In this paper energy and exergy analysis on components of working rectified sprite plant of capacity 11 TPH coal and the gas-fired boiler is carried out. Most of the system Is design on energetic performance criterion and is not sufficient for finding system imperfections. Hence exergy analysis is necessary to improve. It has been observed that Energetic and Exergetic performance of Plate Heat Exchanger use for heating the feed water for the boiler can be optimized. Heat carried away by Spent wash which is waste product of the plant and used as hot fluid in PHE can be utilized more effectively. Analytical calculation is carryout in Excel program to study the change in mass flow effect and by graph it has been observed that by increasing the flow rate of spent wash or decreasing the flow rate of feed water there is an increase in energetic efficiency, exergetic efficiency, and feed water temperature. Also, the effect of adding a gasketed plate has been observed, temperature increase by adding plate but there is also a pressure drop. The experimental is carried out based on analytical result there is an increase in exergetic efficiency of PHE by 6 to 7 % and increases in temperature of feed water 0.90-degree c by increasing the mass flow by 900 kg/hr. Also, other components of the boiler were observed before and after experimentation and found to be increased in performance. The thermal performance of PHE is optimized by adjusting the mass flow rate. © 2022 Author(s).