4. Scale-Up Testing of Advanced Polaris™ Membrane CO₂ Capture Technology (2022)

Vincent Batoon^a, Adam Borsaly^a, Carlos Casillas^a, Thomas Hofmann^a, Ivy Huang^a, Jay Kniep^a, Tim Merkel^a,^*, Craig Paulaha^a, Witopo Salim^a, Erik Westling<sup>a

a</sup>Membrane Technology and Research Inc., 39630 Eureka Drive, Newark CA 94560, United States

Original paper available here (ssrn.com) GHGT-16

Abstract

Gå til overskriften

Membrane processes offer some advantages when applied to post-combustion CO2 capture, including no hazardous chemical storage, handling or emissions issues, simple passive operation, tolerance to high SOx and NOx content, recovery of flue gas water, and use of only electric power. Membrane Technology and Research, Inc. (MTR) of Newark, California, USA has been working on the development of membrane capture technology for more than a decade. Along the way, key material and process innovations have been made, including:

1. A new class of high permeance membranes, called Polaris™, was developed. This membrane is tenfold more permeable than prior commercial CO₂ membranes, resulting in a large decrease in membrane area and capital cost.
2. A membrane selective recycle process was developed. The patented process uses combustion air as a sweep stream to generate driving force for transmembrane CO₂ transport. This selective recycle approach is particularly useful for achieving high capture rates.

Recently, in an effort to optimize capture system footprint while minimizing parasitic pressure drops, MTR developed new planar module stacks designed specifically for low-pressure flue gas operation. These new modules feature the ability for fine control of the flow path on both sides of the membrane, allowing optimal performance. In prior work, these improvements were validated in prototype testing on a small pilot system at the U.S. National Carbon Capture Center (NCCC). At the same flow rate, the new planar module had about 70% lower pressure-drop compared to conventional modules, which would yield savings of approximately 10 MWe in fan power on a full-scale system. In addition to energy savings, we believe the regular geometry of the new module design is more amenable to automated fabrication methods that will reduce cost.

In this paper, the performance of these Polaris modules during an engineering-scale field test at the Technology Centre Mongstad (TCM) in Norway will be reviewed. TCM is a joint venture between Gassnova (on behalf of the Norwegian state), Equinor, Shell, and TotalEnergies. The membrane system at TCM treats a slipstream of flue gas from the Equinor residual fluid catalytic cracker (RFCC) unit. The membrane system includes both the primary capture step and the selective recycle step of the MTR selective recycle process. Depending on system operating parameters, between 50 – 90% of the CO₂ in the inlet slipstream can be captured. Figure 1 shows a conceptual drawing of the membrane module stacks in a containerized form and a picture of an actual one of these containers on the MTR small pilot system at TCM. Future, larger capture systems will simply use multiples of this modular building block.

Work began in 2019 to develop a new site at TCM for hosting 2nd generation CO₂ capture technologies. Utility hook-ups and site preparation work was completed at this site prior to the arrival of the MTR test system at TCM in late May 2021. TCM provided site support and coordinated with MTR on installation, shake-down operations, and hot commissioning activities. The MTR test system was commissioned on flue gas in July 2021 and continued operation through February 2022. The goals of the field test were to identify optimum conditions for different CO₂ capture rates (50 – 90%), to validate the low pressure drops of the planar modules, and to determine system performance under inlet CO₂ concentrations between 14 and 25% corresponding to different industrial cases. CO₂ capture rates up to 91% were achieved during the field test and the planar module pressure drops were even lower than expected (2 kPa vs. 10 kPa). These results from the TCM field test will be used to further refine the MTR CO₂ capture process for power plants and other large point sources, such as cement or steel plants.

Keywords: membrane, CO₂ capture, post-combustion, coal-fired, power plant, industrial capture, cement plant, steel plant