Heat Recovery Steam Generator Optimization Using Analysis of Variance

The present work deals with the analysis and optimization of a heat recovery steam generator (HRSG) using the ANalysis Of VAriance (ANOVA). In order to obtain an optimum thermodynamic configuration of a three pressure levels HRSG, a mathematical model of the generator has been implemented using a generic thermodynamic code. Model management and HRSG control logic have been implemented using code’s macros and Microsoft Excel VBA programming languages. The model has been finely tuned and tested using real HRSG running data in the current plant configuration. Using the model, evaporators’ pressure levels have been modified and thermodynamic data elaborated using ANOVA technique. Results’ analysis shows that reducing low and medium pressure level in the HRSG, global steam production rises up. At the same time, exhaust gas temperature decreases showing a certain heat adsorption increase. On the basis of the results it is possible to state that the proposed HRSG configuration involves increases in plant steam and power production as well as in global efficiency with HRSG minimal modification.