Life cycle assessment of optimised chemical looping air separation systems for electricity production

Abstract

Chemical looping air separation (CLAS) is as a very promising technology for the production of pure oxygen through the cyclic reduction and oxidation of a solid material at elevated temperatures. This study focused on the environmental potential of electricity and CO2 production through oxyfuel combustion of lignite. First, an attributional LCA assessed the operations which mainly contribute to the total environmental impacts for two different scenarios at the limits of the operating window (100% and 25% active material). Then, this study analysed the potential of electricity and pure CO2 production through CLAS when compared with conventional power production technologies from renewable and fossil alternatives, including electricity from hydro power, electricity from wind power, electricity from nuclear, electricity from photovoltaic, electricity from biogas, electricity from biomass, electricity from waste, electricity from hard coal and electricity from natural gas. Overall the results, analysed per MJ of electricity produced, showed how the chemical looping technology consistently performs better than the other technologies, especially thanks to the recovery of the pure CO2 stream used for industrial purposes, which avoids the production of CO2 from fossil resources. However, the cleaning of the flue gas of the oxyfuel combusted lignite strongly limits the toxicities indicators.

Mixed oxides as multi-functional reaction media for chemical looping catalysis

“…Therefore, the use of chemical looping for efficient air separation (CLAS) represents a natural extension of CLC, as explored by many chemical looping researchers. 52–94 Furthermore, marrying the chemical looping strategy with oxidative catalysis offers a unique opportunity to intensify the production of a few important commodity chemicals with substantially decreased energy consumption and CO 2 emissions. 95–136 Given that separation processes consume ∼60% of the total energy usage in chemical and petroleum industries and heterogeneous catalysts are responsible for >80% of all chemical products worldwide, chemical looping catalysis (CLCa) in this article, has the potential to facilitate process intensification throughout the chemical manufacturing sector by combining catalytic reactions with separations.…”

Simulation of a 100-MW solar-powered thermo-chemical air separation system combined with an oxy-fuel power plant for bio-energy with carbon capture and storage (BECCS)

“…To achieve the same combustion characteristics, a higher O 2 volume fraction (here assumed to be 27 vol%) is required during oxy-fuel combustion than during combustion in air (Riaza et al 2012). Tagliaferry et al (Tagliaferri et al 2018) carried out a life cycle assessment of various systems for electricity production and reported that the CLAS + oxy-fuel process had the lowest (and only negative) global warming potential in comparison with the other studied conventional and novel fossil fuel and renewable electricity generation technologies. In this study, the enthalpy required for the O 2 uncoupling is provided by concentrated solar power, and storage of O 2 +CO 2 and CO 2 enables operation of the CLAS process and the oxy-fuel process at different times of the day.…”