Suppliers are devoting development and marketing to significant enhancements to ultrasonic flowmeters. The frontiers of research include:
- Innovative enhancements
- Wet gas in upstream measurement
- Hydrogen, renewable natural gas, and energy transition
Innovative enhancements
Innovative enhancements reduce profile uncertainty, enhance self-diagnosis, mitigate false alarms, and increase accuracy.
Suppliers are introducing ultrasonic meters with innovative path arrangements and other features to provide greater accuracy as well as a clearer and more timely view of what’s happening with meters in the field. This is important as ultrasonic meter users and regulators demand continuous assurance of the accuracy of their measurements while they are in service, and need better means of self-diagnosis. Suppliers are also realizing that flow profiles are not constant, and that pulsation, vortices, harmonics, and other effects can result from a variety of causes – pumps & compressors, sharp edges in a pipe, sharp changes in flow direction, liquids in a gas flow, blockages from dirt and other build-up, even foreign objects. Consequently, they are incorporating self-verification and enhanced diagnostics, including remotely, and reducing the effects from flow disturbances, even without flow conditioners.
Inline ultrasonic flowmeter suppliers are tackling these related frontiers of research in a variety of creative ways:
Sensia’s new self-verifying (SVM) ultrasonic flowmeter claims to be the first gas or liquid custody transfer meter to deliver a quantitative and continuous evaluation of its own performance, calculating its own live measurement uncertainty. The company’s 16-path CALDON SVM 289Ci incorporates new patented technology to estimate simultaneously calculate measurement uncertainty alongside each flow measurement calculation, updated once per second. It builds on the company’s eight-path Caldon 380Ci 280 (liquid) and 380 (gas) models. The SVM uses Sensia’s proven 8-path configuration for its primary measurements and a fifth chordal measurement plane to compare 4-chord (8-path) versus 5-chord (10-paths) results of flow profile uncertainty. The SVM technology also provides axial velocity measurement verification for the chords and a vertical reflective path to detect entrained gas or contamination. The meter removes time-based recalibrations by dynamically alerting operators to any issues in and providing a quantitative evaluation of the meter’s performance. They are also totalized, and can be logged and examined for future reference. Like Sensia’s 8-path meter, the SVM does not require a flow conditioner to address the effects of non-axial flow/swirl. The company claims that error detection is more reliable than two meters in one body, which can be subject to false alarms. The meters can detect and quantify the influence of complex changes such as variations in path geometry and signal detection issues.
Honeywell’s gas Q.Sonicmax meter, launched in June 2017, claims to be the first eight-path ultrasonic meter to combine both reflective and direct paths. The patented path configuration offers detailed flow profile recognition with noise immunity to provide the lowest uncertainty possible with the most extensive diagnostics capabilities. The reflective paths and diagnostics mean the meter quickly identifies swirl, fouling, or liquids inside the meter. The direct paths provide enhanced robustness for higher valve noise immunity and accuracy in CO2-rich applications. The configuration enables Q.Sonicmax to detect and correct for disturbances in the gas flow caused by short inlets, extenders, reducers, manifolds, elbows, and other piping elements common in natural gas plants.
GWF’s SONICO® EDGE ultrasonic flowmeter for drinking and utility water applications uses a time-reverse acoustic principle to provide measuring repeatability unaffected by flow perturbations, water conductivity, or electromagnetic or grounding interference. The meter’s 4D-shape measuring core means it can be installed directly before or after 90o elbows, valves, and pumps without straight runs, and without the need for flow conditioners.
Panametrics Sentinel LCT8 (now part of Crane) for custody transfer of hydrocarbon liquids uses some the meter’s eight paths to cancel the effects of swirl and other disturbances.
KROHNE’s ALTOSONIC inline flowmeters for custody transfer measurement of gas and oil use speed of sound measurement as a continuous verification tool for custody transfer of natural gas. The ALTOSONIC V12’s 12-path configuration eliminates the need for a flow conditioner and makes it immune from swirl. No knowledge of the gas composition is needed. The meter includes extensive condition-based monitoring (CBM) diagnostics. Dedicated diagnostic paths detect deposits, dirt, and other changes in surface roughness. To help ensure gas process continuity if a transducer fails to operate within custody transfer parameter limits, the ALTOSONIC V12 uses dynamic chord substitution that use previously stored velocity ratios between the different chords to calculate the exact velocity at the position of the failed path.
SICK’s FLOWSIC600-XT 2plex (now part of Endress+Hauser) combines a very compact gas flowmeter and control measurement device with an independent measurement path that extends diagnostic functionality. SICK’s FLOWSIC600-XT Forte uses eight paths on two different path levels to deliver high accuracy. The FLOWSIC600-XT Quatro unites two measurement devices for redundant custody transfer measurements into one, with an installation length equivalent to that of a single device.
Faure Herman’s FH Sonic for custody transfer of liquids and other demanding applications integrates up to five parallel measuring paths arranged asymmetrically to optimize flow profile evaluation for measurement correction, plus an embedded sixth path dedicated to diagnostics. This configuration can be “doubled” by adding a second set of five paths, symmetrically arranged in the horizontal plane, to reinforce the analysis and correction capacity of the flow profile or to have an independent check meter in the same unit.
