Problem set 1 number 10
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The document provides information about designing a condenser for a distillation unit, including the vapor flow rate and temperature, heat of condensation, cooling water inlet temperature and cost, optimum heat transfer coefficient, condenser cost parameters, and is asked to determine the optimum cooling water flow rate and exit temperature.
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Problem set 1 number 10
- 2. Problem No. 10 A condenser for a distillation unit must be designed to condense 2000 kg/h of vapor. The effective condensation temperature for the vapor is 132oC.The heat of condensation for the vapor is 350000 J/kg. Cooling water is available at 25oC.The cost of cooling water is $22/1000m3.The optimum Heat Transfer Coefficient is 300 W/m2K.The cost of the installed heat exchanger is $400/m2 and annual fixed charges including maintenance are 20% of the initial investment. The heat capacity of water is 4184 J/kgK. If the condenser is to operate 7200 hrs/yr, determine the cooling water flow rate in kg/hr and exit temperature for optimum economic conditions.
- 3. Solution Given: W steam = 2000 kg/h t steam = 132 o C L steam = 350000 J/kg t 1 = 25 o C C w = $22/1000m3 U = 300 W/m 2 K C A = $400/m 2 K F = .20 Cp = 4184 J/kgK Hy = 7200 hrs/yr Required: a. the cooling water flow rate in kg/hr b. exit temperature for optimum economic conditions
- 4. Solution
- 5. Solution T 2opt = 359.9829562K or 86.98 o C
- 6. Solution W steam * L steam = W*Cp*(t 2opt – t 1 ) (2000 kg/hr)(350000 J/kg) = W*(4186J/kg-K)*(359.9829562-298) W = 2697.904239 kg/ hr