LNG transfer with Custody Transfer Measurement Systems

Streamline your LNG transfer process with ASaP’s cutting-edge Custody Transfer Measurement Systems. Enhance accuracy, efficiency, and profitability in LNG custody transfers. With our LNG Custody Transfer Measurement Systems… You keep it flowing. ASaP is a leading company specializing in the engineering and manufacturing of cutting-edge LNG Custody Transfer Systems (CTMS), LNG Probe-Vaporizers, advanced LNG Samplers, and precise NG analysis systems.

Overview illustration of LNG terminal with fully automated custody transfer measurement systems CTMS - ASaP LNG solutions

The Challenge of Accurate LNG Custody Transfer

In the fast-paced LNG industry, precise LNG transfer of custody measurement is essential. Inaccurate measurements can lead to financial losses and operational setbacks. Are you facing challenges such as inconsistent measurements, lengthy transfer times, or disputable documentation? Time is a valuable asset in the LNG industry, where every hour gained allows an LNG carrier to depart earlier from a FSRU or terminal, resulting in substantial financial benefits. Therefore, it is crucial that LNG Custody Transfer Measurement Systems are able to consistently operate at its peak flow rate, minimizing transfer time.

ASaP’s Custody Transfer Measurement Systems

Experience the power of ASaP’s advanced LNG Custody Transfer Measurement Systems. Our integrated solutions ensure accurate measurements, reduced transfer times, and transparent documentation. No more measurement discrepancies. Trust seamless LNG transfers, and optimized bills of lading.

Service engineer Vinicius Rossetti with ASaP LNG Sampler with AIM predictive maintenance software. LNG transfer with ASaP Custody Transfer Measurement Systems
Field service engineer with ASaP LNG Sampler and AIM predictive maintenance software.

Unlocking the Benefits of ASaP’s CTMS

Maximize LNG Transfer Efficiency

ASaP’s Custody Transfer Measurement Systems bring numerous advantages:

  • Precision: Accurate measurements for reliable transactions.
  • Efficiency: Minimized transfer time for quicker departures.
  • Transparency: Detailed documentation and verification.
  • Cost Savings: Minimized losses and optimized operations.
  • Innovation: Cutting-edge technologies for peak performance.

Choose ASaP for LNG transfers that elevate your operations to a new level.

Key Features of ASaP’s CTMS

Overview illustration of LNG terminal with fully automated custody transfer measurement systems CTMS - ASaP LNG solutions
Measure every BTU of LNG transferred with ASaP’s LNG products.

Discover the complete package features that set ASaP apart

  • LNG Sampler: Precise sample capture for accurate analysis.
  • Cryogenic Probe and Vaporizer: Seamless transition from liquid to gas state.
  • Flow Skid: High-precision flow measurement for billing and settlement.
  • Active Sub-Cooling: Eliminates pre-vaporization for reliable results.
  • Comprehensive Monitoring: Real-time data for better decision-making.
  • Innovative Software: AIM software ensures measurement accuracy.
  • Complete Package: Skid-mounted solutions for ease of integration.

Continue reading for a description of our LNG Custody Transfer package.

LNG Custody Transfer Measurement System package

CTMS for LNG transfer

Custody Transfer Measurement Systems (CTMS) play a pivotal role in ensuring the seamless LNG transfer of Liquefied Natural Gas from production facilities to consumers worldwide. This critical process relies on a well-orchestrated combination of high-end technologies, including LNG vaporizers, samplers, and meticulous measurement, to guarantee accuracy and reliability throughout the supply chain.

36 inch pipe flow metering skid different angle. LNG transfer with ASaP Custody Transfer Measurement Systems
Fully automated CTMS up to 36” line size.

LNG Sampler

An LNG Sampler serves as the bedrock of precise measurement, enabling operators to capture representative samples of LNG at various stages of the transfer process. Advanced sampling techniques, such as Isokinetic and Spot Sampling, are employed to mitigate potential biases and ensure the consistency of results. By obtaining reliable samples, CTMS not only meet regulatory requirements but also provide essential data for commercial and operational decision-making.

LNG sampling with the ASaP LNG Sampler System intermittent sampler. LNG transfer with ASaP Custody Transfer Measurement Systems
LNG Sampler system.

LNG vaporizer

The role of vaporizing in LNG custody transfers cannot be underestimated. When transferring LNG across vast distances, it is essential to convert the supercooled liquid back into its gaseous state. Sophisticated vaporizing technologies effectively convert LNG back into its natural form without compromising its quality or energy content. This vital process ensures a smooth transition and uninterrupted supply to end-users.

