An Experimental Study of Combustion and Emissions of Wheat Straw Pellets in High-Temperature Air Flows

The present work is performed to investigate the combustion and emission behavior of wheat straw pellets of different sizes and shapes in a high temperature air flow. Prior to the combustion experiments, thermogravimetric analysis of the pellet was carried out to understand the thermo-chemical characteristics of the wheat straw pellet. A sequential method was used to determine the kinetic parameters. A combustor using preheated air is used to investigate the effect of different parameters, such as pellet size, starting temperature, and primary air flow velocity on combustion and emission characteristics of biomass pellets. The surface temperatures as well as the time-dependent mass loss rates are recorded to study the ignition behavior of pellets. The results showed that the increase in starting temperature, and air flow velocity and decrease in pellet size leads to a reduction in combustion time and increase in the total combustion rate. The results also showed that the concentration of CO formed increases as the heating time increases and the formation of CO2 increased with increasing the starting air temperature and air flow velocity inside the combustion chamber. It was found that the combustion efficiency ranged from 99% to 100% and the combustion efficiency reached 100% in some experiments due to complete combustion.