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Journal articleKucherenko S, Shah N, Klymenko OV, 2025,
Identification of feasible regions using R-functions
, Journal of Process Control, Vol: 154, ISSN: 0959-1524The primary objective of feasibility analysis is to identify and define the feasibility region, which represents the range of operational conditions (e.g., variations in process parameters) that ensure safe, reliable, and feasible process performance. This work introduces a novel feasibility analysis method that requires only that model constraints (e.g., defining product Critical Quality Attributes or process Key Performance Indicators) be explicitly provided or approximated by a closed-form function, such as a multivariate polynomial model. The method is based on V.L. Rvachev's R-functions, enabling an explicit analytical representation of the feasibility region without relying on complex optimization-based approaches. R-functions offer a framework for describing intricate geometric shapes and performing operations on them using implicit functions and inequality constraints. The theory of R-functions facilitates the identification of feasibility regions through algebraic manipulation, making it a more practical alternative to traditional optimization-based methods. The effectiveness of the proposed approach is demonstrated using a suite of well-known test cases from the literature.
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Journal articleSuleman MY, Judah HL, Bexis P, et al., 2025,
The acetate anion promotes hydrolysis of poly(ethylene terephthalate) in ionic liquid-water mixtures
, Green Chemistry, Vol: 27, Pages: 11475-11490, ISSN: 1463-9262A circular plastic economy reduces raw material consumption and discourages pollution. Chemical recycling upgrades the quality of recyclate and is a complementary approach to thermomechanical recycling of plastic waste. This study investigated the use of aprotic and protic ionic liquids (ILs) as solvents for chemical recycling by the hydrolysis of the most common polyester plastic, poly(ethylene terephthalate) (PET). Combinations of three types of cations (aprotic 1-alkyl-3-methylimidazolium, protic 1-methylimidazolium and protic 1,5-biazocyclo-[4.3.0]non-5-enium) combined with a range of anions (acetate, chloride, methanesulfonate, hydrogen sulfate, methyl sulfate, trifluoromethanesulfonate and chlorozincate) were used to hydrolyse PET in the presence of 15 wt% water as the co-solvent and reagent. PET conversion under the screening conditions (180 °C, 3 h, 5% PET loading) varied between 1 and 100%, with ILs containing the acetate anion enabling >97% PET conversion irrespective of the cation. Acidification with aqueous HCl recovered crude crystallised terephthalic acid (TPA). Significant crude yields (46–93%) were only observed for the acetate ILs. The purity of the crude TPA was 34–98%, with 1-ethy-3-methylimidazolium acetate, [C2C1im][OAc], and 1-methylimidazolium acetate, [C1Him][OAc], yielding more and purer TPA than 1,5-biazocyclo-[4.3.0]non-5-enium acetate, [DBNH][OAc]. TPA solubility, PET conversion and TPA yield generally correlated well with increasing pKa and higher hydrogen bond acceptor strength of the IL anion, suggesting that the depolymerisation mechanism in the acetate IL water mixtures is base catalysed. The screening identifies aqueous mixtures of the (pseudo)-protic IL [C1Him][OAc] as promising catalytic solvent component for the chemical recycling of PET at an industrially feasible temperature, due to high isolated TPA yields and purity achieved at a low solvent cost ($1.74–2.15 per kg). However, an effective separation a
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Journal articleJing R, Wu X, Weng T, et al., 2025,
Uncovering the technical potential of coal-to-nuclear (C2N) power generation on a global scale
, Nexus, Vol: 2, ISSN: 2950-1601Decarbonization urgently calls for a substantial replacement of coal-fired power with carbon-free energy in the global energy landscape. However, the prevailing substitution of coal with variable renewable energy cannot be implemented universally due to possible higher cost and lack of power system flexibility. What is more, well-trained coal-fired power workers and surrounding communities are facing challenges. Therefore, we emphasize the unique value of coal-to-nuclear (C2N) in the energy transition by investigating 9,470 coal-fired power units globally. We identified that 14.3% (i.e., 371.6 GW) of them can be prioritized for C2N. The currently available nuclear technologies are feasible for C2N in three ways. A competitive levelized cost of electricity of US$71.84– US$101.48/MWh could be a strong driver when compared to coal+carbon capture and storage. Overall, C2N offers multifaceted benefits, and it can be a good supplement to the prevailing solar and wind renewables.
