of plasma generation eliminated a problem of soot formation at that region, which was responsible for short reactor lifetime. Using liquid ethanol allows to save energy needed for vaporization. Hydrogen, carbon monoxide and solid carbon were the main outlet products. Other products detected with gas chromatography were CH4, C2H4 and C2H2. The best results concerning hydrogen production were as follows: concentration in the outlet gas up to 28%, production rate up to 1043 L/h, energy yield up to 209 L per kWh of microwave power, and were obtained for liquid C2H5OH flow rate of 3.7 L/h. A numerical 0D model was used to determine contributions of chemical reactions in formation of measured gaseous products. Simplified model involving only radical reactions without any ions and electrons predicts final concentrations of main compounds quite well for microwave power up to 4 kW. [Display omitted] •Ethanol injection outside plasma generation region prevents soot formation there.•Using liquid ethanol allows saving energy needed for its vaporization.•Hydrogen, carbon monoxide and solid carbon were the main outlet products.•Experiment shows that hydrogen volume concentration in the outlet gas was up to 28%.•Simple 0D model predicts final concentrations of main compounds relatively well.