GB/T 23801-2021Determination of fatty acid methyl ester (FAME) content in middle distillates—Infrared spectrometry (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document replaces GB/T 23801-2009 "Determination of Fatty Acid Methyl Ester Content in Middle Distillate Oil by Infrared Spectroscopy", and Compared with GB/T 23801-2009, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) Change "FAME volume fraction is about 1.7%~22.7%" in the range to. "FAME volume fraction is about 0.05%~ 50%" (see Chapter 1, Chapter 1 of the 2009 edition);

b) The normative reference documents GB/T 27867 and GB 25199-2017 were added, and the reference documents EN14103:2003 and

GB/T 20828 (see Chapter 2, Chapter 2 of the 2009 edition);

c) A chapter "Terms and Definitions" has been added (see Chapter 3);

d) Added and changed the method summary content (see Chapter 4, Chapter 3 of the 2009 edition);

e) The contents of reagents and materials have been changed (see Chapter 5, Chapter 4 of the 2009 edition);

f) The technical parameters of the infrared spectrometer and the content of the sample cell materials have been added and supplemented (see Chapter 6, Chapter 5 of the 2009 edition);

g) Part of the test procedure is detailed and supplemented (see Chapter 8, Chapter 7 of the 2009 edition);

h) The calculation content has been changed and added (see Chapter 9, Chapter 8 of the 2009 edition);

i) Added the content of the result presentation (see Chapter 10, Chapter 9 of the 2009 edition);

j) Re-specified precision (see Chapter 11, Chapter 10 of the 2009 edition);

k) An informative appendix "Optical path and dilution factor reference" has been added, and the diagram has been modified accordingly (see Appendix A).

1 Scope

This document describes a method for determining the volume fraction of fatty acid methyl esters (FAME) in middle distillates by infrared spectroscopy.

This document is applicable to the determination of FAME samples that meet the requirements of Appendix C of GB 25199-2017. Suitable for determination of FAME A sample of middle distillate oil with a volume fraction of 0.05% to 50%. For samples with FAME volume fraction exceeding 50%, it can also be used after dilution This method is used for determination, but its precision has not been investigated. If it contains interfering components such as esters and carbonyl-containing compounds, the result of the measurement may be On the high side.

Note: If the mass concentration (g/L) is converted into volume fraction, the density of FAME adopts a fixed value of 883.0kg/m³.

2 Normative references

The contents of the following documents constitute the indispensable clauses of this document through normative references in the text. Among them, dated quotations Only the version corresponding to that date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 4756 Manual sampling method for petroleum liquids

GB 25199-2017 B5 diesel

GB/T 27867 Petroleum liquid pipeline automatic sampling method

3 Terms and definitions

There are no terms and definitions that need to be defined in this document.

4 Method summary

Measure the infrared spectrum of the sample, if necessary, dilute the sample with a FAME-free solvent to a suitable concentration, and read 1745cm-1± The maximum absorbance value of the ester-based band in the range of 5cm-1, and the FAME content in the sample is calculated according to the established calibration curve. accessible The density of FAME (883.0kg/m³) converts mass concentration (g/L) into volume fraction (%).

Different measurement ranges and corresponding dilution multiples should be selected for the FAME concentration range of different samples. It is advisable to choose as far as possible without dilution The measurement method of receiving the sample, such as the sample in the range A adopts a long optical path sample cell or the sample in the range B adopts a short optical path sample cell. For To obtain good measurement precision, the lower the concentration of FAME in the sample, the more strict the measurement process needs to be controlled.

5 Reagents and materials

Unless otherwise specified, all chemical reagents used in the test have a purity of not less than 99%.