The influence of temperature and oxidizing atmosphere on the process of combusting pellets from agricultural and forest biomass in the stream of inert material

• Published in: Renewable energy 2021-05, Vol.168, p.1157-1164
• Main Authors: Kaczyński, Konrad, Kaczyńska, Katarzyna, Pełka, Piotr
• Format: Article
• Language: English
• Subjects: Biomass; Combustion; Fluidization; Oxy-combustion; Pellets
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2020.12.122

Wood pellets are a commonly used biomass for energy production. However, due to the growing demand, many entrepreneurs have begun to produce non-wood biomass pellets. During experimental research, the process of combusting pellets of forest and agricultural origin at different furnace temperatures and different oxidizing atmospheres in a two-phase flow with the use of inert material modelling conditions in the upper zone of the fluidized bed reactor was analyzed. Inert material caused very significant differences in the time and mechanism of forest and agro biomass combustion. These differences are mainly associated with problematic phenomena during combustion, including sintering of ashes. The inert material accelerated the mass loss of forest biomass pellets at all temperatures by about 50–60%. In the case of agro biomass, the combustion time at the temperatures of 650 °C and 750 °C was shortened by about 20–30%, and in the case of the temperature of 850 °C, it was extended by about 10%. Increasing the value of the inert material stream resulted in a reduction of the combustion time at all temperatures. Increasing the concentration of oxidant in the atmosphere of combustion caused the reduction of the combustion time of all tested fuels. •The agro and wood biomass combustion mechanism is different in fluidic conditions.•The ash from different types of biomass contains alkali metal compounds.•The alkali content in the ash affects its softening and melting point.•The high alkali content of biomass can cause damage to the combustion units.