Testing the wettability of structured packing is essential for evaluating its mass transfer efficiency in chemical separation processes. The experimental steps involve sample preparation, contact angle measurement under controlled conditions, and data analysis to quantify surface interaction with process fluids, directly impacting separation performance.
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Detailed Experimental Protocol
To ensure accurate results, follow these steps:
1. Sample Preparation: Select representative packing samples (e.g., metal孔板波纹填料, plastic网孔填料) and cut into 10mm×10mm pieces. Clean with ethanol and deionized water, then dry under vacuum at 60°C to remove surface contaminants.
2. Contact Angle Measurement: Use a high-speed contact angle meter (e.g., Krüss DSA100) with a video recording system. Drop 2-3 μL of test liquid (distilled water, n-hexadecane, or process solvent) onto the packing surface. Capture 5-10 images per sample, measure contact angles via axisymmetric drop shape analysis (ADSA), and calculate the average value.
3. Experimental Conditions: Maintain temperature at 25±1°C, humidity <50%, and avoid air currents. Repeat measurements for 3-5 samples to ensure reproducibility (RSD <5%).
Structured packing, such as metal孔板波纹填料 (350Y, 500Y) or plastic网孔填料 (PVC, PP), is widely used in distillation columns and absorption towers due to its high specific surface area (200-1000 m²/m³). Poor wettability (e.g., hydrophobic surfaces) causes uneven fluid distribution, reducing mass transfer coefficients by 15-30%. By testing wettability, engineers can optimize packing design (e.g., hydrophilic coatings) or process parameters to ensure uniform phase contact, maximizing efficiency in refineries and petrochemical plants.
Q1: Why is wettability critical for structured packing? A: It determines fluid spreading; poor wetting leads to channeling and reduced mass transfer efficiency by 20-40%.
Q2: What liquids are typically used in testing? A: Distilled water (hydrophilicity) and n-hexadecane (hydrophobicity), or process solvents for realistic simulation.
Q3: How to ensure data accuracy? A: Use fresh samples, calibrate the contact angle meter daily, and repeat measurements (RSD <5%).
