Static and dynamic characteristics of rotary kiln reactor during processing of biomass and municipal solid waste

Abstract

The behavior of five types of material (wood pellets, agro pellets, over-sieve fraction (OSF), willow chips and alder chips) in rotary kiln reactor was tested. Basing on the obtained experimental results, the empirical mathematical models were validated to predict mean residence time (MRT). The best fitted correlation generated mean absolute error at level of MAE = 9.4%. Regarding dynamic characteristics, the simplified approach of “first-order + dead time” was successfully applied to model the dynamic characteristic of rotary kiln reactor in terms of solid phase mass flow rate. The characteristic parameters of dynamic model, i.e. τ, min and Θd, min, were determined for every case. Time constant, τ, was in the range of 5.8–34.3 min, whereas dead time, Θd, was in the range of 0.001–73.2 min. Finally, a simplified model to estimate the time (i.e. 3 × τ + Θd) necessary to obtain steady-state conditions in terms of mass flow rate in rotary kiln reactors was proposed.