BS ISO 23978:2020 pdf free.Natural gas — Upstream area — Determinationof composition by Laser Raman spectroscopy.
This document describes a laser Raman spectroscopy method for the quantitative determination ofchemical composition of natural gas in upstream area.
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document(including any amendments) applies.ISO 6142-1,Gas analysis – Preparation of calibration gas mixtures — Part 1: Gravimetric method for Class I mixtures.
ISO 6144,Gas analysis —Preparation of calibration gas mixtures —Static volumetric methodISO 6145,Gas analysis —Preparation of calibration gas mixtures using dynamic methodsISO 10715, Natural gas — Sampling guidelines.
ISO 11095, Linear calibration using reference materials.
sFor the purposes of this document, the following terms and definitions apply.
Raman effect:process,in which photons from a light source are absorbed by the electrons surrounding polyatomicmolecules and result in a new photons being emitted at wavelengths higher or lower than the sourcephoton wavelength
Note 1 to entry: The resulting wavelength changes are called Raman shifts. The Raman shifts are determined bythe vibrational and rotational frequencies of the atomic bonds within each molecule.multichannel photodetector:photosensitive semiconductor device that transports electric charge from one capacitor to another,allowing serial output of parallel data, typically used for digital image capture.
The type of Raman gas analyser is selected according to the types of gases and the natural gasconcentration ranges of interest. The base analyser unit contains a laser,optical path control, gasdetection chamber, photon detection and processing, signal processing,and human/machine interface.The analyser should have sensitivity sufficient to detect the components in the analytical range givenin Table i. It should keep a stable state after zero calibration.The laser shall have a narrow-enough line width with a stable-enough power output and wavelength soas not to compromise the generation and analysis of the Raman spectra. Laser power should be highenough to ensure sufficient sensitivity.BS ISO 23978 pdf free.