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  • Journal article
    Martynov S, Mac Dowell N, Brown S, Mahgerefteh Het al., 2015,

    Assessment of Integral Thermo-Hydraulic Models for Pipeline Transportation of Dense-Phase and Supercritical CO<sub>2</sub>

    , INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 54, Pages: 8587-8599, ISSN: 0888-5885
  • Journal article
    Mac Dowell N, Shah N, 2015,

    The multi-period optimisation of an amine-based CO<sub>2</sub> capture process integrated with a super-critical coal-fired power station for flexible operation

    , COMPUTERS & CHEMICAL ENGINEERING, Vol: 74, Pages: 169-183, ISSN: 0098-1354
  • Journal article
    Al Ghafri SZS, Forte E, Maitland GC, Rodriguez-Henríquez JJ, Trusler JPMet al., 2014,

    Experimental and Modeling Study of the Phase Behavior of (Methane + CO2 + Water) Mixtures

    , The Journal of Physical Chemistry B, Vol: 118, Pages: 14461-14478, ISSN: 1520-5207
  • Journal article
    Strbac G, Pollitt M, Konstantinidis CV, Konstantelos I, Moreno R, Newbery D, Green Ret al., 2014,

    Electricity transmission arrangements in Great Britain: Time for change?

    , Energy Policy, Vol: 73, Pages: 298-311, ISSN: 0301-4215

    In Great Britain (GB) and across Europe significant investment in electricity transmission is expected over the coming years as decarbonisation and market integration efforts are intensified. However, there is also significant uncertainty with the amount, location and timing of new generation connection, which in turn will drive the transmission investment needs. Given the absence of efficient market design, we identify three key areas of concern with the current transmission investment arrangements: (i) a mis-aligned incentives framework for transmission investment and operation; (ii) lack of coordination of investment and operation; and (iii) conflicts of interest. We then propose three options for future evolution of transmission regimes, which cover the full spectrum of institutional arrangements with respect to transmission planning and delivery, i.e. how and who plans, owns, builds and operates the transmission system. For each option we present: key characteristics; evolution of the current regimes; the ability of the option to address the concerns; and key strengths and weaknesses. Overall, we conclude in the case of GB (this conclusion could be extended to other European countries) that the most appropriate option would be that of an Independent System Operator (ISO) who would be responsible for planning and operating the transmission system.
  • Journal article
    Akgul O, Mac Dowell N, Papageorgiou LG, Shah Net al., 2014,

    A mixed integer nonlinear programming (MINLP) supply chain optimisation framework for carbon negative electricity generation using biomass to energy with CCS (BECCS) in the UK

    , INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 28, Pages: 189-202, ISSN: 1750-5836
  • Journal article
    Zhang Q, Shah N, Wassick J, Helling R, van Egerschot Pet al., 2014,

    Sustainable supply chain optimisation: An industrial case study

    , Computers and Industrial Engineering, Vol: 74, Pages: 68-83, ISSN: 0360-8352

    Sustainability plays a key role in the management of a successful and responsible business. When trying to improve the sustainability performance of a business, there are three major challenges that need to be addressed. First, assessment of sustainability requires consideration of not just economic, but also environmental and social impacts. Second, we need to find appropriate sustainability indicators and gather the necessary data in order to quantify sustainability performance. Finally, sustainability has to be seen in the context of the whole system, i.e. it has to include all activities along the supply chain. In this work, we consider all three aspects and propose a multi-objective optimisation framework for the optimisation of a sustainable supply chain. Three sustainability indicators have been considered, namely the total cost, GHG emissions and lead time. We apply this framework to an industrial test case using real-world data drawn from a Dow Chemical business. The results show clear trade-offs between the three different objectives. However, we can also observe that typically a considerable decrease in GHG emissions or lead time can already be achieved by only a relatively small increase in cost. The proposed framework enables us to determine such trade-off relations and consequently make decisions that improve the sustainability performance of the supply chain.
  • Journal article
    Mac Dowell N, Shah N, 2014,

