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defense benjamin peterson

The Development and Optimization of a Produced Water, Biofilm Based Microalgae Cultivation System for Biocrude Conversion with Hydrothermal Liquefaction


Friday, August 11
8:00 AM • ENGR 406


Benjamin Peterson
Master's Candidate Thesis Defense
Department of Biological Engineering

Advisor - Ron Sims, 435-797-3156
ron.sims@usu.edu




Abstract

Extraction of oil and gas in Utah’s Uintah Basin results in large quantities of wastewater, or produced water, with nutrients and residual organic chemical that represent a significant resource for producing energy-related and value-added products. Produced water was obtained as a biomass producing nutrient source from industries operating in Utah’s Uintah Basin. Within the Uintah Basin (defined as Uintah and Duchesne Counties within Utah) approximately 93 million barrels of water were produced in 2013 while only 11% of the water was disposed of through evaporation with the national average at 2%. The rest is reinjected into the subsurface.

The goal of this project was to design a system that utilizes produced water as a nutrient source for growing biomass in a biofilm form using a Rotating Algal Biofilm Reactor (RABR). The biomass would then be harvested and converted into biocrude oil using hydrothermal liquefaction (HTL). The objectives focused on were to optimize the reactor to reduce energy costs to operate while increasing biomass productivity and ultimately increasing feedstock quality for HTL.

The RABR was constructed out of polystyrene disks and experimentation was carried out to optimize rotational speed of the reactor. Two strains of algal biomass were identified as biofilm formers and grown using produced water as the nutrient source. The biomass was then utilized as a HTL feedstock that gave an average yield of 34.5% ash free dry weight.