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Abstract: Van der Waals forces often dominate interactions and adhesion between fine particles and, in turn, decisively influence the bulk behaviour of powders. However, so far there is no effective means to characterize the adhesive behaviour of such particles. A complication is that most powder particles have rough surfaces, and it is the asperities on the surfaces that touch, confounding the actual surface that is in contact. Conventional approaches using surface energy provide limited information regarding adhesion, and pull-off forces measured through atomic force microscope (AFM) are highly variable and difficult to interpret. In this paper we develop a model which combines the Rumpf–Rabinovich and the JKR–DMT theories to account simultaneously for the effects of surface roughness and deformation on adhesion. This is applied to a ‘characteristic asperity’ which may be easily obtained from AFM measurements. The concept of adhesiveness, a material property reflecting the influences of elastic deformability, surface roughness, and interfacial surface energy, is introduced as an efficient and quantitative measure of the adhering tendency of a powder. Furthermore, a novel concept of specific adhesiveness is proposed as a convenient tool for characterizing and benchmarking solid materials. This paper provides an example to illustrate the use of the proposed theories. [Copyright &y& Elsevier]

The mechanism underlying segregation in liquid fluidized beds is investigated in this paper. A binary fluidized bed system not at a stable equilibrium condition, is modelled in the literature as forming a mixed part—corresponding to stable mixture—at the bottom of the bed and a pure layer of excess components always floating on the mixed part. On the basis of this model; (i) comprehensive criteria for binary particles of any type to mix/segregate, and (ii) mixing/segregation regime map in terms of size ratio and density ratio of the particles for a given fluidizing medium, are established in this work. Therefore, knowing the properties of given particles, a second type of particles can be chosen in order to avoid or to promote segregation according to the particular process requirements. The model is then advanced for multi-component fluidized beds and validated against experimental results observed for ternary fluidized beds. [Copyright &y& Elsevier]

Abstract: Permeance, ideal and mixture permeation selectivity have been evaluated based on molecular simulations of gas adsorptions by the grand canonical Monte Carlo simulation and diffusion by molecular dynamics simulation under a flexible framework. Additional transport phenomena are also obtained using transition state theory under rigid framework assumptions. A number of gas systems in the simulation involving H2, CO2, CH4, N2, O2 and Ar penetrating through a thin layer of ZIF-8 membrane are analyzed and compared with permeance, ideal and mixture permeation selectivity experiments. Three contributions have been achieved in this work. Firstly, it is demonstrated that the assumption of a rigid framework may be sufficient for simulating adsorption isotherms while diffusivity requires a flexible framework, especially when a diffusing molecule is bigger than the pore window of the MOFs, with an appropriate force-field and charges. Secondly, simulations of the ideal permeation selectivity are higher than those of mixture permeation selectivity. However, both calculations with flexible framework accuracy may be acceptable for the purpose of screening membrane materials when compared with experiments, especially the permeation selectivity of an equimolar mixture. Finally, even though simulated isotherms, diffusivity and mixture selectivity are consistent with available experiments and the same data have been used for estimating permeance of the membrane, the difference between the estimation and measurement of the permeation at low pressure is considerable. Therefore, it is confirmed that the effects of defections and multi-scale (macroscopic) diffusion cannot be ignored. [Copyright &y& Elsevier]

Abstract: An alternative approach is proposed to develop an improved permeability model for coalbed methane (CBM) and CO2-enhanced CBM (ECBM) recovery, and CO2 geosequestration in coal. This approach integrates the textural and mechanical properties to describe the anisotropy of gas permeability in coal reservoirs. The model accounts for the stress dependent deformation using a stress–strain correlation, which allows determination of directional permeability for coals. The stress–strain correlation was developed by combining mechanical strain with sorption-induced strain for any given direction. The mechanical strain of coal is described by the general thermo-poro-elastic constitutive equations for solid materials under isothermal conditions and the sorption-induced strain is approximated by treating the swelling/shrinkage of coal matrix equivalent to the thermal contraction/expansion of materials. With directional strains, the permeability of coal in any given direction can be modeled based on the theory of rock hydraulics. In this study, the proposed model was tested with both literature data and experiments. The experiments were carried out using a specially designed true tri-axial stress coal permeameter (TTSCP). The results show that the proposed model provides better predictions for the literature data compared with other conventional coal permeability models. The model also gives reasonable agreement between the predicted and measured stress–strains and directional permeabilities under laboratory conditions. [Copyright &y& Elsevier]

