Novel cycles: oxy-combustion turbine cycle systems

Abstract

This chapter presents a discussion of recent developments in oxy-fuel combustion systems for the creation of near-zero emission power plants to control CO 2 emissions. Rather than oxy-fuel approaches for pulverized coal boilers, the focus in this review is on oxy-fuel turbine-based combined cycle systems. These power cycles seek to capitalize on the direct separation of CO 2 from an oxy-fuel combustion product stream as a method to manage CO 2 emissions during power generation. This review discusses some of the novel oxy-fuel cycle configurations and describes the component operating conditions as well as performance needed to achieve high efficiency. A summary of the status of oxy-fuel combustors, turbomachinery and heat exchangers is presented; it discusses points that need to be considered in the development of turbomachinery for oxy-fuel applications. While a variety of different cycle configurations have been proposed in the literature, some of these cycle differences center on the choice of the dominant working fluid (CO 2 or water) and how the cycle exploits the extraction of work from the heated fluid. Compared with existing gas turbines, the change in working fluid is likely to require specially built components to achieve desired efficiencies. Further, the combustion system in these cycles is substantially different from those in conventional natural gas combined cycles because the oxy-fuel process is ideally designed to operate with no excess oxygen. Impacts of these and other differences are discussed.