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The effect of bed height on CO 2 capture was investigated by carbonation/regeneration cyclic operations using a bubbling fluidized bed reactor. We used a potassium-based solid sorbent, SorbKX35T5 which was manufactured by the Korea Electric Power Research Institute. The sorbent consists of 35% K 2 CO 3 for absorption and 65% supporters for mechanical strength. We used a fluidized bed reactor with an inner diameter of 0.05 m and a height of 0.8 m which was made of quartz and placed inside of a furnace. The operating temperatures were fixed at 70 o C and 150 o C for carbonation and regeneration, respectively. The carbonation/regeneration cyclic operations were performed three times at four different L/D (length vs diameter) ratios such as one, two, three, and four. The amount of CO 2 captured was the most when L/D ratio was one, while the period of maintaining 100% CO 2 removal was the longest as 6 minutes when L/D ratio was three. At each cycle, CO 2 sorption capacity (g CO 2 /g sorbent) was decreased as L/D ratio was increased. The results obtained in this study can be applied to design and operate a large scale CO 2 capture process composed of two fluidized bed reactors.

In this study, a lab.-scale twin bubbling fluidized-bed system (TBS) has been used continuously to test the performance for CO 2 adsorption of silica-PEI (S.PEI) adsorbents, containing 40 wt.% of PEI, which were supplied by the University of Nottingham (UNOTT). The TBS comprises bubbling-bed adsorption and desorption reactors, a riser for pneumatic conveying of solids from the adsorption to the desorption reactor, and a cyclone for solid-gas separation. The adsorbent prepared using PEI with a molecular mass of 800 (S.PEI-0.8K) was a preliminarily tested for almost 24 hours at the given operating conditions by varying the inlet sorbent/CO 2 mass ratio at the adsorber to analyse the CO 2 removal efficiency in the adsorption reactor and the dynamic sorption capacity of the adsorbent. A 180-hour continuous test was then carried out by changing various experimental conditions such as the H 2 O concentration, reaction temperature, solid layer height, reaction gas flow rate, and inlet sorbent/CO 2 mass ratio at the adsorber using PEI with a molecular mass of 5000 (S.PEI-5K) adsorbent. In this test, a CO 2 removal efficiency of above 80% and a dynamic sorption capacity greater than 6.0% were achieved.