Abstract: This paper presents the development of an analytical model which can be used to relate the structural parameters of coal to its mechanical properties such as elastic modulus and Poisson’s ratio under a confined stress condition. This model is developed primarily to support process modeling of coalbed methane (CBM) or CO2-enhanced CBM (ECBM) recovery from coal seam. It applied an innovative approach by which stresses acting on and strains occurring in coal are successively combined in rectangular coordinates, leading to the aggregated mechanical constants. These mechanical properties represent important information for improving CBM/ECBM simulations and incorporating within these considerations of directional permeability. The model, consisting of constitutive equations which implement a mechanically consistent stress–strains correlation, can be used as a generalized tool to study the mechanical and fluid behaviors of coal composites. An example using the model to predict the stress–strain correlation of coal under triaxial confined stress by accounting for the elastic and brittle (non-elastic) deformations is discussed. The result shows a good agreement between the prediction and the experimental measurement. [Copyright &y& Elsevier]

Spouted beds have been used in industry for operations such as drying, catalytic reactions, and granulation. Conventional cylindrical spouted beds suffer from the disadvantage of scaleup. Two-dimensional beds have been proposed by other authors as a solution for this problem. Minimum spouting velocity has been studied for such two-dimensional beds. A force balance model has been developed to predict the minimum spouting velocity and the maximum pressure drop. Effect of porosity on minimum spouting velocity and maximum pressure drop has been studied using the model. The predictions are in good agreement with the experiments as well as with the experimental results of other investigators. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study of fluidized-bed coating on thin plates using an orthogonal collocation technique. Inclusion of the latent heat of fusion term in the boundary conditions of the mathematical model accounts for the fact that some polymer powders used in coating may be partially crystalline. Predictions of coating thickness on flat plates were made with actual polymers used in fluidized-bed coating. Reasonably good agreement between numerical predictions of the coating thickness and experimental coating data of Richart was obtained for steel panels preheated to 316 °C. A good agreement was also obtained between numerical predictions and our coating thickness data for nylon-11 and polyethylene powders. Predicted coating thickness for polyethylene powder on flat plates were obtained with values of heat transfer coefficient closer to those obtained from our experiments. [Copyright &y& Elsevier]

Shale - water - CO 2 reactions may occur during CO 2 geological storage, enhanced gas recovery, enhanced oil recovery, or supercritical CO 2 fracturing. Shale-acid reactions occur during fracturing or acid stimulation. The mobilisation of metals from these processes can be an environmental concern if production water leaks or is released at surface. In addition, reactions may cause changes at the pore scale and affect gas or fluid flow. Three gas shales from the Australian Cooper Basin REM sequence were characterised for metals in minerals by synchrotron X-ray fluorescence microscopy. Metals including Zn, As, Ni, Cr were hosted in sphalerite associated with organic matter, Pb was in pyrite cement, and Mn was hosted in siderite. The shales were separately reacted with brine and supercritical CO 2 , with CO 2 -SO 2 , with dilute HCl, or with N 2 at 100 °C and 20 MPa in batch reactors. The solution pH decreased during mineral reactions releasing metals to solution with the general concentrations from reaction with HCl > CO 2 -SO 2 > CO 2 > N 2 and brine. Of the total available Pb, As, Li, and Zn in the shales, from 0 to 17%, 0.3 to 23%, 3 to 13%, and 0.4 to 28% was released to solution respectively. Corrosion of siderite and ankerite was observed after the CO 2 reactions, with precipitation of Fe-oxides. After CO 2 -SO 2 reaction siderite and ankerite were dissolved with pyrite, barite, and Fe-rich precipitates. HCl reactions resulted in complete dissolution of carbonates, with dissolution pits and no mineral precipitation observed. The changes to the fractions of gas accessible mesopores were characterised by small angle neutron scattering (SANS). The Epsilon Formation had the greatest fraction of open accessible pores in the SANS range of 10 to 150 nm, followed by the Murteree and Roseneath shale samples. After CO 2 or CO 2 -SO 2 reactions a small decrease in pore accessibility was more pronounced in the Murteree and Roseneath shales, consistent with mineral precipitation. HCl reaction resulted in opening of pores at 150 nm and closing of the smallest measured pores at 10 nm. Metals were mobilised from siderite, ankerite and sulphide minerals mainly, and were dependent on the mineral and metal content but also on the injected gas stream or fluid composition. CO 2 based fluids may result in cleaner flow back water, than HCl based fluids. Geochemical reactions during CO 2 storage or acid treatment in reactive shales cause pore changes that can affect gas migration. Mineral precipitation during CO 2 and CO 2 -SO 2 reactions can result in favourable self-sealing. [Display omitted] • Cooper Basin REM shales reacted with dilute HCl or supercritical CO 2 or CO 2 - SO 2. • XFM: As, Ni in sulphides in organic matter pores. Pb in pyrite cements. Mn, Cr in siderite. • Siderite/ankerite dissolved with HCl; or corroded with CO 2 and Fe-oxides formed. • Concentrations of metals released to solution HCl > CO 2 -SO 2 > CO 2 > N 2 and brine. • Fraction of CD 4 accessible mesopores increased on HCl reaction, decreased with CO 2. [ABSTRACT FROM AUTHOR]

