Increasingly, biomethane is being injected into national gas transmission networks along with natural gas. The quality of the biomethane, especially moisture content, is monitored to ensure that there is no risk to equipment or loss of calorific value down the line.
The gas is compressed and transported at pressures up to 70 barg. Monitoring the moisture content of the biomethane is essential to ensure that no liquid water condenses in the pipeline to avoid the risk of corrosion or ice formation.
This condensate can combine with other contaminants, such as Carbon Dioxide and/or Hydrogen Sulphide, to form acidic compounds which cause increased corrosion effects in downstream equipment. Drying the gas to a low dew-point greatly reduces formation of these corrosive compounds and increases the overall efficiency of the plant.
QCM technology for responsive moisture measurement in biomethane
A fast-responding moisture analyzer is needed for monitoring the moisture content of the biomethane prior to the point of compression. Quartz Crystal Microbalance technology is a good choice for this application because it is fast and responsive to changes in moisture content. Ideal for monitoring the stream of biomethane at the compressor station.
QCM analyzers are also a low-maintenance option, giving operators a low lifetime cost of ownership.
Self-calibration for additional reliability
The Michell QMA401 process moisture analyzer includes a self-calibration to ensure long-term reliability. The analyzer includes an internal moisture generator, which has a traceable calibration to NIST/NPL. The QMA401 uses this moisture generator as a reference against its own sensor and is able to readjust its measurements to guarantee long-term measurement stability.