Phazer 1.1 LNG vaporization with The Phazer - LNG probe-vaporizer product photo
The Phazer Cryogenic Probe-Vaporizer is a combined vaporizer and probe.

Flow skid

At the core of CTMS lies precision measurement, a crucial aspect of LNG custody transfer. Highly accurate flow meters are employed to determine the exact volume of LNG passing through the system. This data forms the basis for billing and settlement purposes, as well as for quality control, allowing stakeholders to have complete confidence in the fairness and reliability of the LNG transfer process.

LNG custody transfer flow skid with Krohne flow measuring devices. LNG transfer with ASaP Custody Transfer Measurement Systems
Flow skid with LNG flow measuring devices.

Implementing advanced CTMS not only guarantees accurate measurements but also enhances operational efficiency, reduces losses, and minimizes environmental impacts. With the global demand for LNG on the rise, the need for efficient and reliable custody transfer systems has never been more critical.

LNG transfer project satisfied customer

ASaP review stars

“At the request of ASaP this letter may serve as reference.

It is the most advanced design which is currently commercially available on the market. It is the only LNG vaporizer and sampling system which take care for a subcooling of the sample before vaporization. The flange connection avoids any unnecessary heat leak on the sample transfer to the LNG vaporizer system. Due to the flexible design on the orifice and heater system, the flow can be easily adjusted to the process requirements as well as to the required flow rate to overcome the natural heat input to the sample.

There are no moving parts, and it is flexible in configuration. Installation work on site is expected to be kept to a minimum. Operational and maintenance costs are predicted to be minimal. The ASaP solution appears to be the perfect match for a happy customer from the Middle East with regards to technical requirements, flexibility and planning. A return on investment of 1 to 2 weeks is predicted.

The functionality of the system was tested, and the outcome is above expectation. Even without proper insulation on the transfer part, the contact temperature on the bottom part (close to the hot section) was found to be below -150°).”

– Quote from the Factory Acceptance Test (FAT)

Recent LNG transfer projects

Mobile LNG sampling system for fuel quality analysis

Last week marked the successful completion of a Factory Acceptance Test (FAT) for our advanced Mobile LNG sampling system for fuel quality analysis, developed in collaboration with ERT Refrigeration Technology GmbH and DVGW Research Center at Engler-Bunte-Institut of Karlsruhe Institute of Technology.

Factory Acceptance Test FAT for advanced Mobile LNG sampling system for fuel quality analysis

Snam Acquires BW LNG’s FSRU, ASaP supplies Phazers

Snam, an Italian energy firm, has recently completed the acquisition of BW LNG’s FSRU, named BW Singapore, for approximately $400 million. This strategic move is set to enhance Italy’s energy security and supply diversification. ASaP will play a pivotal role in this project by equipping the FSRU with two advanced Phazers 1.0, supplied through Global Gas Solutions. These Phazers, exclusive to ASaP, feature a combination of an LNG probe and vaporizer with patented active sub-cooling technology. This ensures the complete prevention of partial and pre-vaporization of LNG in all conditions, ensuring superior analytical performance of the FSRU.

BW Singapore FSRU - Snam Acquires BW LNG’s FSRU, Equipped with ASaP Technology, to Boost Italy's Energy Security

Golar’s FLNG Hilli Achieves 100th Cargo with ASaP-tech

Golar’s FLNG Hilli, stationed offshore Cameroon’s Kribi, has recently marked a significant milestone by offloading its 100th cargo of liquefied natural gas since commencing operations in 2018. This achievement is not just a testament to Golar’s expertise but also highlights the critical role of ASaP’s technology onboard. ASaP has equipped the FLNG Hilli with two advanced Phazers 1.1 with shut-off valves and one ISO 8943 intermittent LNG Sampling System. These cutting-edge systems, unique to ASaP, combine an LNG probe and vaporizer with patented active sub-cooling technology, ensuring the prevention of partial and pre-vaporization of LNG under all conditions, thus guaranteeing optimal analytical performance.

