Swiss-based mass flowmeter (MFM) manufacturer Endress+Hauser Group shared with Singapore-based bunkering publication on its new bunker metering system for liquefied natural gas (LNG):
Every day, large quantities of hydrocarbons are transported, stored, treated, received, and finally sold to a wide variety of consumers in the marine industry. Bunker metering solutions ensure that the amount of hydrocarbons transferred is measured with the highest possible accuracy. At the same time, the use of LNG as a marine fuel has been increasing in recent years, especially since ship owners and operators are striving to comply with the latest emissions reduction regulations set by the IMO and EU. As a sulphur-free fuel, LNG is a cleaner alternative to traditional fossil fuels.
Standardised LNG bunker metering solution
The infrastructure for LNG bunkering is still developing, but it is growing rapidly as more ports and shipping companies adopt LNG as a marine fuel. Endress+Hauser now offers a standardised LNG bunker metering solution to provide the most accurate real-time metering of LNG transfers. This is supplemented by a variety of options to meet the needs of bunkering operations, maritime operators, and ship builders. The package consists of Proline Promass Coriolis MFMs (mass flowmeters), temperature and pressure sensors, Raman optical analyzers for LNG composition analysis and a regulatory-compliant monitoring system. It guarantees accurate metering of LNG and boil-off-gas (BOG) under cryogenic conditions.
When bunkering with LNG, determining its energy content poses a challenge due to the handling of cryogenic fluids at extremely low temperatures of –160 °C (–256 °F). In addition, the LNG composition often varies due to mixing from different sources and ageing under storage conditions. Providing reliable measurement of the quality of the material transferred is an essential component in the LNG bunker delivery transaction. It is also essential for maintaining safe marine operations.
Analysis in situ and in real time
Gas chromatography (GC) has typically been used to measure the composition of LNG. However, gas chromatographs require that LNG be vaporised and the gas pressure regulated prior to analysis. Vaporizers normally demand frequent downtimes for maintenance to avoid incomplete vaporisation or pre-vaporization. The new solution from Endress+Hauser provides equivalent LNG measurement accuracy with significantly lower operating costs and requires less technical expertise. Furthermore, it has by far the smallest footprint compared to traditional systems. In addition, it is the only one on the market today that can analyse LNG in situ and in real time with our patented Raman technology.
Powerful process analytical tools
Raman spectroscopy not only reduces the complexity of the LNG monitoring system and has faster start-up stabilisation times, but it proves to be more repeatable, responds more quickly to process changes and requires no maintenance throughout the assessment period. It uses a laser to produce light at visible or near-infrared wavelengths and a Raman analyzer looks for specific wavelengths and intensities to create a chemical profile of the sample. The combination of a Raman Rxn-41 probe and a Raman Rxn4 analyzer results in a powerful process analytical tool for real-time composition analysis of LNG and mixed refrigerants, using quantitative Raman spectral analysis.
The Raman Rxn4 analyzer is essentially immune to LNG flow variations and configurable with up to four probes for multiple location analysis. The Rxn-41 probe is a rugged insertion probe designed to be inserted directly into the LNG stream so that it takes the reading in situ, with the moving liquid constantly refreshing the sample. The two components are fully integrated into the LNG bunkering solution to provide customers with a complete system from a single vendor with the lowest OPEX of any solution on the market today.
Outstanding measuring accuracy
Another key component of the package is Proline Promass Q. The Coriolis MFM is designed as a specialist for accurate measurement of cryogenic liquids like LNG. Its incredible temperature stability results in best possible accuracy of the measured quantity, especially under cryogenic conditions. Thanks to its revolutionary 4-tube technology and an extended measuring range for sizes up to DN 250 (10″), customers benefit from low pressure loss and outstanding measuring accuracy (±0.35% mass) for both minimal and very high flow rates. The reduced pressure loss also avoids unwanted cavitation effects or gas breakout.
The innovative meter design combined with our patented MFT (Multi-Frequency Technology) helps to reduce errors from entrained gas. Promass Q offers additional features like integrated Heartbeat Technology, which provides the onboard diagnostics and verification that enhance product and process safety. The complete sensor of the flowmeter, including measuring tubes and electronics, can be verified without interrupting the process by the push of a button, even from the control room.
Photo credit: Endress+Hauser
Published: 16 November, 2023
