NPL provides high-accuracy primary reference gas mixtures (PRGMs) for the analysis of a range of refinery gases (including syngas, coke oven gas, reformer gas and blast furnace gas). The preparation and analysis of these mixtures forms part of NPL's UKAS Calibration (ISO 17025) scope of accreditation.

A flyer detailing NPL's range of refinery gas standards is available for download ( PDF 2.4 MB).

Refinery gas PRGMs are typically used to calibrate gas chromatographs (GCs), enabling the composition of real refinery gases to be determined. This allows the user to calculate the carbon content and other physical parameters of the gas, thus ensuring compliance with carbon trading legislation.

A full list of accredited components, amount fraction ranges and best measurement capabilities in given in the table below. Mixtures are prepared to specific customer requirements and other components (such as hydrogen sulphide) and amount fractions are available on request.

Component	Amount Fraction Range (% mol/mol)	Best Measurement Capability* (% mol/mol)
Nitrogen	0.1 to 95	0.30 % relative + 0.002
Carbon monoxide	0.1 to 11	0.48 % relative + 0.0016
Carbon dioxide	0.3 to 8	0.48 % relative + 0.0016
Oxygen	0.2 to 2.5	0.78 % relative + 0.0005
Hydrogen	1 to 70	0.38 % relative + 0.0025
Helium	5 to 10	0.40 % relative + 0.03
Methane	1 to 85	0.33 % relative + 0.0015
Ethane	0.3 to 35	0.35 % relative + 0.001
Ethene	0.1 to 12	0.35 % relative + 0.0003
Ethyne	0.025 to 2	0.40 % relative + 0.00025
Propane	0.1 to 18	0.40 % relative + 0.0002
Propene	0.04 to 7.0	0.45 % relative + 0.0001
i-butane	0.1 to 4	0.40 % relative + 0.00025
n-butane	0.1 to 6	0.40 % relative + 0.00025
1-butene	0.015 to 1.55	0.45 % relative + 0.0002
i-butene	0.018 to 1.2	0.50 % relative + 0.0002
trans-2-butene	0.015 to 0.85	0.45 % relative + 0.00013
cis-2-butene	0.015 to 0.35	0.45 % relative + 0.00013
1,3-butadiene	0.01 to 0.65	0.55 % relative + 0.00015
i-pentane	0.05 to 0.8	0.45 % relative + 0.0002
n-pentane	0.05 to 0.8	0.45 % relative + 0.0002

* For example, to calculate the best measurement capability (BMC) for ethene at an amount fraction of 4.2% mol/mol:

BMC = [4.2 * (0.35/100)] + 0.0003 = 0.015 % mol/mol (i.e. a relative BMC of 0.357 %)

NPL also offers the certification of refinery gas standards and samples. Analysis is carried out using a validated six-column, three-detector GC system.

Related standards and services

In addition to its range of refinery gas standards, NPL also:

• Provides a range of natural gas standards and natural gas odorant standards
• Organises proficiency testing (PT) schemes to enable laboratories to achieve greater confidence in their analyses of natural gas and refinery gas composition
• Provides a range of LPG, LNG and other liquid hydrocarbon standard mixtures

Contact

Customer Service tel: +44 20 8943 8637
E-mail: gases_enquiries@npl.co.uk