Emerson’s Rosemount 3418 eight-path gas ultrasonic flowmeter uses eight transducer/receiver pairs, each placed to read velocity at four positions, with the first set of four set in the mirror image of the second within the body, with flow in either direction. Each position provides two chords across the pipe diameter, so there are eight measurements taken over 32 milliseconds. This approach creates an accurate picture of gas movement and volume for greater measuring precision.
Fluenta combines two signal types – a variable “chirp” signal and a continuous sine wave signal – to enhance the accuracy and stability of its inline and insertion FGM-160 meters, preventing the loss of signal while measuring the extremes of high and low velocities. Fluenta claims accuracy as high as ±1% and a turndown ratio of 4000:1. The FGM 160 Dual-Path adds higher accuracy (±0.75%) and redundancy with two pairs of transducers mounted opposite each other in several different configurations. If one transducer fails, the other pair of transducers continues to operate at the same accuracy level as a single path FGM 160.
The TUS inline high pressure ultrasonic transit-time gas flowmeter, jointly developed by Goldcard and Tancy, includes built-in WiFi and supports 4G/5G communication. A self-diagnosis function analyzes the device’s status and retrieves historical lifecycle data about the device from the cloud. A built-in high-precision temperature sensor automatically corrects the expansion coefficient of the shell.
The new Smith Meter® Ultra 8c meter from TechnipFMC (now part of Guidant Measurement) for heavy liquids uses eight transducer paths to measure swirl and cancel any resulting transverse velocities. The eight paths and dynamic profile compensation offer ±0.12% linearity over 15:1 normal flow range and repeatability of ±0.02%. Swirl cancellation permits installations with 5D upstream straight runs without flow conditioning. The company’s MPU 1600c custody transfer gas flow measurement, provides minimal pressure drop with only a required 5D upstream straight run in even harsh outdoor petroleum applications. The meter cancels swirl velocities without flow conditioning and offers next generation electronics for improved gas measurement accuracy (nominal accuracy of ±0.1% and repeatability of ±0.05% or better with flow calibration), diagnostic intelligence, and installation flexibility. On-board memory for diagnostic analysis stores continuous, configurable process data that can provide an analysis of process conditions and meter operations by downloading the file – without logging. A web-based interface improves access. Advanced digital signal filtering and processing enhances noise immunity.
Tokyo Keiso’s SONICMAX® UL3400 for liquids integrates a converter and three pairs of ultrasonic sensors. The three-beam measurement technique and digital signal processor (DSP) are designed to provide highly accurate (±0.5% of reading) and stable measurement in a broad range of applications with varying physical or chemical properties, including density, viscosity, and electric conductivity.
Wet gas in upstream measurement
The complex upstream market is a frontier of interest for many ultrasonic flowmeter manufacturers, which see untapped opportunities for measurement as well as possibilities for making inroads in existing differential pressure and turbine usage. Issues in the upstream market include unplanned downtime, greenhouse gas (GHG) emissions monitoring, and opportunities for greater predictive focus on safety and security. But one of the main frontiers – and biggest pain point – for ultrasonic meters in this market is the presence of liquids and other elements at gas measuring points.
Raw natural gas at gas production wells and pipelines or associated gas at oil fields can contain natural gas liquids (NGLs) – hydrocarbons like ethane, propane, butane, isobutane, and pentane; water, oil, or glycol, as well as dirt, dust, and mechanical particles and even wax or paraffin. Shale play areas in particular often have very high BTU gas that consequently may contain NGLs. Some gas producers have determined it is easier to allow the NGLs to flow with the gas until they are separated at a compressor station, measured (often with a Coriolis meter), and then re-injected into the downstream pipeline after compression. This process continues until the gas and the liquids arrive at a cryogenic plant that removes the NGLs and delivers pipeline quality gas.
According to RMG, some gas producing clients are convinced inline ultrasonic gas meters will fail quickly when liquids are present and believe the orifice meter is the best solution for wet gas applications. But tests at CEESI with RMG’s 4-inch and 8-inch GT400-3P inline ultrasonic meters – without a flow conditioner – against a 4-inch orifice plate have shown that inline ultrasonic meters can significantly outperform orifice plates in wet gas conditions. RMG’s six-path USM GT400 gas flowmeter directly measures bulk flowrate, swirls, crossflow, and asymmetry. The meter’s six paths arranged in three parallel planes provide high stability against turbulence. It also features fully encapsulated, robust, dirt-repellent titanium sensors. A patented precision adjustment/echo measurement feature reduces meter uncertainty to as low as ±0.1%. Additional qualitative analysis evaluates the pulse envelope and identifies ultrasonic pulses without slowing the pulse rate. The six-path meters maintain their custody transfer metering capabilities even if any one or two of their acoustic paths fail. The failed paths are reconstructed by a replacement-value function learned by the gas meter using the measuring results of all functioning paths.
