Exergy and Exergoeconomic Assessment of Tehran’S Waste to Energy Power Plant

Abstract

Converting municipal waste into energy through the Waste-to-Energy (WtE) technology has been growing fast during the past decades. Besides the considerable reduction in the waste volume, it can generate steam and/or electricity. In the present work, energy, exergy, and exergoeconomic analysis techniques are used to investigate the performance of Tehran’s 3 MW WtE plant. In the exergoeconomic analysis, the exergy cost of the stream, annual capital investment, and operating and maintenance costs are analyzed. Combination of economic principle and exergy analysis has been used to minimize the power generation costs. MSW is converted to a high enthalpy syngas via gasification to produce the required heat for steam generation in a Rankine power cycle. The effect of different inlet parameters is investigated on the target variables: net produced work, exergy efficiency, and power cost rate. Also, the exergy destruction and the exergetic efficiency of every component is calculated to assess the irreversibilities in the system. Results show that the gasifier has the highest exergy destruction. The overall exergy and energy efficiencies are 14.49% and 17.27%, respectively. Additionally, by increasing the turbine inlet pressure, the power cost rate will decrease and the net produced work and the overall system efficiency increases. It is further realized that the moisture content and gasification temperature have an indirect effect on the exergy efficiency of the gasifier.