Biomass is currently one of the world’s major renewable energy sources. Biomass in a
powder form has been recently proposed as the most encouraging of biomass contours, especially
because it burns like a gas. In the current study, biomass powder was examined, for the first time,
as a direct solid fuel in internal combustion engines. The aim of the current study was to investigate
modeling tools for simulation of biomass powder in combustion engines (CE). The biomass powder
applied was in a micro-scale size with a typical irregular shape; the powder length was in the range
of 75?5800 m, and the diameter was in the range 30?1380 m. Dierent mechanisms for biomass
powder drying and devolatilization/gasification were proposed, including dierent schemes’ and
mechanisms’ rate constants. Acomparison between the proposed models and experiments was carried
out and results showed good matching. Nevertheless, it is important that a biomass powder simulation
addresses overlapping/complicated sub-process. During biomass powder combustion, tar was shown
to be formed at a rate of 57 wt.%, and, accordingly, the formation and thermal decomposition
of tar were modelled in the study, with the results demonstrating that the tar was formed and
then disintegrated at temperatures between 700 and 1050 K. Through biomass powder combustion,
moisture, tar, and gases were released, mostly from one lateral of particles, which caused ejection of
the solid particles. These new phenomena were investigated experimentally and modeled as well.
Results also showed that all the proposed models, along with their rate constants, activation energies,
and other models’ parameters, were capable of reproducing the mass yields of gases, tar, and char at a
wide range of working temperatures. The results showed that the gasification/devolatilization model
3 is somewhat simple and economical in the simulation/computation scheme, however, models 1 and
2 are rather computationally heavy and complicated.