https://doi.org/10.1016/j.ces.2014.05.018
“Fig. 1 shows the schematic and a photograph of the BFB reactor system designed and built for the evaluation of CO2 capture and regeneration using solid adsorbents. The total height of the BFB reactor is 1.7 m, consisting of a fluidized bed section which is 1.2 m in height and 67 mm in internal diameter, and a freeboard section which is 0.5 m in height and 108 mm in internal diameter. The BFB reactor is surrounded by four individually controlled electric heating elements for heating the bed materials to the desired temperatures in adsorption and desorption processes. A series of thermocouples and pressure sensors are installed at different heights of the reactor wall for monitoring the fluidization and reaction behaviour. At the exit of the BFB, a cyclone is used to separate the entrained fine particles from the gas effluent before it is released to the atmosphere. At the bottom of the BFB, three gas streams i.e. air, carbon dioxide and nitrogen with individual valves and mass flow controllers are regulated to serve as the feed gas for adsorption or stripping gas for regeneration for different research purposes. An electrically heated moisture saturator with separate temperature controls is used to generate the moisture for the feed gas or the stripping gas. CO2 concentrations at the inlet and outlet of BFB are continuously monitored by a regularly calibrated gas analyser. Pressure drops, temperatures and the CO2 concentrations are recorded by a data logger.”
“Fig. 1. Schematic and photograph of the bubbling fluidized bed reactor.”
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The adsorbent used throughout this study was synthesized by impregnating a mass ratio of 40% of polyethyleneimine (PEI) into an inorganic mesoporous silica support which had a BET surface area of approximately 250 m2/g, pore volumes of 1.7 cm3/g and a mean pore diameter of approximately 20 nm (Drage et al., 2008). The PEI has a molecular mass (MM) of 1800 in hyperbranched forms acquired from Sigma-Aldrich, UK. PEI was incorporated into the silica support by a wet impregnation method. Characterization of the as-received adsorbent by means of TGA, NMR, DRIFT and XPS can be found in previous publications (Drage et al., 2007, Drage et al., 2008).
The key parameters of the PEI–silica adsorbent and some operational conditions of the BFB reactor system are listed in Table 1. The average particle diameter of 250 μm is deduced through the particle size distribution profiles obtained from standard sieve analysis. Minimum fluidization velocity Umf is determined by air fluidization tests under room conditions (20 °C, 1 atm). The superficial fluidization velocity (20 °C, 1 atm) for both adsorption and desorption tests is adopted to be about 4 times of Umf.
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