TCCS-11 - Trondheim Conference on CO2 Capture, Transport and Storage Trondheim, Norway - June 21-23, 2021 Ainara Moral, NTNU, Trondheim, Norway MODIFIED DOLOMITE-BASED PELLETS FOR HIGH TEMPERATURE POST-COMBUSTION CO2 CAPTURE Ainara Moral 1* , Anne Charlotte Wold 1 , Kumar Ranjan Rout 1,2 , De Chen 1 1 Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Sem Sælands vei 4, N-7491 Trondheim, Norway 2 SINTEF Industry, Norway * Corresponding author e-mail: ainara.moral.larrasoana@ntnu.no Abstract In this study, synthetic dolomite-based pellets were prepared by means of one-pot method. Zr and Ce were used as modifier and aluminate cement was employed as binder. The addition of the promoters by two different routes (1-step or 2-step) was analyzed. The pellets were exposed to several carbonation-calcination cycles in a thermogravimetric analyzer at low CO2 concentration (5 vol.%) and wet conditions (8 vol.% steam) at 600 o C. The calcination was carried in harsh conditions to mimic the realistic process (950 o C, 77 vol.% CO2). The Zr-modified and synthetized by 2-step one-pot method was presented as the most promising among all the sorbents with an initial capturing capacity of 16.9.% in cycle 2 to 14.4 % after cycle 40. It was proved that both, sintering and pore blockage are fairly well prevented. Different characterization techniques were employed, including N2 adsorption-desorption at 77 K, X-ray diffraction (XRD) and scanning electron microscopy combined with energy-dispersive spectroscopy (SEM-EDS). Keywords: Calcium-Looping; dolomite; cement; zirconium 1. Introduction Carbon capture and storage (CCS) was identified by the International Energy Agency (IEA) as a crucial technology to reach the mitigations requirements targeted by United Nations in the Paris agreement in 2015 [1], where the target of keeping temperature increase below 2 °C (above pre-industrial levels) was agreed. As a result, approximately 48 % of the CO2 emission reduction will come from power plants [2]. Within the CCS technologies, post-combustion CO2 capture has raised among the best processes to be implemented in the existing power plants. Currently, the most mature technology employed industrially is the Monoethanolamin Absorption (MEA). However, several problems associated such as, low total efficiency as a result of the extraction of steam in the solvent regeneration [3], solvent degradation [4] or corrosion [5] and the high cost [6] makes necessary to find new technologies. A promising alternative is the calcium-looping (CaL), consisting of a first carbonation step with calcium oxide- based sorbent, following by the regeneration of the sorbent at high temperature in a calciner. The interest on this process has increased due to its potential to achieve a lower energy penalty than the one reached in the MEA. The application of this technology have been investigated in cement [7], coal-fire [8] and Natural Gas Combined Cycle (NGCC) power plants [9] . Several studies have been done to evaluate the performance of the CO2 capture by CaL on the NGCC power plants [9–14]. A significant challenge associated with the combination of the processes are the higher energy requirement due to lower CO2 concentration in the flue gas (4 vol.%) and consequently, lower temperature (600 ºC) in the carbonator comparing to the coal fire plants (650 ºC and 15 vol.%). On the other hand, steam will be a subproduct in combustion flu gas (5-10 vol.%) [15], which will influence the capturing efficiency. Furthermore, the process requirement of harsh calcination conditions (>80 vol.% CO2, T>900 °C) must be taken into account in the sorbent evaluation [16]. Environmental and economic factors regarding the nature of sorbents hinders the development of the CaL. Therefore, the necessity of cost efficient environmentally friendly sorbent is significant for the overall cost. The use of calcium sorbents based on natural resources [17], mainly limestone (CaCO3) and dolomite (CaCO3.MgCO3) might solve this problems. However, they suffer a rapid decrease in CO2 sorption capacity with an increasing number of carbonation/calcination cycles mainly due to sintering and pore collapse. Dolomite presents a significantly lower capacity than limestone, however, its lower decomposition temperature and higher resistance to sintering, due to the action of MgO as a thermally stable support mitigating the capacity loss [18], makes it a promising raw material. Large efforts have been carried out for enhancing the natural sorbents uptake capacity and stability [19]. An interesting approach in material development is the incorporation of inert supporting materials with high melting points. In this respect, Zr modified sorbents have been extensively investigated showing a notable stability over several cycles, attributed to the formation of the thermally resistant CaZrO3 when CaO reacts with ZrO2 96