4-01: Moving towards commercialization of lignocellulosic biomass to fuels and chemicals. How to deal with heterogeneous biomass?

Improvements in individual processes (pretreatment, saccharification, and fermentation) have been ongoing, but few researchers have considered the effect that the incoming heterogeneous raw biomass can have on the process. Even within the same species, biomass is physically and chemically very heterogeneous due to the agronomy practices, water and nutrients management, weed control, harvest and storage, seasonal changes, and age. Rather than designing a biorefinery around an ideal source of a given feedstock, it is preferable to understand how we can process heterogeneous feedstock. How can we alter the heterogeneous biomass to provide the maximum yield of hydrolysable and fermentable sugars from whatever is available? In this paper we discuss how by preconditioning of biomass, online reaction control, techno-economic and life cycle analysis we can deal with heterogeneous biomass such as poplar and forest residues. We will present that by improving the uniformity of heterogeneous biomass in terms of moisture content and particle size we could improve sugar yields by 20%. We will discuss how refining improved homogeneity of steam pretreated poplar and increased cellulose to glucose conversion by 20%. Another means of dealing with heterogeneous biomass is to improve overall process control by increasing the level of data collection. We will show how Raman spectroscopy could provide early detection of feedstock heterogeneity, leading to increased real-time awareness. Finally, when processing heterogeneous biomass overall results of the techno-economic analysis have to be incorporated into life cycle assessment work to estimate life cycle greenhouse gas emissions from mixed lignocellulosics.