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ReportCorujo Simon E, Chachuat B, Kucherenko S, et al., 2025,
Making peptides: enabling a medical revolution
, Making peptides: enabling a medical revolution, Publisher: Sargent Centre for Process Systems Engineering -
Journal articleYang SM, Muazu RI, Tran E, et al., 2025,
Sustainable low-cost carbon fibres produced by integrating wood fractionation with lignin fibre spinning
, RSC Sustainability, Vol: 3, Pages: 3972-3986, ISSN: 2753-8125Conventional carbon fibre manufacturing is costly and relies on fossil-based raw materials with significant environmental impacts. This study presents a new, low-cost route to biobased carbon fibres generated directly from wood by integrating ionosolv wood fractionation with carbon fibre spinning. The approach avoids isolating lignin powders by spinning lignin directly from the black liquor, offering a simpler process with a lower environmental impact. The concept is demonstrated using lignin extracted from eucalyptus wood into the recyclable ionic liquid (IL) N,N-dimethylbutylammonium hydrogen sulfate with 20% water, generating delignified cellulose pulp as a co-product. After adding non-toxic poly(vinyl alcohol) (PVA) into the lignin-containing ionic liquid (with up to a 4.7 : 1 lignin : PVA ratio) continuous lignin–PVA fibres were generated by spinning into an aqueous coagulation bath. Circular, homogenous fibres were formed, which were carbonised at 1000 °C, with carbon fibre yields of up to 37%. The proof-of-concept monofilament carbon fibres (452 MPa tensile strength and 43 GPa tensile modulus) outperformed carbon fibres generated from pre-isolated ionosolv eucalyptus lignin using the same fibre spinning approach. A techno-economic analysis (TEA) of the modelled process at scale suggests that carbon fibre production costs were $9.02 kg−1 for the integrated process and $9.69 kg−1 for the redissolution-spun carbon fibres, while life cycle assessment (LCA) indicated that 20.7 kg CO2-eq and 25.3 kg CO2-eq greenhouse gas emissions were associated with integrated and redissolution spinning, respectively, providing strong motivation for future optimisation of the carbon fibres' mechanical performance and for process development.
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Journal articleGasós A, Pini R, Becattini V, et al., 2025,
Correction: Carbon footprint of oil produced through enhanced oil recovery using carbon dioxide directly captured from air
, Energy and Environmental Science, Vol: 18, Pages: 8088-8088, ISSN: 1754-5692Correction for ‘Carbon footprint of oil produced through enhanced oil recovery using carbon dioxide directly captured from air’ by Antonio Gasós et al., Energy Environ. Sci., 2025, https://doi.org/10.1039/d5ee01752a.
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Journal articleLaksahapsoro B, Bird M, Acha S, et al., 2025,
Optimisation of photovoltaic and battery systems for cost-effective energy solutions in commercial buildings
, Applied Energy, Vol: 392, ISSN: 0306-2619This study investigates the optimisation of photovoltaic (PV) and battery energy storage systems (BESS) for commercial buildings in the UK, addressing the need for cost-effective energy solutions and the challenge of ensuring financial viability. A mixed-integer linear programming (MILP) model is developed to simultaneously optimise the design and operation of PV-BESS systems, focusing on minimising the 15-year net present cost. In doing so, the model comprehensively assesses a wide range of relevant factors, including electricity market dynamics, weather conditions, technology performance and costs, energy demand, and building-specific characteristics. The optimisation model is demonstrated through a case study informed by an actual commercial building in the UK. The results indicate that a combination of mono-crystalline silicon PV modules and lithium iron phosphate (LFP) batteries yields the optimal solution, providing about 46% of the building's annual energy demand. The optimised system successfully achieves a balanced trade-off between cost and technical performance, offering a sensible payback period of 5.5 years and a 15-year NPV of £303.8k, resulting in 20% cost savings compared to the business-as-usual (BaU) scenario. The sensitivity analysis shows that high electricity prices lead to better financial outcomes, while higher energy storage costs reduce system viability. This work provides a practical framework for evaluating the design, operation, and financial viability of PV-BESS systems, while delivering actionable insights to support the broader adoption of these technologies.
