Oxy-combustion Roadmap to Commercialization

Oxy-combustion is a form of low-carbon power generation, where the oxygen is separated from the air for combustion, yielding a flue gas consisting largely of CO2 and water, which in turn allows for relatively easy CO2 capture. Oxy-combustion comes in several forms, including atmospheric oxy-combustion, which can be done at conventional or higher flame temperatures, and a variety of pressurized oxy-combustion concepts. A special case of oxy-combustion is chemical looping combustion (CLC) where the air separation is done using an oxygen carrier, eliminating the need for an energy-intensive cryogenic air separation unit. Another special case, where the oxy-combustion is performed directly within the cycle, is the direct-fired supercritical CO2 (sCO2) power cycle (“Allam Cycle”). Oxy-combustion in its various forms has the potential to capture CO2 economically along with generating water and potentially other revenue streams. However, despite its potential, these technologies are not yet commercial, and their end states are hence unknown. Various oxy-combustion technologies are at different stages of maturity with multiple developers involved. Developing a roadmap that provides the status of the technology and its relative maturity level; reviews potential applications for oxy-combustion; assesses the performance, costs, and benefits; identifies the critical technical challenges that could limit successful commercial deployment; lays out a pathway to address those challenges; and includes a timeline required to reach commercial deployment, is necessary to get a better understanding of the potential of this novel technology. The Electric Power Research Institute, Inc. (EPRI) led a team that developed such an oxy-combustion roadmap, focusing on technologies that have established developers and are beyond lab-scale efforts. These technologies were: • Babcock & Wilcox Company’s (B&W) Coal Direct Chemical Looping: A CLC technology, which uses a form of oxy-combustion where the oxygen separation is done using an oxygen carrier, eliminating the need for an energy-intensive air separation. B&W utilizes iron-based oxygen carriers in its system. • Clean Energy Systems, Inc.’s (CES) Tri-Gen: One of several pressurized oxy-combustion processes that yield smaller components and allow the latent heat recovery of water at useful temperatures designed to improve efficiency. CES’ system uses platelet combustors and customized turbomachinery and heat exchangers with one of its initial targets focused on biomass. • General Electric’s (GE) Limestone Chemical Looping Combustion™: A CLC technology, GE uses a calcium-based oxygen carrier in its system. • Gas Technology Institute’s Oxy-Pressurized Fluidized-Bed Combustion: A pressurized oxy-combustion process that utilizes fluidized beds. • ITEA’s Flameless Pressurized Oxy-Combustion: A pressurized oxy-combustion process that utilizes flameless combustion. • Jupiter Oxygen Corporation’s High-Temperature Oxy-Combustion: A form of atmospheric oxy-combustion that employs high flame temperature through a modified burner designed to improve heat transfer. • Natural Resources Canada’s G2: A pressurized oxy-combustion process that is being designed to be coupled with an sCO2 power cycle. • NET Power, LLC / 8 Rivers, LLC Allam Cycles: Direct-fired, sCO2 power cycle that performs oxy-combustion in-situ, yielding a working fluid of CO2 and water that drives a turbine. NET Power, LLC is developing the natural gas version, while 8 Rivers, LLC is developing the coal-syngas version. • Washington University in St. Louis’ Staged, Pressurized Oxy-Combustion: A pressurized oxy-combustion process that stages the combustion using multiple boilers. The provides detailed information on each technology’s status and work done in the field, assess its maturity level, give data on its costs and performance (in some cases calculated independently by EPRI), review technology gaps that must be addressed, and present multiple timelines for when each is projected to be commercially ready―the first is a deliberate, conservative approach developed by EPRI, and the second was provided by the developer, which generally is an accelerated, more aggressive (and hence riskier) approach that seeks to shorten the timeline.