A mixture of liquid ethanol and n-butanol from a biorefinery will be processed in a batch...

 

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A mixture of liquid ethanol and n-butanol from a biorefinery will be processed in a batch still to enrich the ethanol concentration. In the present process, 100 kgmole of a liquid mixture containing 30 mole% ethanol and 70% n-butanol is initially charged into the batch still at 1.0 atm total system pressure, and the feed is brought up to the bubble point temperature. The distillation process is ended when the ethanol composition remaining in the still is 10 mole% ethanol and 90 mole% n-butanol. The heats of vaporization for ethanol and n-butanol can be considered equal at AH, = 42,000 kJ/kgmole. (a) Determine the amount of bottoms (W) produced. (b) What is the composite distillate composition, and the "recovery" of ethanol in the distillate, based on the amount of ethanol initially charged to the still? (c) If the required distillation time is 3.0 hours, what is the required heat duty on the reboiler, Q? (d) What are the temperatures of the still pot at the beginning AND end of the batch distillation process? (e) Estimate the bottoms and composite distillate composition after a 2.0 hr distillation time at the reboiler heat duty determined under part (c). Hint: a trial-and-error calculation may be required. A mixture of liquid ethanol and n-butanol from a biorefinery will be processed in a batch still to enrich the ethanol concentration. In the present process, 100 kgmole of a liquid mixture containing 30 mole% ethanol and 70% n-butanol is initially charged into the batch still at 1.0 atm total system pressure, and the feed is brought up to the bubble point temperature. The distillation process is ended when the ethanol composition remaining in the still is 10 mole% ethanol and 90 mole% n-butanol. The heats of vaporization for ethanol and n-butanol can be considered equal at AH, = 42,000 kJ/kgmole. (a) Determine the amount of bottoms (W) produced. (b) What is the composite distillate composition, and the "recovery" of ethanol in the distillate, based on the amount of ethanol initially charged to the still? (c) If the required distillation time is 3.0 hours, what is the required heat duty on the reboiler, Q? (d) What are the temperatures of the still pot at the beginning AND end of the batch distillation process? (e) Estimate the bottoms and composite distillate composition after a 2.0 hr distillation time at the reboiler heat duty determined under part (c). Hint: a trial-and-error calculation may be required.

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Batch Distillation of EthanolnButanol Mixture Given Liquid mixture 100 kgmole 30 ethanol 70 nbutanol ... View the full answer