Golar's FLNG Hilli Achieves 100th LNG Cargo Milestone with ASaP Technology Onboard

ASaP’s technologies fuel Ruhe Bio-LNG Plant in Germany

ASaP has made a significant contribution to the Ruhe Group’s latest venture in the bio-LNG sector by delivering a state-of-the-art MicroPhazer. This unique ASaP product combines an LNG probe and vaporizer with patented active sub-cooling technology, ensuring the prevention of partial and pre-vaporization of LNG under all conditions. This guarantees optimal analytical performance, essential for the precision required in bio-LNG production. Alongside this, we’ve provided an analytical system equipped with natural gas chromatographs for measuring the composition of vaporized LNG samples. Furthermore, our delivery includes AIM (Analytical Information Module), a preventive maintenance operation system that continuously monitors the performance of the entire LNG custody transfer system, including gas chromatographs and detectors.

Drone photo of the bio-LNG plant in Parmen. ASaP's technologies fuel Ruhe Bio-LNG Plant in Germany

ASaP Equips Golar’s FLNG Gimi

ASaP has proudly supplied key equipment for Golar LNG’s newly converted floating LNG producer, the FLNG Gimi, set to play a vital role in BP’s Greater Tortue Ahmeyim FLNG project offshore Mauritania and Senegal. Our contribution includes two advanced Phazers 1.1 with shut-off valves. The Phazer, a unique brand offering from ASaP, combines an LNG probe and vaporizer featuring patented active sub-cooling technology. This ensures prevention of partial and pre-vaporization of LNG under all conditions, guaranteeing optimal analytical performance. Additionally, we’ve provided one ISO 8943 intermittent LNG Sampling System, further solidifying our commitment to this groundbreaking project.

ASaP Equips Golar's FLNG Gimi

Höegh Esperanza FSRU – Flawless LNG Sampler inspection

In the second quarter of 2023 Analytical Solutions and Products (ASaP) completed an LNG Sampler System for the Höegh Esperanza (FSRU Floating Storage Regasification Unit). Including probe vaporizers, LNG sampling cabinet, preventive maintenance operating system, natural gas analyzers, and calibration gas facilities.

Höegh Esperanza FSRU - ASaP LNG Sampling System FAT Factory Acceptance Test - From ASaP Bart Berkhout and Peter Kearney

FAQ: Answering key questions about ASaP’s CTMS

What is the purpose of ASaP’s Custody Transfer Measurement Systems?

ASaP’s CTMS ensures accurate measurement and efficient transfer of LNG ownership between parties, reducing financial risks and operational challenges.

Which problems does ASaP’s CTMS solve?

Our CTMS solves issues such as inaccurate measurements, extended transfer times, and disputes by providing precise measurements and seamless transfer processes.

For what applications can ASaP’s CTMS be used?

ASaP’s CTMS is ideal for LNG custody transfers at loading terminals, storage facilities, and during ship-to-ship transfers, ensuring transparent and reliable transactions.

Who is ASaP’s CTMS designed for?

Our CTMS is designed for natural gas industry custody transfer processing, including producers, suppliers, buyers, and shipping companies involved in LNG custody transfers.

What are the benefits of ASaP’s CTMS?

ASaP’s CTMS offers accurate measurements, minimized transfer times, transparent documentation, reduced losses, and enhanced operational efficiency.

What are the features of ASaP’s CTMS?

ASaP’s CTMS features LNG sampling, vaporizing, advanced flow skids, active sub-cooling, comprehensive monitoring, innovative AIM software, and complete skid-mounted solutions.

What is the expert take on LNG transfer of custody?

August 2023 issue of LNG Industry

Hans-Peter Visser, Analytical Solutions and Products B.V., the Netherlands, outlines the needs for fully automated LNG custody transfer measurement systems.

Custody transfer refers to the process of transferring ownership and responsibility of a product or commodity from one party to another. It involves the transfer of physical possession, as well as the associated rights and obligations related to the product. Custody transfer is commonly applied in industries such as oil, gas, petrochemicals, and utilities, where the accurate measurement and verification of quantities and qualities of the transferred material are crucial for commercial transactions and accountability.

August 2023 issue of LNG Industry
August 2023 issue of LNG Industry

In the context of LNG, custody transfer specifically involves the transfer of ownership and responsibility of LNG from the seller to the buyer. It encompasses the accurate measurement of the quantity and quality of LNG being transferred, typically at loading terminals, storage facilities, or during ship-to-ship transfers. Custody transfer ensures transparency, accuracy, and fairness in commercial transactions by providing a standardized process and reliable measurement systems to determine the value and quantity of the transferred LNG.