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Conference paperCunsolo V, Darraj N, Catherine S, et al., 2025,
Characterising Rock Heterogeneity from an Offshore Dutch CO2 Storage Site
, World CCUS Conference 2025 -
Journal articleGasos A, Pini R, Becattini V, et al., 2025,
Carbon footprint of oil produced through enhanced oil recovery using carbon dioxide directly captured from air
, Energy and Environmental Science, Vol: 18, Pages: 7440-7446, ISSN: 1754-5692Some argue that using CO2 from direct air capture (DAC) in enhanced oil recovery (CO2-EOR) can produce carbon-neutral oil by permanently storing more CO2 than is emitted when using the extracted fossil fuels. However, existing analyses often provide case-specific insights based on short-term operations without considering the full life cycle of reservoir exploitation, including primary, secondary, and tertiary (EOR) recovery phases. Here, we present a general, top-down approach based on mass and volume conservation to assess the potential carbon footprint of oil production, applicable to different temporal perspectives of reservoir exploitation. Supported by field data from 16 EOR projects, our analysis shows that 30% of projects appear carbon-neutral when EOR is considered in isolation, but they all become significantly carbon-positive when the full reservoir lifetime is considered. The volume of emitted CO2 exceeds the pore space freed for storage by at least a factor of three, making carbon-neutral oil physically unattainable in conventional reservoirs. The favorable conditions for low-carbon oil production during CO2-EOR exist solely because of extensive prior oil extraction and water injection, and only residual oil zones may truly offer potential for carbon-neutral oil due to their low oil saturation and lack of legacy emissions. While omitting legacy emissions from previously depleted fields may be justifiable and may enable claims of carbon neutrality during the EOR phase, newly developed fields, i.e., developed now or in the future, should be held accountable for the full life-cycle emissions they generate. This necessitates clear and transparent accounting policy frameworks. Although CO2-EOR may reduce oil's carbon footprint, promoting it as a pathway to carbon-neutrality risks legitimizing continued fossil fuel production, ultimately undermining global climate targets.
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Journal articleSoh QY, Acha S, Shah N, et al., 2025,
Simultaneous design and control optimisation of combined rainwater harvesting and flood mitigation systems
, Resources, Conservation and Recycling, Vol: 222, ISSN: 0921-3449The design and operational parameters of large-scale rainwater harvesting (RWH) systems should be optimised for its local environment to maximise their efficiency. This paper looks to address the barriers in RWH system performances when their design and operational strategies are optimised separately. This is achieved using a framework which identifies a set of candidate optimal designs with their corresponding optimal control policies by optimising each possible combination of control policy and actuator location. The globally optimal configuration is then determined using a high-resolution simulation model that evaluates their performance under a wide range of historically observed rainfall profiles. When implemented for a RWH system in a tropical city, the optimal configuration was found to improve harvested water yields by 15%–27% in comparison to when only its design is optimised. The 15% improvement is also achieved with a 25% reduction in capacity, reducing spatial competition with other key utilities for the estate.
