GB/T 2539-2023 (English Version)

Standard No.: GB/T 2539-2023
Language: Chinese, Available in English version
Release Date: 2023
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 2539-2023
Replace: GB/T 2539-2008

Scope: This document describes the method for determining the melting point of petroleum wax by the cooling curve method. This document is applicable to the determination of the melting point of solid petroleum wax at room temperature, but not to the determination of the melting point of petroleum grease, microcrystalline wax, and the mixture of petroleum grease, microcrystalline wax and paraffin or crude paraffin.

Introduction

1. Background and significance of the standard revision

GB/T 2539-2023 is a comprehensive update of the original standard GB/T2539-2008, mainly focusing on the cooling curve method for the determination of the melting point of petroleum wax. The new standard adds requirements for automatic instruments and improves quality control and precision indicators to meet the needs of modern petroleum product testing.

2. Comparison of standard frameworks

Standard content	GB/T2539—2008	GB/T2539—2023
Scope of application	Not specifying specific types of petroleum wax	Clearly stipulates the applicability of paraffin and other types of petroleum wax
Measurement principle	Only mentions the cooling curve method	Increases result calculation content and improves the definition of stagnation period
Instrument requirements	Not specifying automatic equipment in detail	Adds technical parameters and performance requirements for automatic instruments

3. Explanation of professional terms and practical applications

Petroleum wax melting point: refers to the temperature at which the first stagnation period appears on the cooling curve when the melted petroleum wax is cooled under specified conditions.

Cooling curve method: A method of determining the melting point by recording the temperature change during the cooling process of the sample and observing its stagnation period.

For example, in practical applications, when using an automatic melting point tester, the instrument will automatically collect and analyze temperature data and calculate the melting point result with an accuracy of up to 0.01°C.

4. Analysis of the Evolution of Standard Technology

The new standard reflects technological progress in the following aspects:

Added automatic instrument content: Clarified the specific requirements for the measurement range, resolution and control system of the automatic melting point tester.
Improved the quality control system: Introduced a regular calibration mechanism to ensure the long-term stability and accuracy of the equipment.
Refined the precision indicators: Set repeatability and reproducibility standards for manual instruments and automatic instruments (0.10°C and 0.50°C, respectively).

GB/T 2539-2023 Referenced Document

GB/T 27867 Petroleum liquid.Automatic pipeline sampling
GB/T 4756 Method for manual sampling of petroleum liquids
GB/T 514 Specification for liquid-in-glass thermometers for testing of petroleum products
SH/T 0229 Methods of Sampling Solid and Semi-Solid Petroleum Products

GB/T 2539-2023 history

2023 GB/T 2539-2023 Determination of melting point of petroleum wax by cooling curve method
2008 GB/T 2539-2008 Petroleum waxes. Determination of melting point. Cooling curve method
1981 GB/T 2539-1981 Paraffins--Determination of melting point(cooling curve)