SICK, which started investigating the upstream market in 2006, now, as part of E+H, offers the inline FLOWSIC600 DRU series for upstream gas applications that features a protruded transducer position and large transducer bore and as well as remote, real-time monitoring of measurement and diagnostic data. The extracted raw gas can contain water, natural gas condensates, and potentially highly corrosive and toxic components. The robust wet gas sensor provides continuous measurement even with permanently higher liquid loading. CEESI testing found that the SICK meter also provides a significantly more predictable result than an orifice meter, especially under high liquid loading, with a smaller footprint and less carbon release due to isolating meter runs and de-pressuring to inspect and change orifice plates.
Hydrogen, renewable natural gas, and energy transition
Some ultrasonic flowmeter manufacturers now offer meters that measure hydrogen in and are continuing to explore how to best measure hydrogen and hydrogen blends. They are also eyeing whether to enter the renewable energy market, which includes hydrogen renewable natural gas from methane and synthetic fuels.
Hydrogen’s physical properties are quite different from other gases, including natural gas, and flowmeter suppliers have had to adapt to those differences, as well as figure out ways for ultrasonic meters to accurately measure hydrogen blends.
Hydrogen from biogas and other renewable energy is seen as one of the pillars in the current transition to integrating renewables into the broader energy system. The American Gas Association calls green energy’s role “pivotal” in the current energy transition. The AGA believes that the Clean Hydrogen Production Tax Credit and other provisions in the Inflation Reduction Act guarantee that clean hydrogen will be critical going forward and that an important challenge is making hydrogen use scalable, with sufficient production and distribution capabilities.
Most hydrogen today is extracted from fossil fuel natural gas (sometimes called “grey hydrogen”). It is widely used today in industrial processes, including, for example, in manufacturing high-grade steel and as a reactive agent to refine petroleum products by breaking down heavy molecules and removing impurities. In a production process for fatty alcohols, hydrogen is used as a circulating gas. Within the process, hydrogen is used both as a raw material and the primary carrier medium. Hydrogen can also be used to power vehicles, generate electricity, power industry, and heat homes and businesses – although some research indicates that heating with hydrogen is a lot less efficient and more expensive than alternatives such as heat pumps, district heating, and solar thermal.
Now two types of carbon-neutral hydrogen, plus a mixed type, are on the rise:
• Blue hydrogen, extracted from natural gas, captures the CO2 generated during the process and stores it permanently underground for a carbon-neutral footprint.
• Green hydrogen (H2) is produced by splitting water into hydrogen and oxygen in an electrolyzer powered by renewable energy. It is a versatile energy carrier that can be used directly instead of grey hydrogen or combined with other elements to create synthetic electrofuels (e-fuels) like e-ammonia and e-methanol.
• Mixed hydrogen combines blue or green hydrogen in natural gas pipelines to reduce carbon emissions.
Green hydrogen is a versatile energy carrier that can decarbonize a wide range of sectors. It can be used directly or in the form of its derivatives like e-methanol, e-ammonia, or e-fuels to replace fossil fuels, coal or gas. One of the most important aspects of green hydrogen is that it can store and transport solar and wind energy for use where and when it is needed. Green hydrogen can be stored for long time periods, in large quantities, and without loss, and then transported and used directly or converted back into electricity and heat. According to the AGA, hydrogen has “immense potential” for energy storage because the capacity of America’s gas pipelines and gas storage facilities exceed all battery capacity provided by every lithium battery on earth. (Lithium-ion batteries are currently the dominant storage technology for ensuring a reliable supply to electricity grids.) Using hydrogen would allow us to transition to a higher mixture of renewable energy without diminishing the reliability of our energy distribution infrastructure.
KROHNE’s 12-chord ALTOSONIC V12 inline ultrasonic custody transfer (CT) flowmeter measures pure hydrogen, natural gas, and blends of hydrogen with natural gas.
Emerson’s four-path Rosemount™ SeniorSonic 3414 gas ultrasonic meter allows customers to blend hydrogen into their current pipeline at levels of up to 30% and still maintain high accuracy and reliability.
Endress+Hauser’s inline Proline Prosonic Flow B 200 ultrasonic meter deploys loop-powered technology to measure wet biogas and digester gas. An integrated real-time methane fraction analysis provide continuous measuring and monitoring of both gas quality and gas flow.
KROHNE’s dual-beam OPTISONIC 7300 Series accommodates industrial process and pipeline gas, compressed gas, fuel and biogas, and low pressure steam. Titanium sensors with improved signal processing can measure process gases with different and changing compositions, including noise, and avoid measurement errors.
As for blended gases, nine ultrasonic flowmeter manufacturers – RMG, Honeywell, Krohne, FLEXIM, Pietro Fiorentini, Endress+Hauser, Emerson, SICK and Tancy – participated in a joint industry project (JIP) formed in 2020 to understand the performance of flowmeters when hydrogen and CO2 are mixed with natural gas. Two of the nine meters, including RMG’s inline meter, showed no systematic drift behavior although the other seven meters showed drift considered significant as compared to the meter’s transferability, which was defined as the reproducibility from one gas to another gas.