ASTM D4931 Standard Test Method for Gross Moisture in Green Petroleum Coke
6. Apparatus
6.1 Ovens:
6.1.1 Air Drying Oven - A device for passing slightly heated air over the sample. The oven shall be capable of maintaining a temperature of 10 to 15°C (18 to 27°F) above ambient with a maximum oven temperature of 40°C (104°F) unless ambient temperature is above 40°C (104°F), in which case ambient temperature shall be used. Air changes are to be at the rate of 1 to 4/min. A typical oven is shown in Fig. 1.
6.1.2 Drying Oven (for residual moisture on minus 25-mm (1.0-in.) samples sieve USA standard - forced-air type). It shall be capable of maintaining a temperature of 105 +/- 5°C and so constructed that fresh air is introduced to all parts of the oven to ensure the removal of moisture-laden air. Air flow shall be maintained at sufficiently low velocity to prevent loss of fine particles, (for example, one exchange per minute).
6.2 Drying Pans:
6.2.1 Pans for the gross moisture sample (Preparation Procedure) shall be noncorroding, weight-stable at temperature used, and large enough so that the sample can be spread to a depth of not more than twice the diameter of the largest particles, or not more than 25 mm (1.0 in.) depth for smaller coke. The pan sides shall be 50 to 75 mm (2 to 3 in.) high.
6.2.2 Pans for crushed and divided sample shall be noncorroding, weight-stable at temperature used, and large enough so that the sample can be spread to depth of not more than 50 mm (2 in.). The sides shall be not more than 75 mm (3 in.) high.
6.3 Balances:
6.3.1 Balance (Gross Sample) - A balance with a minimum capacity of 10 kg and sensitive to 1 g.
6.3.2 Balance (Crushed Sample) - A balance with a minimum capacity of 4 or sufficient to weigh the pan, sample, and container and sensitive to 0.1 g.
6.4 Laboratory Sample Containers - Noncorroding cans with airtight, friction top or screw top sealed with a rubber gasket and pressure-sensitive tape for use in storage and transport of the laboratory sample. Glass containers, sealed with rubber gaskets, can be used, but care must be taken to avoid breakage in transport.
6.5 Sieves - Meeting Specification E11.
7. Sampling
7.1 The principles, terms, and procedures as set forth in Practice D2234/D2234M shall apply to the collection of the total moisture sample. Particular attention is directed to the section on Sampling Coal for Total Gross Moisture Determination.
7.2 Proceed with determination of moisture without unnecessary delay to minimize the loss (or gain) of moisture to air or the walls of the sample container. Visible condensation on the walls of the sample container indicates a moisture loss by the sample. Determine the moisture on the gross sample and include the sample container in the drying process adding the weight loss of the container to G (mass of sample) to determine the total moisture.
