ASTM D2638 Test Method for Real Density of Calcined Petroleum Coke by Helium Pycnometer
10. Procedure
10.1 Place 5 g to 150 g (80 % to 90 % of the maximum capacity of the particular holder being used) of the prepared crushed, sized and dried test sample into the specimen holder provided with the instrument. Weigh to the nearest milligram.
10.2 Place the pre-weighed test sample and specimen holder into the sample chamber and evacuate.
10.3 Connect, either manually or automatically, the control chamber, containing helium at a higher pressure than the sample chamber, with the sample chamber. Determine the final equilibrated pressure.
10.4 The volume of the calcined petroleum coke sample is calculated from the known volume of the two chambers, the absolute pressures in each chamber prior to connection and the final pressure after the chambers have been connected.
10.5 Record the final sample volume or density when the pycnometer has reached equilibrium.
NOTE 2 - This is a generic procedure which describes the basic steps involved to obtain a final result. For further specific details, the manufacturers' operating instructions 3 are to be reviewed.
11. Calculation
11.1 Determine the real density of the sample in g/cm3 from Eq 1.
Density = M/V
where:
M = mass of sample in g, and
V = volume of helium displaced, cm3.