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Journal articleKucherenko S, Shah N, Klymenko OV, 2025,
Analytical identification of process design spaces using R-functions
, Computers and Chemical Engineering, Vol: 198, ISSN: 0098-1354A process design space (DS) is defined as the combination of process design and operational conditions that guarantees the assurance of product quality. This principle ensures that, as long as a process operates within its DS, it consistently yields a product that meets specifications. A novel DS identification method called the R-DS identifier has been developed in this work. It makes no assumptions about the underlying model - the only requirement is that each model constraint (e.g., defining product Critical Quality Attributes or process Key Performance Indicators) should be approximated by a closed-form function, e.g., a multivariate polynomial model. The method utilizes the methodology of V.L. Rvachev's R-functions and allows for explicit analytical representation of the DS with only a limited number of model runs. R-functions provide a framework for representing complex geometric shapes and performing operations on them through implicit functions and inequalities defining the regions. The theory of R-functions enables the solution of geometric problem such as identification of DS through algebraic manipulation. It is more practical than traditional sampling or optimization-based methods. The method is illustrated using a batch reactor model.
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Journal articleDezashibi AHM, Hallett JP, Fennell PS, 2025,
Design and operation of a cost-effective reactor for large protic ionic liquid synthesis
, CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION, Vol: 213, ISSN: 0255-2701 -
ReportMoustafa N, Saenz Cavazos P, Beath H, et al., 2025,
Destination Net-Zero: what is your best path? Insights for decision-makers navigating the low carbon transition
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Journal articleEluwah C, Fennell PS, 2025,
Novel onboard ammonia cracker for light-duty automotive fuel cell vehicles
, Energy Advances, ISSN: 2753-1457This work introduces an innovative onboard ammonia cracker module integrated with a 100-kW fuel cell system for light-duty automotive fuel cell vehicles. Utilizing a hollow fibre palladium membrane reactor (HFMR), two configurations are explored: a 3 × 3 simultaneous heating and cracking module and a 4 × 4 intermediate heating and cracking module. The 3 × 3 module, arranged in a serpentine configuration, exhibits superior performance with a calculated required volume of 8.9 liters, a total module area of 1.2 m2 and a process thermal efficiency of 93.5%. Each reactor in this module operates isothermally at an exit temperature of 475 °C, achieving ammonia conversion rates that increase from 15.8% in the first reactor (R1) to an impressive 99.99% in the final reactor (R8), facilitated by in situ hydrogen removal through the palladium membrane. The steady-state analysis was carried out using Aspen Plus Software, and validated against experimental data from existing literature. The results demonstrated a high degree of agreement, confirming the model's capability to accurately predict system performance. For transient analysis, Aspen Plus Dynamics was employed to assess the system's responsiveness to varying driving conditions. Utilizing the Hyundai Nexo fuel cell car as a case study, the worldwide harmonised light vehicle test procedure (WLTP) was simulated, to model realistic driving cycles, allowing for a rigorous interrogation of the transient performance of the on-board ammonia cracker. Overall, this research establishes a 3 × 3 simultaneous heating and cracking HFMR module as the optimal configuration for on-board ammonia cracking for hydrogen production in fuel-cell vehicles, highlighting its operational efficiency and potential contribution to sustainable transportation solutions. Future research should focus on optimizing heat management and temperature control within the HFMR module, as well as enhancing transient response characteri
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Journal articleKhan SN, Zhao M, Fennell PS, et al., 2025,
Construction of Highly Mesoporous Metal-Organic Frameworks via Green Metallic Solvents Assisted Route for Chemical CO<sub>2</sub> Fixation
, SMALL, Vol: 21, ISSN: 1613-6810- Cite
- Citations: 4
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Journal articleRiorda A, Negro V, Pantaleo AM, et al., 2025,
Sustainable hydrogen from biomass: what is its potential contribution to the European defossilization targets?
