This Small Business Innovation Research Phase I project will demonstrate a more effective and economical process for extracting the chemical and energy resources from lignocellulosic biomass. Existing lignocellulosic pretreatment technologies use any of a variety of chemicals, heat, and mechanical energy to separate the poorly hydrolyzed lignin from the cellulose, and hemicellulose for enzymatic hydrolysis to sugars, and fermentation of sugars to alcohol, or in the case of anaerobic digestion to biogas. The use of chemicals, or operation at high temperatures and pressures dictate the cost of pretreatment. This research will investigate a process that pretreats lignocellulosic biomass at low temperature and pressure without the use of chemicals. The process operates with very low energy inputs and may be driven by waste heat.
The broader impact/commercial potential of this project will be the adoption of an economical process for the efficient extraction of energy and chemical resources from biomass. The pretreatment process will be used for the production of liquid and gaseous fuels from lignocellulosic biomass. The process will be used to reduce waste residuals from biomass processing by increasing the percentage of the biomass converted to renewable energy. Potential markets include agricultural enterprises that produce liquid and gas fuels from energy crops or crop residues, such as bio-refineries, farms with anaerobic digesters, composting facilities, municipal and industrial solid waste facilities, confined animal feeding operations (CAFOs) and bio-refineries for pre and post consumer solid waste processing. The process is expected to lower the cost of bioenergy production and thereby improve its use while reducing GHG emissions.
All plant material is composed of a tightly woven matrix of cellulose, hemicellulose, and lignin that is resistant to chemical or biological conversion to biofuel. Pretreatment is required to break down the plant structure and separate the poorly hydrolyzed lignin from the cellulose and hemicellulose for enzymatic conversion to alcohol, or in the case of anaerobic digestion to biogas. Although a wide variety of pretreatment technologies are available, most are complex or use toxic acidic or alkaline chemicals. All operate at high temperatures and pressures and as a result are expensive. A simple, inexpensive, and benign process is required to pretreat lignocellulosic biomass for the economical production of biofuel and the extraction of useful organic chemicals from biomass. This research investigated the performance and economics of the ABFX process to achieve the goal of simple, economical, and benign biomass pretreatment for bioenergy production. The research used grass silage and screened manure solids as the biomass substrate. The research was able to establish a conceptual model of the ABFX process and the relationship between the variables. The effect of pretreatment on the degradability of biomass and gas production were established. The ABFX process was proven to be economically feasible since it improves energy recovery from biomass at a small cost. Adequate pretreatment was achieved by simply heating the substrate to low temperatures (± 100°C). Waste heat can be used to produce the low temperatures required. A majority of the organic reagent used can be recovered. Some organic reagent is lost with the biomass but can be recovered in a downstream anaerobic process. The benefits are achievable at low cost. The low cost will significantly improve the economics of renewable biofuel production.
