ETRIC – Effective Thermal Reclaiming Integrated with Capture (Flexible Funding 2023)

Dr Abby Samson, formerly University of Sheffield, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “ETRIC – Effective Thermal Reclaiming Integrated with Capture”.  Marcin Pokora, University of Sheffield, provides an insight into the project.

Why effective solvent reclaiming is needed

Carbon capture using amine-based solvents is now a mature and widely deployed technology. However, it is increasingly clear that CO₂ capture without effective solvent management is not sustainable at scale. During operation, amine solvents degrade through thermal, oxidative, and chemical pathways, producing a complex mixture of by-products. If these degradation products are allowed to accumulate, they reduce capture efficiency and create operational challenges, including corrosion, foaming, increased solvent losses, and rising maintenance costs.

Thermal reclaiming is the primary strategy used to remove degradation products and maintain solvent quality in industrial capture plants. Yet, despite its importance, reclaimer operation remains poorly understood and only weakly optimised, particularly under conditions representative of long-term commercial operation. In some cases, reclaiming itself may unintentionally recycle certain degradation products, allowing them to persist in the solvent inventory.

This research addresses a central challenge for large-scale CO₂ capture: how to operate thermal reclaimers in a way that maintains solvent quality indefinitely, while minimising solvent loss, energy use, and degradation product carryover.

Project overview

The aim of this project is to improve the understanding and operation of thermal reclaiming systems for amine solvents, with a particular focus on monoethanolamine (MEA). The research combines experimental reclaiming studies with process modelling to identify optimal operating conditions, and to determine which degradation products are effectively removed and which are likely to persist.

Specifically, the project seeks to:

1. Identify operational limits that prevent excessive degradation and volatile carryover during reclaiming
2. Quantify trade-offs between maximising solvent recovery and minimising impurity recycling
3. Develop a predictive model for continuous two-stage thermal reclaiming that can support long-term solvent management strategies in commercial plants

Experimental reclaiming capability

A lab-scale thermal reclaimer was designed and constructed using glassware to allow controlled experimental investigation. Early designs, based on conventional distillation setups, suffered from significant heat losses and poor efficiency. Through several iterations, the system was progressively improved with:

• Modified flask shapes
• Enhanced heating using upgraded heating mantles and tapes
• A pump-fed solvent delivery system to improve control and repeatability
• Attached a Coriolis flow meter at the end of the apparatus for real time density measurements

The evolution of the experimental setup is shown in Figure 1.

The final configuration was used to conduct batch thermal reclaiming experiments on industrially degraded end-of-life MEA solvent. Visual changes in solvent appearance before and after reclaiming are shown in Figure 2.

Reclaiming process definition

The batch reclaiming process was structured into three distinct stages:

• Filling and concentration stage: Degraded solvent (with water and caustic added where required) is heated until a characteristic temperature is reached. This temperature marks the onset of excessive degradation and increased volatile carryover.
• MEA recovery stage: The inflow of degraded solvent is stopped and only water is added. As MEA is recovered, the system temperature drops and stabilises, indicating the completion of solvent recovery. At this stage, a balance must be struck between solvent recovery, the risk of recycling volatile degradation products and usage of excessive amounts of water.
• Final concentration stage: Excess water is removed to minimise the volume of the waste stream while maintaining residue flowability. Care is required to avoid unwanted evaporation of non-target components.

While clear visual differences between degraded and reclaimed solvents were observed, further chemical analysis is required to quantify reclaiming effectiveness at this stage.

In-line density monitoring during reclaiming

To explore real-time monitoring of solvent behaviour during reclaiming, a liquid density meter was integrated directly into the reclaiming setup. This enabled continuous measurement of liquid density during operation, providing a non-intrusive proxy for changes in solvent composition as reclaiming progressed.

Density data were temperature-corrected to a reference temperature and compared against predictions from the reclaiming model. As shown in Figure 3, the measured density evolution closely follows the modelled steady-state behaviour, indicating that in-line density monitoring has strong potential as an operational diagnostic tool for reclaiming systems.

Figure 3. Comparison of measured liquid temperature and in-line density of reclaimed 35 wt.% MEA during thermal reclaiming with model-predicted steady-state temperature and calibrated solvent density. Density values are corrected to a reference temperature.

While further validation is required, these early results suggest that density measurements could be used to infer solvent condition and reclaiming progress in real time, reducing reliance on off-line sampling and analysis.

Analytical and modelling approaches

Several analytical methods are being developed and applied to characterise reclaiming performance:

• pH and Conductometric titration have been successfully used to quantify heat-stable salt content, amine concentrations and CO_2.
• Thermogravimetric analysis (TGA) has shown strong potential for determining amine concentration, with promising results currently awaiting publication.
• Gas chromatography (GC) is being explored to quantify specific degradation products, although analytical challenges remain.
• Coriolis Density flow meter has shown potential is monitoring the concentrations of reclaiming solvent in real time and showed matching results to modelling results.

In parallel, a process model for a continuous two-stage thermal reclaiming system has been developed. The objective of the model is to identify operating conditions under which degradation product formation and removal are balanced, allowing solvent quality to be maintained over long timeframes.

Good agreement has been achieved between a detailed MathCAD model and a simplified Excel-based implementation (Figure 4), enabling rapid exploration of operational trends. For example, the model shows that increasing water flow reduces system temperature, while higher non-volatile impurity concentrations increase it.

What we’ve found so far

Lab-scale thermal reclaiming can produce visually cleaner solvent from heavily degraded industrial MEA, but visual improvement alone is insufficient to assess true reclaiming effectiveness.

The reclaiming process involves unavoidable trade-offs between solvent recovery, impurity carryover, and waste stream minimisation.

Modelling results demonstrate that key operating parameters exert predictable and interpretable effects on system behaviour, supporting the feasibility of continuous two-stage reclaiming as a long-term solvent management strategy.

