Abstract:In this study, two adsorbents (A-1, S-1) with microporous structure were selected to conduct n-hexane dynamic adsorption and desorption experiments with various desorption methods (vacuum, vacuum heating, negative pressure + supplemental gas, thermal purge). The effects of temperature, vacuum degree and desorption flow rate on the desorption performance of these two adsorbents were studied. The results showed that in the dynamic adsorption process with a reference point based on the adsorption penetration, the total effective adsorption capacities of these two adsorbents throughout the dynamic adsorption-desorption-re-adsorption process remained stable even if different desorption methods (vacuum, vacuum heating, negative + supplemental gas, thermal purge) were used. Two adsorbents presented different desorption effects due to different pore size distribution, and S-1 had a better desorption performance with more mesoporous and macroporous structure than A1. The desorption method of negative pressure + supplemental gas increased the flow in the tower, reduced the diffusion resistance between particles, broke the concentration polarization layer and improved the desorption efficiency in the desorption process. The desorption process was fitted by quasi-first-order, quasi-second-order, and Bangham kinetic models, and the Bangham kinetic equation presented the best fitting result with R2 greater than 0.99. Therefore, the desorption kinetics of n-hexane on these two adsorbents followed Bangham kinetic model. Key words:oil vapor recovery/ adsorbent/ n-hexane/ desorption/ kinetics.
图1动态吸附与解吸实验装置示意图 Figure1.Schematic diagram of dynamic adsorption and desorption experimental device
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1.Jiangsu Key Laboratory of Oil & Gas Storage and Transportation Technology, Changzhou University, Changzhou 213164, China 2.Changzhou Yiting Environmental Science and Technology Co. Ltd., Changzhou 213164, China Received Date: 2019-12-03 Accepted Date: 2020-01-17 Available Online: 2020-10-14 Keywords:oil vapor recovery/ adsorbent/ n-hexane/ desorption/ kinetics Abstract:In this study, two adsorbents (A-1, S-1) with microporous structure were selected to conduct n-hexane dynamic adsorption and desorption experiments with various desorption methods (vacuum, vacuum heating, negative pressure + supplemental gas, thermal purge). The effects of temperature, vacuum degree and desorption flow rate on the desorption performance of these two adsorbents were studied. The results showed that in the dynamic adsorption process with a reference point based on the adsorption penetration, the total effective adsorption capacities of these two adsorbents throughout the dynamic adsorption-desorption-re-adsorption process remained stable even if different desorption methods (vacuum, vacuum heating, negative + supplemental gas, thermal purge) were used. Two adsorbents presented different desorption effects due to different pore size distribution, and S-1 had a better desorption performance with more mesoporous and macroporous structure than A1. The desorption method of negative pressure + supplemental gas increased the flow in the tower, reduced the diffusion resistance between particles, broke the concentration polarization layer and improved the desorption efficiency in the desorption process. The desorption process was fitted by quasi-first-order, quasi-second-order, and Bangham kinetic models, and the Bangham kinetic equation presented the best fitting result with R2 greater than 0.99. Therefore, the desorption kinetics of n-hexane on these two adsorbents followed Bangham kinetic model.