Analysis of Kalina Cycle Designs with Modifications Including a Distillation Column.

It has been shown in a number of studies that the Kalina cycle can have considerably higher efficiencies than the Rankine cycle. An especially advantageous application is as a bottoming cycle to a gas turbine. In this paper a gas turbine topping cycle has been assumed. Three different configurations of the Kalina bottoming cycle have been examined and compared. One is an original cycle (El-Sayed and Tribus, 1985) with a flash separator. In another configuration, a second feedwater heater is added and in a third a distillation column instead of a flash separator is used. The stages of the column are heated by exchanging heat with two different streams in the Kalina distillation condensation subsystem. For each configuration, the different compositions in the cycle have been varied. The First Law efficiency and the exergetic efficiency have been calculated as well as the rate of exergy loss in each unit. The results show that the cases with the best performance of each of the three configurations differ very little in efficiency. The original cycle has the highest efficiency for the conditions studied.