, Energy and Fuels, Vol: 39, Pages: 6412-6425, ISSN: 0887-0624This study investigates the potential role of hydrogen production from biomass in the EU hydrogen objectives. With the EU aiming to produce 10 million tons of renewable hydrogen by 2030 and significantly scaling this production by 2050, diverse hydrogen production pathways must be explored. Our research focuses on assessing whether biomass-derived hydrogen can serve as a viable and substantial component of the hydrogen production mix alongside and complementing established methods such as electrolysis powered by renewable electricity. Through a comprehensive literature review, the main hydrogen production pathways from biomass have been assessed, including thermochemical and biological methods, with an emphasis on hydrogen yield, production costs, and technology readiness levels (TRLs). The work also considers the availability of biomass resources and potential production scenarios for 2030 and 2050. Our findings suggest that biomass-derived hydrogen can meaningfully contribute to the defossilization of the hydrogen sector, particularly in the midterm scenario for 2030. The analysis suggests that biomass has the potential to contribute a substantial share of the EU’s 2030 hydrogen target, ranging from under 0.1 Mt to over 16 Mt per year. Biomass-derived hydrogen offers additional flexibility and security of supply in the transition to a sustainable hydrogen economy, other than the possibility to benefit from negative emissions in some cases and added value from the coproduction of defossilized materials and chemicals, relying on domestic resources available in Europe.
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Conference paperLewin DR, Shah N, Barzilai A, 2025,
One-week flipped workshop on heat integration
, Pages: 110-120, ISSN: 1749-7728This paper describes the first implementation of a flipped, one-week workshop on heat integration that was taught in Spring 2024 to the 3rd Year cohort of 138 students in Chemical Engineering at Imperial College, London. The “flipped” workshop consisted of three online lessons that cover the core materials on pinch design of heat exchanger networks, which the students were required to complete ahead of each of the corresponding three face-to-face class meetings, which focused on problem-solving exercises largely carried out by the students themselves. The paper describes the teaching methodology applied, presents and analyses the results of a survey conducted to assess the students’ perceptions and degree of satisfaction with the workshop. Learning outcomes relevant to the workshop topic, that is, the ability to design and optimize heat exchanger networks in realistic plant-wide settings, are also presented and compared to those of previous years. The main conclusion is that the short workshop format can successfully achieve the learning objectives, even for relatively large class sizes. Evidently, this workshop can be taught effectively in this concentrated form provided that the workshop participants are given access to the online lessons in advance of the class exercises.
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Journal articleBird M, Andraos R, Acha S, et al., 2025,
Lifetime financial analysis of a model predictive control retrofit for integrated PV-battery systems in commercial buildings
, Energy and Buildings, Vol: 332, ISSN: 0378-7788As electrical grids decarbonise, the need for flexible, real-time energy management systems becomes crucial to handle the variability of renewable sources. This paper investigates the lifetime performance of a commercial PV-battery system under three potential control approaches. Two rule-based controllers and one economic MPC approach are simulated over the lifetime of the battery, considering both the upfront capital and ongoing operational costs. Under the nominal rule-based control, installing the battery system saves 2.9% in operational costs per year. An informed rule-based schedule was then created, based on observing the typical PV and building loads and electricity price dynamics, increasing savings to 4.3%. These additional savings can be realised without any additional capital or operational investment. A supervisory MPC approach is integrated with the existing system control, requiring an upfront investment of $13.7k, combined with additional operational costs of $5.89k/yr. Accounting for these additional costs, net operational savings increase to 6% compared to the baseline operation without a battery system, while also reducing carbon emissions by 9.8%. MPC savings increase to 13.2% when considering the volatile electricity prices seen during the 2022 energy crisis. Despite these encouraging savings, current battery systems remain financially unattractive due to their high upfront cost, and all three control scenarios result in a negative NPV. A sensitivity analysis demonstrates that optimal sizing of batteries and reductions in their cost are the most significant factors when evaluating the lifetime performance of PV-battery systems.