Positive results of MitraClip in terms of improvement in clinical and left ventricular parameters have been described in detail. However, long-term effects on secondary pulmonary hypertension were not investigated in a larger patient cohort to date. 70 patients with severe mitral regurgitation, additional pulmonary hypertension, and right heart failure as a result of left heart disease were treated in the heart centers Hamburg and Góttingen. Immediately after successful MitraClip implantation, a reduction of the RVOT diameter from 3.52 cm to 3.44 cm was observed reaching a statistically significant value of 3.39 cm after 12 months. In contrast, there was a significant reduction in the velocity of the tricuspid regurgitation (TR) from 4.17 m/s to 3.11 m/s, the gradient of the TR from 48.5mmHg to 39.3mmHg, and the systolic pulmonary artery pressure (PAPsyst) from 58.6mmHg to 50.0mmHg. This decline continued in the following months (Vmax TR 3.09 m/s, peak TR 38.6mmHg, and PAPsyst 47.4mmHg).The tricuspid annular plane systolic excursion (TAPSE) increased from 16.5mm to 18.9mm after 12 months. MitraClip implantation improves pulmonary artery pressure, tricuspid regurgitation, and TAPSE after 12 months. At the same time, there is a decrease in the RVOT diameter without significant changes in other right ventricular and right atrial dimensions. [ABSTRACT FROM AUTHOR]

This paper presents an experimental and numerical investigation on anisotropic permeability of coal in order to evaluate the effects of the anisotropic permeability variation on CO 2 sequestration in coal and CO 2 -sequestration enhanced coalbed methane (CO 2 -ECBM) recovery from coal seams. An alternative permeability model has been developed to improve reservoir simulation for CO 2 sequestration in coal and coalbed methane (CBM) recovery and provide better understanding of the CO 2 -ECBM process. Combined with experimental observations, the permeability model adopts a discontinuum medium approach, by which coal is treated as a discontinuum medium containing anisotropic matrixes and cleats. The permeability variations and anisotropic permeability ratios under isotropic net stresses were tested with relatively large coal samples to provide experimental information for model parameterization and validation. The model was further incorporated into a 3D coal reservoir model for reservoir simulations to investigate the impact of the anisotropic permeability of coal on coalbed methane (CBM) recovery. The simulations show good agreements with the experimental data, revealing that the developed model is superior for describing stress- and sorption-induced permeability variations in coals compared with commonly used permeability models that treat coal as isotropic media and use constant values for stress-dependent parameters. The results suggest that anisotropic permeability has significant effects on gas production and CO 2 breakthrough time, implying that it is a critical parameter in determining well pattern and orientation of horizontal wells. [ABSTRACT FROM AUTHOR]

