A triple-effect evaporator using forward feed is to be used to concentrate 14,500 kg/h of an...

 

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A triple-effect evaporator using forward feed is to be used to concentrate 14,500 kg/h of an 8-wt% KCl solution entering at 25°C to 40 wt%. Saturated steam enters the first evaporator at 169.1 kPa absolute. The absolute pressure in the vapor space of the third effect is 19.9 kPa. The heat transfer coefficients in each effect are U₁ = 6432 W/(m².K), U₂ = 4310 W/(m². K), and U3 = 2754 W/(m² .K). Assume that the boiling point ele- vation is negligible and that vapor streams are pure water. However, appreciable heat of dilution (concentration) is present. Calculate the heat transfer area in each evaporator, the steam consumption, the amount of concentrated product, and the amount of total vapor. Notes. . You should be able to calculate all values by creating multiple equations and solving them simultaneously, without assuming any flow rates, areas, etc. . For the enthalpy of potassium chloride solutions (i.e., liquid streams), use the follow- ing equations where the reference state is liquid water at 0°C: HKCI where T [°C] and .x kJ = 1880x² - 665.9x+285.4+3.37 (T-65.6), kg kg KCI kg solution A triple-effect evaporator using forward feed is to be used to concentrate 14,500 kg/h of an 8-wt% KCl solution entering at 25°C to 40 wt%. Saturated steam enters the first evaporator at 169.1 kPa absolute. The absolute pressure in the vapor space of the third effect is 19.9 kPa. The heat transfer coefficients in each effect are U₁ = 6432 W/(m².K), U₂ = 4310 W/(m². K), and U3 = 2754 W/(m² .K). Assume that the boiling point ele- vation is negligible and that vapor streams are pure water. However, appreciable heat of dilution (concentration) is present. Calculate the heat transfer area in each evaporator, the steam consumption, the amount of concentrated product, and the amount of total vapor. Notes. . You should be able to calculate all values by creating multiple equations and solving them simultaneously, without assuming any flow rates, areas, etc. . For the enthalpy of potassium chloride solutions (i.e., liquid streams), use the follow- ing equations where the reference state is liquid water at 0°C: HKCI where T [°C] and .x kJ = 1880x² - 665.9x+285.4+3.37 (T-65.6), kg kg KCI kg solution