    Dynamic modelling and analysis of a coal-fired power plant integrated with a novel split-flow configuration post-combustion CO₂ capture process

    , International Journal of Greenhouse Gas Control, Vol: 27, Pages: 103-119, ISSN: 1750-5836

    We present a model of a coal-fired power plant integrated with a dynamic model of a monoethanolamine (MEA)-based post-combustion CO₂ capture process. We evaluate base- and part-load operating modes of the integrated power and CO₂ capture plant. We propose a simple modification to the base-process which exploits the tradeoff between thermodynamic and rate or kinetic driving forces for mass transfer. This modification returns a portion of the regenerated solvent to the middle of the absorption column at an elevated temperature. Under base-load operation of the power plant, this modification was observed to increase the degree of CO₂ capture by 9.9% and reduce the reboiler duty by 8.3%, improving the net electrical efficiency of the decarbonised power plant from 28.27% to 29.15% - a relative increase of 2.8%. Under part-load operation, the degree of CO₂ capture increased by 1% with a concurrent reduction in reboiler duty of 16.7% and an increase in overall process efficiency of 3.25%
  • Journal article
    Mac Dowell N, Llovell F, Sun N, Hallett JP, George A, Hunt PA, Welton T, Simmons BA, Vega LFet al., 2014,

    New Experimental Density Data and soft-SAFT Models of Alkylimidazolium ([CnC₁im](+)) Chloride (Cl-), Methylsulfate ([MeSO4](-)), and Dimethylphosphate ([Me2PO4](-)) Based Ionic Liquids

    , JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 118, Pages: 6206-6221, ISSN: 1520-6106
  • Journal article
    Chen L, Sharifzadeh M, Mac Dowell N, Welton T, Shah N, Hallett JPet al., 2014,

    Inexpensive ionic liquids: [HSO₄]¯-based solvent production at bulk scale

    , Green Chemistry, Vol: 16, Pages: 3098-3106, ISSN: 1463-9262

    Through more than two decades’ intensive research, ionic liquids (ILs) have exhibited significant potential in various areas of research at laboratory scales. This suggests that ILs-based industrial process development will attract increasing attention in the future. However, there is one core issue that stands in the way of commercialisation: the high cost of most laboratory-synthesized ILs will limit application to small-scale, specialized processes. In this work, we evaluate the economic feasibility of two ILs synthesized via acid–base neutralization using two scenarios for each: conventional and intensification processing. Based upon our initial models, we determined the cost price of each IL and compared the energy requirements of each process option. The cost prices of triethylammonium hydrogen sulfate and 1-methylimidazolium hydrogen sulfate are estimated as $1.24 kg−1 and $2.96–5.88 kg−1, respectively. This compares favourably with organic solvents such as acetone or ethyl acetate, which sell for $1.30–$1.40 kg−1. Moreover, the raw materials contribute the overwhelming majority of this cost and the intensified process using a compact plate reactor is more economical due to lower energy requirements. These results indicate that ionic liquids are not necessarily expensive, and therefore large-scale IL-based processes can become a commercial reality.
  • Journal article
    Bailey L, Lekkerkerker HNW, Maitland GC, 2014,

    Rheology modification of montmorillonite dispersions by colloidal silica

    , RHEOLOGICA ACTA, Vol: 53, Pages: 373-384, ISSN: 0035-4511
  • Journal article
    Green R, Staffell I, Vasilakos N, 2014,

    Divide and Conquer? <i>k</i>-Means Clustering of Demand Data Allows Rapid and Accurate Simulations of the British Electricity System

    , IEEE TRANSACTIONS ON ENGINEERING MANAGEMENT, Vol: 61, Pages: 251-260, ISSN: 0018-9391
  • Report
    Green RJ, Staffell I, 2014,

    The Impact of Government Interventions on Investment in the GB Electricity Market

