Usage and precautions of automatic oxygen bomb calorimeter
Date: 2025-11-25Read: 30
The automatic oxygen bomb calorimeter is a key equipment for measuring the heat generation of fuel and organic matter in the laboratory. The operation should follow the principle of "standardized process+safety protection" to ensure accurate data and avoid high pressure and high temperature risks. The following are detailed usage methods and core precautions:
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Sample preparationAfter drying the solid sample, grind it to a particle size of ≤ 0.2mm, accurately weigh 0.9~1.1g (error ≤ 0.0001g), and place it in a crucible; Liquid samples should be stored in specialized sealed crucibles with a sampling volume of ≤ 0.5g to avoid leakage. Fix the ignition wire on the oxygen bomb electrode to ensure good contact with the sample and no short circuit.
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Oxygen bomb assemblyPlace the crucible containing the sample and ignition wire into an oxygen bomb, add 10mL of distilled water (absorbing combustion products), tighten the bomb cover, and check the sealing. Use an oxygenator to oxygenate the oxygen bomb, with a pressure controlled between 2.8~3.0MPa and an oxygenation time of 1-2 minutes. After oxygenation, let it stand for 30 seconds for leak detection.
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Instrument debuggingTurn on the power of the calorimeter, the cooling water system, and set parameters such as ambient temperature (usually 20 ± 2 ℃) and stirring speed. Place the oxygen bomb into the inner cylinder, inject a certain amount of distilled water into the inner cylinder (ensuring complete immersion of the oxygen bomb), and cover the instrument cover.
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Calibration and TestingFor the first time or every week, it is necessary to calibrate the instrument with benzoic acid standard, enter the sample name, quality and other information, and start the testing program. The instrument automatically completes ignition, combustion, temperature acquisition, and data calculation, and automatically displays the heat generation results after the test is completed.
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Experimental ConclusionWait for the oxygen bomb to cool to room temperature, slowly release pressure (release time ≥ 1 minute), open the bomb cover, clean the internal ash and carbon deposits, rinse the oxygen bomb with distilled water, and air dry for later use.
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safety protectionOperators should wear protective goggles and heat-resistant gloves, and stay away from the front of the oxygen bomb during oxygenation and testing; Oxygen bombs should not be filled with oxygen under overpressure, and it is strictly prohibited to open the bomb cover before pressure relief; The laboratory needs good ventilation, equipped with fire extinguishers, and kept away from flammable and explosive materials.
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精度保障The sample should be evenly dried to avoid moisture or volatile components; The ignition wire should be made of standard materials to avoid affecting heat calculation due to material differences; Cooling water temperature fluctuation ≤ 1 ℃, regularly replace to prevent scale accumulation.
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Equipment maintenanceClean the oxygen bomb after each experiment, regularly apply silicone grease to the sealing ring for maintenance, and replace it promptly if aging or damage is found; Check the oxygen pipeline, pressure gauge, and safety valve monthly to ensure they are within the valid calibration period; When not in use for a long time, exhaust the pipeline gas and cut off the power supply.
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exception handlingIf ignition fails, it is necessary to release pressure and check the connection of the ignition wire and the sample size. After troubleshooting, perform a re oxygenation test; If incomplete combustion occurs, reduce the sample size or check the oxygenation pressure; When the data deviation is too large, recalibrate the instrument with standard samples.