Project general information
Project: Advanced thermo-chemical looping cycles for the poly-generation of decarbonised energy vectors: Material synthesis and characterisation, process modelling and life cycle analysis
Funding body: Romanian-Swiss Research Programme: Swiss National Science Foundation (SNSF) and Executive Agency for Financing Higher Education, Research, Development and Innovation Funding (UEFISCDI)
Project code: 13 RO-CH/RSRP/2013 ( IZERZO _141976/1)
Period: 2013 - 2015
The anthropogenic emission of CO2 from the combustion of fossil fuels has led to anincrease in the concentration of CO2 in the atmosphere from a pre-industrial level of ~280 ppm to its current level of ~380 ppm (IPCC, 2007). This significant increase in CO2 concentration is most likely linked to long-term climate change. Considering thatthe use of coal is projected to increase by ~ 80 % over the next 20 years, it isimperative to find ways of using coal which limit the release of CO2 into theatmosphere.
A short to mid-term strategy to mitigate climate change is the“sustainable” use of fossil fuels i.e. their usage in combination with CO2 capture andstorage (CCS). However, the currently available CO2 capture technology, i.e. aminescrubbing, comes with a large penalty on plant efficiency. Therefore, advanced CO2capture techniques, such as carbonate looping and chemical looping combustion (CLC), subsequently referred to as chemical looping, have been proposed. These twochemical looping cycles can be modified to allow the production of hydrogen, i.e.enabling the possibility of poly-generation of decarbonized energy vectors.
Research into CLC using solid fuels has concentratedmainly on investigating the feasibility of different reactor designs and operationoptions. Experimental research in these areas has often used naturally occurring ores,which are usually of comparatively low reactivity. On the other hand, studiesinvestigating the sorbent enhanced (SE) reforming and water-gas shift (WGS) reactionshave predominantly focused on demonstrating the feasibility of the concept, typicallyusing a mixture of commercial catalyst and naturally occurring CO2 sorbents.
Therefore, the development of highly reactive, attrition andagglomeration resistant, catalytic, oxygen carriers and Ca-based CO2 sorbents ispivotal for the development of the chemical looping cycles investigated here. So far the development of synthetic materials for chemical looping has mainly involved “simple”preparation techniques, such as mechanical mixing, which do not allow key structuralproperties of the final product, such as pore structure, thermal, mechanical andchemical behaviour, to be tailored easily. However, manipulation of these structuralproperties is crucial for the design of materials that are highly reactive and stable overmany cycles. The development of synthetic materials has been hindered further by a
lack of fundamental understanding in three key areas: (i) the structural changes thatoccur during repeated cycles of reduction and oxidation, (ii) formation anddecomposition of mixed oxides and (iii) identification of reaction pathways andmechanisms.
An additional issue of the previous research into CLC and the SEreforming and WGS reactions has been the “separation” between experimental andconceptual research, resulting in situations where experiments were performed underunreasonable conditions, on the one hand, and un-realistic performancecharacteristics were assumed for the materials, on the other.
One objective of this proposal is the development of novel, multi-functional materialsfor chemical looping that possess (i) a high loading of active material, (ii) fast reaction kinetics, (iii) tolerance towards sulphurous and alkali metal compounds, (iv) resistancetowards attrition and (v) the capability to crack tars.
The second objective of the proposal is a critical technical, economical and environmental assessments of the two cycles investigated here. Crucially, the techno-economicalanalysis will be based on the detailed experimental measurements obtained andmathematical reactor and process flow models for the whole energy conversion processchain. These detailed analyses shall determine the potential of chemical loopingtechnology in comparison with other carbon capture options as a reliable solution forfuture low carbon energy technologies. In addition, the techno-economic and life cycleanalysis studies will also allow us to address the crucial question of whether thedevelopment of synthetic materials is economically viable.
The successful completion of this project would be an important step towards therational design of highly efficient oxygen carriers and (catalytic) CO2 sorbents that would pave the way for processes for the poly-generation of decarbonized energyvectors. In addition optimal operation conditions, the costs of the H2 produced and the CO2 captured and the potential of synthetic material that possess excellent reactioncharacteristics when compared to naturally occurring material, will be determined. Progress in this research area will be of great importance, since there is a growing drivein Europe, Asia and the USA for the development of processes that generate hydrogenand/or power from coal with zero or near zero emissions of CO2 ("Clean CoalTechnology”).