Publications
244 results found
Smit B, Styring P, Wilson G, et al., 2016, Modelling - from molecules to megascale: general discussion, Faraday Discussions, Vol: 192, Pages: 493-509, ISSN: 1359-6640
Maitland G, 2016, Importance of CCS, Chemistry & Industry, Vol: 80, Pages: 32-32, ISSN: 0009-3068
Peng C, Anabaraonye BU, Crawshaw JP, et al., 2016, Kinetics of carbonate mineral dissolution in CO2-acidified brines at storage reservoir conditions., Faraday Discussions, Vol: 192, Pages: 545-560, ISSN: 1364-5498
We report experimental measurements of the dissolution rate of several carbonate minerals in CO2-saturated water or brine at temperatures between 323 K and 373 K and at pressures up to 15 MPa. The dissolution kinetics of pure calcite were studied in CO2-saturated NaCl brines with molalities of up to 5 mol kg(-1). The results of these experiments were found to depend only weakly on the brine molality and to conform reasonably well with a kinetic model involving two parallel first-order reactions: one involving reactions with protons and the other involving reaction with carbonic acid. The dissolution rates of dolomite and magnesite were studied in both aqueous HCl solution and in CO2-saturated water. For these minerals, the dissolution rates could be explained by a simpler kinetic model involving only direct reaction between protons and the mineral surface. Finally, the rates of dissolution of two carbonate-reservoir analogue minerals (Ketton limestone and North-Sea chalk) in CO2-saturated water were found to follow the same kinetics as found for pure calcite. Vertical scanning interferometry was used to study the surface morphology of unreacted and reacted samples. The results of the present study may find application in reactive-flow simulations of CO2-injection into carbonate-mineral saline aquifers.
Chow YTF, Eriksen DK, Galindo A, et al., 2016, Interfacial tensions of systems comprising water, carbon dioxide and diluent gases at high pressures: experimental measurements and modelling with SAFT-VR Mie and square-gradient theory, Fluid Phase Equilibria, Vol: 407, Pages: 159-176, ISSN: 0378-3812
Experimental interfacial tensions of the systems (H<inf>2</inf>O+CO<inf>2</inf>), (H<inf>2</inf>O+N<inf>2</inf>), (H<inf>2</inf>O+Ar), (H<inf>2</inf>O+CO<inf>2</inf> +N<inf>2</inf>) and (H<inf>2</inf>O+CO<inf>2</inf> +Ar) are compared with calculations based on the statistical associating fluid theory for variable range potentials of the Mie form (SAFT-VR Mie) in combination with the square-gradient theory (SGT). Comparisons are made at temperatures from (298 to 473)K and at pressures up to 60MPa. Experimental data for the systems (H<inf>2</inf>O+CO<inf>2</inf>), (H<inf>2</inf>O+N<inf>2</inf>) and (H<inf>2</inf>O+CO<inf>2</inf> +N<inf>2</inf>) are taken from the literature. For the (H<inf>2</inf>O+Ar) and (H<inf>2</inf>O+CO<inf>2</inf> +Ar) systems, we report new experimental interfacial-tension data at temperatures of (298.15-473.15)K and pressures from (2 to 50)MPa, measured by the pendant-drop method. The expanded uncertainties at 95% confidence are 0.05K for temperature, 70kPa for pressure, 0.016× γ for interfacial tension in the binary (Ar+H<inf>2</inf>O) system and 0.018× γ for interfacial tension in the ternary (CO<inf>2</inf> +Ar+H<inf>2</inf>O) system.The parameters in the SAFT-VR Mie equation of state are estimated entirely from phase-equilibrium data for the pure components and binary mixtures. For pure water, the SGT influence parameter is determined from vapour-liquid surface-tension data, as is common practice. Since the other components are supercritical over most or the entire temperature range under consideration, their pure-component influence parameters are regressed by comparison with the binary interfacial-tension data. A geometric-mean combining rule
Schmidt KAG, Pagnutti D, Curran MD, et al., 2016, Correction to "New experimental data and reference models for the viscosity and density of squalane", Journal of Chemical and Engineering Data, Vol: 61, Pages: 698-698, ISSN: 1520-5134