It is important to note that the specific details and procedures of LNG custody transfer may vary depending on the parties involved, contractual agreements, regional regulations, etc.

Current standards for LNG transfer

LNG custody transfer is based on the GIIGNL Custody Transfer handbook 6th edition and ISO 8943:2007. The ISO 8943:2007 is focused on the quality of the LNG by means of composite sampling and on-line (gas chromatograph) analysis, while the GIIGNL has it overall coverage. The GIIGNL advise also how to determine the quantity of the LNG transferred which is done by means of gauging.

Gauging is a manual procedure, taking in account various measured physical properties and process parameters, consulting tables, and the need for a highly skilled and experienced surveyor. This is a labour-intensive, time-consuming and costly process where accuracy and reproducibility depend on the quality of the surveyor. Everyone knows that one surveyor is not like another surveyor, and that even the best surveyor has a bad day. In other words, there is a human error factor which may impact the determination of a high US dollar value of an LNG cargo.

More and more end-users, especially in the US, are requesting a fully automated LNG custody transfer measurement system. This includes automated time and flow proportional LNG sampling according to ISO 8943:2007 as well.

Figure 1. Anonymized quality certificate copy
Figure 1. Anonymized quality certificate.

EPC contractors require the same, including integration of the whole the system to a compact skid with clear battery limits. Their benefit is to have just one single point of contact for project execution, commissioning, and start-up.

The need for in-line flow measurements and metrological traceability

With the current technology in place, it is possible to measure the flow of LNG either via Coriolis flow meters or Ultrasonic flow meters.

The major challenge for LNG flow meters was metrological traceability and how to determine the accuracy of an LNG flowmeter. Based on studies and tests, there was the assumption that there was a correlation between LNG and water measurements for LNG, which is currently used in the market. Recent tests show differently; to be sure that LNG flow meters measure correctly during use, they need to be calibrated at cryogenic conditions with LNG. Recently, a new standard – ISO 21903:2020 – was published by the International Standards Organization (ISO), to specify the metrological and technical requirements for flow meters that can dynamically measure LNG and other refrigerated hydrocarbon fluids.

VSL’s calibration and test facility for LNG flow meters

In March 2023, the Dutch National Metrology Institute VSL (re)opened its brand-new European Center for Flow Measurement on the Rotterdam Maasvlakte in the Netherlands. This unique test facility includes the LNG calibration and test facility for LNG flow meters for mass and volume at cryogenic conditions with LNG. VSL can determine any output signal utilizing the master meter method of calibration. This calibration facility is traceable to the National Standard of the Netherlands, has a low measurement uncertainty (CMC), and is currently the only one in the world. All flow meter calibrations of VSL, including LNG, are well accepted around the world. Until now, the maximum flow meter size was 8 in.

Figure 2. VSL LNG test facility in the Netherlands
Figure 2. VSL LNG test facility in the Netherlands

Currently, for custody transfer measurement systems of LNG, several dynamic measurement systems are already delivered, installed, and in successful operation. Typical applications are LNG run-down line measurements and LNG allocation measurements.
The flow meters are typically built on so-called skids where nowadays also the complete quality package can be integrated, such as the LNG probe/vaporizer, the online quality measurement, and the composite sampling.

The market requests more and more, especially from the US, for complete custody transfer measurement systems (CTMS), with ultrasonic flow meters up to 36 in. Measurement systems are available now, including the complete analysis and sampling part.

It is even possible to integrate the analysis and sampling of both the cooling line and boil-off gas (BOG) return line to create a complete energy transfer equation. The challenge for large size LNG flow meters is how to calibrate these.

Continuous improvement of analytical measurement and sampling of LNG

With an average production of more than 20 LNG quality measurement and sampling systems per year, ASaP belongs to the top of value providers to LNG customers and end-users.

As a market leader, the company sees it as its obligation to the market to continuously innovate and to answer every analysis and sampling related question for every cryogenic application properly and effectively.

In-depth application and system knowledge, combined with extensive field experience, creates more and more insights and value to those using the company’s systems.

Figure 3. AIM overall and detailed performance monitoring dashboard copy
Figure 3. AIM overall and detailed performance monitoring dasboard

In May 2022, an article was published in LNG Industry about the right way to measure and sample in a cost effective and accurate manner. The purpose of this article was to outline the importance of continuously ensuring the proper operation of the analysis and sampling systems and obtaining the highest available accuracy possible for high US dollar LNG cargo values.

