A review of recent developments in carbon capture utilizing oxy-fuel combustion in conventional and ion transport membrane systems

Abstract

SUMMARYFossil fuels provide a significant fraction of the global energy resources, and this is likely to remain so for several decades. Carbon dioxide (CO 2 ) emissions have been correlated with climate change, and carbon capture is essential to enable the continuing use of fossil fuels while reducing the emissions of CO 2 into the atmosphere thereby mitigating global climate changes. Among the proposed methods of CO 2 capture, oxyfuel combustion technology provides a promising option, which is applicable to power generation systems. This technology is based on combustion with pure oxygen (O 2 ) instead of air, resulting in flue gas that consists mainly of CO 2 and water (H 2 O), that latter can be separated easily via condensation, while removing other contaminants leaving pure CO 2 for storage. However, fuel combustion in pure O 2 results in intolerably high combustion temperatures. In order to provide the dilution effect of the absent nitrogen (N 2 ) and to moderate the furnace/combustor temperatures, part of the flue gas is recycled back into the combustion chamber. An efficient source of O 2 is required to make oxycombustion a competitive CO 2 capture technology. Conventional O 2 production utilizing the cryogenic distillation process is energetically expensive. Ceramic membranes made from mixed ion-electronic conducting oxides have received increasing attention because of their potential to mitigate the cost of O 2 production, thus helping to promote these clean energy technologies. Some effort has also been expended in using these membranes to improve the performance of the O 2 separation processes by combining air separation and high-temperature oxidation into a single chamber. This paper provides a review of the performance of combustors utilizing oxy-fuel combustion process, materials utilized in ion-transport membranes and the integration of such reactors in power cycles. The review is focused on carbon capture potential, developments of oxyfuel applications and O 2 separation and combustion in membrane reactors. The recent developments in oxyfuel power cycles are discussed focusing on the main concepts of manipulating exergy flows within each cycle and the reported thermal efficiencies.

Oxy-combustion of liquid fuel in an ion transport membrane reactor

“…Behrouzifar et al [29] suggested that if the surface reactions (13) and (14) are associated with the oxygen adsorption/dis-association on the feed side and then the oxygen recombination/desorption on the permeate side are elementary (single step) as assumed by Xu and Thomson (1999) [14] then n = 0.5. Behrouzifar et al [29] have accounted for non-elementary (multi-step) surface reactions and the derived a new value for n = 0.25.…”

“…In order for the cost of ITM to be reduced and their commercialization to be feasible, next generation ITMs should achieve high permeation fluxes while operating at low temperatures. The aforementioned approaches for ITMs, if developed successfully can commercialize ITM reactor systems [13]. However, important process parameters including ion exchange at the surface, diffusion in porous media and mass transfer either by convection or diffusion should not be neglected [14].…”

“…The performance of oxy-fuel combustors was reviewed by Habib et al [13]. They also reviewed the materials used in the ITMs and the implementation of these ITMs in reactors that can be integrated in power generation plants.…”

Low Temperature Performance of Selective Catalytic Reduction of NO with NH3 under a Concentrated CO2 Atmosphere

“…It is realized that oxy-fuel combustion is attracting increasing interest. Using pure oxygen instead of air for combustion generates a flue gas which consists of mainly CO 2 and H 2 O, where CO 2 can be easily captured [20][21][22][23]. Therefore, more understanding of NH 3 -SCR in the presence of an abundance of CO 2 is essential for the future development of SCR technology combined with oxy-fuel combustion processes.…”

Effect of dilution of fuel in CO2 on the conversion of NH3 to NO x during oxy-fuel combustion

“…CO 2 is considered to be one of the most important anthropogenic gas emission species involved in global warming (Habib et al, 2011). Oxy-fuel combustion is one of the advanced technologies used to capture CO 2 when burning fossil fuels (Buhre et al, 2005).…”