Novel Hybrid Microbial Electrochemical System for Efficient Hydrogen Generation from Biomass (Final Technical Report)
- Oregon State Univ., Corvallis, OR (United States)
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
The overall goal of this proposal was to develop a novel microbial electrochemical system for H2 production from biomass at a cost less than $2/kg H2. The specific objectives of this project were: (1) design and fabricate a low-cost, robust, and highly efficient hybrid fermentation and microbial electrochemical cell (MEC) reactor, and (2) determine the techno-economic feasibility of the system for H2 generation from lignocellulosic biomass hydrolysates and sugar-rich wastewater. We achieved the first objective by developing a system with the following characteristics: (a) a hybrid bioreactor that combines the strengths of dark fermentation and microbial electrolysis processes; (b) novel electrode assembly in the reactor that contains robust, low-cost, efficient catalyst, electrode and separator materials; (c) optimized operational conditions that lower the energy input and enhance H2 yield and production rate. We achieved the second objective by developing a cost-performance model to identify key factors that affect performance and cost of H2 production and guide/prioritize research. The research conducted in this project has advanced the knowledge in the fields of dark fermentation, microbial electrochemistry and technologies, and electrocatalysis. It has enhanced our understanding of how the H2 production is affected by the bacterial culture, feedstock composition, and environmental conditions in both dark fermentation and MEC processes and what are the key microbial processes that hinder the H2 production using single chamber MEC reactors and mixed bacterial cultures. The research has revealed the synthesis-structure-property relationship of a H2 evolution reaction (HER) catalyst. This proposed technology represents a green and renewable approach for H2 production from biomass. The biomass harvested in the country could provide enough H2 to fuel light-duty vehicles in the US. When using wastewater as feedstock, the simultaneous wastewater treatment during H2 production process can further increase the environmental sustainability. The research conducted in this project has brought the biological H2 production technologies closer to practical applications by: 1) determining the suitable mixed bacterial cultures using complex feedstocks; 2) developing fermentative bacterial enrichment and immobilization methods for enhancing the H2 production rate; 3) developing low-cost molybdenum phosphide (MoP) HER catalysts to lower the capital cost; 4) determining the suitable design (e.g. reactor configuration, electrode surface area to rector volume ratio, liquid/gas separator) and operational conditions (e.g. pH, temperature, feedstock loading, mixing conditions) to lower the capital and operational costs; 5) fabricating a 10-L hybrid reactor to demonstrate the potential of H2 production. Our cost performance analysis suggests that further increasing the current density and reducing the electrode costs are critical to meet the $2/kg cost target using lignocellulosic biomass feedstock and the cost target is achievable using wastewater as feedstock if the wastewater treatment credit is considered.
- Research Organization:
- Oregon State Univ., Corvallis, OR (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Fuel Cell Technologies Office
- DOE Contract Number:
- EE0007269
- OSTI ID:
- 1813870
- Report Number(s):
- DOE-OSU-07269
- Country of Publication:
- United States
- Language:
- English
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