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Journal articleSarkis M, Shah N, Papathanasiou MM, 2025,
Resilient pharmaceutical supply chains: Assessment of stochastic optimization strategies for process uncertainty integration in network design problems
, COMPUTERS & CHEMICAL ENGINEERING, Vol: 195, ISSN: 0098-1354- Cite
- Citations: 3
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Journal articleEckel A-ME, Rovelli A, Pini R, 2025,
Direct characterization of free solutal convection in porous rocks for CO₂ storage applications
, Environmental Science & Technology, Vol: 59, Pages: 4618-4630, ISSN: 0013-936XFree solutal convection refers to the mixing process induced and sustained by local density differences arising from solute dissolution. This process underpins the long-term storage of carbon dioxide (CO2) following its injection and dissolution in the formation brine of subsurface rock formations, such as saline aquifers. Direct experimental evidence of free solutal convection in porous rocks is to-date still lacking, leaving large uncertainties on the realized rate of CO2 dissolution and its contribution toward storage. Using an analogue solute–solvent pair and 4D X-ray computed tomography, we report direct observations of this mixing process in rock core samples, including sandstones and carbonates. The imagery is used to characterize the mixing structures that arise upon solute dissolution and to quantify differences between the rock types. Thus, we compute the temporal evolution of spatial moments of the concentration distribution to derive practical properties, such as the effective transport velocity of the solute plumes. Unlike previous studies on random bead packs, we observe that these measures do not scale well with core-scale rock properties (permeability, porosity, Rayleigh number) and are influenced by microscale rock characteristics (subcore and pore-scale heterogeneities). The latter may need consideration when evaluating the CO2 storage potential of candidate formations.
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Journal articleAldren C, Shah N, Hawkes A, 2025,
Quantifying key economic uncertainties in the cost of trading green hydrogen
, Cell Reports Sustainability, ISSN: 2949-7906In a fully decarbonized global energy system, hydrogen is likely to be one of few energy vectors that can facilitate long-distance export of renewable energy. However, because of divergent literature findings, consensus is yet to be reached on the total supply chain costs of shipping hydrogen either as a cryogenic liquid or ammonia. To this end, this article presents a detailed process systems-based economic analysis of a typical hydrogen value chain in 2050, employing the method of elementary effects to quantify the effect of uncertainties. With expected landed costs for liquid hydrogen of $4.60 kg−1(H2) and ammonia of $3.30 kg−1(H2), the importance of uncertainty quantification is demonstrated, given that specific parametric combinations can yield landed costs below $2.50 kg−1(H2). Given our delivered hydrogen cost of $4.70 kg−1(H2), these results demonstrate the stark difference between the aspirations of decarbonization policy (with some countries aiming for prices below $1 kg−1 by 2050) and the present techno-economic reality.
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Journal articleYang D, Yang Y, Wong T, et al., 2025,
Solution-processable polymer membranes with hydrophilic subnanometre pores for sustainable lithium extraction
, nature water, Vol: 3, Pages: 319-333, ISSN: 2731-6084Membrane-based separation processes hold great promise for sustainable extraction of lithium from brines for the rapidly expanding electric vehicle industry and renewable energy storage. However, it remains challenging to develop high-selectivity membranes that can be upscaled for industrial processes. Here we report solution-processable polymer membranes with subnanometre pores with excellent ion separation selectivity in electrodialysis processes for lithium extraction. Polymers of intrinsic microporosity incorporated with hydrophilic functional groups enable fast transport of monovalent alkali cations (Li+, Na+ and K+) while rejecting relatively larger divalent ions such as Mg2+. The polymer of intrinsic microporosity membranes surpasses the performance of most existing membrane materials. Furthermore, the membranes were scaled up and integrated into an electrodialysis stack, demonstrating excellent selectivity in simulated salt-lake brines. This work will inspire the development of selective membranes for a wide range of sustainable separation processes critical for resource recovery and a global circular economy.