Empirical models for the density and the viscosity of squalane (C30H62; 2,6,10,15,19,23-hexamethyltetracosane) have been developed based on an exhaustive review of the data available in the literature and new experimental density and viscosity measurements carried out as a part of this work. The literature review shows there is a substantial lack of density and viscosity data at high temperature (373 to 473) K and high pressure conditions (pressures up to 200 MPa). These gaps were addressed with new experimental measurements carried out at temperatures of (338 to 473) K and at pressures of (1 to 202.1) MPa. The new data were utilized in the model development to improve the density and viscosity calculation of squalane at all conditions including high temperatures and high pressures. The model presented in this work reproduces the best squalane density and viscosity data available based on a new combined outlier and regression algorithm. The combination of the empirical models and the regression approach resulted in models which could reproduce the experimental density data with average absolute percent deviation of 0.04 %, bias of 0.000 %, standard deviation of 0.05 %, and maximum absolute percent deviation of 0.14 % and reproduce the experimental viscosity data with average absolute percent deviation of 1.4 %, bias of 0.02 %, standard deviation of 1.8 %, and maximum absolute percent deviation of 4.9 % over a wide range of temperatures and pressures. On the basis of the data set used in the model regression (without outliers), the density model is limited to the pressure and temperature ranges of (0.1 to 202.1) MPa and (273 to 525) K, whereas the viscosity model is limited to the pressure and temperature ranges of (0.1 to 467.0) MPa and (273 to 473) K. These models can be used to calibrate laboratory densitometers and viscometers at relevant high-temperature, high-pressure conditions.
Al Ghafri SZS, Forte E, Galindo A, et al., 2015, Experimental and Modeling Study of the Phase Behavior of (Heptane plus Carbon Dioxide plus Water) Mixtures, Journal of Chemical and Engineering Data, Vol: 60, Pages: 3670-3681, ISSN: 1520-5134
We report experimental measurements ofthree-phase equilibria in the system (heptane + carbon dioxide+ water) obtained with a quasi-static analytical apparatus withcompositional analysis by means of gas chromatography. Theapparatus was calibrated by an absolute area method and thewhole measurement system was validated by means ofcomparison with the published literature data of the system(heptane + carbon dioxide). The compositions of the threephases coexisting in equilibrium were measured along fiveisotherms at temperatures from (323.15 to 413.15) K withpressures ranging from approximately 2 MPa to the uppercritical end point pressure at which the two nonaqueousphases became critical. The experimental results have been compared with the predictions of the statistical associating fluidtheory for potentials of variable range. The unlike binary interaction parameters used here are consistent with a previous study fora ternary mixture of a different n-alkane, while the alkane−water binary interaction parameter is found to be transferable and thealkane−carbon dioxide binary interaction parameter is predicted using a modified Hudson-McCoubrey combining rule.Generally, good agreement between experiment and theory was found
Chow YTF, Maitland GC, Trusler JPM, 2015, Interfacial tensions of the (CO2 + N-2 + H2O) system at temperatures of (298 to 448) K and pressures up to 40 MPa, Journal of Chemical Thermodynamics, Vol: 93, Pages: 392-403, ISSN: 1096-3626
Interfacial tension measurements of the (CO2 + N2 + H2O) and (N2 + H2O) systems are reported at pressures of (2 to 40) MPa, and temperatures of (298.15 to 448.15) K. The pendant drop method was used in which it is necessary to know the density difference between the two phases. To permit calculation of this difference, the compositions of the coexisting phases were first computed from a combination of the Peng–Robinson equation of state (applied to the non-aqueous phase) and the NRTL model (applied to the aqueous phase). Densities of the non-aqueous phase were computed from the GERG-2008 equation of state, while those of the aqueous phase were calculated knowing the partial molar volumes of the solutes. The expanded uncertainties at 95% confidence are 0.05 K for temperature, 0.07 MPa for pressure, 0.019γ for interfacial tension in the binary (N2 + H2O) system; and 0.032γ for interfacial tension in the ternary (CO2 + N2 + H2O) system. The interfacial tensions in both systems were found to decrease with both increasing pressure and increasing temperature. An empirical correlation has been developed for the interfacial tension of the (N2 + H2O) system in the full range of conditions investigated, with an average absolute deviation of 0.20 mN · m−1, and this is used to facilitate a comparison with literature values. Estimates of the interfacial tension for the (CO2 + N2 + H2O) ternary system, by means of empirical combining rules based on the coexisting phase compositions and the interfacial tensions of the binary sub-systems, (N2 + H2O) and (CO2 + H2O), were found to be somewhat inadequate at low temperatures, with an average absolute deviation of 1.9 mN · m−1 for all the conditions investigated. To enable this analysis, selected literature data for the interfacial tensions of the (CO2 + H2O) binary system have been re-analysed, allowing for improved estimates of the density difference between the two phases. The revised resu
