GB/T 26982-2022 in English

Core changes in the standard revision

Technical points of method A

Key instrument configuration

It needs to be equipped with core equipment such as wax content tester (temperature control -20℃±1℃), glass adsorption column (see Figure 2), G3 sand core funnel, etc. Silica gel activation needs to be carried out at 180℃±10℃ for 6 hours.

Operational risk warning

• The asphaltene removal stage requires light-proof sedimentation for 16 hours
• The dewaxing solvent (acetone-toluene 2:1) needs to be pre-cooled to -20℃
• The flow rate is controlled at 5mL/min
during wax layer filtration

Innovation analysis of method B

Comparison of technical principles

The 250-550℃ fraction is obtained by reduced pressure distillation (0.133-0.266kPa), and ethanol-ether (2:1) mixed solvent is used for dewaxing to avoid the silica gel adsorption step.

Implementation Precautions

1. Water content＞0.1% must be dehydrated according to GB/T8929 first
2. The fraction must be kept in a molten state at 60-80℃ during transfer
3. The dewaxing solvent must be gradient filtered 3-4 times

Decision-making guide for comparing new and old methods

Standard implementation recommendations

Key points for quality control

• Regularly verify the temperature uniformity of the constant temperature bath (±1°C)
• The adsorption activity of each batch of silica gel needs to be measured before use
• The constant weight of wax crystals needs to be controlled under 110-120°C drying conditions

Result verification

When the wax content is greater than 6%, the reproducibility difference between method A and method B can reach 6.9%. It is recommended to compare the two methods for controversial samples.