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Journal articleJaeggi A, Eckel A-M, Pini R, et al., 2025,
Exploring disordered packing of non-equant particles: Insights from computed tomography and Monte Carlo simulations
, POWDER TECHNOLOGY, Vol: 452, ISSN: 0032-5910 -
Journal articleAlanazi K, Mittal S, Hawkes A, et al., 2025,
Renewable hydrogen trade in a global decarbonised energy system
, International Journal of Hydrogen Energy, Vol: 101, Pages: 712-730, ISSN: 0360-3199Renewable hydrogen has emerged as a potentially critical energy carrier for achieving climate change mitigation goals. International trade could play a key role in meeting hydrogen demand in a globally decarbonized energy system. To better understand this role, we have developed a modelling framework that incorporates hydrogen supply and demand curves and a market equilibrium model to maximize social welfare. Applying this framework, we investigate two scenarios: an unrestricted trade scenario where hydrogen trade is allowed between all regions globally, and a regional independence scenario where trade is restricted to be intra-regional only. Under the unrestricted trade scenario, global hydrogen demand could reach 234 Mt by 2050, with 31.2% met through international trade. Key trade routes identified include North Africa to Europe, the Middle East to Developing Asia, and South America to Japan and South Korea. In the regional independence scenario, most regions could meet their demand domestically, except for Japan and South Korea due to self-insufficiency. Finally, this analysis reveals that producers in North Africa and South America are likely to gain more economic value from international trade compared to other producing regions. The results offer key insights for policymakers and investors for shaping future hydrogen trade policies and investment decisions.
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Journal articleKurotori T, Zahasky C, Benson S, et al., 2025,
Direct observations of solute dispersion in rocks with distinct degree of sub-micron porosity
, Water Resources Research, Vol: 61, ISSN: 0043-1397The transport of chemical species in rocks is affected by their structural heterogeneity to yield a wide spectrum of local solute concentrations. To quantify such imperfect mixing, advanced methodologies are needed that augment the traditional breakthrough curve analysis by probing solute concentration within the fluids locally. Here, we demonstrate the application of asynchronous, multimodality imaging by X-ray computed tomography (XCT) and positron emission tomography (PET) to the study of passive tracer experiments in laboratory rock cores. The four-dimensional concentration maps measured by PET reveal specific signatures of the transport process, which we have quantified using fundamental measures of mixing and spreading. We observe that the extent of solute spreading correlate strongly with the strength of subcore-scale porosity heterogeneity measured by XCT, while dilution is enhanced in rocks containing substantial sub-micron porosity. We observe that the analysis of different metrics is necessary, as they can differ in their sensitivity to the strength and forms of heterogeneity. The multimodality imaging approach is uniquely suited to probe the fundamental difference between spreading and mixing in heterogeneous media. We propose that when multi-dimensional data is available, mixing and spreading can be independently quantified using the same metric. We also demonstrate that one-dimensional transport models have limited predictive ability toward the internal evolution of the solute concentration, when the model is solely calibrated against the effluent breakthrough curves. The data set generated in this study can be used to build realistic digital rock models and to benchmark transport simulations that account deterministically for rock property heterogeneity.
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Journal articlePan Z, Trusler JPM, Jin Z, et al., 2025,
Interfacial property determination from dynamic pendant-drop characterizations
, Nature Protocols, Vol: 20, Pages: 363-386, ISSN: 1750-2799The properties of the interface between materials have practical implications in various fields, encompassing capillary action, foam and emulsion stability, adhesion properties of materials and mass and heat transfer processes. Studying the dynamics of interfaces is also fundamental for understanding intermolecular interactions, change of molecular conformations and molecular aggregations. Pendant-drop tensiometry and its extension, the oscillating drop method, are simple, versatile methods used to measure surface tension, interfacial tension and interfacial rheological properties. These methods can, however, generate unreliable results because of inadequate material preparation, an incorrect calibration method, inappropriate selection of data for analysis, neglect of optical influences or operating the system outside the linear viscoelastic regime. In addition, many studies fail to report accurate uncertainties. This protocol addresses all these critical points and provides detailed descriptions of some operation tips relating to purifying methods for different kinds of material, the time frame for analyzing measurement data, the correction method for optical effects, implementation of the oscillating method with a common programmable pump and remedies for some common problems encountered during the measurement. Examples of interfacial tension measurements for two- and three-phase systems, as well as interfacial dilational modulus measurements for N2 and surfactant solutions, are provided to illustrate procedural details and results. A single measurement takes minutes to hours to complete, while the entire protocol, including the leak test, cleaning, repeated measurements and data analysis, may take several days.
