Design, Fabrication, and Preliminary Testing of a Simple Oxygen Bomb Calorimeter

Author : Alcasid III, Petronilo Mule
Major Adviser : Capareda, Sergio C.
Committee Members : Movillon, Jovita A.; Abrigo Jr., Casiano S.
Year : 1994
Month : March
Type : Thesis
Degree: BS
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A simple plain jacketed oxygen bomb calorimeter was designed, fabricated and tested. The calorimeter vessel is made up of gauge 14 stainless steel alloy that measures 30.48 cm (12 inches) high, 25.4 cm (10 inches) outside diameter, and 20.32 cm (8 inches) inside diameter. It has a 2.54 cm (1 inch) thick glass wool for insulation purposes. It has a thermometer, stirrer and external wiring (for the bomb) all placed o the top cover of the calorimeter. The volume of the calorimeter is 9.88 Li. (603 inches³). The oxygen bomb is also made of stainless steel alloy. It measures 24.13 cm (9.5 inches) in height (including valves and terminals), 13.01 cm (5.1215 inches) outside diameter (including the flange seal, and inside diameter of 7.94 cm (3.125 inches). It uses a simple static flange seal CO₂ charging valve, and press type release valve. It has a volume of 0.6520 Li (39.79 in³). The design of the oxygen bomb as a pressure vessel has a maximum capacity of 5,000 psi although is normal operation it is charge at 160 psi.

Benzoic Acid was used to standardize the designed oxygen bomb calorimeter. Rice hull was used as the test sample for preliminary testing. The temperature sensor used was a laboratory thermometer with a 1 degree graduation.

The operating principles for the standardization and actual gross heating value determination are as follows: a weighed (approx. 1 gram) sample is burned in an oxygen -filled metal bomb while the bomb is held in a measured quantity of water and knowing the energy equivalent of the calorimeter, the amount of energy released by a sample can be calculated.

The test results showed that the average energy equivalent of the designed calorimeter (W ave.) was 3695.7067 cal/C. The average measured gross heating value of the sample rice hull (HHv ave.) was 4188.7979 cal/g (17.5259 MJ/kg). The % error of HHv ave. was 13.4366 %. Comparison was based on the estimated gross heating value of rice hull (3692.6386 cal/g or 15.4603 MJ/kg) derived using Boie equation. Using the actual measured values of rice hull (3857.5526 cal/g or 16.14 MJ/kg) derived from using a standard bomb calorimeter, the % error of HHv average is 8.59%.

Further test are required to established to accurately the energy equivalent of the designed calorimeter and to compare its’ performance with a commercially available bomb calorimeter using the same sample. A more accurate temperature measurement with high sensitivity is also recommended for use in the bomb calorimeter.

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