Hydrothermal liquefaction of wild-harvested cyanobacterial bloom from hypereutrophic Lake Tainter, Wisconsin

This study demonstrates the potential of Harmful Algae Blooms (HABs) as a feedstock for generating biofuels hydrothermal liquefaction (HTL) and asserts that HTL is a uniquely practical technology for use of this biohazardous material. Using a wild-harvested cyanobacteria HAB from Lake Tainter, Wisconsin as a low-cost feedstock for HTL, the projected Minimum Fuel Selling Price of reformed biocrude produced from the Lake Tainter HAB is 18-29% lower than biocrude produced from cultivated algae. The biocrude produced is of sufficient yield and quality to realize a net energy profit making HTL an important environmental remediation strategy for air and water quality. HTL reactions were conducted over a range of reaction temperatures (280-350°C), holding times (30-60 min), and feedstock total biomass solids content (10%-25%TS) using fresh and aged biomass. Bulk biocrude properties (e.g., yield, elemental analysis, high heating value (HHV)), energy balances, and nutrient recovery in the products were compared from each condition. Using HTL, at 340°C and 50 min retention time with 20%TS, 41.8±6.1% daf biocrude yield is possible with this feedstock. The biocrude produced has an HHV of 32.5 MJ/kg, recovering 73.9% of the energy in the biomass and 1:3.3 ratio for energy input for heating to energy recoverable in the crude. Promisingly, this biocrude has a low sulfur content (0.07% wt.) and 60% wt. of the crude is in the light and medium molecular weight fractions (volatile<350ºC). However, high nitrogen (5.93% wt.) and oxygen (16.74% wt. by calc.) contents, and probable acidic nature of the biocrude indicate upgrading is needed pre-refinery. At this temperature, 47% of the nitrogen in the feedstock is recoverable in the post-hydrothermal processing wastewater (HPW), with 55.8% of it as ammoniacal nitrogen.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Agricultural & Biological Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Swoboda, Megan

Contributors dc:contributor

• Zhang, Yuanhui
• Akdeniz, Neslihan
• Davidson, Paul

• algae blooms, cyanobacteria, eutrophication, biocrude oil, hydrothermal liquefaction, catalysis, nutrient recovery, Lake Tainter, Menomonie

Statement dc:rights

• Copyright 2018 Megan Swoboda

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/102439

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/102439