Simulation of Storage Conditions of Mixed Biomass Pellets for Bioenergy Generation: Study of the Thermodynamic Properties

Abstract

Experimental and mathematical modeling of the moisture sorption isotherms for biomass pellets during storage is performed in this study. The tested pellets are a mixture of 50% wood: spruce or pine, and 50% switchgrass agricultural biomass. Storage conditions, i.e., temperature and humidity, are tested by varying the environment conditions in a conditioning chamber. The experimental results show that the moisture sorption isotherms are not affected by the temperature. Nevertheless, the equilibrium moisture content depends on the kind of the tested pellets. Mathematical modeling of the experimental isotherms is performed using four common models: the Oswin, GAB, Henderson and Peleg models. The Oswin model is defined as the most appropriate model to predict the moisture sorption isotherms of the spruce–switchgrass pellets. It presents a coefficient of determination equal to 0.998, a standard error around 0.049 and a chi-square approaching 0.007. On the other hand, Henderson and GAB models show the best results for pine–switchgrass pellets, with a coefficient of determination varying between 0.998 and 0.997, a standard error range 0.054–0.065 and chi-square error between 0.008 and 0.009. The thermodynamic properties, which include the net isosteric of heat and the entropy changes of sorption, are also determined for all tested samples.

Anti-Thermal Shock Binding of Liquid-State Food Waste to Non-Wood Pellets

“…If the pellet is highly hygroscopic, it cannot resist microbial degradation for long, thus rotting easily [88]. Other relevant negative aspects in the transport, storage, and processing of hygroscopic pellets include the real possibilities of fire and generation of pollutants [89,90]. Thus, pellets with addition by spraying of liquid-state food boiled for the shortest amount of time would be the most suitable pathways for the safe and efficient transport and storage of biomass, as their hygroscopicity was the lowest even after freezing and defrosting.…”

Moisture Sorption Isotherms of Sweet Cherry (Prunus Avium L.): Comparative Study of Kinetics and Thermodynamic Modeling of Five Varieties

“…This relationship is typically described by the moisture sorption isotherm equations. The moisture sorption isotherm of food graphically relates its equilibrium moisture content in either desorption or adsorption to the water activity ( a w ) at a definite temperature [ 11 ].…”

Effect of Torrefaction Conditions on Physical and Thermal Properties of High- and Low- Quality Palm Pruning Residue Pellets

“…Due to the increasing usage of pellets worldwide, it is estimated that woody biomass feedstock will not be able to meet the increasing need for pellets. Therefore, the focus has been now on evaluating alternative raw materials [5].…”