超重力系統中以深共熔溶 劑混合醇胺 吸收二氧化碳

Capture of Carbon Dioxide by a Mixture of Alkanolamine and Deep Eutectic Slovent in a Rotating Packed Bed

吳逸甯(Yi-Ning Wu)

指導教授 ： 陳昱劭

中原大學/工學院/化學工程研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600672

摘要

本研究於旋轉填充床反應器中利用化學吸收之方式移除二氧化碳，吸收劑為單乙醇胺(MEA)和2-甲基乙醇胺(MMEA)混合深共熔溶劑(DES)，其中DES為氯化膽鹼/乙二醇，並改變轉速、氣體流率、溫度與吸收劑配方之醇胺濃度及吸收劑中水與DES比例等操作參數，藉由測量實驗系統中氣體出口之二氧化碳濃度數值變化，探討操作參數對二氧化碳移除率、總括體積氣膜質傳係數及吸收劑之二氧化碳負載量之影響。
實驗結果顯示，移除率會隨著溫度、吸收劑中醇胺濃度及吸收劑中水的比例的增加而上升，隨氣體流率增加而下降，在轉速為600~1800 rpm時，移除率會隨轉速上升，當轉速提升至2400 rpm時則有些微下降，而MMEA的移除率高於MEA。總括體積氣膜質傳係數隨轉速、溫度、吸收劑中醇胺濃度及吸收劑中水的比例的增加而上升，但是提高氣量會使氣-液在床體中接觸時間縮短，不利反應，故提高氣量會使總括體積氣膜質傳係數下降。吸收劑之二氧化碳負載量則會隨著轉速、氣體流率、溫度及吸收劑中水的比例的增加而上升，隨吸收劑中醇胺濃度增加而下降。再生能量隨吸收劑中水量減少再生能量下降，且吸收劑中含MMEA之再生能量較MEA低。
本實驗在吸收劑為MMEA/DES/H2O(30:40:30)操作在氣量為50 L/min、液量為0.1 L/min、溫度為40℃及轉速在2400 rpm下，與30 wt% MEA水溶液相比，移除率可提高20.5%，再生能量則可由3.61 GJ/ton CO2降低為2.88 GJ/ton CO2。

關鍵字

旋轉填充床 ； 二氧化碳 ； 深共熔溶劑 ； 醇胺

並列摘要

In this study, a mixture of alkanolamine, such as MEA and MMEA, with a deep eutectic solvent (DES) of choline chloride (ChCl)/ethylene glycol (EG) used as an absorbent to capture CO2 from gas stream in a rotating packed bed. The effects of rotating speed, gas flow rate, temperature, concentration of alkanolamine and ratio of water and DES in the absorbent on CO2 removal efficiency (E), mass transfer coefficient (KGa) and CO2 loading were investigated.
Experimental results showed that CO2 removal efficiency increased with increasing temperature, concentration of alkanolamine, ratio of water in the absorbent and rotating speed ranging between 600 and 1800 rpm, but decreased with increasing gas flow rate. A decreased of ratio of water in the absorbent reduced the removal efficiency because of the increasing viscosity. The removal efficiency of MMEA is higher than that of MEA, because of the reaction rate of MMEA is higher. The mass transfer coefficient values increased with increasing rotating speed, temperature, concentration of alkanolamine and ratio of water in the absorbent. Increasing gas flow rate reduced the contact time of gas and liquid in the rotating packed bed, and thus, the mass transfer coefficient decreased with the gas flow rate. The regeneration energy of each absorbent was calculated in this study. Results showed that the regeneration energy decreased with increasing the ratio of water in the absorbent. Besides, the regeneration energy of MMEA is lower than that of MEA.
In this study, an optimum composition of absorbent of MMEA/DES/H2O (30:40:30) was obtained. Compared with 30 wt% MEA solution, the removal efficiency of the proposed absorbent was increased from 69% to 86.8% at gas flow rate of 50 L/min, liquid flow rate of 0.1 L/min, while the regeneration energy can be reduced from 3.61 GJ/ton CO2 to 2.88 GJ/ton CO2. This shows that the use of DES mixed with alkanolamine has a great potential for CO2 capture in a higee system.

並列關鍵字

rotating packed bed ； carbon dioxide ； deep eutectic solvent ； alkanolamine

參考文獻

黃小萍；“使用氣提法在旋轉填充床中移除氨之研究,” 中原大學碩士論文2013.

Abbott, A.P., Boothby, D., Capper, G., Davies, D.L., Rasheed, R.K., “Deep Eutectic Solvents Formed between Choline Chloride and Carboxylic Acids: Versatile Alternatives to Ionic Liquids,” J. Am. Chem. Soc., 2004, 126, 9142-9147.

Abbott, A.P., Capper, G., Davies, D.L., Rasheed, R., “Ionic Liquids Based upon Metal Halide/Substituted Quaternary Ammonium Salt Mixtures,” Inorg. Chem., 2004, 43, 11, 3447-3452.

Abbott, A.P., Capper, G., Davies, D.L., Rasheed, R.K., “Ionic Liquid Analogues Formed from Hydrated Metal Salts,” Chem. Eur. J., 2004, 10, 3769-3774.

Abbott, A.P., Capper, G., McKenzie, K.J., Ryder, K.S., “Electrodeposition of Zinc-Tin Alloys from Deep Eutectic Solvents Based on Choline Chloride,” J. Electroanal. Chem., 2007, 599, 288-294.