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Boilup ratio constant

A batch distillation column with three theoretical stages (the first stage is the still pot) is charged with 100 kmol of a 20 mol% n-hexane in n-octane mixture. At a constant reflux ratio R - 1.0, how many moles of the charge must be distilled if an average product composition of 70 mol% n-hexane is required If the boilup ratio is 10 kmol/h, calculate the distillation time. The equilibrium distribution curve at column pressure is given in Figure 6.27. [Pg.400]

G7. You have an ordinary, single feed distillation column separating methanol, ethanol, n-propanol, and n-butanol. There are 24 trays in column and feed location in column is tray 14 (input above stage), boilup ratio is 4.0, pressure is 3.0 atm (operate column at constant pressure), total condenser with saturated liquid reflux, kettle type reboiler, feed flow rate is 200 kmol/h, feed mole fractions methanol = 0.30 ethanol = 0.20, n-propanol = 0.25, and n-butanol = 0.25, feed pressure is 3.0 atm, feed temperature is 50.0°C, D = 100 kmol/h, adiabatic column, and use the NRTL VLE package. Open a new blank file, simulate this system with RADFRAC, and answer the following questions ... [Pg.268]

Figure 3.39 gives the response of the system to a step 20% increase in the flowrate of the reactor effluent. The control structure provides good base-level regulatory control. The maximum deviation in reactor temperature is 0.6 K. Three cases are shown. In the first, the reflux flowrate is held constant. In the second, the reflux is ratioed to the feed. There is little difference in the responses of the reactor. But with a fixed reflux flowrate, the impurity of C in the distillate xDC increases from 0.0164 to about 0.025 mole fraction C. With the reflux-to-feed ratio, the impurity remains about the same. The change in the vapor boilup is larger with the reflux-to-feed structure. [Pg.142]

A liquid binary mixture with Bo = 10 kmol and xbo = <0.6, 0.4> molefraction is subject to conventional batch distillation shown in Figure 4.3. The relative volatility of the mixture over the operating temperature range is assumed constant with a value of (a=) 2. The total number of plates is, N = 20. The vapour boilup rate is, V = 5.0 kmol/hr and the reflux ratio is, r = 0.75. The condenser and total plate holdups are 0.2 and 0.2 kmol respectively. [Pg.66]

Table 5.2 summarises the results for two cases (i) constant vapour boil-up rate, (ii) variable vapour boilup rate. The initial and final time optimal reflux ratio values are shown in Table 5.2 for both cases. The optimal reflux ratios between these two points follow according to Equation P.13 for each case. See details in the original reference (Robinson, 1969). [Pg.130]

The time t required for batch rectification at constant reflux ratio and negligible holdup in the trap can be computed by a total material balance based on a constant boilup rate V, as shown by Block. ... [Pg.573]

Figure 7.1 shows other variahles plotted vs. reflux ratio at a constant overhead rate. A graph of B, the bottoms rate expressed as a fraction of the feed, is, of course, constant at 0.5 when the overhead rate is 50 mol/hr. The condenser and leboiler duties, Qc and vary considerably with the reflux ratio, as may be expected due to the variation of condensation and boilup rates as the reflux ratio varies. Since the product compositions do not vary significantly at a constant product rate, the product temperatures also do not vary much with reflux ratio. Fine-tuning of the compositions of key components and adjacent components by adjusting the reflux ratio does not affect the product temperatures to a great extent. [Pg.197]

Table 3.7 provides the optimum design results for the conventional process over a range of temperature-dependent relative volatilities. Because the column relative volatilities are only slightly lower than those of the constant relative volatility case, we assume that the three design optimization variables are the same as in the constant relative volatility case. The slightly lower relative volatilities produce small increases in the number of trays, the reflux ratios, and the vapor boilups in both columns. There is a small increase in the recycle flowrate (D2). [Pg.64]


See other pages where Boilup ratio constant is mentioned: [Pg.283]    [Pg.420]    [Pg.239]    [Pg.11]    [Pg.344]    [Pg.126]    [Pg.187]    [Pg.255]    [Pg.246]    [Pg.139]   
See also in sourсe #XX -- [ Pg.294 , Pg.295 , Pg.308 ]




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