How to make water for coal quality test?

The detection of internal moisture in coal quality test is mainly to detect the moisture content in coal, which is one of the important parameters in coal quality analysis. The following are the methods of internal water detection:

Air-drying method: after the sample to be tested is dried to constant weight at room temperature, it is dried at high temperature to evaporate all the water in it. This is the so-called air-dried sample. Then the air-dried sample is placed in a constant temperature and humidity environment until the water contained in the relative equilibrium humidity is reabsorbed by the sample. Weigh again to find out the moisture content in the sample.

Drying method: dry the sample to be tested at 105℃ to constant weight, and then dry at 60℃ and 100℃ for 2 hours respectively, so that the water in the sample can be completely evaporated. Finally, the sample is placed in a constant temperature and humidity environment with a relative humidity of no more than 80% to make the sample absorb water again. After weighing, calculate the moisture content in the sample.

Methanol spray method: dissolve the sample to be tested in methanol, and then spray the methanol solution to dryness to evaporate all the water in the sample. Then put the sample in a constant temperature and humidity environment with a relative humidity of no more than 80%, and let the sample absorb water again. Finally, weigh and calculate the moisture content in the sample.

The above are several common internal water detection methods, and the choice of different methods depends on the nature of the sample and the experimental conditions. It should be noted that standard methods should be followed and experimental conditions should be strictly controlled to ensure the accuracy and comparability of experimental results.