del Rio-Chanona EA, Dechatiwongse P, Zhang D, et al., 2015, Optimal Operation Strategy for Biohydrogen Production, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, Vol: 54, Pages: 6334-6343, ISSN: 0888-5885
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- Citations: 25
Zhang D, Dechatiwongse P, del Rio-Chanona EA, et al., 2015, Dynamic modelling of high biomass density cultivation and biohydrogen production in different scales of flat plate photobioreactors, Biotechnology and Bioengineering, Vol: 112, Pages: 2429-2438, ISSN: 1097-0290
This paper investigates the scaling-up of cyanobacterial biomass cultivation and biohydrogen production from laboratory to industrial scale. Two main aspects are investigated and presented, which to the best of our knowledge have never been addressed, namely the construction of an accurate dynamic model to simulate cyanobacterial photo-heterotrophic growth and biohydrogen production and the prediction of the maximum biomass and hydrogen production in different scales of photobioreactors. To achieve the current goals, experimental data obtained from a laboratory experimental setup are fitted by a dynamic model. Based on the current model, two key original findings are made in this work. First, it is found that selecting low-chlorophyll mutants is an efficient way to increase both biomass concentration and hydrogen production particularly in a large scale photobioreactor. Second, the current work proposes that the width of industrial scale photobioreactors should not exceed 0.20 m for biomass cultivation and 0.05 m for biohydrogen production, as severe light attenuation can be induced in the reactor beyond this threshold.
Zhang D, Dechatiwongse P, Del-Rio-Chanona EA, et al., 2015, Analysis of the cyanobacterial hydrogen photoproduction process via model identification and process simulation, CHEMICAL ENGINEERING SCIENCE, Vol: 128, Pages: 130-146, ISSN: 0009-2509
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- Citations: 26
Dechatiwongse P, Maitland C G, Hellgardt K, 2015, Demonstration of a two-stage aerobic/anaerobic chemostat for the enhanced production of hydrogen and biomass from unicellular nitrogen-fixing cyanobacterium, Algal Research-Biomass Biofuels and Bioproducts, ISSN: 2211-9264
Zhang D, Dechatiwongse P, del Rio-Chanona EA, et al., 2015, Modelling of light and temperature influences on cyanobacterial growth and biohydrogen production, Algal Research, Vol: 9, Pages: 263-274, ISSN: 2211-9264
Dynamic simulation is a valuable tool to assist the scale-up and transition of biofuel production from laboratory scale to potential industrial implementation. In the present study two dynamic models are constructed, based on the Aiba equation, the improved Lambert–Beer's law and the Arrhenius equation. The aims are to simulate the effects of incident light intensity, light attenuation and temperature upon the photo-autotrophic growth and the hydrogen production of the nitrogen-fixing cyanobacterium Cyanothece sp. ATCC 51142. The results are based on experimental data derived from an experimental setup using two different geometries of laboratory scale photobioreactors: tubular and flat-plate. All of the model parameters are determined by an advanced parameter estimation methodology and subsequently verified by sensitivity analysis. The optimal temperature and light intensity facilitating biohydrogen production in the absence of light attenuation have been determined computationally to be 34 °C and 247 μmol m− 2 s− 1, respectively, whereas for cyanobacterial biomass production they are 37 °C and 261 μmol m− 2 s− 1, respectively. Biomass concentration higher than 0.8 g L− 1 is also demonstrated to significantly enhance the light attenuation effect, which in turn inducing photolimitation phenomena. At a higher biomass concentration (3.5 g L− 1), cyanobacteria are unable to activate photosynthesis to maintain their lives in a photo-autotrophic growth culture, and biohydrogen production is significantly inhibited due to the severe light attenuation.
