Instruments and equipment:
1. Crucible of volatilization Height 40 mm, inner diameter of upper opening:30 mm, external diameter:33 mm, external diameter of bottomr:18 mm, external diameter of cover:35 mm, slot external diameter is 29mm and the external slot depth:4 mm, total weight:15 to 19 g.
2. A stopwatch.
3. The muffle furnace: The temperature can be kept at 900±10℃ and enough constant temperature zone (900 + 5 ℃) is available.
4. Crucible support: Made of nichrome wire or other heat resistant metal.
5. Crucible support clamp:
6. Electronic balance: Sensitivity of 0.0001 g.
Methods of measurement
1.Use the cupel that has been burnt under 900℃ that has been burnt to mass constant cupel, to weigh the air dried 1± 0.01g coal samples with particle size under 0.2 mm, with accuracy of 0.0002 g, and then slightly vibrate the cupel to flat the coal samples, and then cover the coal samples with cover , and put it on the cupel shelf.
2. (Take the cupel from the furnace and put it  in the air for cooling for about  5 minutes, then move it into the dryer for cooling (about 20 min), then weight it.
3. The results of calculation:
                       m1    
        Vad=                   ×100－Mad
                        m 
Vad -volatile yield of  air dried-basis coal sample, %
m1 - mass reduced of coal sample after being heated, g.
m - the mass of the coal sample, g
Mad -moisture content of air dried coal sample, %.

4.Precision of volatile measurement    

The repeatability of volatile measurement is shown in the table