An absorption operation is required to remove CO2 from a 250 kmol/hr flue gas stream using an aquaeous 20 mole% MEA solution supplied at a flow rate of 1.5 times the minimum. The gas feed contains 13 mole% CO2 in air, and the exhaust gas stream should contain no more than 0.7 mole% CO2. The supplied MEA solution contains 1.1 mole% CO2. This absorption operation column has internal height and diameter of 10 and 1 m, respectively. The column should be designed for a pressure drop of 0.5 inches H2O per foot of packing.
a) Determine the mole% CO2 in the liquid stream leaving the column and determine the number of transfer units.
x:0.010 0.0125 0.015 0.0175 0.020 0.0225 0.025 0.0275 0.030 0.035 0.040 0.045 y:0.002 0.005 0.009 0.015 0.021 0.028 0.037 0.047 0.059 0.090 0.135 0.19
𝑀̅𝑠𝑜𝑙𝑣𝑒𝑛𝑡 = 26.6, 𝑀̅CO2 = 44 g.mol-1 , kOG = 0.85 mol.m-2 .s-1 , ρg,ave. = 1.28 kg.m-3 , ρl,ave. = 1000 kg.m-3 , ηave. = 1.0 cSt
To solve the problem, you need to build a graph in Excel or MatLab.
To do this, it is necessary to take into account the 1.5-fold excess of carbon dioxide. So, if one mole of carbon dioxide is needed, the mass of the supplied should be 66 g.
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