Energy from biomass has, historically, been a significant part of Hawaii’s energy mix. With the decline of the sugar industry and aggressive State goals to reduce fossil fuel usage, there has been considerable effort in the state to identify new, cost effective means to produce biofuels and/or energy from biomass. Biofuels and bioenergy products often require development of a value chain that includes production of the biomass resource, resource collection logistics, conversion technology(s), product distribution, and end use. While HNEI works with partners inside and outside the University to inform and enable development of the entire value chain, HNEI’s activities are focused primarily on the development of cost-effective conversion technologies and management of various technical and resource assessments (See Alternate Fuel Assessments, below). Ongoing work includes research on biocarbons, gasification technology, anaerobic digestion and bio-oil extraction, and the development of bioplastics and other high value products from waste streams. These activities support efforts to improve energy, food, and water security for Hawaii and the US.
HNEI’s work in biomass and biofuel development spans the value chain:
Biocarbons are a key ingredient in the production of silicon, are used to clean water and cook food, and are used as a substitute for coal in powerplants. The latter use greatly reduces harmful emissions of CO2, SOx, and heavy metals. HNEI's efforts in this area focus on scale-up of the Flash-Carbonization™ technology; improving the speed, efficiency, and economics of the carbonization process; and the reducing emissions during processing. Studies of the pyrolysis of biomass in pure oxygen at elevated pressure in sealed vessels has been initiated.
Biomass and Fuel Processing (Gasification)
Biomass from agricultural, silvicultural, and urban sources can be used as the starting material to produce electricity, fuels, and higher value products. Chemical and fuel properties of these materials can vary significantly. Processing can serve to reduce variability and improve properties for a targeted end use application. Processes under investigation include biomass fractionation and thermochemical conversion of biomass to intermediate products. Research in gasification focuses on producing liquid fuels from synthesis gas. This spans the spectrum of biomass energy conversion including pretreatment, conversion processes, and downstream processing.
Anaerobic Digestion & Bio-Oil Extraction
HNEI is conducting research to develop cost-effective high rate anaerobic digestion (HRAD) of dilute waste to develop integrated platforms that efficiently treat wastewater, with the concomitant recovery of energy, nutrient rich irrigation water, and soil amendments.
With its partners, HNEI personnel collaboratively conceptualize and evaluate early stage translational research on (i) immobilization media that improve yield and reaction rates, (ii) system designs that integrate HRAD with pre-existing aerobic digestion technology, and (iii) biochar addition to soils as a means to improve their productivity and long-term resiliency to long-term irrigation with anaerobically treated wastewater. Researchers in the Biochemical Engineering Laboratory are also developing liquid solvents with unique chemical and physical properties to improve extraction and separation of oil from biomass. Research on solvent properties includes ionically charged electrolytes, hydrophobic/hydrophilic molecules and structural considerations.
Bioplastics and High Value Products
HNEI is developing a new technology to produce liquid fuel from the syngas. The technology includes: (a) catalytic conversion of CO and H2O into CO2 and H2; (b) capture and conversion of CO2 and H2 by an autotrophic bacterium into polyester; and (c) thermal degradation of polyester into a liquid fuel.
Researchers in the Bioprocessing Lab are also developing a novel microbial process in which polyhydroxyalkanoates (biopolyesters or “bioplastics”) are biologically synthesized from renewable feedstocks and waste streams. The biopolyesters can be converted into green chemicals and other value-added materials, as well as a renewable, “drop-in” gasoline.