    , Brussels, Publisher: European Commission

    Report to DG Competition of the European Commission in the State Aid case concerning the Hinkley Point C nuclear power station
  • Journal article
    Mukherjee S, Kumar P, Hosseini A, Yang A, Fennell Pet al., 2014,

    Comparative Assessment of Gasification Based Coal Power Plants with Various CO<sub>2</sub> Capture Technologies Producing Electricity and Hydrogen

    , ENERGY & FUELS, Vol: 28, Pages: 1028-1040, ISSN: 0887-0624
  • Conference paper
    Niu B, Krevor S, 2014,

    The impact of reservoir conditions on the measurement of multiphase flow properties for CO2-brine systems

    , Pages: 77-81

    Successful industrial scale carbon dioxide injection into deep saline aquifers will be dependent on the ability to model the flow of the fluid and to quantify the impact of various trapping mechanisms. The effectiveness of the models is in turn dependent on high quality laboratory measurements ofbasic multiphase flow properties such as relative permeability and residual trapping at reservoir conditions. At the same time there exists general uncertainty around the few existing published data on these properties for CO2-brine systems. In this study we present results from a newly constructed reservoir condition coreflooding and imaging laboratory designed to measure multiphase flow properties, capillary pressure, relative permeability and residual trapping at a range of reservoir conditions. The proper approach to measuring relative permeability for CO2-brine system is proposed and demonstrated. The changes in residual trapping correlated to pressure, temperature, brine salinity, interfacial tension, and contact angle are also reported. We also show with a combination of simulations of corefloods and experiments performed at various conditions that high precision results can be obtained for this system when the appropriate conditions are used. Copyright © (2014) by the European Association of Geoscientists & Engineers. All rights reserved.
  • Journal article
    Boot-Handford ME, Abanades JC, Anthony EJ, Blunt MJ, Brandani S, Mac Dowell N, Fernandez JR, Ferrari M-C, Gross R, Hallett JP, Haszeldine RS, Heptonstall P, Lyngfelt A, Makuch Z, Mangano E, Porter RTJ, Pourkashanian M, Rochelle GT, Shah N, Yao JG, Fennell PSet al., 2014,

    Carbon capture and storage update

    , Energy and Environmental Science, Vol: 7, Pages: 130-189, ISSN: 1754-5692

    In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.
  • Conference paper
    Al-Menhali A, Reynolds C, Lai P, Niu B, Nicholls N, Crawshaw J, Krevor Set al., 2014,

    Advanced reservoir characterization for CO<inf>2</inf> storage

    , Pages: 503-512

    Injection of CO2 into the subsurface is of interest for CO 2 storage and enhanced oil recovery (EOR). There are, however, major unresolved questions around the multiphase flow physics and reactive processes that will take place after CO2 is injected, particularly in carbonate rock reservoirs. For example, the wetting properties of CO2-brine- rock systems will impact the efficiency of EOR operations and CO2 storage but reported contact angles range widely from strongly water-wet to intermediate wet. Similar uncertainties exist for properties including the relative permeability and the impact of chemical reaction on flow. In this presentation we present initial results from laboratory studies investigating the physics of multiphase flow and reactive transport for CO2-brine systems. We use traditional and novel core flooding techniques and x-ray imaging to resolve uncertainties around the CO2-brine contact angle, relative permeability, residual trapping, and feedbacks between chemical reaction and flow in carbonate rocks. Copyright 2014, International Petroleum Technology Conference.
  • Conference paper
    Brown S, Martynov S, Mahgerefteh H, Fairweather M, Woolley RM, Wareing CJ, Falle SAEG, Rutters H, Niemi A, Zhang YC, Chen S, Besnebat J, Shah N, Mac Dowell N, Proust C, Farret R, Economou IG, Tsangaris DM, Boulougouris GC, Van Wittenberghe Jet al., 2014,

    CO<sub>2</sub>QUEST: Techno-economic assessment of CO<sub>2</sub> quality effect on its storage and transport

