Gas analyzers for LNG processing, biogas and biomethane upgrades

At the petrol pump, the fuels are accurately metered to ensure that you get the amount of fuel that you pay for. Thinking on behalf of the oil company, they deliver the right amount of fuel for the money they receive. Precise measurement makes sense for both parties. The same can be said for LNG metering.

The monthly value of Asia’s LNG imports is regularly more than US$10 billion. With such vast sums of money changing hands, the importance of accurate metering of the LNG is clear. The gas analyzers used in this application are process gas chromatographs which measure the heating value of the LNG as it is transferred from the production stations to LNG tankers. But these are not delicate laboratory instruments, they are rugged and robust devices capable of withstanding harsh environmental conditions.

This is not the highly controlled laboratory environment of bench-mounted gas chromatographs, it’s the high seas. The ABB NGC8200 series of process gas chromatographs can withstand ambient temperatures from -18 °C to +55 °C. Furthermore, with Class 1, Division 1 explosion-proof rating, they are suitable for LNG tanker and FLNG applications.

When it comes to accuracy, modern process GC’s can match many of their laboratory-based cousins. The requirement for a Class A device is an accuracy of plus or minus 0.5% and the accuracy of the NGC8200 series can be 0.1% which surpasses these requirements by a factor of 5. Measurement accuracy is a big deal – every cent counts when trading these precious natural resources.

Bio-reactors consuming energy crops such as maize or grass, food processing waste such as pineapple husks or domestic sewage produce ‘bio-gas’. This is a crude mixture of methane, carbon dioxide and other gases such as hydrogen sulphide or carbonyl sulphide. Upgrading of biogas to biomethane requires a range of gas analysis for which products such as the Uras26 and PGC1000 are ideal. In addition to using these facilities for methane production for natural gas grid injection or electrical power generation, they are also now being used as sources of carbon dioxide for food processing, beverage dispense and industrial applications in water treatment and manufacturing.

Uras26 – NDIR (non-dispersive infrared) analyzer configurable to a range of gases including carbon monoxide, carbon dioxide, methane and other light hydrocarbons. Typical applications include biogas to biomethane process control and quality assurance.

Caldos27 – TCD (thermal conductivity detector) analyzer for permanent gases including nitrogen. Typical applications include LNG process stream analysis.

Fidas24 – FID (flame ionisation detector) analyzer for total hydrocarbon analysis. Also available with a cutter for total non-methane hydrocarbons. Typical applications include hydrocarbon measurement in biogas and biomethane. Also used for online indication of natural gas stream composition.

PGC1000 series – rapid response process gas chromatograph for mixed gas stream analysis. Typical applications include calorific value (BTU) determination of natural gas, biomethane and biogas.

PGC5000 series – highly flexible and robust process gas chromatograph for gas and liquid stream analysis.Typical applications include full compositional analysis of natural gas, biogas and biomethane streams. Can also be applied to a wide range of process and safety applications in the downstream hydrocarbon processing and chemicals sectors where natural gas is further processed, for example methanol, syngas, hydrogen and ammonia production.

NGC8200 series – purpose built range of high precision process GCs for natural gas composition and energy value analysis.  Especially suited to custody transfer and product metering applications. Ensures accurate invoicing and fair value exchange for traded LNG.

RVP4500 series – accurately measures Reid Vapor Pressure throughout the gasoline range and its feedstocks from 0-20 psi to 0-225 psi. Often used to measure the vapor pressure of the condensate in LNG plants.