Concentration of off-gases in a scale down wood pellet storage system
Authors: Yazdanpanah, F, S Sokhansanj, Cj Lim, A Lau, T Bi, S Melin
Description: Wood pellets are emerging as a viable economic activity in forest industry in Canada. Roughly 90% of the 2 million metric ton wood pellets produced in Canada are exported. European and Pacific Rim countries are major export destinations. Wood pellets destined for export often remain in silos and shipping holds up to 3 months. Wood pellets emit gases such as CO, CO2 and CH4 during storage especially in high temperature conditions. This study investigates the storage environment in a pilot scale sealed storage container, 1.3 m diameter and 5 m high. The data recorded include the concentration of off gasses, temperature and relative humidity in vertical and horizontal directions. The objective is to develop aeration/purging system to prevent spontaneous combustion and decrease the potential for self-heating and evolution of off-gasses. Results from 63 days of storage of white wood pellets showed stratification of CH4 after 18 days and with the highest concentration of gas at upper sections of the reactor and close to the interface of wood pellets and headspace. A very clear stratification was recorded for CO after 18 days of storage with the highest concentration at the height of 2.03-2.54 m from the bottom of the reactor. Some stratification was also recorded for CO2.
Keywords: wood pellet, storage, aeration, purging, off-gassing, gas stratification, storage temperature, storage management
Technical field: technical_fields_app1
Session name: Biological systems