QUESTION 1 A continuous fractionating column is to be designed to separate 30,000 kg/h of a...

 

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QUESTION 1 A continuous fractionating column is to be designed to separate 30,000 kg/h of a mixture of 40 percent benzene and 60 percent toluene into an overhead product containing 97 percent benzene and a bottom product containing 98 percent toluene. These percentages are by weight. A reflux ratio of 3.5 mol to 1 mol of product is to be used. The equilibrium data is shown in Table 11.1-1. The feed has a boiling point of 95°C at a pressure of 1 atm. (MW of benzene and toluene are 78 and 90 g/mol, respectively). TABLE 11.1-1. Vapor-Pressure and Equilibrium-Mole-Fraction Data for Benzene-Toluene System Vapor Pressure Mole Fraction Benzene at 101.325 kPa Temperature Benzene Toluene K C kPa mm Hg kPa mm Hg XA 353.3 80.1 101.32 760 1.000 1.000 358.2 85 116.9 877 46.0 345 0.780 0.900 363.2 90 135.5 1016 54.0 405 0.581 0.777 368.2 95 155.7 1168 63.3 475 0.411 0.632 373.2 100 179.2 1344 74.3 557 0.258 0.456 378.2 105 204.2 1532 86.0 645 0.130 0.261 383.8 110.6 240.0 1800 101.32 760 0 0 (a) Calculate the moles of overhead product and bottom product per hour. (b) Determine the number of ideal plates and the position of the feed plate if the feed is at its dew point (saturated vapor). QUESTION 1 A continuous fractionating column is to be designed to separate 30,000 kg/h of a mixture of 40 percent benzene and 60 percent toluene into an overhead product containing 97 percent benzene and a bottom product containing 98 percent toluene. These percentages are by weight. A reflux ratio of 3.5 mol to 1 mol of product is to be used. The equilibrium data is shown in Table 11.1-1. The feed has a boiling point of 95°C at a pressure of 1 atm. (MW of benzene and toluene are 78 and 90 g/mol, respectively). TABLE 11.1-1. Vapor-Pressure and Equilibrium-Mole-Fraction Data for Benzene-Toluene System Vapor Pressure Mole Fraction Benzene at 101.325 kPa Temperature Benzene Toluene K C kPa mm Hg kPa mm Hg XA 353.3 80.1 101.32 760 1.000 1.000 358.2 85 116.9 877 46.0 345 0.780 0.900 363.2 90 135.5 1016 54.0 405 0.581 0.777 368.2 95 155.7 1168 63.3 475 0.411 0.632 373.2 100 179.2 1344 74.3 557 0.258 0.456 378.2 105 204.2 1532 86.0 645 0.130 0.261 383.8 110.6 240.0 1800 101.32 760 0 0 (a) Calculate the moles of overhead product and bottom product per hour. (b) Determine the number of ideal plates and the position of the feed plate if the feed is at its dew point (saturated vapor).

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