Peng C, Crawshaw JP, Maitland GC, et al., 2015, Kinetics of calcite dissolution in CO2-saturated water at temperatures between (323 and 373) K and pressures up to 13.8 MPa, Chemical Geology, Vol: 403, Pages: 74-85, ISSN: 1872-6836
We report measurements of the calcite dissolution rate in CO2-saturated water at pressures ranging from (6.0 to 13.8) MPa and temperatures from (323 to 373) K. The rate of calcite dissolution in HCl(aq) at temperatures from (298 to 353) K was also measured at ambient pressure with pH between 2.0 and 3.3. A specially-designed batch reactor system, implementing a rotating disc technique, was used to obtain the dissolution rate at the solid/liquid interface of a single crystal, free of mass transfer effects. We used vertical scanning interferometry to examine the texture of the calcite surface produced by the experiment and the results suggested that at far-from-equilibrium conditions, the measured calcite dissolution rate was independent of the initial defect density due to the development of a dynamic dissolution pattern which became steady-state shortly after the onset of dissolution. The results of this study indicate that the calcite dissolution rate under surface-reaction-controlled conditions increases with the increase of temperature from (323 to 373) K and CO2 partial pressure from (6.0 to 13.8) MPa. Fitting the conventional first order transition state kinetic model to the observed rate suggested that, although sufficient to describe calcite dissolution in CO2-free HCl(aq), this model clearly underestimate the calcite dissolution rate in the (CO2 + H2O) system over the range of conditions studied. A kinetic model incorporating both pH and the activity of CO2(aq) has been developed to represent the dissolution rates found in this study. We report correlations for the corresponding reaction rate coefficients based on the Arrhenius equation and compare the apparent activation energies with values from the literature. The results of this study should facilitate more rigorous modelling of mineral dissolution in deep saline aquifers used for CO2 storage.
Cadogan S, Maitland GC, Mistry B, et al., 2015, Diffusion coefficients of carbon dioxide in liquid hydrocarbons at high pressures: Experiment and modeling, Pages: 69-75
Maitland G, 2015, Refining in the reservoir, TCE The Chemical Engineer, Pages: 32-35, ISSN: 0302-0797
Cadogan S, Maitland GC, Mistry B, et al., 2015, Diffusion coefficients of carbon dioxide in liquid hydrocarbons at high pressures: Experiment and modeling, Pages: 144-150
In this work we have: • Obtained new experimental data for CO2 diffusion in normal alkanes from C6 to C16 and in squalane (C30H62) • Developed a universal correlation for the n-alkane systems in terms of temperature, solvent molar volume and carbon number • Squalane data suggests that the correlation should become nonlinear at high densities.
