Biochar fracture resistance

Biochar is a brittle material that tends to break under mechanical stress. This could be an advantage if it is intended to obtain a char powder, but it is typically unwanted since it generates dust that induce biochar losses or even explosion risk. Mechanical stresses are typically observed inside pyrolysis reactors (Scala et al., 2006), during transport/storage and finally inside the soil (Spokas et al., 2014). There are few data in the literature regarding the mechanical strength of char (Capon et al., 1980). This study aims at assessing the impact of pyrolysis temperature and biomass species on fracture resistance. Please click on the file below for full content of the abstract

Depolymerization of fractionated wood by hydrothermal liquefaction

Direct thermochemical conversion of lignocellulosic biomass produces a mixture of compounds that have to be separated to produce purified building blocks. Moreover, lignin derived products have a detrimental effect on further biological conversion processes, such as fermentation. For all these reasons, it is important to develop an integrated approach for a better fractionation and valorisation of macromolecules (carbohydrates and lignin) in bio-refineries. Please click Additional Files below to see the full abstract

Batch fermentation of d-glucose/cellobiose mixtures by clostridium acetobutylicum atcc 824: energetic and carbon source regulation

Lignocellulosic biomass presents an interesting alternative to fossil carbon sources as a source of renewable energy that respects the environment. Indeed, this abundant resource can be converted by a wide range of thermal, chemical and biological techniques to compounds that can be used as substrate in anaerobic fermentation to produce biofuels and building blocks. As a general rule, micro-organisms possess regulation mechanisms that ensure the sequential use of the carbon and energy sources present in their environment. These regulations may consequently play a vital role in biomass to energy and building blocks conversion performances. Clostridium acetobutylicum, a promising biomass transformation organism, has the capacity to utilize a wide variety of compounds as carbon and energy sources. These compounds may be present in a complex mixture produced from cellulose conversion. Therefore it is of high importance to understand the potential synergy or inhibiting effects of the cellulose-derived products. The aim of this work is to study this regulation mechanism by using glucose and cellobiose as model substrates, provided alone and in mixtures to Clostridium acetobutylicum. Our experiments show a total consumption of both substrates, alone or in mixtures, with an increment of 30% of microbial growth production of cellobiose over glucose. A diauxic growth (cell growth in two phases) occurs in the presence of different mixtures of D-glucose and cellobiose. In general, D-glucose is the preferred substrate and after its complete consumption, when exhausted, the growth kinetics exhibits an adaptation time, of approximately 1-2 hours, before to be able to use cellobiose (figure 1). This adaptation is probably due to an induction stage that is also accompanied of acid consumption (lactic acid). This study provides a first approach to understand the metabolic changes related to substrate utilization in Clostridia. Please click Additional Files below to see the full abstract

Effect of pressure and gas velocity on biochar formation: hindered tar evaporation or tar cracking?

Please click Additional Files below to see the full abstrac

Pyrolysis of plastics: highlighting the potential interest of a reflux to control liquid products

Please click Additional Files below to see the full abstrac

Multi-technique characterization of biochar formation

It is known that biomass forms an intermediate liquid before forming the solid “char” (figure 1) but the role of this intermediate liquid on the structure of char and on the mechanisms of pyrolysis is still poorly understood. In this talk we will present how in-situ rheology and 1H NMR analysis [2] are interesting technique to understand the mechanism of biochar formation through an intermediate “visco-elastic” material. These techniques allow assessing the physical-chemistry of biomass conversion to char at real-time and high temperature conditions. Please click on the file below for full content of the abstract

On-line Photoionisation Mass Spectrometry: an Interesting Technique to Study Biomass Pyrolysis

Please click Additional Files below to see the full abstrac

Transport multi-composants dans les polymères : séparation hydrocarbures / hydrogène par membrane à sélectivité inverse

Hydrocarbon / hydrogen separation by reverse selectivity membranes is investigated. The first goal is to develop materials showing an increased selectivity. Silicone membranes loaded with inorganic fillers have been prepared, but the expected enhancement is not observed. The second goal is to model the multi- component transport through rubbers. Indeed the permeability model is not able to predict correctly permeation when a vapour is present. Thus many phenomena have to be considered: diffusional interdependancy, sorption synergy, membrane swelling and drag effect. The dependence of diffusivities with the local composition is modelled according to free-volume theory. The model resolution allows to predict the permeation flow-rates of mixed species from their pure sorption and diffusion data. For the systems under consideration, the diffusional interdependancy is shown to be preponderant. Besides, sorption synergy importance is pointed out, whereas it is most often neglected.La séparation hydrocarbures / hydrogène par membrane à sélectivité inverse est étudiée. Le premier objectif est d'élaborer des matériaux dont la sélectivité est accrue. Des composites silicone - charges minérales sont réalisées, mais l'amélioration attendue n'est pas observée. Le second objectif est de modéliser le transport de plusieurs pénétrants dans les élastomères. En effet, le modèle de perméabilité ne permet pas de décrire correctement la perméation lorsque des vapeurs sont présentes. Dès lors, plusieurs phénomènes sont considérés: l'interdépendance diffusionnelle, la synergie de sorption, le gonflement et l'entraînement convectif. La dépendance des diffusivités avec la composition est représentée par la théorie du volume libre. La résolution numérique du modèle permet de prédire correctement les flux en mélange à partir des mesures sur les corps purs. Pour les systèmes étudiés, l'interdépendance diffusionnelle est prépondérante et la synergie de sorption ne peut être négligée

R&D en Lorraine pour la conversion thermique de la biomasse

National audienc