ASaP’s proprietary software, Analysis Information Module (AIM), is multifunctional. Its functions include the CTMS operating and control system, the online and continuous performance monitoring system, and the maintenance optimizer. It automatically generates both the cargo quality certificate and the Bill of Lading. If these two important documents are generated automatically, there is a guarantee that the measurements and calculations are matching the LNG cargo characteristics for 100%.

A new feature in AIM is the online generation of the LNG phase envelope. The phase envelop is determined by the measured process pressure and temperature near the sample take off probe, and the measuring results of the gas chromatograph downstream from the sample take-off probe. Based on the phase envelope and the sample take-off conditions, the degree of sub-cooling can be determined continuously and online.
As specified in ISO 8943:2007, a sample must be taken at the highest possible degree of sub-cooling. Until now, it was not possible to determine the actual degree of sub-cooling. However, developments in software, like AIM, can give an update of the degree of sub-cooling every 10 seconds.

Recently, the value of the new feature of online phase diagram of LNG project determination became clear to a number of users. During the start-up of an LNG factory, it was assumed that the LNG transfer line was completely filled with LNG and that measurements were being carried out correctly under the right conditions.

However, due to the start-up, there was a two-phase situation in the transfer line, which made the analysis results invalid. Further investigation learned, based on the AIM software, that the extraction sample probe was not installed at one of the LNG sample points at the shipyard.

Being aware of this flaw, a new extraction probe could be manufactured and installed on time. If the installation of the sample extraction probe had not happened at this time, the next opportunity would have been five years later during a maintenance shutdown. During these
five years, the analysis and sampling results would not have been correct. Due to the standard feature of the online phase diagram determination, this measurement error with a huge financial impact has been prevented.

Added value of small scale (bio-)LNG (truck) loading facilities

In Europe, the use of sustainable bio-LNG becomes more and more common as fuel for trucks and ships. Also, these small installations have to measure the quality and quantity delivered.

For small scale LNG installations, the initial cost for measurement and sampling equipment has a significant impact on the overall plant construction costs. Therefore, a creative approach was required to fulfill all measurement requirements.

At the end of the day, all requirements are met, and the first installations are in operation successfully. Some installations have both a truck weighing scale and an LNG end-product flow meter installed for automated custody transfer. Soon, a program will start where the correlation between the absolute LNG mass delivered, and LNG flow delivered will be determined. The results of this correlation program may add a significant contribution for large scale LNG custody transfer measurement systems.


Fully automated custody transfer measurement systems are available but are limited by the LNG flow meter sizes due to their calibration. Meanwhile, various correlations tests are planned to obtain the uncertainly and traceability data of large LNG flow meters.

Need help choosing your next LNG transfer CTMS solution?

Need help choosing your next LNG transfer solution?

Custody Transfer

Service engineer Vinicius Rossetti with ASaP LNG Sampler with AIM predictive maintenance software

Cryogenic Sampling

ASaP LNG Sampler and the Phazer LNG-Probe Vaporizer

Natural gas analyzers

Process gas chromatograph analyzers PGCs ABB NGC8206 Yokogawa GC8000 Honeywell EnCal 3000 Emerson Rosemount 370xa Process gas chromatograph analyzers PGCs

Mercury sampling

Integrated Mercury sampling HMI with intuitive user software

Contact our Custody Transfer Measurement System specialist

Contact our LNG transfer specialist directly

You can contact us is you have a question about LNG transfer when it suits you. See our specialist’s contact information below.

Hans-Peter Visser - ASaP - Address and contact persons





Let our LNG transfer specialist contact you

Let us know how we can reach you to discuss LNG transfer. We will only use this information for contacting you.

LNG transfer practical solutions

With LNG transfer ASaP offers practical total solutions. The well-established and complementary ASaP analytical package of services and products is an important contribution to the right solutions for your analytical needs. Moreover, the team spirit and the cooperation with specific partners give us the opportunity to design, build, locally install and commission tailor made sample probes, analyzer systems and shelters for you. All these products and systems can be built according to the latest industry guidelines and certifications.

ASaP is the reputable provider of analytical solutions; We can provide you with a full-service package for including engineering, manufacturing, software development, offshore service, gas analyzers, system integration, and cutting-edge bio-LNG or LNG Custody Transfer Systems (CTMS), LNG Probe-Vaporizers, advanced LNG Sampling Systems, and precise natural gas analysis systems. You are kindly invited to consult our team about LNG transfer or any analytical challenge!

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