A study of heat balance in the Kiln system at Tororo cement factory

Abstract

This research is aimed at determining the heat balance of the kiln system (Kiln, Preheaters and Cooler) at Tororo Cement factory limited and the results out of it are used to advice management and operators on the necessary management and operational adjustments to be taken and above all to provide an accurate account of heat consumption and heat use of different components to reveal the detailed information needed for determining the possible opportunities for heat conservation. Waste heat recovery from hot gases and hot kiln surfaces in the kiln system are known as potential ways to improve overall efficiency. Therefore this research focuses on the heat audit of a horizontal rotary kiln system, which is used by Tororo Cement Ltd in Uganda. A detailed thermodynamic analysis of the kiln system is first given and then, possible approaches of heat recovery from some major heat loss sources are discussed. In order to analyze the kiln system thermodynamically, the following assumptions have to be made: Steady state working conditions. The change in ambient temperature is neglected Therefore when a detailed analysis of heat balance of the kiln system (Kiln, Preheater and Cooler) has been made. The distribution of input heat energy to the system components revealed a good agreement between the total input and output heat and gave significant insights about the reasons for the low overall system efficiency. According to the results obtained, it was found out that the system efficiency is 37.71%. The major heat loss were found at the Kiln Exhaust and it was quantified as 29.50% of total input, cooler exhaust being 1.64% of total input and combined radiation and convection heat transfer from kiln surface were finally found as 0.53% of total input.