Heat rate of a coal based power plant is one such parameter which abbreviates the performance of whole plant in one figure and can be used as good indicator of the health of plant and operational aspect. Performance of power plant is checked periodically by offline experimentation. In the present work a methodology has been developed for estimation of heat rate of a power plant using plant operation parameters and some reference coal composition. A computer code in C++ has been developed for the same. Prediction results were compared with the offline boiler performance testing results. Care was taken to collect the plant data for the same date and time at which offline performance testing was carried out. The comparisons are encouraging, and the code can be used to obtain an on-line estimate of heat rate.

It was initially intended to corroborate the heat rate results by measuring the pulverized fuel flow. Flow through orifice is an established methodology for measurement of single phase flows and we wanted to study its applicability in measuring coal flow in power plant using pressure drop against flow balancing orifice installed in coal pipe lines. For this we needed a calibration standard to calibrate the orifice for measurement of dust laden flows. It was decided to first simulate the dust laden flow through orifice using a CFD tool like Fluent and then validate its results. However the study was done on 50mm bore pipe due to difficulties involved in performing experiment on a running power plant.

To study such a flow the first step was the numerical simulation of single phase flow through orifice. The simulation of such a flow was done using FLUENT software and results of pressure drop against orifice were found in line with standard Cd-Re relationship given by ISO. Discrete phase model was used to simulate dust laden flow through orifice. Experiment was also done to compare the pressure drop results. Although flow through orifice looks to be a simple flow problem to analyze, its simulation was an experience other way. More study is required to decide about applicability of the technique on dust laden flow measurement.