Apport du couplage d'une thermobalance gravimétrique et d'un analyseur calorimétrique différentiel pour la mesure de l'activité de l'eau dans un mélange liquide solide

International audienc

Evaluation of Energy Recovery Potential by Anaerobic Digestion and Dark Fermentation of Residual Biomass in Colombia

This study provides the first overview in Colombia on energy recovery potential by anaerobic digestion (AD) and dark fermentation (DF) of three different residual biomasses: coffee mucilage (CFM), cocoa mucilage (CCM), and swine manure (SM). First, AD and DF models were developed based on the ADM1 model. Then, simulated biogas production yields were compared to experimental data to validate the models. The results of comparative simulations indicate that energy recovery potentials from biogas for the different Colombian departments range from 148 to 48,990 toe, according to the local production amounts of CFM, CCM, and SM in 2017. The study provides crucial information that can be used to assess the best design, operation mode, and locations of AD and DF plants in Colombia. The results indicate that biogas production performances and energy recovery yields improve by increasing CFM/SM and/or CCM/SM ratios of the feed, and by increasing organic load from 2 to 26 gCOD∙l−1

Stoichiometry impact on the optimum efficiency of biomass conversion to biofuels

International audienceBiomass has the specific characteristic of being included in a short regeneration cycle that minimizes its ecological impact and should give it a preferential role in the energy transition. The scale up in the deployment of bioenergy requires an objective approach to processes. It is necessary to identify, according to a defined and available biomass, the most appropriate processes and products to extend their deployment This requires deep process analysis to identify achievable optimizations and opportunities of improvement. In order to provide criteria to identify the upper theoretical limits of biomass conversion, a theoretical approach to the conversion of two biomass (lignocellulosic and microalguae) into simple energy vector as alkanes, alcohols, carbon monoxide or hydrogen is carried out. Modelling highlights the importance of stoichiometry in the feasibility and efficiency of biomass conversions. The impact of hydrogen supply and its energy cost in improving conversion efficiency is also underlined. In terms of biomass conversion results, microalgae provide better conversion efficiency than lignocellulosic biomass. For these reactions, an optimal carbon conversion ratio is identified. The optimum conversion ratios are about 36% to 46% for short chains such as methane or methanol and 64% to 75% for long chains. • Stoichiometry plays a major role in the biomass conversion • Optimum limit for biomass conversions are identified for alkanes, alcohols, H 2 and CO production • Hydrogen supply source can improve conversion efficiency • Proposal of a methodology to calculate efficiency for biomass conversio

Analyse de l'efficacité de la conversion de la biomasse en bioproduit : Rôle de la stœchiométrie et proposition d'une efficacité théorique maximale

International audienc

DEVELOPPEMENT D'OUTILS EXPERIMENTAUX POUR LE DIMENSIONNEMENT DE PROCEDES DE SECHAGE CONDUCTIF AVEC AGITATION (APPLICATION A DES BOUES DE STATIONS D'EPURATION URBAINES)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Simultaneous heat-flow differential calorimetry and thermogravimetry for fast determination of sorption isotherms and heat of sorption in environmental or food engineering

International audienceA new experimental technique is described for the determination of desorption characteristics for engineering purposes. A TGA-DSC setup is used in isothermal mode to achieve the thermal desorption of deformable standard materials like microcrystalline cellulose and kaolin in dry air. Assumptions on heat and mass transfer are made and discussed in order to derive desorption isotherms and heat of sorptions from the calorimetric and gravimetric signals. The method is rapid and accurate for high-temperature desorption processes T ¿ 40 • C. It is particularly reliable for small water activity values 0 6 aw 6 0:4 where a good agreement with standard methods is observed in spite of small apparent diusion coecients D ∼ = 10 −10 m 2 s −1 for the two products tested. The method is suitable for heat sensitive biological products because of the small residence time in the furnace (1 or 2 h)

A practical method to derive sample temperature during nonisothermal coupled thermogravimetry analysis and differential scanning calorimetry experiments

International audienceNonisothermal thermogravimetry differential scanning calorimetry (TG-DSC) mounting is intensively used for the determination of kinetic parameters and reaction heat along the chemical transformation of a solid. Nevertheless, when tests are performed with heating rates as high as those encountered in industrial processes, e.g., several tens of K min-1 , there is great uncertainty in the knowledge of the exact sample temperature. In this work, a method to derive a simple mathematical expression is proposed and fully described in order to calculate the real sample temperature throughout a temperature-ramped test on a commercial apparatus. The furnace temperature and the heat flow signals were used, together with the crucible specific heat and the heating rate. A number of validation tests were performed to derive similar reaction rates for a reference. First-order kinetic reactions were presented and reconciled over a large range of heating rates from 3 to 50 K min-1

Isothermal calorimetry for enzymatic hydrolysis

International audienc

Use of a heat pump to supply energy to the Iodine-sulphur thermochemical cycle for hydrogen production

International audienceThe hydrogen world consumption should increase significantly to progressively replace hydrocarbons. Due to its high power density, nuclear reactor should take an important place in this production. This paper focuses on the hydrogen production by thermochemical cycle using the heat available at 900°C of a new generation nuclear reactor. The chosen thermochemical cycle for this study is the iodine-sulphur thermochemical cycle water splitting.The process flowsheet under consideration has high total energy consumption. It has also many local energy needs unevenly distributed over a wide temperature range. The raw distribution of this energy gives a hydrogen production efficiency of 14.0%. To improve this, the proposed coupling is built using an energy distribution network with a coolant to meet the safety requirements. In this simple case, the efficiency of hydrogen production comes to 21.9%. By integrating a heat pump into the energy distribution network, the efficiency of production increases to 42.0%. The exergetic efficiency, increases from 59.3% to 85.8%