Dissemination and engagement

Over the past two years, this work has been presented at three UKCCSRC conferences and was awarded the Early Career Researcher poster prize at the UKCCSRC Spring 2024 Conference (Figure 5).

Figure 5. Winning the ECR poster prize. Picture taken from the UK Carbon Capture and Storage Research Centre

The research was also presented as an oral poster format at the 2024 GHGT-17 conference in Calgary, Canada, enabling direct engagement with researchers and industrial stakeholders working on solvent management and reclaiming (Figure 6). A conference paper entitled “An Experimental Investigation of Optimum Conditions for Continuous Two-Stage Reclaiming of MEA Solvent Inventories from Commercial Plants” accompanied this presentation.

Furthermore, this research was selected as an oral presentation at the 2025 PCCC-8 conference in Marseille, France (Figure 7).

Next steps

Several key areas remain to be addressed:

• Sub-atmospheric reclaiming operation, to assess its impact on efficiency and degradation behaviour
• Optimisation of caustic addition, including best practice for heat-stable salt neutralisation and minimising excess usage
• Experimental validation of the two-stage reclaiming model using real reclaiming data

Further dissemination is planned in multiple journal publications covering:

• Amine thermal reclaimer configurations and operation for post-combustion capture plants – insights from a generic open-access model
• Performance of two-stage reclaiming systems
• Optimum reclaiming conditions and degradation product carryover

Conclusion

This work highlights the complexity and critical importance of solvent reclaiming in amine-based CO₂ capture systems. The diversity of degradation products and their behaviour during reclaiming present both analytical and operational challenges, helping to explain the limited published literature in this area.

As CO₂ capture deployment accelerates and investment increases, robust well-understood solvent management strategies will be essential for ensuring long-term plant reliability and economic viability. This research contributes experimental capability, modelling tools, and practical insight towards that goal and provides a foundation for improving reclaiming practice in future commercial capture plants.

Read more on Abby’s Flexible Funding 2023 project page.

Dr Lee Hosking, Brunel University of London, was awarded funding through the UKCCSRC’s Flexible Funding 2023 call to investigate “C-WELL: CO2 injection well integrity under operational thermo-hydro-mechanical loading”, in partnership with Quintessa Ltd., Net Zero Technology Centre and The Solent Cluster.

One of the most important aspects of any CCS project is to ensure the secure, long-term storage of CO₂ within its intended subsurface reservoir. CO₂ leakage can pose challenges to environmental health, require additional monitoring and corrective measures, and have legal and regulatory implications. Any leaked CO₂ that reaches the atmosphere also undermines both the intended climate action and the investments of human capacity and funds.

In this context, the C-WELL project, delivered by Brunel University of London in collaboration with industry partners Quintessa, Net Zero Technology Centre and the Solent Cluster, has focused on one of the pathways by which CO₂ may migrate upwards from its storage reservoir: the injection wells themselves. Since these wells penetrate the confining layers of rock, they must be engineered to maintain an effective barrier to upward migration of the injected CO₂. To achieve this, each injection well is a composite of three main structural components: the steel casing, the cement sheath, and the surrounding rock itself, as shown in Figure 1. Also shown are the various defects that might develop into leakage pathways.

The C-WELL project team has employed numerical modelling and laboratory testing to investigate the performance of the cement sheath. Our focus has been two-fold: firstly, to predict the conditions and extent of debonding and microannulus growth at the interfaces of the cement sheath with the casing and cap rock, and secondly, to study the engineering properties and performance of different cement mixes for injection wells. This blog post focuses on the first of these.

Figure 1 – Potential defects in CO2 injection wells (Hosking and Zhou, 2025)

A model to predict damage evolution in CO₂ injection wells

As part of C-WELL, a new numerical model was developed to predict the thermal, hydraulic and mechanical behaviour of the composite well system, including interface damage and microannulus growth based on a cohesive zone model. These advancements allowed the performance of the cement sheath interfaces to be investigated under operational conditions, including in the presence of initial defects and for a wide range of CO₂ injection scenarios.

Importance of pre-existing defects

The role of a pre-existing defect was investigated in the form of an initially debonded surface following the cement job (Hosking and Zhou, 2025), which is a commonplace defect due to the challenges of deep well engineering. Figure 2 compares the interface damage predictions for an initially intact well to a well with an initially debonded segment at the casing-cement interface. A microannulus can be seen in both cases at the casing-cement interface – it is the blank space (white gap) close to the inner surface of the well. The peak microannulus is visibly larger for the defective case, reaching over double the mechanical aperture, highlighting the importance of accounting for the imperfect condition of wells when predicting leakage risk.

Figure 2 – Contour plots of displacement magnitude (in m) at 30-days near the centreline of the injection well. Black lines indicate original locations of the casing and cement with displacements are scaled up for clarity. Arrow surfaces show the direction and relative magnitude of displacement for (a) an initially intact well and (b) a well with a pre-existing defect in the form of a 45⁰ debonded azimuth (Hosking and Zhou, 2025)

Role of injection pressure and temperature

In research presented at the 17^th Greenhouse Gas Technologies (GHGT-17) conference held in Calgary, Canada, 20–24 October 2024 (Hosking et al., 2024), the C-WELL team identified that the damage initiation “window” for the casing-cement interface corresponds with conditions that could reasonably be expected at the bottomhole of CO₂ injection wells.

As an example, the findings of 171 simulations, each for different combinations of injection pressure and temperature, are expressed in Figure 3 in terms of the predicted aperture of the microannulus after 30 days of continuous CO₂ injection. Microannuli with mechanical apertures exceeding 0.12 mm were predicted for lower injection pressures and temperatures, with further research needed to determine the associated hydraulic aperture and axial extent of the damage. This future research direction has been facilitated by the C-WELL project supported by the UKCCSRC Flexible Funding Call 2023, and will build upon the present findings as we seek to better understand the CO₂ leakage risk posed by defects and damage development in injection wells.

