Thermoeconomic Analysis of Geothermal Power Cycles. A Case Study of IDDP-1

Abstract

This paper presents a thermoeconomic analysis of power cycles proposed to utilize geothermal fluid in a superheated state with acid chloride impurities. A case study was performed where utilization models of the fluid from the well IDDP-1 proposing four different viable power cycles. Each cycle includes a technique to overcome or mitigate the chloride present in the superheated steam before it is utilized for power generation. The techniques are based on either an application of a wet scrubbing process or using a binary cycle. In order to perform the thermoeconomic analysis, exergy analysis and cost estimation were done for each component and for the cycle as a whole. The four different cycles for which the thermoeconomic analysis was done include: a single flash power cycle with wet scrubbing, a power cycle with an additional turbine and wet scrubbing, a power cycle with heat recovery and wet scrubbing and a binary cycle without any scrubbing process. The cycle containing heat recovery performs best, having highest power output and lowest unit cost of product exergy. The binary cycle turned out to be the most expensive one in unit cost of product exergy and the cycle with wet scrubbing performed the worst in power output. The study highlights the importance of taking into account exergetic efficiency and exergy cost using thermoeconomic analysis, when comparing power cycle options for geothermal utilization.