National Physical Laboratory

Ensuring safe natural gas transportation

New automatic monitoring technique prevents the liquefaction of natural gas in transportation pipelines.

Automatic hydrocarbon dewpoint monitor
Automatic hydrocarbon dewpoint monitor

The Challenge

Natural gas is a complex mixture of hydrocarbons and other species (nitrogen, carbon dioxide etc). The main components are usually methane and ethane but also with a proportion of higher hydrocarbon (C6+) species. The gas is extracted from the ground and transported by pipeline to where it will be used. Depending on the pressure, temperature and composition of the gas, hydrocarbon liquids may separate out in the pipeline. The point at which this occurs is known as the hydrocarbon dewpoint.

This can lead to problems such as monitoring meters filling with liquid or damage to components, and in the worse case, pipeline shutdown. As gas valued at £1.5 million is transported through the UK network each hour, any shut down can have serious financial consequences.

The Solution

To avoid liquefaction, gas transmission companies such as National Grid (formerly Transco) manually monitor the hydrocarbon dewpoint at strategic locations across the UK pipeline network using a manual 'chilled mirror' technique.

Now two UK SMEs, Michell Instruments Ltd and EffecTech Ltd, have developed innovative automatic methods based on different techniques that allow dewpoints to be monitored remotely. The SMEs teamed up with NPL under a Joint Industry Project to undertake a rigorous comparison of the methods.

The Impact

In general, very good agreement was found between the two techniques which will be of significant benefit to the partners, allowing them to achieve an increased market share for their products. National Grid will gain from the highest level of accuracy in dewpoint measurement, helping to ensure the safe and cost effective transport of gas through the UK pipeline network and thereby benefiting UK public and industry. The project has also given rise to further collaborative intercomparison work and development of best practice in natural gas analysis.

"The project demonstrates the superiority of the innovative, automated measurement techniques over manual methods of determination"
Dr Nick Bates, National Grid

Find out more about NPL's research in Analytical Science

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Last Updated: 8 Oct 2012
Created: 28 Oct 2010


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