Comprehensive Feasibility Assessment of Combined Heat, Hydrogen, and Power Production via Hydrothermal Liquefaction of Saccharina japonica

Abstract

An increase in population and a decrease in natural resources have shifted the research focus toward renewable energy alternatives such as biofuel produced from algal biomass. The inherently high moisture content of macroalgae makes hydrothermal liquefaction (HTL) a viable approach for using macroalgae to generate renewable energy. This study focuses on experimental and economic feasibility studies regarding HTL of Saccharina japonica as a feedstock for combined heat, hydrogen, and power (CHHP) production. An experimental study was performed using various operating parameters, viz., temperature, reaction time, and macroalgae to water ratio. The optimal experimental conditions resulted in a bio-oil yield of 20.26 wt % and the highest liquefaction conversion of 91.0 wt %. Based on the experimental results, an industrial-scale CHHP process via HTL of S. japonica was developed and the economic viability of this process was evaluated. We assessed the economics of three different designs with different process configurations for 480 000 tons/year of dry macroalgae. The optimal CHHP process provided 17.7 MW of net power, net LP steam production of 60 000 kg/h, and a total hydrogen production of 5104 kg/h with a minimum hydrogen selling price (MHSP) of $3.00 kg(-1). The proposed CHHP process based on HTL of S. japonica could be a promising alternative for energy production.