    , 12th International Conference on Greenhouse Gas Control Technologies (GHGT), Publisher: ELSEVIER SCIENCE BV, Pages: 2622-2629, ISSN: 1876-6102
  • Book chapter
    Green RJ, Mulugetta Y, Zhang ZX, 2014,

    Sustainable Energy Policy

    , Handbook of Sustainable Development, 2nd Edition, Editors: Atkinson, Dietz, Neumayer, Agarwala, Cheltenham, Publisher: Edward Elgar, Pages: 532-550, ISBN: 978-1-78254-469-2
  • Conference paper
    Mac Dowell N, Shah N, 2014,

    Optimisation of post-combustion CO<sub>2</sub> capture for flexible operation

    , 12th International Conference on Greenhouse Gas Control Technologies (GHGT), Publisher: ELSEVIER SCIENCE BV, Pages: 1525-1535, ISSN: 1876-6102
  • Conference paper
    Lucquiaud M, Fernandez ES, Chalmers H, Mac Dowell N, Gibbins Jet al., 2014,

    Enhanced operating flexibility and optimised off-design operation of coal plants with post-combustion capture

    , 12th International Conference on Greenhouse Gas Control Technologies (GHGT), Publisher: ELSEVIER SCIENCE BV, Pages: 7494-7507, ISSN: 1876-6102
  • Journal article
    Al Ghafri SZ, Maitland GC, Trusler JPM, 2013,

    Experimental and modeling study of the phase behavior of synthetic crude oil + CO2

    , Fluid Phase Equilibria, Vol: 365, Pages: 20-40, ISSN: 0378-3812

    A full understanding of the phase behavior of CO2–hydrocarbon mixtures at reservoir conditions is essential for the proper design, construction and operation of carbon capture and storage (CCS) and enhanced oil recovery (EOR) processes. While equilibrium data for binary CO2–hydrocarbon mixtures are plentiful, equilibrium data and validated equations of state having reasonable predictive capability for multi-component CO2–hydrocarbon mixtures are limited. In this work, a new synthetic apparatus was constructed to measure the phase behavior of systems containing CO2 and multicomponent hydrocarbons at reservoir temperatures and pressures. The apparatus consisted of a thermostated variable-volume view cell driven by a computer-controlled servo motor system, and equipped with a sapphire window for visual observation. Two calibrated syringe pumps were used for quantitative fluid injection. The maximum operating pressure and temperature were 40 MPa and 473.15 K, respectively. The apparatus was validated by means of isothermal vapor–liquid equilibrium measurement on (CO2 + heptane), the results of which were found to be in good agreement with literature data.In this work, we report experimental measurements of the phase behavior and density of (CO2 + synthetic crude oil) mixtures. The ‘dead’ oil contained a total of 17 components including alkanes, branched-alkanes, cyclo-alkanes, and aromatics. Solution gas (0.81 methane + 0.13 ethane + 0.06 propane) was added to obtain live synthetic crudes with gas-oil ratios of either 58 or 160. Phase equilibrium and density measurements are reported for the ‘dead’ oil and the two ‘live’ oils under the addition of CO2. The measurements were carried out at temperatures of 298.15, 323.15, 373.15 and 423.15 K and at pressures up to 36 MPa, and included vapor–liquid, liquid–liquid and vapor–liquid–liquid equilibrium conditions. The results are qualitatively
  • Journal article
    Ciotta F, Trusler JPM, Vesovic V, 2013,

    Extended hard-sphere model for the viscosity of dense fluids

    , Fluid Phase Equilibria, Vol: 363, Pages: 239-247, ISSN: 0378-3812

    An extended hard-sphere model is reported that may be applied to correlate and predict the viscosity of gases, liquids and supercritical fluids. The method is based on the hard-sphere model of Dymond and Assael and uses their roughness factors and molar core volumes to relate reduced viscosity to a universal function of reduced volume. The extended model behaves correctly in the limit of low densities and offers improved accuracy at high densities. The new universal reference function was determined from a large database of experimental viscosities for alkanes extending up to reduced densities of 0.84. It has been tested by correlating the viscosity of two high-viscosity liquids not used in the development of the universal function and has shown to perform satisfactorily up to reduced densities of approximately 0.9.
  • Journal article
    Maitland G, 2013,

