混合溶劑DETA + PZ水溶液吸收二氧化碳反應動力學數據量測研究

Kinetics of Absorption of Carbon Dioxide into Aqueous Solutions of Diethylenetriamine and Piperazine

陳冠合(Guan-He Chen)

指導教授 ： 李夢輝

中原大學/工學院/化學工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200534

摘要

本研究主要探討二氧化碳與DETA水溶液及混合溶液PZ/DETA水溶液的吸收反應動力學，實驗是使用濕壁柱來量測二氧化碳的吸收，系統濃度範圍DETA (530 wt%) + H2O以及PZ (4 wt%) + DETA (26 wt%) + H2O、PZ (8 wt%) + DETA (22 wt%) + H2O和PZ (12 wt%) + DETA (18 wt%) + H2O三個系統，溫度是30、35和40°C。而研究的實驗結果以混合擬一級及兩性離子機構的反應動力學模式來探討，反應機構模式的參數由實驗結果以數值迴歸方法得到。
此外本研究同時有量測相關的物理性質如密度、黏度、亨利常數及擴散係數等相關數據，只是二氧化碳在醇胺水溶液中的亨利常數及擴散係數無法直接量測得到，所以我們必須使用N2O類比理論來求得亨利常數及擴散係數。為有效設計酸性氣體的吸收設備，亨利常數及擴散係數的數據是相當重要的，而且正確的亨利常數及擴散係數值也是化學吸收模式探討的重要基礎。
研究結果發現混合溶劑DETA + PZ水溶液能有效增加系統吸收二氧化碳的吸收速率。

關鍵字

量測 ； 動力學 ； 混合溶劑 ； 二氧化碳 ； 吸收

並列摘要

The reaction kinetics for the absorption of CO2 into aqueous solutions of Diethylenetriamine (DETA) and into mixed aqueous solutions of DETA and Piperazine (PZ) were investigated by a wetted wall column at 30, 35 and 40°C. The systems studied were: DETA (5, 10, 15, 20, 25, and 30 wt%) + H2O and DETA (26 wt%) + PZ (4 wt%) + H2O, DETA (22 wt%) + PZ (8 wt%) + H2O, DETA (18 wt%) + PZ (12 wt%) + H2O. The physical properties such as density, viscosity, Henry’s constant and diffusivity of the studied systems were also measured. Due to the reactivity of CO2 to the amine system, an N2O analogy was used to estimate the solubility and diffusivity of CO2 in the aqueous amine solutions.
From the kinetics measurements, the absorption rates of CO2 in the aqueous blended DETA/PZ solutions were found to be significantly faster than in conventional amine systems. The reaction rate constants were calculated by applying a hybrid model which combines a pseudo-first-order model with a zwitterion mechanism. This model was found to satisfactorily represent the absorption of CO2 in both the aqueous DETA and aqueous blended DETA/PZ systems. It can be concluded that the results of this study can be used in the design of absorption processes which employ aqueous solutions of DETA or DETA/PZ as absorbents.

並列關鍵字

absorption ； kinetics ； piperazine ； carbon dioxide ； diethylenetriamine

參考文獻

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