以混合醇胺溶液（MEA＋AMP）吸收二氧化碳溫室效應氣體之可行性研究

Abstract

本研究分別以半連續流及半連續流實驗，來探討混合醇胺溶液（MEA+AMP）吸收二化氧化碳溫室氣體之可行性研究。使用混合醇胺（ MEA+AMP）的主要目的是要改良 MEA溶劑的缺點，藉由結合醇胺的吸收特性，以發展出兼及高吸收量、高吸收速率與回收時較低能源消耗的吸收液。 由半連續流實驗結果顯示，二氧化碳是最大去除率隨 MEA在溶液中之比例增加而增加，顯示MEA比 AMP有較快的反應速率。不同組成混合醇胺在 25℃到35℃之操作溫度時，二氧化碳最大去除率相差不多。而混合醇胺中 AMP比重愈大，吸收容量也愈大，但需注意其操作溫度不可太高，以免吸收容量下降。由於每單位 MEA所放出的熱量大於 AMP，使得溶劑再生時，每單位MEA 所需的熱量也大於AMP，故為節約能源起見，混合醇胺中之AMP比例愈大愈好，而在半連續流實驗中所得之最佳混合醇胺組成比例，在 30%(w/w)之總濃度下為MEA=18% (W/W) , AMP=12%(W/W) 。 由連續流實驗結果顯示，當使用混合醇胺（MEA=18%, AMP=12%W/W）時，液╱氣比為 2.5ml/l，二氧化碳去除率為 83.11%，其吸收量為 0.502mol-CO2/mlo-醇胺；當使用30%w/w之 MEA 溶劑時，液╱氣比為2.5ml/l，二氧化碳去除率為 90.46%，其吸收量則為 0.450mol-CO2/mol-醇胺。混合醇胺溶液與單純 MEA溶劑之總質傳係數（ KGa）隨著液╱氣比例增加而增加， KGa值分別為 0.029~0.113 kmol/m3 kPa與 0.053~0.123 kmol/m3h kPa。混合醇胺溶液與單純 MEA 溶劑之總質傳單位數值（NoG）也隨著液╱氣比增加而增加， NoG值分別為 1.51~5.89與 2.78~6.38。

In this study semi-continuous flow and continuous flow experiments using mixed MEA+AMP solutions were conducted to see their feasibility as scrubbing agents of CO2 greenhouse gas removal from stack gas. The mixed amines (MEA+AMP) solution improved the disadvatage of using pure MEA solution as the C02 scrubbing agent. The use of mixed amines combined the absorption characteristics of pure amines. As a result, it brought about a considerable improvement in teh absorption capacity and great savings in the neergy requirement. A semi-continuous flow reactor was employed in this study to determine the best composition of mixed MEA/AMP amines soultion for both high operation efficiency and high absorption capacity. The results showed that the best composition for MEA and AMP are 18% and 12%, respectively, in a 30% by weight mixed amines soultion . A continuous flow reactor was then used to study the effect of liquid/gas (L/G) ratio on the absorption capacity of mixed MEA/AMP solution and the pure MEA solution (30% w/w). It is shown that at a L/G ratio of 2.5 ml/l, the CO2 removal efficiency of the mixed MEA/AMP solution is lower than that of the pure MEA solution, but the absorption capacity of mixed MEA/AMP solution is larger than that of the pure MEA solution. The overall mass transfer coefficient (KGa) of the mixed MEA/AMP solution increases with the L/G ratio. It ranges from 0.029 to 0.113 kmol/m3 kPa with L/G ratio ranging from 1.5 ml/l to 4.5 ml/l. The number of transfer unit (NoG) of the mixed MEA/AMP solution also increases with the L/G ratio and it ranges from 1.51 to 5.89.