<p>Biomass liquefaction is a nascent field within biorefinery research and has arisen in response to the bottleneck created from materials handling at the front end of the biorefinery. The basic concept is that if the biomass were to be converted into a flowable slurry at the front-end of the process, then the material could smoothly flow into the biorefinery pretreatment and down time due to the material forming a plug would be minimized or eliminated. Three liquefaction routes were studied in this work. These routes were: enzyme route, enzyme mimetic route, and a combined route of enzyme and enzyme mimetic. Through a Techno-economic assessment (TEA), it is possible to determine which route is most-economical to scale up and also to understand the extent to which liquefaction increases/decreases of the price of the biorefinery product.</p> <p>Gasification is a bio-based technology that has recently acquired more attention as it is an efficient conversion process for a variety of feedstocks. As new techniques and process routes are discovered, it is important to analyze which process technique is feasible for commercial scale up, as the highest performing technique may not be the most economical option to pursue. Along the same philosophy, a process concept was developed on Aspen Plus® to treat syn-gas impurities and also recycle the spent solvents. A TEA study was performed to determine the unit cost of treatment and to explore avenues of cost saving.</p>

<p dir="ltr">Feedstock variability represents a challenge in the adoption of lignocellulosic biomass for biofuels and biochemicals production, due to the differences in critical chemical and physical properties like lignin content, and water absorption respectively. Thus, difficult continuous manufacturing processes in biorefineries, hinder the transition from liquid feedstocks to renewable materials that consisting of solid particles. Modeling of flow properties based on rheological measurements of treated biomass is a quantitative metric for identifying if different feedstocks form pumpable slurries. Additionally, the correlation of yield stress to physical and chemical properties gives a measure that accounts for the variability in the processing design. This research models rheological properties and relates these to compositional data from different non-pretreated fractions of corn stover biomass slurries. Slurries were formed with solids concentrations of 300 g/L in a 6 hours fed-batch process using the commercial enzymes Celluclast 1.5L or Ctec-2 at 1FPU/g or 3 FPU/g of dry solids, basis to enable the liquefaction (i.e., slurry-forming) mechanism. We found that insoluble lignin content of the different fractions was related to water absorption in pellets and free water on slurries and that free water was a good indicator of the potential for a material to form slurry. Higher flowability (lower yield stress) was found at higher content of lignin, particularly for materials containing 26% lignin where yield stress was reduced to 254Pa when compared with mixtures of 14% lignin that presented yield stresses of around 4000 Pa. We show that rheology modeling linked to compositional characteristics for biomass slurries can be used to predict material flow behavior in a biorefinery to optimize and achieve high solids loadings that enhance the production of ethanol for biofuels. This insight and the ability to form high concentration slurries before pretreatment holds the potential to develop new processing strategies that could help to foster a more efficient and sustainable bio-based industry. </p>

Ce travail porte sur l'étude des voies réactionnelles accompagnant la liquéfaction desconstituants de la biomasse lignocellulosique dans un milieu aqueux proche du pointcritique. La stratégie expérimentale consiste à étudier la réaction en unité pilote decomposés lignocellulosiques modèles et à développer une approche analytiquemultitechnique originale afin de caractériser les structures et les masses moléculairesdes produits. Les résultats obtenus montrent que les schémas réactionnels sontcomplexes faisant intervenir de nombreuses voies de fragmentation et de condensationcompétitives. L'étude cinétique à différents temps de séjour montre que la fractionglucidique de la biomasse lignocellulosique a une réactivité très différente de sa fractionligneuse. / This work deals with the study of the reaction pathway during the lignocellulosicconstituent liquefaction by water near its critical point. Experimental method consists ininvestigation of lignocellulosic model compounds conversion in pilot plant combined withdevelopment of a new multitechnique analytical approach in order to characterizeproduct chemical structures and molecular weights. Results show that reaction pathwaysare very complex consisting to several fragmentation and condensation competitivereactions. The kinetic study with different reaction times reveals an important differenceof comportment for the glucidic fraction than the lignin fraction of biomass.