Simulation and Optimization of a Dual-Adsorbent, Two-Bed Vacuum Swing Adsorption Process for CO2 Capture from Wet Flue Gas

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• 作者：Shreenath Krishnamurthy ; Reza Haghpanah ; Arvind Rajendran ; Shamsuzzaman Farooq
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：September 17, 2014
• 年：2014
• 卷：53
• 期：37
• 页码：14462-14473
• 全文大小：521K
• ISSN：1520-5045

文摘

Various options for the capture and concentration of CO₂ from a wet flue gas at 25 掳C containing 15% CO₂ in 82% N₂ and 3% moisture have been analyzed through detailed simulation and optimization. First, a proven cycle for dry flue gas, consisting of four steps including light product pressurization in a column packed with zeolite 13X established in an earlier communication (Haghpanah et al. AIChE J. 2013, 59, 4735) and demonstrated at the pilot scale (Krishnamurthy et al. AIChE J. 2014, 60, 1830), was applied to the wet flue gas. Detailed optimization studies using a nondominated sorting genetic algorithm (NSGA-II) in MATLAB were carried out first to maximize purity and recovery. Further optimization was carried out to obtain the operating conditions corresponding to minimum energy consumption subject to 95% purity and 90% recovery constraints. The minimum energy consumption in this process required to achieve 95% purity (dry basis) and 90% recovery was 230 kWh (t of CO₂ captured)^鈭? with a productivity of 1.03 t of CO₂ (m³ of 13X)^鈭? day^鈥?. This energy consumption was considerably higher and the productivity was considerably lower than those reported for dry flue gas (Haghpanah et al. AIChE J. 2013, 59, 4735). Next, to improve the performance, a new dual-adsorbent, four-step vacuum swing adsorption (VSA) process with silica gel and zeolite 13X packed separately in two beds was proposed. By separating the two adsorbents in two beds, instead of layering them in the same column, it was possible to avoid rewetting of the concentrated CO₂. The process optimization of the new cycle revealed that the 95% purity and 90% recovery target could be achieved at a lower energy penalty [177 kWh (t of CO₂ captured)^鈭?] while also improving the productivity [1.82 t of CO₂ (m³ of 13X)^鈭? day^鈥?, 1.29 t of CO₂ (m³ of total adsorbent)^鈭? day^鈥?].