Dimensional change behavior of caribbean pine using an environmental scanning electron microscope

Moisture transport and dimensional change during wood drying or wetting processes were analyzed based on pictures from an environmental scanning electron microscope (ESEM). This provides quantitative relationships between dimensional changes of total area, cell wall, and lumen, and moisture content for earlywood and latewood. Earlywood and latewood behave similarly but show some quantitative differences. The overall outcome for sections containing both kinds of wood seems to be dominated by the latewood behavior. The observed strain behavior of wood during drying is anisotropic in ways that are inconsistent with explanations solely related to microfibril orientation or earlywood/latewood interactions and more likely may be influenced by ray tracheids.

The drying of sewage sludge by immersion frying

The objective of this work was to dry sewage sludge using a fry-drying process. The frying experiments were carried out in commercial fryers modified by adding thermocouples to the setup. During frying, typical drying curves were obtained and it was verified that, in relation to the parameters: oil temperature, oil type and shape of the sample, the shape factor the most effect on the drying rate, at least within the range chosen for the variables studied. Oil uptake and calorific value were also analyzed. The calorific value of the samples increased with frying time, reaching values around 24MJ/kg after 600s of frying (comparable to biocombustibles such as wood and sugarcane bagasse). The process of immersion frying showed great potential for drying materials, especially sewage sludge, obtaining a product with a high energy content, thereby increasing its value as a combustible.