ASTM D4931 Standard Test Method for Gross Moisture in Green Petroleum Coke
4. Summary of Test Method
4.1 This test method is based on the loss in mass of a green petroleum coke sample in an air atmosphere under controlled conditions of temperature, time, and air flow.
4.1.1 Preparation Procedure shall be used when the petroleum coke sample contains free water. The gross moisture sample is weighed and air dried to equilibrate it with the atmosphere. Determination of residual moisture is that determined using the Drying Oven Method. Air drying and residual moisture losses are combined to report gross moisture.
4.1.2 Drying Oven Method shall be used in routine commercial practice when the sample does not contain free water. The sample is crushed to at least minus 25 mm (1 in.) top sieve size and divided into analytical portions of at least 500 g each. Determination of total gross moisture is calculated by summing the results of the Drying Oven Method and the results of the Preparation Procedure.
5. Significance and Use
5.1 Moisture adds weight to the coke and serves no useful purpose. A knowledge of the moisture content is important in the purchase and sale of green petroleum coke, both of which are conducted on a dry basis.
5.2 The collection of the sample as specified for the Drying Oven Method is intended for the express purpose of determining the total moisture of green petroleum coke. The standard is available to producers, sellers, and consumers for determination when other techniques or modifications are not mutually agreed on.
5.3 The Preparation Procedure is used only when sample contains free water. Obtaining a representative sample of a coke source is compounded by the presence of free water.
