Dolomite-based Sorbents for High Temperature Carbon dioxide capture.

• Main Author: Mawanga, Moses
• Other Authors: Chen, De, Ranjan Rout, Kumar
• Format: Master Thesis
• Language: English
• Published: NTNU 2017
• Subjects: Chemical Engineering; Arctic
• Online Access: http://hdl.handle.net/11250/2457798

The impact of doping with inert oxides on the long term performance of dolomite-based sorbents for high temperature CO_2 has been investigated in this work. Arctic dolomite was doped with with various oxides Al2O3, ZrO_2, MgO, CaAl2O4 and effect of the amount of oxide were studied. The unmodified and doped dolomite were subjected to multi cyclic operation with dry conditions in a thermo gravimetric reactor. Experimental results demonstrated that the mixed dopants comprising 3.5\%Al (5.5\% Al2O3) and 2\%Zr (1.96\% ZrO2) satisfactorily improved the stability of Arctic dolomite during 120 cycles where as a single oxide dopant only marginally improved the stability of the dolomite. The morphology, thermal gravimetric data, phase composition, Nitrogen adsorption all showed that dolomite when subjected to dry conditions is stable when doped with this mixed oxide. Up to 120 cycles of carbonation/desorption were carried out in thermo-gravimetric Analyser. There seemed to exist some kind of synergistic effect caused by the mixed dopants towards improving the stability of dolomite. \ce{N2} adsorption analyses revealed that the best case sorbent had a very small surface area of only 5.4 m2/g with the pore size distribution increase significantly. By optimizing the pore size distribution upon cyclic explicates the enhanced stability.