Design, Fabrication and Preliminary Testing of a Laboratory-Scale Packed Column

Author : Butardo, Elmo Valentino F.
Major Adviser : Alcanzare, Edilberto A.; Demafelis, Rex B.
Committee Members :
Year : 1991
Month : October
Type : Thesis
Degree: BS
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A laboratory-scale packed column was designed and fabricated at the Department of Agricultural Machinery and Engineering Technology (DAMET) and tested at the Department of Chemical Engineering, College of Engineering and Agro-Industrial Technology (CEAT), UPLB.

The fabricated packed column has a total height of approximately 40 inches consisting of 25 inches packed bed, a 6.5-inch upper section, another 6.5-inch lower section and 1.5-inch-high conical base. The column has a diameter of about 5.5 inches packed randomly with approximately 3,098 Raschig rings having a nominal size of about 5/8 inch. The column was designed to recover 84.1515 % of the ammonia gas from a 25 mole percent ammonia-air mixture using water. The design strong liquor concentration was 7.62 mole percent while the design lean gas concentration was 5 mole percent.

Testing of the equipment was done to evaluate the efficiency of the fabricated packed column and to calculate the actual mass transfer coefficient. The column was operated with counterflow of the weak liquor and the rich gas using the NH3-air-H2O system. The equipment was tested at a lower gas and liquid flowrates due to the non-availability of appropriate flowmeters of the desired capacity. The weak liquor flowrate ranged from 245 to 255 ml per minute while the rich flowrate was maintained at 5.81 cubic feet per minute. The results showed that the actual percent recovery of NH3 from a 25 mole percent NH3– air gas mixture by distilled water was on the average 86.54% compared to the theoretical recovery of 94.27%. The average strong liquor concentration obtained was about 9.30 mole percent NH3 which was below the theoretical value of 10.20%. The overall actual gas phase composite mass transfer coefficient ranged from 3.61 to 7.89 lbmole/hr atm ft3 averaging 5.89 lbmole/hr atm ft3. The average actual mass transfer coefficient was lower than the theoretical mass transfer coefficient of 10.20 lbmole/hr atm ft3.

Recommendations were made to fully test the operational capability of the equipment and to improve the absorption efficiency of the fabricated packed column.

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