Preparation before calibration

Before calibrating the coal calorimeter, it is necessary to make full preparations. First, prepare standard benzoic acid, which has high purity and stable calorific value, and is the key substance for calibration. At the same time, ensure that the calorimeter is in good operating condition, check whether the components of the instrument are connected normally, the oxygen bomb has no leakage, and the oxygen bomb oxygenation device can provide the required pressure stably.

Second, the correction operation steps

1. Weigh the reference material: Use a high-precision balance to accurately weigh a certain quality of standard benzoic acid, usually between 0.9 and 1.1 grams, and record the exact mass value, accurate to 0.001 grams.

2. Sampling and oxygenation: put the weighed standard benzoic acid into the oxygen bomb, install the ignition wire to 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. Put in the instrument and start: carefully put the oxygen bomb into the inner cylinder of the calorimeter, connect the ignition electrode, and cover the instrument cover. According to the instrument operation process, start the calorimeter and start measuring.

4. Recording and calculation: After the measurement is completed, record the calorific value data displayed by the instrument. According to the known calorific value of standard benzoic acid and the actual weighed mass, the correction factor is calculated through the formula. For example, if the calorific value of standard benzoic acid is known as Q scale, the weighed mass is m scale, and the measured calorific value is Q scale, then the correction factor K = Q scale × m scale/Q scale.

Verification after correction

After the correction is completed, in order to verify the correction effect, the standard benzoic acid can be used for measurement again. If the deviation between the multiple measurement results and the standard calorific value is within the allowable range, the correction is successful; if the deviation is large, the correction process needs to be re-checked to find out the problem and correct again to ensure that the measurement accuracy of the calorimeter meets the requirements, providing reliable data support for coal quality inspection.