Figure 3 – Surface plots of the casing-cement microannulus aperture at the end of the 30-day simulation period. Surfaces are formed from the results of 171 simulation scenarios (Hosking et al., 2024)

Improved CO₂ storage risk assessment

New quantitative evidence from C-WELL will next be used to improve the decision trees of project partner Quintessa’s TESLA decision support software, which will ultimately lead to more effective leakage risk assessments and corrective measures planning for CO₂ storage sites in the UK and internationally.

Read more on Lee’s Flexible Funding 2023 project page.

References

Hosking, L., Al-Noaimat, Y., Zhou, X., Zagorscak, R., Benbow, S., Metcalfe, R., 2024. Interface Damage and Microannulus Growth in CO₂ Injection Wells: Parametric Modelling for Pressure and Thermal Loading. In Proceedings of the 17^th Greenhouse Gas Technologies Conference, Calgary, Canada, 20–24 October 2024. https://doi.org/10.2139/ssrn.5034771

Hosking, L.J., Zhou, X. 2025. Damage modelling of CO₂ injection well interfaces under coupled thermal, hydraulic and mechanical behaviour. Deep Underground Science and Engineering.

Dr Ali Nabavi, Cranfield University, was awarded funding through the UKCCSRC’s Flexible Funding 2023 call to investigate, in collaboration with Immaterial Ltd., the performance of their novel monolithic metal-organic frameworks (MOFs) for industrial carbon capture applications.

Adsorption separation using porous solid sorbents has been considered a promising CO₂ capture and removal approach to curbing the deleterious effect of anthropogenic CO₂. Cyclic adsorption processes using nanoporous sorbents are the key building blocks in deriving industrial carbon capture, fuel switching and negative emission technologies. Aligned with the UK climate ambition, the cost and energy penalty of the existing carbon capture technologies must be reduced to be widely deployed.  Porous solid adsorbents, including metal organic frameworks (MOFs), when optimised, offer a substantial cost reduction for CO₂ capture due to lower energy requirements for regeneration, compared to the conventional approaches.

MOFs offer high surface area, tuneable pore structures and exceptional adsorption properties. Their porosity and adjustable chemistry enable them to exhibit a significantly higher CO₂ adsorption capacity compared to conventional sorbents. Despite their versatility and tunable properties, conventional MOFs face several challenges that hinder their widespread implementation in carbon capture from industrial flue gases. These challenges include issues related to their stability in the presence of water, steam and flue gas, difficulties in scaling up production and low volumetric adsorption capacity. Furthermore, although there have been advancements in the performance and stability of MOFs, their powder form is impractical for direct use in separation columns. To address these challenges, Immaterial has developed monolithic MOFs (m-MOFs) that benefit from production scalability and a form factor that targets the drawbacks of conventional MOFs. Therefore, owing to better material packing, the volumetric adsorption performance has been shown to increase significantly.

Recognising the potential of m-MOFs for carbon capture, the UKCCSRC has in-part funded a collaborative project between Immaterial Ltd and Cranfield University, to investigate the effect of water, steam and flue gas impurities (i.e. SOx, and NOx) on adsorption characteristics and hydro-chemical stability of m-MOFs, to explore their feasibility for carbon capture from industries.

To assess the feasibility, Cranfield University upgraded one of its bench-scale facilities to conduct fixed-bed breakthrough analysis under various scenarios to determine CO₂ adsorption-desorption kinetics. The assessment covered CO₂ adsorption properties, CO₂ concentration in flue gas, flue gas relative humidity, and the impact of flue gas impurities under various conditions, including short- and long-term exposure to dry and wet gas streams with or without O₂, NO₂ and SO₂. In addition, Dynamic Mechanical Analysis (DMA) was used to assess the mechanical stability of the material, providing insights into its structural integrity under different operating conditions.

The findings from these assessments demonstrated the hydrothermal stability of m-MOFs under flue gas impurities. Moreover, the material demonstrated excellent robustness, maintaining its structural integrity and performance despite prolonged exposure to industrial gas streams or mechanical attrition. Such features will be crucial in ensuring the commercial viability and widespread implementation of m-MOF for carbon capture from industries.

As global demand for viable carbon capture solutions increases, research partnerships like the collaboration between Immaterial and Cranfield University through this project are vital for advancing net-zero commitments. This project highlights the potential of m-MOFs as promising CO₂ sorbents, offering a scalable and cost-effective alternative to conventional carbon capture approaches and paving the way for the adoption of adsorption-based CO₂ capture processes for industrial decarbonisation.

Cranfield University research team working on the breakthrough rig

Cranfield Principal Investigator: Dr Ali Nabavi, Reader in Low Carbon Energy Systems

Cranfield Researchers: Mr Fayez Qureshi, Mr Sunera Athauda, and Dr Ziqi Shen

Industrial Sponsor: Immaterial Ltd.

Read more on Ali’s Flexible Funding 2023 project page.

Dr Yihuai Zhang, University of Glasgow, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “Dynamic CO₂ Residual Trapping in Carbonate Rock”.

Project Overview

As the impacts of climate change become more pronounced, the need for effective strategies to reduce atmospheric CO₂ levels has never been greater. Among the promising measures under development, carbon capture and storage (CCS) stands out for its potential to securely store CO₂ deep underground, preventing its release into the atmosphere. One particular geological formation gaining attention for CCS is carbonate reservoirs, which are notable for their sizable storage capacity. However, the introduction of CO₂-saturated water into these formations can trigger chemical reactions that may alter rock pore structures over time, ultimately affecting the capacity of these reservoirs to trap CO₂. Our project aims to shed light on these complex chemical and physical processes, and how they influence the safe, long-term sequestration of CO₂ in carbonate reservoirs.

Why carbonate rock?

