Summary
Liquefied natural gas (LNG) producers, terminal operators and custody transfer stakeholders require accurate, reliable composition measurement to support energy calculations, product quality verification and commercial transactions. Because LNG is stored and transported at approximately -260 °F (-162 °C), traditional analysis methods typically require the liquid sample to be vaporized before measurement. This adds complexity, maintenance requirements and potential measurement uncertainty.
The benefits:
By measuring LNG composition directly in the liquid phase, Endress+Hauser Raman spectroscopy helps operators simplify analytical infrastructure, reduce maintenance requirements and improve measurement reliability. Eliminating the vaporizer reduces system complexity and removes a major potential source of uncertainty in traditional LNG analysis.
The faster response time of Raman analyzers can provide improved visibility during dynamic operations such as loading, unloading and bunkering. With minimal stabilization time, measurement can resume quickly when flow returns, helping operators maintain more consistent composition data during start-stop processes.
The technology also supports continuous measurement of LNG components used to calculate heating value, density and Wobbe Index, giving stakeholders the data needed for custody transfer, product quality verification and operational decision-making.
With no vaporizer required, faster cycle times, reduced maintenance needs and proven applicability in LNG measurement, Endress+Hauser Raman spectroscopy offers a practical solution for improving the reliability and efficiency of LNG composition analysis.
What is Raman spectroscopy?
Raman spectroscopy is a process analytical technology (PAT) that uses laser light to measure the molecular composition of a sample in real time. By generating a unique molecular fingerprint for each substance, Raman analyzers provide continuous insight into product quality, composition and process performance directly within the manufacturing process.
What equipment is needed for Raman analysis?
A complete Raman solution consists of a probe, analyzer (spectrometer), control software and chemometric data models. The right spectrometer is selected by considering the process environment, sample type (liquid, solid, gas or slurry), installation method, regulatory requirements and the specific process variables that need to be measured in real time.
The challenge:
LNG is composed primarily of methane, with smaller amounts of ethane, propane, butane, pentane and nitrogen. Its composition directly impacts heating value, density, Wobbe Index and overall commercial value, making accurate methane and hydrocarbon measurement essential for custody transfer and quality control.
As global LNG demand has increased, the United States has become the world’s leading LNG exporter, with large export terminals along the Gulf Coast supplying customers across Europe, Asia and South America. This growth has increased the need for dependable analytical technologies that can support custody transfer, product quality and operational efficiency.
Conventional LNG analysis often relies on vaporizer and gas chromatograph systems. Before entering a gas chromatograph, the LNG sample must be converted from liquid to gas. This vaporization step can increase system complexity, introduce additional maintenance requirements and become a significant source of measurement uncertainty.
For operations such as LNG loading, unloading, truck loading and bunkering, frequent process starts and stops can create additional challenges. Analytical systems must respond quickly, stabilize efficiently and deliver reliable composition data without excessive sample conditioning or manual intervention.
Our solution:
Endress+Hauser Raman spectroscopy uses a laser to interact with molecules and measure. Each molecule produces a distinct spectral fingerprint, allowing the analyzer to identify and quantify components within the process stream. In LNG applications, Raman technology can measure methane and other LNG components in real time and provide composition data that can be used to calculate key values such as heating value, density and Wobbe Index.
Unlike traditional systems that require vaporization before analysis, Endress+Hauser Raman technology measures LNG directly in the liquid phase. A cryogenic Raman probe can be installed in the LNG process pipeline or fast loop, enabling continuous in-situ measurement without a vaporizer, sample transport system, carrier gases or extensive sample conditioning equipment.
This direct measurement approach helps reduce installation complexity and removes many common sources of measurement error. Because the analyzer remains connected to the process, it can provide continuous composition measurements with faster response to changing process conditions.
Endress+Hauser Raman analyzers are designed for continuous process measurement and can support demanding natural gas and LNG applications, including custody transfer and LNG bunkering. The technology offers a smaller footprint and simplified operation compared with conventional vaporizer and gas chromatograph systems.
