Dynamic Analysis of CO2-SO2 Recompression Rankine Cycle Using Waste Heat

Highly valuable attributes such as high efficiency and competitive capital costs are the underlying factors for the prominence of carbon dioxide (CO2) cycles not only in theoretical fields but also in commercial applications. As a result, we are witnessing an increasing number of research projects and support for activities related to these cycles. Recently, there has been a new initiative to develop an even more promising working fluid by mixing CO2 with certain dopants. One of them seems to be the CO2-SO2 mixture. Given the promising potential of this specific mixture, which seems to be exceptionally well-suited for application in transcritical cycles [1], this paper provides an overview of the early results of the transient analysis of transcritical Rankine cycle using this mixture in waste heat recovery applications (WHR). The primary focus of this paper is to utilize the CO2-SO2 mixture in a 70-30 ratio for the double recuperated recompression Rankine cycle. In doing so, this study not only examines the unique characteristics of this mixture but also explores its potential applications for WHR under fluctuating operational conditions. The paper describes the modeling methodology implemented in Aspen Plus software and illustrates the key plant components transient operating conditions. By conducting the analysis of this working fluid, the paper aims to evaluate its effectiveness in harnessing waste heat, thereby contributing to the advancement of more sustainable and efficient energy solutions.