A systematic approach to the multi fuel fired lime mud reburning kiln operation with respect to energy and environment

Abstract

An Optimization study was carried out for multi fuel fired lime kiln operation with respect to energy and environment. The fuels used were biogas and furnace oil. The objective of the lime kiln process is to convert lime mud (CaCO3) into burnt lime (CaO) by calcining reaction. Initially the critical operating parameters were optimized using Taguchi method of parameter design to minimize the heat rate with respect to lime production. The experiments have been designed using an L16 orthogonal array with five factors and four levels each. The critical parameters considered in the multi fuel fired lime kiln operation is furnace oil pressure, furnace oil temperature, biogas pressure, feed lime sludge moisture, biogas to furnace oil ratio for this optimization study. The aforesaid parameters were optimized using Taguchi method and the optimization study reveals that furnace oil pressure is crucial factor for energy efficient to run the lime kiln. From the optimization results, the furnace oil pressure 2.5 Kg/cm2 and the biogas pressure 0.30 kg/cm2 are optimum for lower heat rate of lime production. From this Taguchi method results, further optimization has been carried out using response surface methodology for heat rate with respect to burnt lime purity. The critical parameters such as furnace oil pressure, biogas pressure, feed lime sludge moisture, biogas to furnace oil ratio, burning zone temperature, feed end temperature and excess Oxygen have been considered for this study. This study also reveals that the most influencing parameter for heat rate is furnace oil pressure. The optimum furnace oil pressure is 2.36 Kg/cm2 which is more refined value than the optimum value arrived using Taguchi method. newline