Analytical measurements for natural gas processing

One of the first steps in a natural gas treatment plant is the reduction of acid gas components.

Raw natural gas is a complex mixture of methane (CH₄), hydrocarbon condensates (natural gas liquids – NGLs), water, and contaminants; hydrogen sulfide (H₂S), and carbon dioxide (CO₂).

Reliable solutions that help to efficiently control the process of separating methane from other hydrocarbons, water and contaminants are indispensable. Monitoring contaminants is particularly critical for process optimisation and gas quality.

But how do you most effectively monitor H₂O, H₂S, CO₂, and O₂ in natural gas?

Traditional approaches

• Lead acetate tape analysers work but have high maintenance requirements to replace and dispose of the tapes in an environmentally safe manner
• On-line gas chromatographs take 3 – 6 minutes between measurement updates and do not sense rapid changes. High OPEX due to consumption of carrier gas and flame fuel cylinder gases
• Broadband UV light sources and narrow band pass filters are prone to interference from changing background concentration

Gas processing made easy

High resolution Tunable Diode Laser Absorption Spectroscopy (TDLAS) analysers from SpectraSensors, an Endress+Hauser company, provide significant advantages over other technologies for monitoring H₂O, H₂S, and CO₂ in natural gas and NGLs.

• Eliminate errors due to interference encountered with other spectroscopic techniques
• Exceptionally fast response
• No field calibration/ re-calibration required
• Low cost of ownership - no consumable items needed

Example natural gas processing applications

On-line monitoring of H₂S and CO₂ in Gas Sweetening: Measure acid gas concentration at the inlet and outlet of an amine treatment unit to help optimise the performance of this module. TDLAS analysers have fast response to H₂S and CO₂ concentration changes.

On-line monitoring of trace-level H₂O: Detect adsorbent bed saturation and breakthrough to enable highly effective control of molecular sieve dehydration systems. Laser-based measurement is highly selective and accurate for H₂O in natural gas.

Find out more about how Endress+Hauser can make gas processing easy.

Take a look at two specific application notes: H₂S in amine treatment unit outlet and CO₂ in amine treatment unit outlet.