Experimental and economic assessment of alkaline electrolyzer for dual-fuel operation in low-displacement diesel engines

Abstract

This investigation evaluated the integration of an alkaline electrolyzer for dual-fuel operation in an experimental test bench of a diesel engine from a techno-economic viewpoint. The characterization of the electrolyzer operation indicated that higher electrolyte (KOH) concentrations (30 – 40% w/w) improve the overall performance since less voltage is required for electrolysis, thus featuring higher efficiencies (50 – 60%) and hydrogen production (4 – 6 LPM). The economic analysis demonstrated that hydrogen cost remains competitive (4.3-5.6 USD/kg), and it is greatly dependent on the electrolyte concentration. Additionally, the operation of the engine with hydrogen injection at 20 LPM and a palm biodiesel blend reduced the fuel consumption rate between 10 – 31% depending on the load rate when compared to pure diesel. In contrast, dual-fuel operation generated a minor reduction in fuel conversion efficiency (< 5%), which reflects on the power output. Overall, this technology stands as a promising avenue to improve the fuel utilization ratio.