This blog was co-authored by Sergio Ramirez-Solis, School of Chemical and Process Engineering (SCAPE), University of Leeds, Leeds, LS2 9JT, UK and Khalil Al Hanashi, Low Carbon Energy and Resources Technologies, The University of Nottingham, Nottingham, NG7 2TU, UK.
Chemical looping combustion (CLC) as an emerging technology to reduce CO2 emissions has its origins in the ’80s. Professor Ben Anthony from Cranfield University, who is an expert in the field of CCUS, has highlighted that the actual situation of CLC is in the demonstration stage with pilot facilities in countries such as Spain, USA, China, etc. Dr Anthony cited that an advantage of CLC is its flexibility to be used in different applications such as power plants, the cement industry, etc. However, although there are some pilot plants that have been run with high efficiencies for more than 9 years (La Pereda), there is still work left in R&D. The development of novel materials for CLC (bi- or tri-metallic oxides) with enhanced mechanical, thermal and chemical properties that allow CO2-free combustion is part of these challenges. R&D for the implementation of CLC materials in the industry also needs to be done, and it consists of improving existing preparation methods to scale-up their production.
Post-combustion capture technology (PCC) has demonstrated feasibility for removing CO2 from flue gas streams. Professor Jon Gibbins (University of Sheffield) mentioned that flexibility is one of the virtues of PCC as it permits to retrofit power plants at competitive costs but strongly believes that they can be reduced by learning from its implementation (e.g. Brown coal retrofit study - PCC system - Australia). Numerous studies and implementations also demonstrate that PCC systems application can be extended beyond coal power plants, namely in the cement industry and biomass or gas-based power generation plants.
Supercritical carbon dioxide (s-CO2) power cycle for stationary power generation is a promising way to produce ready CO2 for storage at a low cost using compact systems. Professor Pourkashanian, who has been working in this field in the last years, mentioned that this is an effective option to get an integration of three technologies CCSU, power-to-gas and s-CO2 pumping. However, technical challenges make to define this system as a next-generation technology. Thus, its application is restricted to a full understanding of reactions schemes at high pressures (chemical kinetics), the effect of heat transfer, and the impact of impurities.
Solid adsorbents used in cyclic processes are one of the most cost-effective CO2 capture technologies. Dr David Danci from Imperial college presented his work on the adsorbent screening tool. This techno-economic screening tool that can be used to rapidly assess the applicability of any available adsorbent for a specific capture process. The tool promises rapid evaluation and uses inputs related to process-performance and process-economics. Several common adsorbents like activated carbons and zeolites were assessed, and the results showed that the cost of the carbon capture by solid adsorbents was mainly driven by the requirement for vacuum pumps for the regeneration of the adsorbent and by adsorber column size.
Hydrogen can replace natural gas to provide a clean energy source for electricity production. Dr Laura Herraiz from the Institue for Energy systems at the University of Edinburgh presented multiple synergetic design options for low-carbon hydrogen and electricity production from natural gas to achieve capital cost reduction and lower CO2 emission. This study showed that Integrating Combined Cycle Gas Turbine (CCGT), Steam Methane Reforming (SMR) for hydrogen production and Post Combustion Capture (PCC) systems could provide a reduction of 40% in flue gas flow rate and achieve a net thermal efficiency of 53%
Research on solid adsorbents for CO2 capture was dominant in the capture session of the UKCCSRC conference this year. The last presentation in the capture session by Dr Matthias Schnellmann shed light on the ongoing research at Cambridge University in the field of solid adsorbents processes. Fixed bed processes were seen as a well-established process to employ solid adsorbents for CO2 capture. The need for simultaneous consideration of both adsorbent materials and cyclic fixed bed processes in the design was highlighted as one of the main findings of the study.