Thermoeconomic Analysis of a One-Pressure Level Heat Recovery Steam Generator Considering Real Steam Turbine Cost

Nowadays, gradual depletion of fossil fuels associated with emissions constraints due to greenhouse gases, leads to reuse wasted heat from power plant in order to increase the global efficiency. One of the implemented technologies for improvements is the application of combined cycles. In this scenario, the steam cycle is frequently combined with a Brayton cycle and the power plant performances and costs are competitive in the global market. Often, an energetic engineering company defines and studies the performance of the bottom steam cycle, thus it imposes operational conditions of steam turbine and heat recovery boiler and requires these components are built by two different manufacturers. For this reason, the plant cannot be globally optimized. From a steam turbines manufacturer point of view, the integration between proprietary simulation code and an energy balance code is an opportunity to simulate a complete bottom-cycle in order to define the best plant configuration. In the present paper, aone-pressure level heat recovery steam generator is studied in term of thermodynamic performance and cost analysis. The thermodynamic analysis is realized using a fixed steam turbine isentropic efficiency (as an energetic engineering company can do) and using anisentropic efficiency determined from steam turbine industrial tool, so a different best performance can be determined. Moreover, a comparison between two academic steam turbine cost correlations and steam turbine cost suggested by industrial cost is carried out.