The solvent distillates and carries the water along with it as a vapor mixture.
| Method | Water Range | Advantages | Disadvantages | |---|---|---|---| | | 0–25% | Direct measurement, no calibration required, works with colored/dark samples | Takes 60–110 minutes, requires large samples, uses hazardous solvents | | Karl Fischer (KF) Titration | ppm to 100% | High accuracy, fast (<10 minutes), small samples, widely automated | Requires calibration, expensive reagents, affected by certain compounds | | ASTM D1796 (Centrifuge) | 0–30% | Simple, quick, low cost | Less precise for low water content, difficult with heavy oils | | Hot Plate Crackle Test | Qualitative only | Extremely simple, no equipment | Not quantitative, cannot detect dissolved water |
: During the sale and transport of crude oil and bitumen, accurate water measurement ensures that buyers only pay for the actual product, not the water mixed in. Refining Safety
Read the volume of the accumulated water layer at the bottom of the graduated trap directly from the meniscus. 📊 Calculating the Results
The water content is calculated using the following formula:\textWater Content (%) = \frac(\textVolume of Water in Trap - \textWater in Solvent Blank) \times 100\textSample Volume or Weight Astm D95 Pdf
If the cooling water is too warm, water vapor escapes out of the top of the apparatus, resulting in underestimated water content.
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Typically a glass round-bottom or short-neck flask ranging from 500 mL to 1000 mL in capacity, or a metal still for bituminous materials. The solvent distillates and carries the water along
: The vapors rise into a reflux condenser, where they are cooled and liquefied. Separation
A water-cooled glass reflux condenser (usually a straight-tube or Liebeg type) is placed vertically on top of the trap to ensure all vapors return to liquid form. 4. Step-by-Step Test Procedure
Whether you need help in your current distillation setup
: Excessive water can cause "mayonnaise effects" (emulsions) or damage equipment during processing. 📊 Calculating the Results The water content is
Continue distillation until no more water is visible in any part of the apparatus except the bottom of the trap.
Crude oil is sold by volume; however, water content (often referred to as Basic Sediment and Water, or BS&W) is an impurity. Buyers utilize ASTM D95 to ensure they are paying for oil, not water.
Add an equal volume of the selected carrier solvent (e.g., 100 mL of xylene) into the flask. Throw in a few boiling chips or anti-bumping granules to ensure smooth, even boiling. 3. Assembly and Heating