Engineering study of a pilot scale process plant for microalgae-oil production utilizing municipal wastewater and flue gases: Fukushima pilot plant

Abstract

This article presents an engineering study of an integrated system to produce bio-oil from microalgae biomass. The analysis is based on a pilot plant located at Minami-soma Fukushima, Japan, which further simulates 1 ha based-cultivation. Municipal wastewater and flue gases were utilized as nutrient sources for the microalgae culture of the proposed design. A flow sheet diagram of the integrated plant was synthesized by process engineering software to allow simulation of a continuous system. The design and sizing of the process equipment were performed to obtain a realistic estimation of possible production cost. The results demonstrated that nutrient savings was achieved by wastewater and CO2 utilization to the polyculture of native microalgae. Process simulation gave an estimated CO2 sequestration of 82.77 to 140.58 tons ha-1year-1 with 63 to 107 tons ha-1year-1 of potential biomass production. The integrated process significantly improved the energy balance and economics of biofuel production and also the wastewater treatment plant (WWTP). The economic analysis confirmed that higher biomass production and technology improvement were required to achieve operational feasibility and profitability of the current microalgae-based bio-oil production.