GB/T 386-2021Standard test method for cetane number of diesel fuel oil (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 386-2010 "Determination of Diesel Cetane Number". Compared with GB/T 386-2010, except for structural adjustment and compilation In addition to the editorial changes, the main technical changes are as follows.

a) The term "quality control sample" has been added (see 3.6);

b) Amend the term "fire lag time table" to "cetane number table". Added the name and initial use of previous cetane number tables A description of the number of years (see 3.7, 3.2.1 of the 2010 edition);

c) Added the low cetane component pentamethylheptane as a substitute for heptamethylnonane (see 3.14);

d) "The difference between the cetane number of the two standard fuels is not more than 5.5 units" is changed to "the cetane number of the two standard fuels is not much different." At 5.6 units" (see 5.2, 4.2 of the 2010 edition);

e) Change the standard fuel "density value at 15.56°C" to "density value at 20°C" (see 7.3.2, 2010 edition 6.3.2);

f) Added Table 2 positive standard fuel technical indicators (see 8.3), Table 3 secondary standard fuel technical indicators (see 8.4) and Table 4 test fuels Technical indicators (see 8.5);

g) The calculation formula for the cetane number of the mixture of pentamethylheptane and n-hexadecane has been added (see 8.3.3);

h) The requirement for positive standard fuel storage conditions has been added (see 8.3.4);

i) The cetane numbers of T fuel and U fuel were revised to 73~76 and 19~22 respectively (see 8.4.1, 8.4.2, 7.4.1 of the 2010 edition) 7.4.2);

j) Amend "15°C above the cloud point of the fuel" to "14°C above the cloud point of the fuel" (see 8.4.3, 7.4.4 in the 2010 edition);

k) Added sub-standard fuel matching requirements (see 8.4.4);

l) Amend "Sample to be placed for at least a few hours" to "Sample to be placed for at least 2h" (see 9.2, 8.2 of the 2010 edition);

m) The requirements for the minimum temperature of the diesel fuel sample before measurement and filtration are clearly specified (see 9.2);

n) Deleted the description of valve clearance during shutdown and cold state (see 10.3.6, 9.3.6.1 of the 2010 edition);

o) Added content about optimizing gap settings for specific sensors (see 10.3.25);

p) Added related content about correcting engine conditions (see 11.2);

q) Added quality control and quality control tests (see 11.4);

r) Added the preparation method and requirements of the secondary standard fuel for the determination of high cetane number samples (see 12.8, 12.9);

s) Added the requirement that the difference between the cetane number corresponding to two consecutive sets of handwheel readings is not more than 1.4 units (see 12.10);

t) Added the handwheel reading determination sequence diagram of fuel in Figure 3 and Figure 4 (see 12.10);

u) The calculation method of the cetane number of samples whose cetane number is higher than the approved reference value of T fuel has been added (see 13.2.2);

v) Added the content of reporting standard fuels (see 14.2);

w) The description of the measurement deviation between the cetane number control board and the double-reading cetane number table has been added (see 15.2.2).

Introduction

The cetane number is a measure of the ignition properties of diesel in a compression ignition engine. It is carried out at a constant speed in a compression ignition test engine.

Determination. Cetane number is widely used in the petrochemical industry, refineries, distributors, and engine production plants, as a fuel and engine corresponding The main indicators are measured.

The correlation between the performance of the test engine and the engine with full scale, variable speed, and variable load is not yet fully understood. This file is available It is used for the quantitative determination of cetane number of unconventional fuels, such as synthetic fuels, vegetable oils and similar products. When measuring unconventional fuels, The relevance of the nature of this oil in the engine is not fully understood.

Determination of Cetane Number of Diesel Fuel Warning---Personnel using this document should have practical experience in formal laboratory work. The use of this document may involve certain dangerous This document does not point out all safety issues. The user is responsible for taking appropriate safety, health and environmental protection measures And ensure compliance with the conditions stipulated by relevant national laws and regulations. See Appendix A for the content of safety warnings.

1 Scope

This document describes the test method for determining the cetane number of diesel fuel with a cetane number tester. The sample is under specific operating conditions by a The standard single-cylinder, four-stroke, variable compression ratio, intermittent injection diesel engine was tested.

This document is applicable to the quantitative determination of the cetane number of compression ignition engine fuel. The cetane number ranges from 0 to 100, but a typical test The range is 30~65.

This document is also applicable to the quantitative determination of cetane number of unconventional fuels, such as synthetic fuels, vegetable oils and similar products.

Note: This document adopts the [SI] International System of Units, with English units in parentheses as a reference.

2 Normative references

The content of the following documents constitutes an indispensable clause 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) applies to this document.

GB/T 265 Petroleum products kinematic viscosity determination method and dynamic viscosity calculation method

GB/T 4756 Manual sampling method for petroleum liquids

GB/T 6682-2008 Analytical laboratory water specifications and test methods

GB/T 6986 Determination of Cloud Point of Petroleum Products

GB/T 27867 Petroleum liquid pipeline automatic sampling method

SH/T 0176 Jet fuel peroxide value determination method

3 Terms and definitions

The following terms and definitions apply to this document.