General exergy balance of a system with variation of environmental conditions and some applications

Exergy analysis of a control volume helps to identify sources of losses. However establishing exergy balance necessitates correction terms if environmental conditions change over the time period under consideration. Applications show that the effect of this variation is considerable in some cases

Energy and exergy analyses in a rotary burner with pre-calcinations in cement production

WOS: 000223035700014Cement production facilities are often located in rural areas and close to quarries, where the raw materials required for cement production are present, i.e. limestone and shale. Although energy analysis, based on the first law of thermodynamics, is used to reduce heat losses or enhance heat recovery, it does not give any information on the degradation of energy that occurs in the process. Exergy analysis, based on the first and second laws of thermodynamics, facilitates improvement of the operation or technology by clearly indicating the locations of energy degradation in the process. In this study, the applications of energy and exergy analyses are examined for a dry system rotary burner (RB) with pre-calcinations in a cement plant of an important cement producer in Turkey. The RB includes thermal and chemical processes. Besides, real figures of the cement factory have been used in this work. In conclusion, the values of the first and second law efficiencies have been found and compared. (C) 2004 Elsevier Ltd. All rights reserved

Exergy balance of a general system with variation of environmental conditions and some applications

An exergy balance of a system helps to identify causes of losses. Establishing an exergy balance necessitates correction terms if environmental conditions change over the time period under consideration or the system is moving with respect to the environment. Applications show that these effects are considerable in some cases. On the other hand an exergy balance is also a means for checking a computational procedure. (C) 2002 Published by Elsevier Science Ltd