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Design a distillation column for the separation of a mixture composed of 50% ethanol and 50% water. The column must produce a distillate that is at least 95% ethanol and a bottoms stream that is at most 5% ethanol. The feed rate is 1000 kg/h and the reflux ratio is to be determined by the student. Provide the complete design of the distillation column including the number of th

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To design a distillation column for the separation of a 50% ethanol and 50% water mixture, we will follow these steps:1. Determine the operating conditions2. Calculate the number of theoretical trays3. Determine the feed tray location4. Calculate the column diameterStep 1: Determine the operating conditionsThe boiling points of ethanol and water are 78.37C and 100C, respectively. We will operate the column at 1 atm pressure. Step 2: Calculate the number of theoretical traysWe will use the Fenske equation to determine the minimum number of theoretical trays  Nmin  required for the separation:Nmin =  log  xD 1 - xB  / xB 1 - xD     / log  where xD is the mole fraction of ethanol in the distillate  0.95 , xB is the mole fraction of ethanol in the bottoms  0.05 , and  is the relative volatility of ethanol to water. Assuming a relative volatility    of 2.3 for ethanol to water at 1 atm:Nmin =  log  0.95 1 - 0.05  / 0.05 1 - 0.95     / log 2.3   11.9We will round up to 12 theoretical trays as the minimum number required for the separation.To account for the actual column efficiency, we will use a Murphree tray efficiency of 70%. Therefore, the actual number of trays required is:Nactual = Nmin / tray efficiency = 12 / 0.7  17.1We will round up to 18 actual trays for the column.Step 3: Determine the feed tray locationWe will use the feed condition as a basis for determining the feed tray location. Assuming the feed is a saturated liquid  q = 1 , we can use the following equation:q =  L1/V  *  xF - xD  /  xB - xD where L1 and V are the liquid and vapor flow rates on the rectifying section, and xF is the mole fraction of ethanol in the feed  0.5 . Rearranging the equation to solve for L1/V:L1/V =  0.5 - 0.95  /  0.05 - 0.95  = 0.45 /  -0.9  = 0.5Assuming a reflux ratio  L1/D  of 1.5, we can calculate the feed tray location:Feed tray location = Nmin *  L1/V  /  1 +  L1/V   = 12 *  0.5  /  1 + 0.5   8We will place the feed tray at the 8th tray from the top.Step 4: Calculate the column diameterThe column diameter can be calculated using the following equation:D =  4 * F  /   * L * vL where F is the feed rate  1000 kg/h , L is the liquid density  assumed to be 900 kg/m for the ethanol-water mixture , and vL is the liquid velocity  assumed to be 0.01 m/s .D =  4 * 1000  /   * 900 * 0.01   1.41 mWe will use a column diameter of 1.41 meters.In summary, the distillation column design for the separation of a 50% ethanol and 50% water mixture is as follows:- Number of theoretical trays: 12  18 actual trays - Feed tray location: 8th tray from the top- Column diameter: 1.41 meters- Reflux ratio: 1.5

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