Review of Pulverized Combustion of Non-Woody Residues

The intense use of wood-derived fuels in (co)firing processes results in an enormous pressure on the forest. In order to alleviate this pressure and to proceed with the CO2 emissions reduction process, it is necessary to increase the use of non-woody residues, in particular herbaceous materials and agricultural residues. (Co)firing using such residues can cause a number of problems due to the presence of alkali metals, chlorine, and other ash-related impacts as well as corrosion of metallic surfaces and particulate matter emissions. This may limit the variety of biomass residues that can actually be used in (co)firing processes. This review aims to summarize recent developments in the combustion of pulverized non-woody residues and includes experimental and numerical studies of single particle combustion and combustion in small- and large-scale furnaces. The review provides an overview of the properties of non-woody residues, describes the existing research facilities to study the subject, and summarizes the experimental studies on the combustion of non-woody residues, including studies on single particle combustion, drop tube furnaces and entrained flow reactors, and large-scale furnaces. The review also concentrates on numerical modeling, namely on the formulation of combustion models and their application in computational fluid dynamics. Finally, the main conclusions are summarized and the research needs listed.