232 results found
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
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
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
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.
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
Cadogan SP, Hallett JP, Maidand GC, et al., 2015, Diffusion Coefficients of Carbon Dioxide in Brines Measured Using C-13 Pulsed-Field Gradient Nuclear Magnetic Resonance, JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 60, Pages: 181-184, ISSN: 0021-9568
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
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 Cyanothece sp ATCC 51142, ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS, Vol: 5, Pages: 103-111, ISSN: 2211-9264
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
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
Peng C, Crawshaw JP, Maitland GC, et al., 2013, The pH of CO2-saturated water at temperatures between 308 K and 423 K at pressures up to 15 MPa, The Journal of Supercritical Fluids, Vol: 82, Pages: 129-137, ISSN: 0896-8446
Abstract We report pH measurements for CO2-saturated water in the pressure range from (0.28 to 15.3) MPa and temperatures from (308.3 to 423.2) K. Commercially available pH and Ag/AgCl electrodes were used together with a high pressure equilibrium vessel operating under conditions of precisely controlled temperature and pressure. The results of the study indicate that pH decreases along an isotherm in proportion to −log10(x), where x is the mole fraction of dissolved CO2 in H2O. The expanded uncertainty of the pH measurements is 0.06 pH units with a coverage factor of 2. The reported results are in good agreement with the literature in pressure ranges up to 16 MPa at temperatures below 343 K. An empirical equation has been developed to represent the present results with an expanded uncertainty of 0.05 pH units. We also compare our results with a chemical equilibrium model and find agreement to within 0.1 pH unit.
Georgiadis A, Berg S, Makurat A, et al., 2013, Pore-scale micro-computed-tomography imaging: Nonwetting-phase cluster-size distribution during drainage and imbibition, Physical Review E, Vol: 88, ISSN: 1539-3755
We investigated the cluster-size distribution of the residual nonwetting phase in a sintered glass-bead porousmedium at two-phase flow conditions, by means of micro-computed-tomography (μCT) imaging with pore-scaleresolution. Cluster-size distribution functions and cluster volumes were obtained by image analysis for a range ofinjected pore volumes under both imbibition and drainage conditions; the field of view was larger thanthe porosity-based representative elementary volume (REV). We did not attempt to make a definition for atwo-phase REV but used the nonwetting-phase cluster-size distribution as an indicator. Most of the nonwettingphasetotal volume was found to be contained in clusters that were one to two orders of magnitude larger thanthe porosity-based REV. The largest observed clusters in fact ranged in volume from 65% to 99% of the entirenonwetting phase in the field of view. As a consequence, the largest clusters observed were statistically notrepresented and were found to be smaller than the estimated maximum cluster length. The results indicate thatthe two-phase REV is larger than the field of view attainable by μCT scanning, at a resolution which allows forthe accurate determination of cluster connectivity.
Tong D, Maitland GC, Trusler MJP, et al., 2013, Solubility of carbon dioxide in aqueous blends of 2-amino-2-methyl-1-propanol and piperazine, Chemical Engineering Science, Vol: 101, Pages: 851-864, ISSN: 0009-2509
In this work, we report new solubility data for carbon dioxide in aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). A static-analytical apparatus, validated in previous work, was employed to obtain the results at temperatures of (313.2, 333.2, 373.2, 393.2) K, and at total pressures up to 460 kPa. Two different solvent blends were studied, both having a total amine mass fraction of 30%: (25 mass% AMP+5 mass% PZ) and (20 mass% AMP+10 mass% PZ). Comparisons between these PZ activated aqueous AMP systems and 30 mass% aqueous AMP have been made in terms of their cyclic capacities under typical scrubbing conditions of 313 K in the absorber and 393 K in the stripper. The Kent–Eisenberg model was used to correlate the experimental data.
Hou S-X, Maitland GC, Trusler JPM, 2013, Phase equilibria of (CO2 + H2O + NaCl) and (CO2 + H2O + KCl): Measurements and modeling, JOURNAL OF SUPERCRITICAL FLUIDS, Vol: 78, Pages: 78-88, ISSN: 0896-8446
Li X, Ross DA, Trusler JPM, et al., 2013, Molecular Dynamics Simulations of CO2 and Brine Interfacial Tension at High Temperatures and Pressures, JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 117, Pages: 5647-5652, ISSN: 1520-6106
Al Ghafri SZ, Maitland GC, Trusler JPM, 2013, Densities of SrCl2(aq), Na2SO4(aq), NaHCO3(aq), and Two Synthetic Reservoir Brines at Temperatures between (298 and 473) K, Pressures up to 68.5 MPa, and Molalities up to 3 mol.kg(-1), JOURNAL OF CHEMICAL AND ENGINEERING DATA, Vol: 58, Pages: 402-412, ISSN: 0021-9568
Al Ghafri S, Maitland G, Trusler JPM, 2013, Experimental and modeling study of the phase behavior of (Synthetic Crude Oil + CO<inf>2</inf>), Pages: 527-529
Tamburic B, Dechatiwongse P, Zemichael FW, et al., 2013, Process and reactor design for biophotolytic hydrogen production, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 15, Pages: 10783-10794, ISSN: 1463-9076
Hou S-X, Maitland GC, Trusler JPM, 2013, Measurement and modeling of the phase behavior of the (carbon dioxide + water) mixture at temperatures from 298.15 K to 448.15 K, The Journal of Supercritical Fluids, Vol: 73, Pages: 87-96
Tong D, Trusler JPM, Maitland GC, et al., 2012, Solubility of carbon dioxide in aqueous solution of monoethanolamine or 2-amino-2-methyl-1-propanol: Experimental measurements and modelling, International Journal of Greenhouse Gas Control, Vol: 6, Pages: 37-47
Despite the importance of the accurate measurement of vapour–liquid equilibria (VLE) data, the reported values, even for well-studied systems such as MEA–H2O–CO2, are scattered. This work centres on the development of an experimental method to measure accurately the VLE of various aqueous amine systems. A static-analytic type of VLE apparatus has been constructed and employed to measure the VLE of CO2 in aqueous monoethanolamine and 2-amino-2-methyl-1-propanol. Gas chromatography was used to analyse the liquid phase compositions. The setup has been validated against literature data for 30 mass% MEA (monoethanolamine) at T = 313 and 393 K and was shown to be capable of generating reliable and repeatable data. New measurements for 30 mass% aqueous AMP (2-amino-2-methyl-1-propanol) solutions are also presented at temperatures between 313 and 393 K and a total pressure range of 23–983 kPa. A quasi-chemical model has been employed to interpret the experimental data for the MEA–H2O–CO2 and AMP–H2O–CO2 systems. The average absolute deviation (ΔAAD) between model prediction and experimental data is within 7%.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.