Introduction: LNG project EPC instrumentation procurement leads need to align cryogenic temperature, custody transfer duties, wetted material choices, and Datasheet completeness before advancing an OPTIMASS 6400 inquiry.
When an LNG project shifts from process design into instrument procurement, the Coriolis meter decision expands beyond line size. The device will operate in liquefied gas at deep cryogenic conditions, sit inside a custody transfer chain, follow hazardous area rules, and face a schedule where late configuration changes create expensive ripple effects. The KROHNE OPTIMASS 6400 is a candidate because its published media temperature range extends to -200°C, and its custody transfer, material, pressure, safety, and diagnostic options can be assessed against the project operating envelope. The practical first step is to organize LNG process conditions and project documentation, then decide whether to move into a configuration review and quotation.
LNG service places a Coriolis meter in a selection space shaped by cold fluid behavior, custody transfer discipline, and construction sequencing. The U.S. Department of Energy’s LNG overview describes the cryogenic supply chain across liquefaction, storage, and transport, which explains why instrument teams treat the meter body, measuring tubes, flanges, gaskets, insulation, and electronics as one cold-service assembly rather than separate parts. Material behavior becomes the first engineering concern. At cryogenic temperature, metals contract at different rates, thermal gradients create stress paths, and the relationship between the sensor tube and adjacent piping influences zero stability. The OPTIMASS 6400 covers media temperatures from -200°C to 400°C, so LNG conditions can be compared with a documented range. Material options listed for the wetted path include duplex stainless steel and Alloy 22, giving the selection team two starting points for mechanical stability and corrosion resistance. The final material call follows LNG composition, chloride exposure, purge and cooldown practice, and project documentation. Metering behavior is the second concern. LNG often operates close to its boiling point, and modest pressure changes can create vapor or two-phase pockets that disturb conventional measurement. A Coriolis meter measures mass flow directly; the OPTIMASS 6400 also reports density, volume flow, and temperature. That multi-parameter output helps the control system and commercial team see what is moving through the line. Custody transfer adds another layer because stable zero, correct installation, and documented calibration carry as much weight as the headline accuracy class. Project execution is the third concern. LNG projects use strict hazardous area classification, traceable calibration records, and detailed Datasheets. The meter must match line size, flange standard, pressure class, electrical interface, and the safety function of the package. A supplier should enter the conversation while these variables remain open, because changing wetted material, custody transfer options, or the diagnostic package after order placement affects lead time, documentation, and site acceptance planning.
The OPTIMASS 6400 specification set is broad, and LNG custody transfer narrows the review to linked decisions: cold-service hardware, mass flow accuracy, legal metrology class, pressure rating, functional safety, and diagnostics. These choices interact, so the EPC team gains more from reviewing them as a system than from selecting the highest number in isolation. Project-specific confirmation still comes through the Datasheet and order review, where OIML, SIL, material, pressure, and temperature details are tied to the selected device configuration.
The published media temperature span of -200°C to 400°C is the first technical fact to compare with LNG operating data. Because the lowest value reaches -200°C, cryogenic LNG service can be evaluated against it, allowing the instrument team to check minimum process temperature, ambient conditions, insulation strategy, and cooldown procedure in one review. The wetted material list names duplex stainless steel and Alloy 22. Duplex stainless steel is often chosen for strength and stress corrosion resistance in process piping, while Alloy 22 is a nickel-chromium-molybdenum alloy used where chlorides and oxidizing media demand a higher alloy. For LNG, review those materials against gas composition, carryover from upstream treatment, and cleaning or purging methods before cooldown. Final material certificates follow the configured device documentation.
