ISO 2613-2:2023 天然ガスの分析 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 193, Natural gas, Subcommittee SC 1, Analysis of natural gas, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 408, Natural gas and biomethane for use in transport and biomethane for injection in the natural gas grid, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

A list of all parts in the ISO 2613 series can be found on the ISO website.

Introduction

This document describes a method for the determination of the siloxane content of biomethane that is applicable to both laboratory and online analyses.

Siloxanes are a common contaminant in biogas, caused by their extensive use in common household products such as cosmetics and detergents. These products eventually become entrained in waste streams that are used to generate biogas. Additionally, siloxanes are sometimes added to digesters as anti-foaming agents to improve generation efficiency.

If not effectively removed, siloxanes can cause damage to gas processing and vehicle injection equipment through formation of silica deposits at high temperatures. Many gas distributors require measurement reports to demonstrate that the resultant biomethane conforms with their requirements, which typically includes siloxane content due to its potential to cause damage. Additionally, producers may wish to monitor siloxane content for process optimisation purposes.

The technique described in this document is commercially available and tailored specifically to measuring siloxanes within biomethane at low concentrations (for instance, as specified in EN 16723-1^[10] and EN 16723-2^[11]). It is suitable for use both in the laboratory and field.

1 Scope

This document describes a gas chromatography – ion mobility spectroscopy (GC-IMS) method for the determination of the concentration of siloxanes in biomethane. The method is applicable to the following siloxanes:

• hexamethyldisiloxane (L2);
• octamethyltrisiloxane (L3);
• decamethyltetrasiloxane (L4);
• dodecamethylpentasiloxane (L5);
• hexamethylcyclotrisiloxane (D3);
• octamethylcyclotetrasiloxane (D4);
• decamethylcyclopentasiloxane (D5);
• dodecamethylcyclohexasiloxane (D6).

This document describes suitable calibration and measurement strategies to quantify siloxanes in (bio)methane around and above the 0,3 mg m^-3 (14 µmol mol^-1) level and applies to analyses within absolute pressure ranges of 1 bar – 2 bar ¹ , temperatures of 0 °C – 40 °C and relative humidity < 90 %.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC Guide 98-3, ISO 7504, ISO 14532 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

Bibliography