Carbonate reservoirs—such as limestones and dolomites—are abundant worldwide and hold immense storage capacity (e.g. the depleted oil and gas carbonate reservoirs). But they’re also reactive. When CO₂ dissolves into the formation water of the reservoir, it produces a weak carbonic acid. This acid can dissolve certain minerals in the rock matrix, effectively enlarging or connecting pores over time. Such changes can lower the resistance to fluid flow and modify how CO₂ is trapped in the reservoir’s pore spaces. Understanding these dynamics is crucial: if too much dissolution occurs, the reservoir’s ability to retain CO₂ safely could be compromised.

Our Approach: 4D High-Resolution X-Ray Imaging

To capture these rapid chemical and physical changes at the pore scale, our team employed in situ core flooding tests under 4D high-resolution X-ray synchrotron imaging at the I13 beamline in the Diamond Light Source. This cutting-edge facility allowed us to visualise the rock’s interior in real-time and observe exactly how CO₂-rich fluid travels through and alters the carbonate matrix, as well as how the CO₂ is trapped inside the sample before and after the damage. By segmenting and reconstructing these high-resolution images, we could identify zones of dissolution (e.g., channel formation) and quantify changes in porosity, permeability and capillary trapping. This allowed us to map how dissolution fronts spread and to measure how much the rock’s structure was altered.

Figure 1. The in situ core flooding set up at the I13 beamline in the Diamond Light Source.

Some Findings:

Channelled Dissolution Patterns

Our results revealed a channelled dissolution pattern, where fluid flow became increasingly focused through newly enlarged or connected pore networks. This channelling correlated with a measurable rise in porosity over time.

Reduced Capillary Entry Pressure

Through pore-scale simulations of fluid flow (drainage and imbibition), we found that as pore connectivity increased, the resistance to fluid penetration (capillary entry pressure) decreased. This could mean CO₂ can more easily invade and travel through these formations, altering the balance between retention and mobility.

Slight Reduction in Trapping Efficiency 

A key component of CCS is ensuring CO₂ gets “trapped” rather than freely migrating. Our findings show that as the pores become broader and better connected, overall trapping efficiency is likely to decrease slightly—though remaining a viable mechanism for CO₂ sequestration.

Figure 2. Examples of the raw images and 3D reconstructed image of the rock damage along the CO2 reactive brine injection.

Next Steps

Our ongoing work focuses on in situ contact angle measurements and dynamic flow effects to further refine our understanding of how local wettability and flow rates influence CO₂ trapping in real subsurface conditions. These insights will be published soon after the analysis is finished. We hope that the knowledge we’re generating can help industry and policymakers better gauge the long-term security of CCS in carbonate reservoirs. By pinpointing when, where and how dissolution-driven changes may occur, and how they can impact the residual trappings, we aim to optimise injection strategies, enhance monitoring tools and ensure that CCS lives up to its promise as a cornerstone of climate change mitigation.

Read more on Yihuai’s Flexible Funding 2023 project page.

Professor Sophie L Nixon, University of Manchester, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “Microbial Impacts of CCS: Potential Benefits and Problems During Geological CO2 Storage”.

Carbon capture and storage (CCS) is considered crucial to the delivery of global 2050 Net Zero emissions targets, which are now a legal obligation for the UK. In order for CCS to succeed, CO₂ must be permanently stored in deep (>800m) geological formations, namely saline aquifers and depleted oil and gas reservoirs, with target storage times in excess of 10,000 years (Alcalde, Flude et al. 2018).

It is well established that conventional oil and gas reservoirs can have significant issues with problematic microbial activity within the subsurface, leading to reservoir souring, biofouling at the injection well and also microbially-influenced corrosion (MIC) (Bodtker, Thorstenson et al. 2008, Johnson, Folwell et al. 2017, Skovhus, Eckert et al. 2017, Vigneron, Alsop et al. 2017). Therefore, in sites where there is already a significant, and costly, microbial presence, it would be remiss of the industry to not take into account the potential impacts of the subsurface microbiology once these depleted oil and gas reservoirs are repurposed for long-term CO₂ storage.

However, the metabolic reactions driven by CO₂ fixation in subsurface communities are not well understood, and could feasibly result in a net gain or loss of CO₂, production of methane, and microbially induced corrosion (Tyne, Barry et al. 2021, Tyne, Barry et al. 2023). This microbial activity could compromise the capacity, integrity and long-term safety of CO₂ storage sites. Alternatively, microbially-enhanced CO₂ sequestration could enhance the mineralization of CO₂ within the subsurface, improve the overall success of CCS operations and uncover novel ways to convert waste CO₂ into useful products (Matter, Stute et al. 2016, Trias, Menez et al. 2017, Bachleitner, Ata et al. 2023).

In this study, we aimed to take a first look at the response of a mature oil-field derived microbial community to a CO₂ saturated environment (Dutta, Smith et al. 2020). By utilising 16S rRNA gene sequencing, we were able to determine how the microbial community changed over the 12-month incubation period, and identify the proliferation of any potential problematic or beneficial microbial processes that could indicate potential shifts within the microbiome of depleted oil and gas reservoirs when utilised for subsurface CO₂ storage.

The results from this study demonstrate that mature oilfield communities can persist under CO₂ storage conditions (i.e. saturated CO₂ seawater and a CO₂ gas headspace), and that heterotrophic microbial processes, including sulfide production, were observed within a 12-month incubation period in the presence of readily utilisable hydrocarbons (i.e. VFAs).

The enrichment of heterotrophic taxa within the CO₂ enrichments demonstrates that hydrocarbon degradation, and sulfide production were able to occur under high concentrations of CO₂ and a reduced pH, and were supported by a reduction in available concentrations of VFAs (acetate, propionate and butyrate) throughout the 12-month incubation period.

Desulfallas-Sporotomaculum was the most abundant sulfate-reducing genus within the Test 6 (CO₂+VFA) enrichments after 12-months of incubation, and is a known anaerobic, spore-forming, sulfate-reducing genus which can be moderately thermophilic and is known to utilise short and long chain fatty acids (Watanabe, Kojima et al. 2018).  It can therefore be surmised that Desulfallas-Sporotomaculum species were able to utilise the available fatty acids within the enrichment medium as electron donors and facilitate dissimilatory sulfate-reducing processes. This is further supported by the low relative abundance of Desulfallas-Sporotomaculum within the Test 1 (CO₂) enrichments, where there was no additional readily metabolisable hydrocarbon added to the saline media prior to incubation.