For custody transfer, the OPTIMASS 6400 offers OIML 0.3 class, giving the project a recognized accuracy class for discussion with the metering authority and commercial parties. An optional ±0.05% accuracy configuration is available for projects that need tighter measurement performance; it is not the standard default across every model, so the inquiry should state the required accuracy option clearly. Pressure capability reaches up to 200 barg, supporting high-pressure LNG and related process lines when selected flange and sensor ratings match the project. SIL 2/3 is available up to DN200 / 8 in, which matters when the meter forms part of a safety instrumented function. HART communication, Bluetooth setup with OPTICHECK Flow Mobile, and NE 107 diagnostics support configuration and device-health checks. Entrained Gas Management (EGM) is also part of the OPTIMASS 6400 feature set for applications where gas bubbles appear. For LNG, keep the primary selection decision on the custody transfer and cryogenic conditions recorded in the Datasheet.
An LNG Datasheet turns a general meter inquiry into a reviewable quotation, and its quality determines how quickly the supplier can confirm whether OPTIMASS 6400 is the right configuration. Start with the fluid: LNG composition, density at operating conditions, temperature range, pressure range, flow range, and expected turndown. Add line data: nominal size, flange standard, pressure class, face-to-face length if fixed, insulation or cold-box details, and installation orientation. These inputs let the supplier confirm whether the selected sensor size gives useful accuracy across expected flow and whether the meter can be built for the project. Next, separate commercial metering requirements from basic process requirements. State whether the meter is for custody transfer, internal allocation, or process control. If custody transfer applies, list required accuracy class, calibration certificate, traceability requirements, and any national metrology approval needed for the project location. NIST Handbook 44 and BIPM gravimetry work are useful background for how legal metrology and mass traceability are organized, while the project’s own approval documents and calibration scope remain the controlling references. For safety, note hazardous area classification, SIL level, proof-test expectations, and whether the meter will sit in a safety instrumented function. For operations, list required communication protocol, diagnostic output, and whether Bluetooth or HART configuration is expected. Finally, package the Datasheet with the project schedule. Include required delivery date, inspection and test plan, documentation language, spare parts list, and any site acceptance test requirements. A KROHNE flow meter supplier can then compare the requested configuration against available OPTIMASS 6400 options, flag long-lead items such as special materials or large line sizes, and prepare a quotation the EPC team can review without reopening basic process data. Aotuhui supports this step as a multi-brand industrial process instrumentation supplier, with technical review and priority quotation support for LNG and other process projects. The clearer the Datasheet, the faster the team can decide whether to advance the OPTIMASS 6400 inquiry.
Cryogenic LNG service changes Coriolis flow meter selection because temperature, material behavior, custody transfer class, and project documentation all interact. The OPTIMASS 6400 publishes a media temperature span from -200°C to 400°C, OIML 0.3 custody transfer class, optional ±0.05% accuracy, wetted materials including duplex stainless steel and Alloy 22, pressure capability up to 200 barg, SIL 2/3 up to DN200 / 8 in, and diagnostics such as NE 107. Submit the LNG Datasheet with process, material, metering, safety, and schedule requirements so the project team can confirm the right configuration, calibration scope, documentation, and lead time for a quotation.
A：The meter’s published media temperature range reaches -200°C, so cryogenic LNG conditions can be assessed against that range; final suitability is fixed by LNG composition, minimum operating temperature, pressure, selected materials, and the configuration recorded in the project Datasheet and order review.
A：For the OPTIMASS 6400, the wetted material options include duplex stainless steel and Alloy 22. Review them against LNG composition, chloride exposure, cleaning and purging practice, and the required pressure and temperature range; project documentation for the selected device establishes final material certificates.
A：Provide LNG process conditions, line size, flange and pressure class, flow range, required accuracy and custody transfer class, hazardous area and SIL requirements, communication and diagnostic needs, calibration and documentation scope, and required delivery date. That Datasheet lets the supplier confirm the OPTIMASS 6400 configuration, long-lead items, and commercial quotation.
Liquefied Natural Gas (LNG) - Department of Energy
NIST Handbook 44 - Current Edition
CCM Working Group on Gravimetry - BIPM
