Decomposition of powders in horizontal rotary drum reactors

Abstract

In a continuously operated laboratory rotary drum reactor 600 mm long and 250 mm in diameter, the mixing of cold and hot particles of soda was investigated and the mixing time was evaluated. The formal kinetics of the decomposition of sodium hydrogen carbonate to sodium carbonate (soda) was evaluated in a batch-operated drum. The distribution of residence times of the particles was measured by means of a radiotracer (Na 24) technique. The longitudinal temperature profiles and the conversion of the reaction were also measured. To describe the longitudinal temperature profile in the particle bulk without reaction, the variations of the cross-sectional area of the particle bulk and temperature of the wall must be taken into account. The heat transfer coefficients evaluated in [7] yield satisfactory results under these conditions. It is possible to calculate the longitudinal conversion and temperature profiles in the rotary drum by applying the energy and material balances for every small section of the reactor and by using reaction rates and transport coefficients estimated by separate measurements.