Exergy balance and efficiency of the absorptive and adsorptive processes by the example of deaerator

Abstract

The work is devoted to assessing of the effectiveness of chemical-technological processes on the basis of exergy analysis method by the example of the processes in the deaerator. Aim: The aim of the work is to demonstrate the features of the application of exergy analysis method for sorption and desorption processes via example of the deaerator. Materials and Methods: The advantage of the exergy method is in the accounting not only the quantity but also the quality of energy flows and multicomponent material flows that characterize the energy balance of any power technology system that puts this method on the first place on their objectivity in comparison with traditional methods of thermodynamic analysis. Complexity of the exergy analysis devices with multi-component flows, where separation processes such as water solutions occur, is that the main technical effect of the process is shown in two ways: in one case, the major problem is to obtain clean water flow, and in another case to obtain the concentrate flow. For those processes, where the main objective is to obtain clean water, an exergy effect is manifested in the increase of the exergy flow. In processes where the main task is solution thickening the useful effect is in the growing of exergy concentrate. Results: The exergy flows value was illustrated numerically and graphically including exergy gases sorption and desorption that characterizing the chemical and thermal transformations in the deaerator. It is showing an extremely low efficiency of the processes of oxygen removing in the deaerator from the standpoint of transformation of exergy and the ability to identify ways to improve the processes of gases removing based on exergy method. Calculations of heat and physic-chemical exergy flows indicate that the deaerator is effective as a heat exchanger (95%), and absolutely no effective as mass exchanger (0.071%). This technique makes it possible to evaluate the chemical-technological processes in which the components are separating and therefore suitable not only for gas constituents but also for the solid.