By the end of the study, the Test 1 (CO₂) and Test 6 (CO₂+VFA) enrichments were dominated by hydrocarbon degrading genera, such as Parvibaculum, Marinobacter, Marinobacterium and Breoghania. All of these genera have previously been isolated from hydrocarbon associated marine environments, and are known to have the capacity to degrade hydrocarbon compounds (Gallego, Vila et al. 2010, Lai, Wang et al. 2011, Rosario-Passapera, Keddis et al. 2012, Bae, Jung et al. 2018, Scheffer, Hubert et al. 2021).

Genus-level microbial community composition of the CO2 saturated enrichments monthly (T0-T6) and then after 12-months of incubation (T7) using 16S rRNA gene sequencing.

Therefore, the results from this study demonstrate that microbial activity can persist under saturated CO₂ conditions, and that evidence of potentially problematic microbial activity (e.g. hydrogen sulfide production) can occur in hydrocarbon saturated environments that are utilised for CCS operations.

Ongoing research will encompass the use of groundwater and formation fluid samples from industrially relevant CO₂ storage sites of interest to profile the baseline microbial community and associated functional potential, and also identify the subsequent response to saturated CO₂ environments.

Read more on Sophie’s Flexible Funding 2023 project page.

Principal Investigator: Prof. Sophie Nixon (Chair of Environmental Microbiology and Biotechnology)

Researcher Co-Investigator: Leanne Walker (Research Associate in Subsurface Microbiology (CCS))

Research Institution: The University of Manchester

Industrial Sponsor: ExxonMobil

References

Alcalde, J., S. Flude, M. Wilkinson, G. Johnson, K. Edlmann, C. E. Bond, V. Scott, S. M. V. Gilfillan, X. Ogaya and R. S. Haszeldine (2018). “Estimating geological CO2 storage security to deliver on climate mitigation.” Nature Communications 9(1): 2201.

Bachleitner, S., Ö. Ata and D. Mattanovich (2023). “The potential of CO(2)-based production cycles in biotechnology to fight the climate crisis.” Nat Commun 14(1): 6978.

Bae, S. S., J. Jung, D. Chung and K. Baek (2018). “Marinobacterium aestuarii sp. nov., a benzene-degrading marine bacterium isolated from estuary sediment.” Int J Syst Evol Microbiol 68(2): 651-656.

Bodtker, G., T. Thorstenson, B. L. Lillebo, B. E. Thorbjornsen, R. H. Ulvoen, E. Sunde and T. Torsvik (2008). “The effect of long-term nitrate treatment on SRB activity, corrosion rate and bacterial community composition in offshore water injection systems.” J Ind Microbiol Biotechnol 35(12): 1625-1636.

Dutta, A., B. Smith, T. Goldman, L. Walker, M. Streets, B. Eden, R. Dirmeier and J. S. Bowman (2020). “Understanding Microbial Community Dynamics in Up-Flow Bioreactors to Improve Mitigation Strategies for Oil Souring.” Front Microbiol 11: 585943.

Gallego, S., J. Vila, J. María Nieto, M. Urdiain, R. Rosselló-Móra and M. Grifoll (2010). “Breoghania corrubedonensis gen. nov. sp. nov., a novel alphaproteobacterium isolated from a Galician beach (NW Spain) after the Prestige fuel oil spill, and emended description of the family Cohaesibacteraceae and the species Cohaesibacter gelatinilyticus.” Syst Appl Microbiol 33(6): 316-321.

Government, U. (2019, 26th June 2019). “The Climate Change Act 2008 (2050 Target Amendment) Order 2019 ”   Retrieved 4th January 2024, 2024, from https://www.legislation.gov.uk/uksi/2019/1056/pdfs/uksi_20191056_en.pdf.

Johnson, R. J., B. D. Folwell, A. Wirekoh, M. Frenzel and T. L. Skovhus (2017). “Reservoir Souring – Latest developments for application and mitigation.” J Biotechnol 256: 57-67.

Lai, Q., L. Wang, Y. Liu, J. Yuan, F. Sun and Z. Shao (2011). “Parvibaculum indicum sp. nov., isolated from deep-sea water.” Int J Syst Evol Microbiol 61(Pt 2): 271-274.

Matter, J. M., M. Stute, S. Snæbjörnsdottir, E. H. Oelkers, S. R. Gislason, E. S. Aradottir, B. Sigfusson, I. Gunnarsson, H. Sigurdardottir, E. Gunnlaugsson, G. Axelsson, H. A. Alfredsson, D. Wolff-Boenisch, K. Mesfin, D. Fernandez de la Reguera Taya, J. Hall, K. Dideriksen and W. S. Broecker (2016). “Rapid carbon mineralization for permanent disposal of anthropogenic carbon dioxide emissions.” Science 352(6291): 1312-1314.

Rosario-Passapera, R., R. Keddis, R. Wong, R. A. Lutz, V. Starovoytov and C. Vetriani (2012). “Parvibaculum hydrocarboniclasticum sp. nov., a mesophilic, alkane-oxidizing alphaproteobacterium isolated from a deep-sea hydrothermal vent on the East Pacific Rise.” Int J Syst Evol Microbiol 62(Pt 12): 2921-2926.

Scheffer, G., C. R. J. Hubert, D. R. Enning, S. Lahme, J. Mand and J. R. de Rezende (2021). “Metagenomic Investigation of a Low Diversity, High Salinity Offshore Oil Reservoir.” Microorganisms 9(11).

Skovhus, T. L., R. B. Eckert and E. Rodrigues (2017). “Management and control of microbiologically influenced corrosion (MIC) in the oil and gas industry-Overview and a North Sea case study.” J Biotechnol 256: 31-45.