Cadogan SP, Hallett JP, Maidand GC, et al., 2015, Diffusion Coefficients of Carbon Dioxide in Brines Measured Using <SUP>13</SUP>C Pulsed-Field Gradient Nuclear Magnetic Resonance, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 60, Pages: 181-184, ISSN: 0021-9568
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- Citations: 19
Schmidt KAG, Pagnutti D, Curran MD, et al., 2015, New Experimental Data and Reference Models for the Viscosity and Density of Squalane, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 60, Pages: 137-150, ISSN: 0021-9568
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- Citations: 43
McBride-Wright M, Maitland GC, Trusler JPM, 2015, Viscosity and Density of Aqueous Solutions of Carbon Dioxide at Temperatures from (274 to 449) K and at Pressures up to 100 MPa, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 60, Pages: 171-180, ISSN: 0021-9568
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- Citations: 49
Bailey L, Lekkerkerker HNW, Maitland GC, 2015, Smectite clay - inorganic nanoparticle mixed suspensions: phase behaviour and rheology, SOFT MATTER, Vol: 11, Pages: 222-236, ISSN: 1744-683X
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- Citations: 60
Remiezowicz E, Spooren J, Bay E, et al., 2015, Capture agents, conversion mechanisms, biotransformations and biomimetics: general discussion, FARADAY DISCUSSIONS, Vol: 183, Pages: 463-487, ISSN: 1359-6640
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- Citations: 1
Hou S-X, Maitland GC, Trusler JPM, 2014, Phase equilibria of (CO2 + butylbenzene) and (CO2 + butylcyclohexane) at temperatures between (323.15 and 423.15) K and at pressures up to 21 MPa, Fluid Phase Equilibria, Vol: 387, Pages: 111-116, ISSN: 0378-3812
Experimental measurements of the phase equilibria of (CO2 + butylbenzene) and (CO2 + butylcyclohexane) have been made with an analytical apparatus at temperatures of (323.15, 373.15 and 423.15) K at pressures from 2 MPa to the mixture critical pressure. These are the first results to be published for (CO2 + butylcyclohexane), while for (CO2 + butylbenzene) they are the first at pressures above 6 MPa. To model the data, we use the Peng–Robinson equation of state with Wong–Sandler mixing rules incorporating the NRTL equation. The model describes the measured bubble point curves very well at all temperatures, except close to the mixture critical points at high pressures. The dew point curves are described well only at the lowest temperature; otherwise, deviations increase in the approach to the mixture critical point.
Al Ghafri SZS, Forte E, Maitland GC, et 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
Dechatiwongse P, Srisamai S, Maitland G, et al., 2014, Effects of light and temperature on the photoautotrophic growth and photoinhibition of nitrogen-fixing cyanobacterium <i>Cyanothece</i> sp ATCC 51142, ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS, Vol: 5, Pages: 103-111, ISSN: 2211-9264
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- Citations: 40
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
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- Citations: 16
Cadogan SP, Maitland GC, Trusler JPM, 2014, Diffusion coefficients of CO2 and N-2 in water at temperatures between 298.15 K and 423.15 K at pressures up to 45 MPa, Journal of Chemical and Engineering Data, Vol: 59, Pages: 519-525, ISSN: 1520-5134
We report measurements of the diffusion coefficients of CO2 and N2 in pure water at temperatures between (298.15 and 423.15) K and pressures between (15 and 45) MPa. The measurements were made by the Taylor dispersion method and have a standard relative uncertainty of 2.3 %. The results were found to be essentially independent of pressure over the range investigated and a simple relation, based on the Stokes–Einstein equation, is proposed to correlate the experimental data. Some experimental difficulties arising in the measurement of the diffusivities of slightly soluble acid-gas solutes such as CO2 in water are also discussed.
Maitland G, 2014, Putting CO<inf>2</inf> in its place, TCE The Chemical Engineer, Pages: 34-37, ISSN: 0302-0797
Al Ghafri SZS, 2014, Phase behaviour and physical properties of reservoir fluids under addition of carbon dioxide
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
Maitland G, 2013, Towards a low-carbon fossil fuels future, TCE The Chemical Engineer, Pages: 32-37, ISSN: 0302-0797
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