CO2 capture; hydrogen; calcium; solid sorbents; fluidized bed
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(2014), Development of highly effective CaO-based, MgO-stabilized CO2 sorbents via a scalable, "one-pot" recrystallization technique, in Advanced Functional Materials
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(2014), Sol-gel-derived, CaO-based, ZrO2-stabilized CO2 sorbents, in Fuel
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(2013), High-purity hydrogen via the sorption-enhanced steam methane reforming reaction over a synthetic CaO-based sorbent and a Ni catalyst, in Environmental Science & Technology
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(2013), High-purity hydrogen via the sorption-enhanced steam methane reforming reaction over a synthetic CaO-based sorbent and a Ni catalyst, in 5th HTSLCN Meeting
(2013), Sorbent enhanced steam methane reforming: Development of a bi-functional Ni-Ca-based catalyst/CO2 sorbent, in XIthe European Congress on Catalysis
(2013), Synthesis of calcium-based, Al2O3-stabilized sorbents for CO2 capture using a co-precipitation technique, in International Journal of Greenhouse Gas Control
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(2013), Synthesis of CaO based, ZrO2-stabilized sorbents for CO2 capture, in 7th Trondheim Conference on CO2 Capture, Transport and Storage
(2013), The Synthesis of Highly Efficient Ca-Based CO2 Sorbents Containing a Hierarchical Pore Structure, in AICHE 2013 Annual Meeting
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(2012), Application of the Sol-Gel Technique to Develop Synthetic Calcium-Based Sorbents with Excellent Carbon Dioxide Capture Characteristics, in CHEMSUSCHEM
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(2012), Development of calcium-based, copper-functionalised CO2 sorbents to integrate chemical looping combustion into calcium looping, in ENERGY & ENVIRONMENTAL SCIENCE
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(2012), Highly Efficient CO2 Sorbents: Development of Synthetic, Calcium-Rich Dolomites, in ENVIRONMENTAL SCIENCE & TECHNOLOGY
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(2012), Investigation of the sorbent enhanced methane reforming reaction, in International Conference on Chemical Looping
(2012), Sorbent enhanced methane reforming over a Ni-Ca-based, bi-functional catalyst sorbent, in ACS Catalysis
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(2012), The influence of the calcination and carbonation conditions on the CO2 uptake of synthetic Ca-based CO2 sorbents, in Environmental Science & Technology
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(2011), Development of synthetic, Ca-based sorbents for CO2 capture using the co-precipitation technique, in Seventh Mediterranean Combustion Symposium, 2012
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, Synthesis of Highly Efficient, Ca-Based, Al2O3-Stabilized, Carbon Gel-Templated CO2 Sorbents, in ADVANCED MATERIALS
, The sorbent enhanced steam methane reforming reaction studied over a synthetic Ca-based, Al2O3-stabilized CO2 sorbent and a Ni catalyst, in Chemical Engineering & Technology
The emission of CO2 from the combustion of fossil fuels has led to an increase in the CO2 concentration in the atmosphere from a pre-industrial level of ~280 ppm to its current level of ~380 ppm . This significant increase in CO2 concentration is almost certainly linked to long-term climate change. Since the use of coal is projected to increase by ~ 80 % over the next 20 years, it is imperative to find ways of using coal which limit the release of CO2 into the atmosphere. Post-combustion capture of CO2 is potentially an attractive option. However, the currently available CO2 capture technology, i.e. amine scrubbing, comes with a large penalty on plant efficiency. Therefore, more efficient CO2 sorbents have to be developed. Ca-based sorbents possess a high theoretical up-take of CO2 compared to other potential capture materials, e.g. zeolites, hydrotalcites or functionalized carbon nanotubes. However, the CO2 capture capacity of natural Ca-based sorbents decreases markedly with the number of cycles of carbonation and calcination, potentially resulting in the use of unsustainably large amounts of sorbent. Thus, the development of synthetic CO2 sorbents with high cyclic stability and reactivity is an important research objective. Compared to the vast amount of research performed on natural sorbents, studies on synthetic sorbents are limited and have mainly focused on “simple” preparation techniques, e.g. mechanical mixing. These preparation techniques do not allow key properties of the final product, such as pore size distribution, to be tailored easily. However, research on natural sorbents has indicated that a large pore volume in pores of diameter dp < 100 nm is crucial for a high CO2 capture capacity. The development of synthetic sorbents has been hindered further by a lack of fundamental understanding of the structural changes that occur during repeated cycles of carbonation and calcination, such as sintering, pore blockage and product layer formation. Thus, cyclic carrying capacities of only ~50 % of the theoretical maximum have been achieved.The overall objective of this proposal is to develop novel, synthetic, Ca-based sorbents for CO2 capture. These sorbents shall possess high cyclic reactivity and CO2 capacity, tolerance towards sulphur and a low tendency for attrition. Two advanced particle preparation techniques, i.e. co-precipitation and sol-gel, which offer the possibility to tailor key parameters of the sorbent, such as pore size distribution, which in turn influence the overall CO2 uptake strongly, will be applied. The development of these sorbents shall be aided by an improved understanding of the underlying mechanisms which strongly affect CO2 uptake and reaction kinetics, i.e. sintering, pore blockage and product layer formation. Since these mechanisms occur on a nanometre-scale, 3D tomographic measurements of the sorbent structure and changes thereof during repeated cycles of calcination and carbonation are required. We propose the novel application of: (i) 3D High Angle Annular Dark Field Scanning Transmission Electron Microscopy (HAADF-STEM) and (ii) Laser Local Electrode Atom Probe (LEAP), to provide such detailed measurements on a nanometre-scale. HAADF-STEM and LEAP images will be acquired for sorbents which have undergone (i) various degrees of carbonation and (ii) different numbers of cycles of calcination and carbonation. The results from the imaging work will be used to determine, (i) which mechanisms govern the formation and control the product layer thickness, (ii) what kind of pores are accessible for carbonation and how they fill (pore blockage) and (iii) how grains can be efficiently stabilised to avoid sintering. These detailed measurements will also be used to elucidate the influence of parameters of the preparation techniques, e.g. pH, on the structural properties, such as surface area and pore size distribution. Consequently, based on a detailed, fundamental understanding of the preparation method and the underlying structural changes occurring during reaction, it is envisaged that this research will enable the knowledge-based design of highly efficient CO2 sorbents. The second objective of this proposal is to extent the work to develop CO2 sorbents for use in the sorbent-enhanced water gas shift reaction. This promising technique may allow the production of hydrogen from syngas derived from biomass or coal, in a single step. Since CaO is a poor catalyst for the water-gas shift reaction, this requires the addition of catalytic compounds in the sorbent preparation step. An important facet will be the development of catalytic sorbents for use in realistic operating conditions, i.e. for gases that contain sulphur compounds and tars. The successful completion of this project would be an important step towards the design of highly efficient particles that would pave the way for a process for capturing CO2 with a small energy penalty. The detailed 3D tomographic measurements of chemical and structural changes in the nanometre scale are not only important in the field of CO2 sorbents, but will aid a better understanding of gas-solid reactions in general. The new spatial and chemical information would also be highly beneficial for the current generation of gas-solid models, which usually rely on simplistic assumptions, e.g. cylindrical pore geometry, due to the lack of detailed measurements.