The qualification of torrefied wooden biomass and agricultural wastes products for gasification processes

• The development of the porous structure of pine wood, beech wood and palm kernel shells with increasing torrefaction temperature is presented.
• From DTA results it can be concluded, that the highest torrefaction temperature at which an autothermic process mode is achievable is different for each investigated biomass.
• Therefore the gasification characteristics for each torrefied biomass must be unique.
• Investigation methods are presented to evaluate commercially available torrefied products and the potential of torrefaction process for industrial fast gasification purposes.

The present work is focused on the characterization of torrefied biomass and their application for (fast) gasification purposes. Since the upscaling of the torrefaction process from laboratory scale to commercially pilot plants is not fully understood, laboratory results do not reflect the characteristics of commercially available torrefied products gained from theses plants.A step toward bridging this gap lies in a general evaluation of commercially available torrefied products, which should be independent from the preceding processing conditions and which focuses on the specific requirements of the product's technical application.In this spirit, this work focuses on different torrefied products and torrefaction degrees examined with selected, common characterization methods. The influence of the torrefaction process on surface characteristics, especially the development of the porous structure, is investigated. The torrefied material is evaluated in terms of its process temperature management via combined thermogravimetric and differential scanning calorimetric analysis. Since empiric predictions based on fossil coals do not match the characteristics of torrefied material, common analytical methods for fossil coals like ultimate and proximate analysis are also discussed.The methodology laid out in this work enables the user to establish a pre-selection of the torrefied biomass type and the torrefaction temperature for its further application in industrial fast gasification processes.