Method for analysing the heat recovery potential of thermoprocessing equipment

Abstract

The importance of a heat recovery capability on thermoprocessing systems for increased cost-efficiency is rising steadily, along with energy costs. Accordingly, an increasing number of methods for recovering heat from exhaust gas have emerged in recent years, and the processes in question are being applied to ever more fields. For a plant-related assessment of diverse exhaust gas heat recovery solutions from an economic and/or process engineering viewpoint, it is imperative to analyze the plant-specific energy flows and to present the resulting findings in a clear-cut manner. On the basis of this analysis it is then possible to perform a plant-related evaluation and selection of the most suitable heat recovery method. The present article describes a method that facilitates an economic assessment of the heat recovery potential of thermoprocessing equipment while also permitting a comparison of the plant-specific savings potentials for a given heat recovery process. To this end, a thermodynamic model is first developed to analyze the plant-specific energy flows; this model then enables us to compute these energy flows on the basis of process data. It is further shown how the results are presented in a clearly structured fashion to serve as the basis for further investigation. Next, it is explained how suitable heat recovery solutions can be selected for various equipment results and how the associated savings potentials can be determined. The method is applied, by way of example, to the dataset of an industrial furnace and the results obtained are discussed. It is shown that the method permits an economic evaluation of diverse heat recovery solutions for different plants in day-today operation. In addition, the data analysis provides a capability to detect defective equipment components and unidentified energy flows.