A Comparative Technoeconomic Analysis of Algal Thermochemical Conversion Technologies for Diluent Production

Microalgae offer desirable attributes as a renewable feedstock. Herein, a technoeconomic assessment of using microalgae to produce chemicals (diluent) for bitumen transport is conducted. Two thermochemical technologies, hydrothermal liquefaction (HTL) and fast pyrolysis, are analyzed for a plant of 2000 dry t day(-1). A detailed process model is developed for the two thermochemical conversion technologies and used to perform a data-intensive technoeconomic assessment to estimate diluent cost using biomass. The product values of diluents from HTL and pyrolysis are 1.60 +/- 0.09 and 1.69 +/- 0.11 $ L-1, respectively. The sensitivity analysis indicates that product yield has the highest impact on product value, followed by the biomass cost. The effect of using industrial carbon dioxide in a situation where the producer pays to the algae conversion plant to avoid paying a carbon levy is assessed. For HTL and fast pyrolysis, diluent cost falls to 1.06 and 1.16 $ L-1, respectively, when carbon tax increases to 40 $ t(-1). Herein, insights into the technoeconomic feasibility of producing chemicals from algal-based thermochemical technologies are offered.