Design, Fabrication, and Preliminary Testing of Coil-Type Evaporator

Author : Florece Jr., Edmundo Dino 
Major Adviser : Demafelis, Rex B.
Committee Members :
Year : 1991
Month : March
Type : Thesis
Degree: BS
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A laboratory-scale, coil type evaporator was designed, fabricated and tested. The evaporator was designed to concentrate a 16% mass sugar solution to 21% in continuous process. The major feature of the evaporator is the heating section consisting of copper tubing wound into concentric coils of helix diameter 9 and 6 inches. Both coils have 25 turns of copper tube with a diameter of 0.25 inch. The body of the evaporator was constructed from gauge 18 stainless steel sheet.

The evaporator was tested in a continuous process at steady-state conditions. Steam was used as the heating medium. Data obtained at steady state were used to compute for steam economy, heat transfer efficiency, percent evaporation, overall heat transfer coefficient, and evaporation coefficient The value of economy for water at feed rate of 0.39 li/min was 0.6433 lbm vapor/lbm steam while the efficiency was 91.98%. For feed using sugar solution at the rate of 0.392 li/min and 0.512 li/min, the economy were 0.4959 with efficiency of 74.00% and 0.5422 econony with 85.91% efficiency respectively. The overall heat transfer coefficient for water at 0.39 li/min as 130.69 BTU/hr ft2 °F. For sugar solution, 111.85 BTU/hr ft2 °F and 129.85 BTU/hr ft2 °F were obtained for 0.392 li/min and 0.512 li/min respectively.

The percent evaporation for water at feed rate of 0.39 li/min was 33.56% with evaporation coefficient of 2.74 lbm/ hr ft2. For sugar solution, percent evaporation were 25.03% and 20.95 with corresponding evaporation coefficient of 2.16 lbm/hr ft2 and 2.36 lbm/hr ft2 at feed flowrates of 0.392 li/min and 0.512 li/min respectively. Further testing is recommended to determine the optimum operating conditions of the fabricated evaporator.

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