Attention should be paid to the determination of the yield of volatile matter in coal

What should be paid attention to when measuring the volatile matter yield of coal?

In order to obtain the volatile results available, we must pay attention to the following issues:

1. The measurement temperature should be strictly controlled at 900 ± 10 ℃.

(1) Regularly calibrate the thermocouple and the millivoltmeter. When calibrating and using the thermocouple, the cold end of the thermocouple should be put in ice water or the zero point should be adjusted to room temperature, or a cold junction compensator should be used;

(2) Periodically measure the constant temperature zone of the muffle furnace. The crucible with coal samples must be placed in the constant temperature zone of the muffle furnace.

2. After the crucible containing the coal sample is put into the muffle furnace, the furnace temperature should be restored to 900 ± 10 ℃ within 3min.

(1) The muffle furnace should always verify whether its temperature recovery speed meets the requirements, or it should be manually controlled to ensure that it meets the above requirements;

(2) It is best to put the same number of crucibles in each test to ensure that the heat capacity of the crucible and its support are basically the same.

Third, the total heating time (including temperature recovery time) should be strictly controlled at 7min .;

4. To use a crucible that complies with GB211, the lid of the crucible must be tightly fitted.

5. A crucible holder made of heat-resistant metal shall not peel off when heated. If it is on the crucible, it will affect the measurement result.

6. After the crucible is taken out of the muffle furnace, the cooling time in the air should not be too long to prevent the slag from absorbing water