Trias, R., B. Menez, P. le Campion, Y. Zivanovic, L. Lecourt, A. Lecoeuvre, P. Schmitt-Kopplin, J. Uhl, S. R. Gislason, H. A. Alfreethsson, K. G. Mesfin, S. O. Snaebjornsdottir, E. S. Aradottir, I. Gunnarsson, J. M. Matter, M. Stute, E. H. Oelkers and E. Gerard (2017). “High reactivity of deep biota under anthropogenic CO(2) injection into basalt.” Nat Commun 8(1): 1063.

Tyne, R. L., P. H. Barry, M. Lawson, D. J. Byrne, O. Warr, H. Xie, D. J. Hillegonds, M. Formolo, Z. M. Summers, B. Skinner, J. M. Eiler and C. J. Ballentine (2021). “Rapid microbial methanogenesis during CO(2) storage in hydrocarbon reservoirs.” Nature 600(7890): 670-674.

Tyne, R. L., P. H. Barry, M. Lawson, K. G. Lloyd, D. Giovannelli, Z. M. Summers and C. J. Ballentine (2023). “Identifying and Understanding Microbial Methanogenesis in CO(2) Storage.” Environ Sci Technol 57(26): 9459-9473.

Vigneron, A., E. B. Alsop, B. P. Lomans, N. C. Kyrpides, I. M. Head and N. Tsesmetzis (2017). “Succession in the petroleum reservoir microbiome through an oil field production lifecycle.” ISME J 11(9): 2141-2154.

Watanabe, M., H. Kojima and M. Fukui (2018). “Review of Desulfotomaculum species and proposal of the genera Desulfallas gen. nov., Desulfofundulus gen. nov., Desulfofarcimen gen. nov. and Desulfohalotomaculum gen. nov.” Int J Syst Evol Microbiol 68(9): 2891-2899.

Jiacheng Sun, University of Edinburgh, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “An integrated strategy for long-term carbon sink and sustainable supercapacitor material production”.

The Microalgae Biochar Supercapacitor Material (MBSM) project was developed to tackle multiple global challenges, focusing on the production of sustainable materials, carbon capture and storage. In the MBSM project, biochar derived from lignocellulosic biomass and wastewater algae is optimized for use in supercapacitor applications, while simultaneously contributing to carbon sequestration and phosphorus recovery. The project’s sub-projects explore the activation techniques and feedstock choices to enhance the electrochemical properties of biochar.

The MBSM project focuses on producing biochar with specific properties that support energy storage while offering environmental benefits. The project is structured around two sub-projects, each addressing different aspects of biochar optimization: supercapacitor performance of lignocellulosic biochar and phosphorus recovery from algae biochar.

Figure 1 illustrates the flowchart of biochar produced from different feedstocks and activation processes. Lignocellulosic biochar, derived from straw and wood, showed varying degrees of specific capacitance based on the type of feedstock used and the activation method employed.

Figure 1. Lignocellulosic biochar based supercapacitor materials

The Role of Feedstock and Activation Process

The first sub-project, titled “The Role of Feedstock and Activation Process on Supercapacitor Performance of Lignocellulosic Biochar”, investigated the effects of different biomass feedstocks and activation methods on biochar’s electrochemical properties. This sub-project analyzed wood and straw feedstocks, and used CO2, steam and KOH activation to optimize biochar performance.

• Feedstock Performance: Straw-derived biochar was found to have higher specific capacitance than wood-derived biochar, despite the latter having greater electrical conductivity and porosity. This highlights the importance of feedstock selection in maximizing performance.
• Activation Trade-offs: Chemical activation using KOH produced biochar with higher surface areas and capacitance, but at the expense of electrical conductivity, indicating a balance needs to be struck between these properties.

This research provides valuable data on how different feedstocks and activation processes can be tailored to meet supercapacitor material requirements, which are essential for sustainable energy storage applications.

Phosphorus Recovery and Algae Biochar Performance

In the second sub-project, “Synergistic Valorisation of Wastewater Microalgae: Sulphuric Acid-Assisted Phosphorus Recovery and Enhanced Electrochemical Performance of Biochar for Supercapacitors”, the focus shifted to algae-derived biochar. Phosphorus recovery from wastewater algae was optimized using sulphuric acid, which also enhanced the biochar’s electrochemical properties (Figure 2).

• Phosphorus Recovery: Sulphuric acid leaching enabled phosphorus recovery rates of up to 95%, providing a solution for phosphorus pollution while promoting its reuse in agriculture, aligned with circular economy principles.
• Electrochemical Enhancement: The process improved the porosity of algae biochar and introduced sulfur-containing functional groups, increasing its specific capacitance to as high as 486.3 F g⁻¹, making it a promising candidate for supercapacitor electrodes.

Analysis of the phosphorus recovery process offers crucial insights into the dual benefits of algae biochar for both environmental remediation and energy storage.

Figure 2. Cyclic voltammetry curves of AN550 (Seaweed) and WM550 (Wastewater microalgae) derived biochar materials at scan rates of 10, 20, 40, 60, and 80 mV s−1.

Synergy Between Sub-Projects

Both sub-projects are integral to the overarching goals of the MBSM project, demonstrating the multifaceted applications of biochar in sustainability and technology.

• Sustainable Material Development: By exploring different biomass feedstocks, including lignocellulosic materials and wastewater algae, the project shows how biochar can be converted into high-performance supercapacitor materials, contributing to the transition to renewable energy.
• Carbon Sequestration: Biochar’s ability to lock carbon in stable forms supports the project’s carbon-negative approach. The results of both sub-projects emphasize the potential of biochar to reduce carbon emissions, whilst addressing the growing need for sustainable materials.
• Phosphorus Recovery: The algae biochar sub-project adds an environmental dimension by tackling phosphorus pollution and recovery. Phosphorus, a critical agricultural resource, is effectively reused, closing the loop in a circular economy model.

