Exergy calculation and its applications

The first part of this paper explains the concept of and gives calculation procedures of by equation of state(PR)and some technical details.It also analyzes the obscure concept of negative exergy caused by low pressure,especially when the condition vacuum is taken into consideration,showing that like the at a low temperature,negative exergy is another valuable kind of exergy.The last part of the paper contains analysis reports about two important chemical processes,rectification and heat exchange with the support of the three layers theory.The research indicates that energy-saving in the process of rectification is a specific case study instead of adjusting reflux ratio only.In the process of heat exchange,the pressure loss should be specially chosen as well as heat loss to save expensive high level exergy—electricity.