(A) study on improving the techno-economic feasibility of microalgal biodiesel production processes

Abstract

Microalgae, as renewable energy feedstocks, have been the limelight lately as one of the solutions to global warming and exhaustion of fossil fuel. Despite its advantages such as the fast growth, year-round cultivation, high yield per area, use of lower quality land, high oil content per weight, utilization of CO2 and value-added byproducts, microalgae biofuels stand commercially unviable at this point as they are much more expensive than conventional biofuel. Therefore, to figure out the potential feasibility of microalgal biofuel, techno-economic analysis (TEA) is essential process to understand the economical states of algal technologies and look for improvement plan. However, until now, most of detailed TEA studies are only focused on cultivation process. Moreover, the production costs of TEA results of each research have a big variability because each paper has respective process boundaries, target pathway, simulation condition, and assumptions. Therefore, comparative TEA of each technologies for biodiesel production process on the same lines is needs for fair evaluation.

In this thesis, first, the economic feasibility of several transesterification technologies is compared with microalgal biodiesel production cost. Each case based on each technology are analyzed in detail with same simulation condition and assumptions. Sensitivity analysis is followed to figure out the key parameter and quantify the effect of changing each parameters to final biodiesel cost. Moreover, detailed strategies for improvement of the economic feasibility of microalgal biodiesel production process is suggested. For the next step, the practical process design and techno-economic analysis for the entire production process from cultivation to biodiesel production are performed. Microalgae species is determined which is suitable for large scale biodiesel production. Catalytic TE technology and in situ TE technology are compared with the same scale of other processes to examine and figure out the economic process. After the evaluation, to make microalgae biodiesel production process more economically, DHA production is considered as new scenarios. In this thesis, not only the part of the microalgae biorefinery, but the entire process for producing biodiesel is economically evaluated with the same boundaries, condition, and assumptions. The results of this thesis could help the direction of the scale-up and commercialization of microalgae biodiesel production.