The quality of the biochar produced in the MBSM project is strongly dependent on the feedstock and activation methods used. Both sub-projects demonstrate the potential of biochar to serve as a sustainable material for supercapacitors, whilst contributing to environmental goals like carbon sequestration and phosphorus recovery. Although further research is needed to refine these methods for commercial applications, the MBSM project offers promising pathways for addressing pressing sustainability challenges.

Read more on Jiacheng’s Flexible Funding 2023 project page.

Dr Emma Michie, University of Liverpool, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “Faulting in siliciclastic – carbonate sequences; an improved characterization for de-risking faulted CCS sites”.

Project Overview

The main project aim was to reduce uncertainty when analysing fault seal behaviour within siliciclastic – carbonate (mixed) sequences within the subsurface, benefiting CO₂ storage site assessment. Several proposed CO₂ storage sites contain mixed sequences within the overburden, with mudstones interbedded with carbonate units.  To increase worldwide stored CO_2, is it likely that we will utilise complex sites influenced, or bound, by faults cutting these mixed sequences. However, we currently have no tools to accurately predict their sealing potential. Further, the influence of carbonate interbeds on fault seal is currently unknown.

This research project focused on outcropping analogues of faulted siliciclastic-carbonate sequences with the attempt to start to fill the knowledge gap of how to characterise these structures within the subsurface.  Previous studies have focused efforts into understanding fault seal potential either within siliciclastic sequences (sand-shale) or carbonates, but rarely combining the two, despite the commonality for the heterogeneous sequence. Outcrop analogues utilised for this study are in the northern and central Apennines.

What We Did

This project generated new collaborations with researchers from Italy, bringing their wealth of knowledge into local geology, suggesting suitable outcrop analogues.  Together, we came up with a work programme for sampling outcrops that most accurately represent potential CO₂ storage sites.

We focused on two outcrop analogues in the northern and central Apennines, Italy, collecting 20 samples from the host and the fault zone. The samples were measured for porosity and permeability, as well as generating thin section for associated microscopy analysis using optical and SEM methods.

Some outcrop localities were in easy reach.  Others meant a more laborious hike, which included sliding back down due to a downpour that occurred whilst at the top of the hill, turning the road into a mud slide!

Whilst conducting fieldwork, I couldn’t resist indulging in some nearby geotourism. I explored the lingering devastation from the 2016 Amatrice earthquake, a poignant reminder of nature’s force, and marvelled at the chance to touch the well-preserved K-Pg boundary in Gubbio—a tangible connection to one of Earth’s most dramatic events.

Key Findings

Complicated fault zone architectures were recorded within these mixed carbonate-marl sequences, creating wide zones with multiple slip surfaces. Where carbonate lithologies dominate, the fault zone narrows slightly, localising deformation to create (proto)cataclastic rock fabrics on the slip surfaces.  Where marl lithologies dominate, multiple slip surfaces are observed, distributing the strain.  Significant veining is observed in more competent lithologies that have been juxtaposed.

Measured permeability values do not seem to vary significant from host to fault rock samples within the marl units. However, the permeability is recorded as increasing within the fault rock of the more competent carbonate units, associated with the observed veining. Such results will help refine subsurface modelling. This increased permeability may have implications for storage site assessment.

What’s Next

This project has now reached completion, and one of the research papers from this project will be submitted early 2025.  Research will continue, with further analyses of the collected samples, including XRD analysis and XCT image analysis.

Read more on Emma’s Flexible Funding 2023 project page.

Mohadeseh Motie, Heriot-Watt University, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “Enhanced Decision-Making in CO2 Storage Projects: A Bayesian Networks Approach for Value of Information Analysis”.

Climate change mitigation strategies have become increasingly crucial in our efforts to limit global temperature rise. Among these strategies, Carbon Capture and Storage (CCS) has emerged as a promising technology to reduce greenhouse gas emissions. However, the implementation of CCS projects is fraught with uncertainties that can significantly impact their viability and effectiveness. This blog post explores how advanced analytical tools, specifically Bayesian networks and Value of Information (VOI) analysis, can enhance decision-making processes in CO₂ storage projects.

In our study, we constructed a Bayesian network to model the relationships between storage capacity, leakage risk, CO₂ prices and overall project viability. This approach allowed us to:

• Quantify the probabilistic dependencies between these factors
• Update our understanding of project viability as new data becomes available
• Perform scenario analyses to assess the impact of different variable states on project outcomes

Value of Information: Optimizing Data Acquisition

While Bayesian networks provide a robust framework for modelling uncertainties, the Value of Information (VOI) analysis offers a quantitative method for assessing the potential benefits of acquiring additional information before making investment decisions.

In our case study, we evaluated the VOI for conducting a detailed geological survey to better understand the storage capacity of a potential CO₂ storage site. The analysis revealed:

• Without additional information, the investment project of signing a 10-year contract to store 20mln ton CO₂ had a slightly negative expected Net Present Value (NPV) of -$6.83 million
• The VOI for the geological survey was calculated to be $12.55 million
• The cost of the survey was estimated at $2 million

These results indicate that acquiring this information would be highly beneficial, as the potential value gained significantly outweighs the cost of the survey.

Implications for Decision-Making in CCS Projects

The integration of Bayesian networks and VOI analysis in our decision-making framework led to several key insights:

• Improved risk assessment: By modelling the interdependencies between various uncertainties, we gained a more comprehensive understanding of project risks.
• Optimized information gathering: VOI analysis provided a quantitative basis for prioritizing data acquisition efforts, ensuring that resources are allocated efficiently.
• Enhanced decision support: The combined approach allowed for the development of more robust decision strategies, potentially increasing the expected NPV from -$6.83 million to $15.71 million in our case study.
• Dynamic updating: As new information becomes available throughout the project lifecycle, the Bayesian network can be updated, providing continual decision support.

