# 164 the middle section operating line has this slope

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Unformatted text preview: 27. In the lower section operating line below the sidestream, for a liquid sidestream flow rate of 15 kmol/h, L&quot; = L' - S = 181.3 - 15 = 166.3 kmol/h and V&quot; = V' = 155.75 kmol/h. Thus, L&quot;/V&quot; = 166.3/155.75 = 1.068. This line passes through the point y=0.05 and x = 0.05 with the slope of 1.068. It also intersects the middle section operating line at the sidestream composition, xs = 0.20. These three operating lines are drawn in the McCabe-Thiele diagram, showing that the middle section operating line lies below Analysis: (continued) Exercise 7.36 (continued) the equilibrium curve. Therefore, the assumption that the minimum reflux is controlled by the feed stage is verified and the minimum reflux ratio is 1.427. For actual operation, reflux ratio = 1.2Rmin = 1.2(1.427) = 1.712. Reflux rate in upper section = L = 1.2Lmin = 1.2(106.3) = 127.6 kmol/h. Vapor rate = V = L + D = 127.6 + 74.45 = 202.05 kmol/h. Slope of upper section operating line = L/V = 127.6/202.05 = 0.632. For c...
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