Paper details

Title:

Sustainability Assessment of Hydrothermal Liquefaction of Algae for the Production of Refined Bio-crude: Effects of CO₂ Sourcing

Author(s):

Arora, P., Realff, M.J., Thomas, V.M., Yuan, Y., Chance, R.

Document(s):

Abstract:

Algal biofuels provide an exciting opportunity to effectively replace the conventional crude-based fossil fuels. The greenhouse gas (GHG) emissions benefit of algal biofuels is derived from the fact that the algae growth process consumes a considerable amount of carbon dioxide. This consumed CO2 is subsequently released during the utilization of the algal biofuels. Thus, the only emissions accounted to algal biofuels are the emissions associated with the nutrient and feedstock supply chains, and the conversion and up-grading processes. A considerable amount of emissions is associated with the supply of CO2, which is required for achieving the optimal productivity of algae. The supply of CO2 needs to be synchronized with the diurnal cycle of algae growth, which makes it even more important to understand the different CO2 supply scenarios. The present study highlights the GHG emissions associated with the production of algal biofuels through the hydrothermal liquefaction route. Four different CO2 supply scenarios have been compared, and their integration with the algal biorefinery has been presented. The CO2 supply from the combustion of biomass can lead to a potential reduction of 120% in the GHG footprint of the refined bio-crude when compared to GHG footprint conventional fossil fuels. Alternately, CO2 supply from an NGCC plant built near an algal biorefinery with a specific purpose of supplying CO2 for the biorefinery is expected to have a GHG footprint, which is higher than that of conventional fossil fuels. This study, thus, establishes the greenhouse gas emissions characteristics of different CO2 supply scenarios for an algal biorefinery.

Keywords:

algae, LCA, hydrothermal liquefaction, bio-crude, CO₂ sources, catalytic hydrothermal gasification

Topic:

Bioeconomy Sustainability, Impacts and Policies

Subtopic:

Climate impacts and GHG performance

Event:

28th European Biomass Conference and Exhibition

Session:

4AV.2.11

Pages:

845 - 851

ISBN:

978-88-89407-20-2

Paper DOI:

10.5071/28thEUBCE2020-4AV.2.11

Price:

FREE