Tube-in-Basket burner for rice husk. II: Performance of TiB burners

Abstract

Three working models, TiB MK II, MK IIK and III, capable of continuous combustion, are described. It is shown that these burners can be operated continuously in a stable pseudo-steady-state manner by means of intermittent charging of husk from the top and discharging of ash from the bottom. Mass and heat balance data, flame temperatures, combustion efficiencies and heat transfer efficiencies for heating water in a vessel are included. Combustion efficiency of about 72% was achieved in TiB MK II by making a significant change in the basket design, the lower half being made conical. The efficiency was boosted further to roughly 82% in MK IIK by extending the bottom rim of the cone straight down by an additional 7·5 cm and replacing the upper basket cylinder by a fully enclosed box. A water heating jacket was also incorporated in this model around the upper end of its burner tube. This modification resulted in a highly efficient water heating or steam raising device. Comparison with step-grate furnaces shows that TiB burners have similar or superior performance characteristics with additional advantages of simplicity, compactness and low cost.