Figure 1. Bayesian Network for a CO2 storage project in a synthetic simulated aquifer

Conclusion and Future Directions

While CCS technology presents a promising avenue for mitigating climate change, its successful implementation requires sophisticated approaches to managing uncertainties and optimizing decision-making processes. The combination of Bayesian networks and Value of Information analysis offers a powerful toolkit for addressing these challenges by generating insights for investment decisions.

Future research in this area could explore:

• Integration of additional uncertainties, such as regulatory risks and technological advancements
• Application of this methodology to real-world CCS projects to validate its effectiveness
• Development of user-friendly software tools to make these analytical techniques more accessible to project managers and policymakers

Read more on Motie’s Flexible Funding 2023 project page.

Dr Laura Herraiz, Heriot-Watt University, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “Exploring the use of Rotary Adsorption Systems for Direct Air Carbon Capture and Storage (DACCS) applications”.

Direct Air Carbon Capture and Storage (DACCS) is an essential technology for mitigating climate change by capturing CO₂ directly from the atmosphere. It is a critical component of the UK’s strategy to achieve net-zero greenhouse gas (GHG) emissions by 2050. Rotary adsorption systems, particularly those using Temperature Swing Adsorption (TSA), offer a promising approach for DACCS due to their compact design, scalability and ability to handle large volumes of ambient air, which contains low concentrations of CO₂ (~0.04%).

The rotary system’s continuous operation allows for cyclic adsorption and desorption, making it energy-efficient by minimizing pressure drops and ensuring rapid regeneration. The ability to rotate the adsorbent, and alternate between capturing CO₂ from air and regenerating the adsorbent using steam or indirect heating, is a key advantage. This system could reduce capital and operational costs by combining fast adsorption kinetics, efficient heat transfer and modular scalability.

Schematic representation of a Rotary Adsorption Wheel with steam regeneration

Despite these advantages, several key challenges remain:

1. Material Selection and Water Adsorption: The selection of adsorbent materials is crucial for the efficiency of DACCS. Materials must have high selectivity for CO₂ over nitrogen and water, but water vapor in ambient air complicates the process. Water competes for adsorption sites, particularly on hydrophilic materials, reducing CO₂ capture efficiency. This issue is exacerbated in humid conditions, where water can saturate the adsorbent, requiring significant energy for desorption. MOFs (Metal-Organic Frameworks) have been identified as promising materials due to their tunable properties, but finding water-stable MOFs remains a challenge.
2. Adsorption Isotherms: Modeling the co-adsorption of CO₂ and water accurately is difficult, especially since water adsorption isotherms often exhibit hysteresis. This leads to discrepancies in the amount of water and CO₂ adsorbed and desorbed at the same relative humidity, complicating regeneration and energy efficiency predictions.
3. Regeneration Process: Achieving uniform heat distribution for regeneration in large-scale rotary systems is technically challenging. Indirect heating may lead to inefficiencies, while direct heating with steam introduces complexities in managing the condensation of water and CO₂.

The development of this DACCS model, based on open-source software and collaboration with industry partners, is still ongoing. Overcoming these challenges is crucial for creating a scalable, cost-effective solution for removing CO₂ from the atmosphere and contributing to global net-zero targets.

Read more on Laura’s Flexible Funding 2023 project page.

Dr Aliakbar Hassanpouryouzband, University of Edinburgh, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “CRYSTAL-CCS: Clathrate-Based Geological Carbon Capture and Storage”.

CRYSTAL-CCS: A Collaborative Solution for Carbon Capture and Storage

The CRYSTAL-CCS project, funded by the UKCCSRC, has successfully explored a new method for capturing and storing carbon dioxide (CO2). As CO2 emissions continue to be a major contributor to climate change, finding safe and effective ways to store CO2 underground is crucial. This project focused on using clathrate hydrates, a special type of structure that forms when CO2 is trapped in water molecules, as a potential solution for long-term CO2 storage.

One of the standout achievements of the CRYSTAL-CCS project is the international collaboration it fostered. Researchers from the UK, China and Germany worked together, combining their expertise to advance this promising carbon capture technology. The project has now reached completion, and the final research paper is currently under review.

How CRYSTAL-CCS Works

The CRYSTAL-CCS project investigates the ability of clathrate hydrates to trap and store CO2 in a stable form. Clathrate hydrates are similar to ice but have gas molecules like CO2 locked inside their structure. These hydrates can form naturally under certain pressure and temperature conditions, making them a potential way to store CO2 safely in deep water-saturated sediments.

Our research has focused on understanding how quickly these hydrates form, how stable they are over time, and how much CO2 they can store. We conducted experiments under controlled conditions that simulate real-world environments, allowing us to test the potential of this method for large-scale CO2 storage.

An International Research Effort

A key achievement of the CRYSTAL-CCS project has been the successful collaboration with scientists from China and Germany. By combining different areas of expertise, we have been able to approach the challenge of carbon capture and storage from multiple angles, improving the overall effectiveness of the research.

The results of our research are currently under review in a comprehensive paper, which will be published soon. This paper will provide valuable insights into how clathrate hydrates can be used as a new method for storing CO2, offering an alternative to more traditional carbon capture methods.

What’s Next

With the successful completion of the CRYSTAL-CCS project, we are excited to share our findings with the scientific community and other stakeholders. The results will soon be made available through publications and will also be featured on the UKCCSRC website. These findings will help inform future research and development in the field of carbon capture and storage.

Read more on Aliakbar’s Flexible Funding 2023 project page.

Ali presenting at UFRJ, with attendance from companies in Brazil, which also included results from the Crystal CCS project

The UK Carbon Capture and Storage Research Community (UKCCSRC) is supported by the Engineering and Physical Sciences Research Council (EPSRC) as part of the UK Research and Innovation (UKRI) Energy Programme.

The mission of the UKCCSRC is to ensure that carbon capture and storage (CCS) plays an effective role in helping the UK achieve net-zero greenhouse gas emissions by 2050.

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