The Importance of Coal calorimeter Calibration

The coal calorimeter is a key equipment for accurately measuring the calorific value of coal, and the accuracy of its measurement results directly affects the coal quality evaluation and transaction settlement. If the calorimeter is not accurately calibrated, it will lead to the deviation of the calorific value data, which will bring many problems to the production and use of coal. Therefore, regular scientific calibration of the coal calorimeter is the core premise to ensure the reliability of the detection data.

Preparation before calibration

Before calibration, it is necessary to ensure that the calorimeter is in a stable operating state, check whether the various components of the instrument are connected normally, whether the oxygen bomb is damaged, and whether the seal is good. At the same time, prepare the standard benzoic acid, whose calorific value is known and stable, which is an ideal material for calibration. An analytical balance with sufficient accuracy is also required to accurately weigh the quality of the standard benzoic acid. In addition, the purity of oxygen needs to reach more than 99.5% to ensure sufficient combustion.

Specific calibration steps

1. Weigh the standard material: Use an analytical balance to accurately weigh a certain mass (usually 0.9-1.1g) of standard benzoic acid, and the weighing error should be controlled within 0.0002g. The weighed benzoic acid should be pressed into a sheet and placed in a crucible.

2. Sampling and oxygenation: Put the crucible filled with benzoic acid into the oxygen bomb, connect the ignition wire, and ensure that the ignition wire is in good contact with the benzoic acid. Then fill the oxygen bomb with oxygen, the pressure is controlled at 2.8-3.0MPa, and the oxygenation time is not less than 15 seconds to ensure sufficient oxygen.

3. Instrument setting and ignition: Put the oxygen bomb into the inner barrel of the calorimeter, set the relevant parameters according to the instrument operation process, and start the ignition procedure. After the benzoic acid is completely burned, the instrument records the temperature change data.

4. Calculate the calibration coefficient: According to the known calorific value of standard benzoic acid, combined with the temperature rise data measured by the instrument, the calibration coefficient of the calorimeter is calculated through the formula. Repeat the calibration many times and take the average value to improve the calibration accuracy.

Verification and maintenance after calibration

After the calibration is completed, a standard coal sample with known calorific value needs to be used for verification and testing. If the deviation between the test results and the standard value is within the allowable range, it means that the calibration is valid. In daily use, regularly check the performance of the calorimeter, keep the instrument clean, and replace the aging parts in time to ensure that the calorimeter is always in accurate operation, providing a reliable guarantee for coal heat detection.