Design, construction and installation of Cignus mass-flow meter prototype for CO₂-testing at Equinor P-Lab.

Background
Cignus Instruments AS is developing a new and patented concept for mass flow metering of liquids and gases with special advantages within emerging H2 and CCS value chains.

Within current and future CCS projects, the industry will need measurement principles with sufficiently high accuracy, high rates, and therefore large dimensions, as well as measurement of direct mass flow. As of today, there are major limitations on the dimensioning of mass flow meters for CCS, where no existing technologies fully satisfy all specification requirements. Traditional Coriolis meters are considered the most accurate technology, but have limitations when scaling to large dimensions, especially at high operating pressures. In addition, this technology has a significant internal pressure drop causing challenges when measuring liquids close to the boiling point with the risk of cavitation and thus increased measurement uncertainty.

Cignus’ measurement principle provides simplified and more accurate CO₂ metering when scaling to large pipelines and high operating pressures, and is also suited for seabed installation. An important first step is to test an industrial prototype with CO₂, in both gas, liquid and supercritical phase, for further development of the principle for use in the CCS industry.

Objective
The project objective is to demonstrate the technological advantages of Cignus technology for a simpler and more accurate mass flow measurement of CO₂ when scaling up to large-scale CCS facilities, and experimentally verify that Cignus’ solution has the potential to close technology gaps through the CCS value chain.

Activities
Main activities in the project have been the design and construction of an industrial prototype CO₂-meter, development of electronics and software algorithms for the instrument, adaptation and installation of the instrument in a semi-industrial test loop at Equinor P-Lab, as well as conducting a dedicated CO₂ test campaign in both gas, liquid and supercritical phase. A successful CO₂ test campaign at Equinor P-Lab will provide valuable data to accelerate the development of the final product and for industry to adopt the technology.

What has the project achieved
The CO₂ instrument prototype have previously been tested in water and nitrogen flow at independent calibration laboratories, which have demonstrated accuracy potential comparable to traditional Coriolis meters. In addition, initial characterization in CO₂ has been carried out at the IFE Falcon test loop for the development of driver and sensor algorithms, as well as compensation algorithms.

The CO₂ instrument prototype was installed in a test loop at Equinor P-Lab in September, and the CO₂ test campaign carried out in October/November 2023. The most important technical results from these tests are that the pressure drop through the meter is limited to approx. 1/10 of the pressure drop through a straight pipe Coriolis meter with the same capacity, and that the measurement deviation for the Cignus meter is similar to that of the straight pipe coriolis meter. A low permanent pressure drop is very important to minimize the risk of boiling and thus increased measurement uncertainty when measuring CO₂ in the liquid phase.

The main objective of demonstrating the Cignus technology advantage of low permanent pressure drop for CCS applications has thus been achieved. Since the tests at P-Lab are still within the specification range of traditional coriolis technology, the disadvantages of that technology have not been fully demonstrated, although it is known that full-scale CCS plants lack good solutions for simple and sufficiently accurate fiscal measurements.

Future plans
The next step in the development is to build an upscaled CO₂ meter for installation in a large-scale CCS pilot plant, such as Northern Lights phase 1, or similar CCS pilot plant early 2025. The motivation for this is earliest possible test of our technology in a scaled-up installation during continuous operation, thereby gaining the most possible field experience for new metering technology.

In parallel with such a pilot installation, we are planning for the construction and qualification of the final product for installation in large-scale CCS applications from 2026.

In parallel with such a pilot installation, we are planning for the construction and qualification of the final product for installation in large-scale CCS applications from 2026.