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D4931-23 – Standard Test Method Technical Guide
The ASTM D4931-23 standard outlines a reliable test method for measuring gross moisture in green petroleum coke, incorporating procedures for sample preparation and moisture determination under controlled conditions. This method is crucial for quality control in the petroleum coke industry.
📊 Overview and Scope of D4931-23
This test method addresses both the preparation procedure for samples containing free water, known as air drying loss (ADL), and the determination of gross moisture content. The values are reported in SI units, which are considered standard, while values in parentheses are for informational purposes. The standard emphasizes that it does not cover all safety concerns, and users are responsible for establishing appropriate safety and health practices. Additionally, this international standard aligns with WTO principles.
⚙️ Test Procedures and Conditions
The test method comprises two key procedures: the Preparation Procedure and the Drying Oven Method. The Preparation Procedure is employed when the sample contains free water. It involves determining the gross moisture sample mass, air drying it to equilibrate with the atmosphere, and then measuring residual moisture using the Drying Oven Method. The air drying and residual moisture losses are combined to report gross moisture.
The Drying Oven Method is used in routine commercial practice when no free water is present. The sample is crushed to a top sieve size of minus 25 mm (1 in.) and divided into analytical portions of at least 500 g each. The total gross moisture is calculated by summing the results from the Drying Oven Method and the Preparation Procedure, if applicable.
| 🟦 Parameter | 📏 Specification |
|---|---|
| Sample Top Sieve Size | Minus 25 mm (1 in.) |
| Analysis Portion Mass | At least 500 g each |
| Drying Atmosphere | Air |
| Controlled Conditions | Temperature, time, and air flow per D3302 |
💡 Tip: The Preparation Procedure is essential for samples with free water to ensure accurate gross moisture results by accounting for air drying loss.
📏 Essential Terminology and Definitions
Gross Moisture: The loss in mass in an air atmosphere under rigidly controlled conditions of temperature, time, and air flow, as prescribed by Test Method D3302. It is synonymous with total moisture.
Free Water: Visible unbound water present in the sample.
Air Drying: A process of partial drying to bring the green petroleum coke sample to near equilibrium with the atmosphere in the room where further reduction or division takes place.
Air Dry Loss (ADL): The loss in mass, expressed as a percentage, resulting from each air drying operation.
Green Petroleum Coke: Solid carbonaceous residue produced by thermal decomposition of heavy petroleum fractions or cracked stocks, also known as raw petroleum coke.
Residual Moisture: The moisture remaining in the sample after air drying.
Total Moisture: Synonym for gross moisture.
⚠️ Warning: Users must adhere to regulatory limitations and establish safety practices when handling green petroleum coke samples.
❓ Frequently Asked Questions
🔍 What is gross moisture in green petroleum coke?
Gross moisture is the loss in mass determined in an air atmosphere under controlled conditions of temperature, time, and air flow, as per Test Method D3302.
💡 When is the Preparation Procedure required?
The Preparation Procedure is required when the green petroleum coke sample contains free water.
⚡ How is gross moisture calculated?
Gross moisture is calculated by combining the air drying loss from the Preparation Procedure and the residual moisture from the Drying Oven Method.
📌 What is the difference between free water and residual moisture?
Free water is visible unbound water in the sample, while residual moisture is the moisture remaining after air drying.