BS ISO 23978:2020 pdf free

BS ISO 23978:2020 pdf free.Natural gas一Upstream area一Determination of composition by Laser Raman spectroscopy
The laser shall have a narrow-enough line width with a stable-enough power output and wavelength so as not to compromise the generation and analysis of the Raman spectra. Laser power should be high-enough to ensure sufficient sensitivity.
一laser wavelength should be in the range of 500 nm to 800 nm, and a laser of wavelength 785 nm is generally suggested;
一laser wavelength stability, initially less than +0,005 nm, less than ±0,05 nm after 10 000 h of operation;
一laser poweris typically 0,5 W to 5,0 W dependingon Raman photoncollection and detection fficiency;
一Laser power stability, short term (seconds) ±0,5 % average power, less than 20 % after 10 000 h of operation.
The detection module should be capable of sufficient resolution, high throughput and stability.
Raman spectroscopy software is included as a part of the analyser to process the detector data and provide a user interface. Software should be able to indicate gases measured, calculate the gas concentrations, track key diagnostic factors such as temperatures, spectral intensity, and laser power, and maintain and check instrument calibration and drift.
Particulates and aerosols larger than 0,2 um should be removed by filtration prior to entering the detector. The filter housing and sample probe shall be made of a material which is inert, non-adsorptive and non-permeable to components in the gas sample, stainless steel is preferred.
For sulfur-containing natural gas, hydrogen sulfide corrosion resistant gas pressure regulators should be selected.
Regular calibration shall perform using working standard gas mixtures in accordance with ISO 6142-1, ISO 6144 or with ISO 6145. The working standard gas mixtures shall contain appropriate concentrations and cover the analytic range of the analyser. All components in the reference standard shall be homogenous in the vapour state at the time of use. The concentration of a component in the reference standard gas shall be close to the actual sample gas concentration, shall be less than relatively 20 % of the corresponding component in the test gas, the minimum concentration shall be greater than 0,02 %.BS ISO 23978 pdf download.