    Towards a low-carbon fossil fuels future

    , TCE The Chemical Engineer, Pages: 32-37, ISSN: 0302-0797
  • Journal article
    Giarola S, Bezzo F, Shah N, 2013,

    A risk management approach to the economic and environmental strategic design of ethanol supply chains

    , BIOMASS & BIOENERGY, Vol: 58, Pages: 31-51, ISSN: 0961-9534
  • Report
    Green RJ, 2013,

    The Future Role of Energy in Manufacturing

    , London, Publisher: Government Office for Science

    This report considers the present and future role of energy in manufacturing, in the context of the need to deliver a low-carbon economy. That need presents two threats to UK-based manufacturers, and two opportunities. The first threat is that the price of energy in the UK will rise, compared to the cost faced by competitor firms abroad, placing UK manufacturers at a significant disadvantage. The second threat is that a low-carbon electricity supply will be unreliable, and that the cost of power cuts will rise. The first opportunity is related to this threat – manufacturing sites that can reduce their electricity imports at times when the power system is under stress are already paid for doing so. The need for such demand-side management, the options for providing it, and the price paid are all likely to increase over time. The second opportunity is that new low-carbon products will be needed – not least in the transport sector – and UK-based firms may be able to break into these new markets.
  • Journal article
    Napp TA, Gambhir A, Hills TP, Florin N, Fennell PSet al., 2013,

    A review of the technologies, economics and policy instruments for decarbonising energy-intensive manufacturing industries

    , Renewable & Sustainable Energy Reviews

    Industrial processes account for one-third of global energy demand. The iron and steel, cement and refining sectors are particularly energy-intensive, together making up over 30% of total industrial energy consumption and producing millions of tonnes of CO2 per year. The aim of this paper is to provide a comprehensive overview of the technologies for reducing emissions from industrial processes by collating information from a wide range of sources. The paper begins with a summary of energy consumption and emissions in the industrial sector. This is followed by a detailed description of process improvements in the three sectors mentioned above, as well as cross-cutting technologies that are relevant to many industries. Lastly, a discussion of the effectiveness of government policies to facilitate the adoption of those technologies is presented. Whilst there has been significant improvement in energy efficiency in recent years, cost-effective energy efficient options still remain. Key energy efficiency measures include upgrading process units to Best Practice, installing new electrical equipment such as pumps and even replacing the process completely. However, these are insufficient to achieve the deep carbon reductions required if we are to avoid dangerous climate change. The paper concludes with recommendations for action to achieve further decarbonisation.
  • Journal article
    Krause M, Krevor S, Benson SM, 2013,

    A Procedure for the Accurate Determination of Sub-Core Scale Permeability Distributions with Error Quantification

    , TRANSPORT IN POROUS MEDIA, Vol: 98, Pages: 565-588, ISSN: 0169-3913
  • Journal article
    Mac Dowell N, Shah N, 2013,

    Identification of the cost-optimal degree of CO₂ capture: An optimisation study using dynamic process models

    , INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 13, Pages: 44-58, ISSN: 1750-5836
  • Journal article
    Staffell I, Green R, 2013,

    The cost of domestic fuel cell micro-CHP systems

    , International Journal of Hydrogen Energy, Vol: 38, Pages: 1088-1102, ISSN: 0360-3199
  • Journal article
    Mac Dowell N, Samsatli NJ, Shah N, 2013,

    Dynamic modelling and analysis of an amine-based post-combustion CO₂ capture absorption column

    , INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL, Vol: 12, Pages: 247-258, ISSN: 1750-5836

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