(768e) A Process Model for Converting Low-Lipid Microalgae into Biocrude Oil Via Hydrothermal Liquefaction

This study aims to develop a process model for an integrated system that can simultaneously treat wild-harvested algal biomass and generate bioenergy. Previous studies focused more on high-lipid algae that normally require nitrogen depletion and contamination free culture condition, which result in low yield. On the contrary, low-lipid algae which contain large fraction of protein and carbohydrate typically have higher biomass production rate and can grow in harsher conditions. Hydrothermal liquefaction (HTL) process of biomass has shown encouraging results in converting whole algae into biocrude oil. Biocrude oil with high heating value is produced by HTL as a promising alternative for petroleum oil. After separation of biocrude oil, the aqueous phase contains large quantities of carbon, nitrogen, phosphate and other nutrients, which could be utilized in further reuse.

Investigating different configurations of the feedstock pretreatment, hydrothermal liquefaction (HTL) conditions, upgrading of biocrude oil and recycle of nutrients will help develop a sustainable and robust system for the highest net energy production and the lowest greenhouse gas emission. The present work intends to use process simulation tools to analyze the feasibility of HTL process that employs wild-harvested microalgae and cyanobacteria to produce biocrude oil and recycle the nutrients. A detailed mass balance, energy balance, techno-economic analysis will be investigated from feedstock to the final products. The simulation will be carried out by using Aspen Plus software, based on experimental results from model compounds and whole algae via HTL process.