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Journal articleBrotto JDO, Danaci D, Fennell PS, et al., 2025,
Enhancing low-carbon iron and steel production with torrefied biomass
, BIOMASS & BIOENERGY, Vol: 193, ISSN: 0961-9534- Cite
- Citations: 1
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Journal articleAzzan H, Gmyrek K, Danaci D, et al., 2025,
Effective macropore diffusivity of carbon dioxide on binderless pellets of Y-type zeolites
, Adsorption, Vol: 31, ISSN: 0929-5607The adsorption kinetics of carbon dioxide (CO2) in three cationic forms of binderless pellets of Y-types zeolites (H-Y, Na-Y, and TMA exchanged Na-Y) are studied using the zero-length column (ZLC) technique. The measurements were carried out at 288.15 K, 298.15 K and 308.15 K using different flowrates and an initial CO2 partial pressure of 0.10 bar – conditions representative of post-combustion CO2 capture applications. The mass transport within the adsorbent pellets was described using a 1-D Fickian diffusion model accounting for intra- and inter-crystalline mass transport. For the latter, the parallel pore model formulation was used to explicitly account for the adsorbent’s macropore size distribution in estimating the volume-averaged diffusivity of the gas. Experiments carried out using different carrier gases, namely helium and nitrogen, were used (i) to determine that these systems are macropore diffusion limited and (ii) to simplify the parameter estimation to a single parameter - the macropore tortuosity. The latter (τ = 1.3 − 2.5) was in good agreement with independent measurements using MIP (τ ≈ 1.7). The associated diffusion coefficient, Demac, was found to vary due to differences in the materials’ macropore size distributions and overall porosity. Upon combining the parallel pore model formulation with the temperature dependencies for the pore diffusivities derived from molecular theories of gases, we predict Demac ∝ Tb with b = [0.78 − 0.88] depending on the macropore size distribution. Notably, for the range of temperature tested in this study, Demac varies approximately linearly with temperature (b ≈ 1)– in contrast to the commonly reported correlation of b = 1.75, which may be more appropriate for systems where molecular diffusion dominates and Knudsen diffusion is negligible. The binderless pellets of Y-type zeolites studied exhibit generally higher values for the effective macropore diffus
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Journal articleKaerger J, Valiullin R, Brandani S, et al., 2025,
Diffusion in nanoporous materials with special consideration of the measurement of determining parameters (IUPAC Technical Report)
, Pure and Applied Chemistry, Vol: 97, Pages: 1-89, ISSN: 0033-4545The random motion (the diffusion) of guest molecules in nanoporous host materials is key to their manifold technological applications and, simultaneously, a ubiquitous phenomenon in nature quite in general. Based on a specification of the different conditions under which molecular diffusion in nanoporous materials may occur and of the thus resulting relevant parameters, a survey of the various ways of the measurement of the determining parameters is given. Starting with a condensed introduction to the respective measuring principles, the survey notably includes a summary of the various parameters accessible by each individual technique, jointly with an overview of their strengths and weaknesses as well as of the respective ranges of observation. The presentation is complemented by basic relations of diffusion theory and molecular modeling in nanoporous materials, illustrating their significance for enhancing the informative value of each measuring technique and the added value attainable by their combination. By providing guidelines for the measurement and reporting of diffusion properties of chemical compounds in nanopores, the document aims to contribute to the clarification and standardization of the presentation, nomenclature, and methodology associated with the documentation of diffusion phenomena in nanoporous materials serving for catalytic, mass separation, and other relevant purposes.
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Journal articleBukar I, Bell R, Muggeridge AH, et al., 2025,
Carbon Dioxide Migration Along Faults at the Illinois Basin-Decatur Project Revealed Using Time Shift Analysis of Seismic Monitoring Data
, GEOPHYSICAL RESEARCH LETTERS, Vol: 52, ISSN: 0094-8276- Cite
- Citations: 5
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