A mixture of 40 mol% benzene and 60 mol% toluene is fed in liquid form into a flash vessel. The feed is 100 kmol/h, and the drum operates at a temperature of 30%, which imposes a vaporization of 100 kmol/h. The table below presents benzene-toluene equilibrium data in terms of benzene composition (most volatile). x is the composition in the liquid and y in the gas, both on a molar basis. The data equilibrium for the case of mixing at 1 atm. α indicates the relative volatility. As benzene and toluene form a liquid solution approximated by the ideal case, the relative volatility is nothing more than the ratio of the vapor system to the equilibrium temperature: Note that the relative volatility changes little with the composition, in which case, for engineering calculations in general, we can consider it to be close to the average: about 2.5. a) Use the defined relative volatility and flash vessel knowledge to determine the compositions of the liquid and gaseous products of the described operation. Then set the vessel operating temperature. (response 95.7 °C; x = 0.38; y = 0.61) b) Given item a, what would be the feed temperature required for the presented configuration?
A mixture of 40 mol% benzene and 60 mol% toluene is fed in liquid form into a flash vessel. The feed is 100 kmol/h, and the drum operates at a temperature of 30%, which imposes a vaporization of 100 kmol/h.
The table below presents benzene-toluene equilibrium data in terms of benzene composition (most volatile). x is the composition in the liquid and y in the gas, both on a molar basis. The data equilibrium for the case of mixing at 1 atm. α indicates the relative volatility. As benzene and toluene form a liquid solution approximated by the ideal case, the relative volatility is nothing more than the ratio of the vapor system to the equilibrium temperature:
Note that the relative volatility changes little with the composition, in which case, for engineering calculations in general, we can consider it to be close to the average: about 2.5.
a) Use the defined relative volatility and flash vessel knowledge to determine the compositions of the liquid and gaseous products of the described operation. Then set the vessel operating temperature. (response 95.7 °C; x = 0.38; y = 0.61)
b) Given item a, what would be the feed temperature required for the presented configuration?
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