Overview

SpectraSensors moisture analysers have earned credibility as the standard of moisture measurement for a large number of natural gas companies, with over 900 successful installations around the world. Reliable results and strong correlation to traditional standards, as well as fast response, low maintenance for years of trustworthy service, and no consumables means the cost-of-ownership is a fraction of conventional moisture analysers.

The analyser employs tunable diode laser spectroscopy, the newest technology for moisture and other corrosives measurements. It is the fastest, most accurate, and most contamination-immune technology available. Its laser-precise sensor does not contact the gas or contaminants. As a result, the system is so stable that no recalibration is required on continuous basis. Better yet, the data will be more credible in a shut-in event. The wall-mount models are designed for high reliability in harsh weather and hazardous locations. Additionally, the portable unit is designed for fast hook-ups and battery operation.

Theory of operation

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SpectraSensors gas analysers utilise laser absorption spectroscopy to detect the presence of one or more gases in a mixture of background gases. A tunable diode laser emits near-infrared light at wavelengths absorbed by moisture or CO2 in natural gas. The IR light passes through the gas sample and is measured by a solid-state detector. As the laser wavelength is tuned across a water vapour or CO2 absorption line, energy is absorbed, reducing the amount of light arriving at the detector. The fraction of light that is absorbed is in direct proportion to the concentration of moisture or CO2. Because the laser is tuned across the line four times each second it can be used for fast and accurate measurements independent of contamination or laser intensity.

Features and benefits

The SpectraSensors sensor heads are immune to excess levels of moisture or chemicals, which translates into reliability, speed and virtually no maintenance cost, meaning there is a low cost of ownership.

The SpectraSensors technique also gives superior performance: hydrocarbons, as well as traces of contaminants like hydrogen sulphide and glycol may be present in natural gas. These gas components interfere with conventional sensors in unpredictable manners, but the SpectraSensors laser sensor does not make contact with the gas sample.

Also, the SS-Series Analysers supply continuous, 24/7, real time measurement with no wet-up or dry-down delays. The speed of response can be less than one second.

Leading natural gas companies rely on SpectraSensors analysers to quantify levels of moisture in pipelines in order to prevent catastrophic failures. The SpectraSensors analysers have been proven in harsh environments and have delivered fast, accurate and reliable data, making them a product with exceptional reliability.

Conclusion

The new laser-based moisture analyser from SpectraSensors provides a significant cost reduction for the user by reducing maintenance and operational costs. It eliminates the costs and downtime incurred by having to either return the analyser to the manufacturer for reconditioning/calibrations or having to store spare sensors on the shelf. Users will also experience an improvement in productivity of their measurement personnel using the analyser due to its ease of operation, quick response time and resistance to the vapour phase contaminates normally found in natural gas.

SpectraSensors Analysers have proven long-term reliability in the hundreds of installations around the world where they are the key ingredients to the assurance of reliable, accurate, real-time measurements.