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The main objective of this paper is to establish a mathematical framework to analyze the complex thermal economic performance of the calcination process. To find the factors affecting exergy efficiency loss, different exergy destruction is investigated in detail. Furthermore, the exergy flow cost model for exergy cost saving has also been developed. The results show that the vertical shaft furnace is a self-sufficiency equipment without additional fuel required, but the overall exergy destruction accounts for 54.11% of the total exergy input. In addition, the energy efficiency of the waste heat recovery boiler and thermal deaerator are 83.52% and 96.40%, whereas the exergy efficiency of the two equipment are 65.98% and 94.27%. Furthermore, the import exergy flow cost of vertical shaft furnace, waste heat recovery boiler and thermal deaerator are 366.5197 RMB per MJ, 0.1426 RMB per MJ, and 0.0020 RMB per MJ, respectively. Based on the result, several suggestions were proposed to improve the exergoeconomic performance. Assessing the performance of suggested improvements, the total exergy destruction of vertical shaft furnace is reduced to 134.34 GJ per hours and the exergy efficiency of waste heat recovery boiler is raised up to 66.02%. Moreover, the import exergy flow cost of the three different equipment is reduced to 0.0329 RMB per MJ, 0.1304 RMB per MJ, and 0.0002 RMB per MJ, respectively. [ABSTRACT FROM AUTHOR]

A walking beam type reheating furnace with advanced control technology has been evaluated by combined energy and exergy analysis. In order to gain insight into the performance of the present furnace, the results of energy analysis are compared with those in published papers and the irreversibility of the furnace is analyzed via exergy destruction calculation. The results show that slabs preheated before charged into the furnace can save fuel and improve energy utilization. The structure and material of the wall and roof show good thermal insulation. However, the oxidized scale is a little more and the temperature of flue gas is high in the present reheating furnace. The energy efficiency of the furnace is 71.01%, while exergy efficiency is 51.41%, indicating a potential for energy-saving improvements of the present furnace. The exergy destruction of the furnace accounts for 28.36% of total exergy input which is mainly caused by heat transfer through a finite temperature difference (14.71%), fuel combustion (11.66%), and scale formation (1.99%). [ABSTRACT FROM AUTHOR]