Participants on I-CEMITURE projects will develop skillsets that can be used to foster innovation and economic growth in US communities, particularly the southeast. The southeast US is rich in forestry and it has long been acknowledged that there is much potential for the development of industries focused on sustainable biomass. In this training experience at Lermab at the University of Lorraine in Épinal, France, students will be mentored by leaders in the field of wood pyrolysis on the following projects described below.
Wood is one of the most widely promoted building materials. However, when exposed to outdoor conditions, unprotected wood undergoes degradation, induced essentially by fungal activity. Torrefaction is a wood heat treatment process with temperatures ranging from 180°C to 240°C, under inert atmosphere. Torrefaction is a type of preservation process that does not have an adverse effect on the environment, since only heat is used. It is therefore a superb alternative to the chemical treatment processes that are typically used to preserve wood.
Wood preservation by heat treatment is fast-growing in many European countries, with several processes having been developed since 1980. Despite the fast industrial development, current procedures for torrefaction results in wide variations in the final properties of the treated material. So, it is very difficult to obtain heat treated wood-biomass of consistently good quality, even for well-known wood species. The establishment of a more energy efficient process and mathematical (kinetic) models that can accurately predict the final properties of torrefied wood will open the door to more strategic and wider commercial use of locally abundant, low-cost biomass.
The main objectives of I-CEMITURE projects are (a) to establish a mathematical (kinetic) model that provides a better description of biomass torrefaction than currently existing kinetic models, and (b) test this model on both small and semi-industrial scale levels. Scholars on Projects 1-4 (below) will work in sync to accomplish these objectives.
Project Title: Designing the Kinetic Model
Working between experimental and theoretical (kinetic/mathematical models) data, scholars will refine a preliminary “two-step kinetic model” by considering variables in the wood’s content and the experimental procedures such as minerals in the wood, reaction atmosphere, and nature of woody biomass used (hardwood vs softwood). Discrepancies between preliminary models and experimental data will guide the incorporation of correcting factors based on results obtained from projects 2, 3, and 4.
Project Title: Refining the Kinetic Model, the Mineral Content Variable
Scholars will perform experiments to obtain data on the effects of the wood’s mineral content on the torrefaction process. They will use their experimental data to validate the mathematical model developed in project 1. Scholars will select different biomass with known mineral content under the guidance of their mentors in France. The influence of mineral content on the biomass torrefaction process will be evaluated by thoroughly monitoring degradation of the selected biomasses. The treatment temperature will be varied and the most promising conditions will be reproduced at a semi-industrial scale.
Project Title: Refining the Kinetic Model, the Atmosphere Variable
Scholars will conduct experiments to determine the effect of the reaction atmosphere (vacuum, nitrogen, or water vapor) on the torrefaction process. Experiments will be conducted under vacuum, nitrogen, and water vapor. After evaluating different combinations of atmospheres and treatment temperatures, the most promising conditions will be reproduced at a semi-industrial scale, using the unique facilities at Lermab (University of Lorraine). The results covering the effects of the atmospheric conditions will be used to refine the kinetic model developed in Project 1.
Project Title: Refining the Kinetic Model, the Biomass Composition Variable
Scholars will conduct the torrefaction of two pre-selected biomasses according to their composition. One example of softwood biomass and one example of hardwood biomass will be pre-selected by mentors in France. Experiments will investigate the effects of temperature and different lengths of time for heating and results will be used to improve the kinetic model developed in Project 1. Similar to other projects, the most promising results will be reproduced on a semi-industrial scale.
Technical Skills and Training: All I-CEMITURE participants will develop skills in the use of instruments and interpretation of data for thermogravimetric analysis (TGA), Infrared (IR) Spectroscopy, and Elemental Analysis. Scholars will also learn how to design reliable, multi-variable mathematical models for chemical processes.
Last updated: 12/22/2020