A high pressure supercritical CO 2 (HP-ScCO 2 ) geochemical reactor was used to simulate CO 2 sequestration into deep coal seam under around 40 °C and 9.8 MPa for 72 h and fractal analysis were employed to study the mercury intrusion data of 4 different coal rank samples before and after the ScCO 2 –H 2 O treatment, focusing on the pore structure. It is revealed from the mercury porosimetry data that after exposure to the ScCO 2 –H 2 O fluid, the true density of coal samples are changed as well as total pore volume and porosity most importantly in the increase of micro-pore range. Fractal analysis is introduced to distinguish inter- and intraparticle pores at lower mercury intrusion pressure and to identify the initial pressure associated with the coal compressibility. Three values of fractal dimension ( D 1 , D 2 and D 3 ) are obtained under different pressure ranges, which can be classified corresponding to three different mercury intrusion processes. Varied D 1 values are mainly due to the accumulation mode of samples in the penetrometer and can be used to distinguish the interpore and intrapore intrusion process at lower pressure range of mercury intrusion. D 2 values represents the mercury intrusion into intrapores. D 3 value is decreasing as coal rank increased and can be used to describe the initial pressure when coal samples begin to be compressed or deformed at higher pressure of mercury intrusion. The experiments revealed that CO 2 sequestration process changed the physical properties of coal samples, especially in compression resistance. Coal rank and ash content in coal are very important factors which will affect the variation of coal structure during CO 2 sequestration. [ABSTRACT FROM AUTHOR]

During geological CO 2 storage traditionally CO 2 is injected subsurface into a high permeability reservoir capped by a low permeability seal to trap the buoyant supercritical plume. Wastewater from oil and gas production is also currently disposed of by subsurface injection into suitable reservoirs, most notably in the USA and Canada. Injection of CO 2 dissolved in water may both increase storage security by reducing vertical migration and enhancing dissolution and mineral trapping. There is potential for surface dissolution of CO 2 into wastewater that is already being stored subsurface. CO 2 -water-rock reactions in different sandstone or limestone reservoir rocks with either saline coal production water or low salinity water were geochemically modelled. The geochemical potential for mineral trapping of CO 2 , and associated changes to pH for potential reservoirs is compared. For a mineralogically clean quartz-rich saline sandstone reservoir only 0.18 and 0.20 kg/m3 CO 2 was mineral trapped as ankerite and calcite over 30 or 1000 years. Feldspars, clays and carbonate minerals were converted to kaolinite, calcite, ankerite and smectites, as pH increased to 5.65. The specific silicate minerals present controlled mineral trapping potential e.g. with an Fe-rich chlorite present rather than a clinochlore chlorite 6.3 and 6.8 kg/m3 CO 2 was trapped at 30 and 1000 years respectively as siderite and ankerite. Dissolution trapping dominated in the low salinity or limestone reservoirs with minor mineral trapping. The presence of small amounts of SO 2 or H 2 S in the CO 2 stream resulted in dissolved S sequestered as elemental S, pyrite, barite, and anhydrite. The effects of low CO 2 content or potential reservoir cooling induced by injection fluids were also investigated. The low pH of the injection fluid could potentially corrode legacy wellbores, one solution is a form of amendment such as liming to neutralise pH. [Display omitted] • Large volumes of production water are reinjected dissolved CO 2 could be co-injected. • Reservoir rock reactivity to CO 2 dissolved in production water compared. • Precipitation of smectite, kaolinite, ankerite, siderite, dawsonite in sandstones. • With H 2 S or SO 4 present S, pyrite, barite, and anhydrite precipitate trapping S. • Low pH injection fluid could be amended with liming to avoid wellbore corrosion. [ABSTRACT FROM AUTHOR]

EfficientCO2capture by chemical absorption is currentlygaining interests for the control greenhouse gas emissions. In thiswork, a nonaqueous process was developed to regenerate CO2below 373 K by removing methanol first after the hybrid solventof monoethanolamine (MEA) and methanol had absorbed CO2. A model was accordingly developed to analyze the performance ofthe desorption process. Experiments were performed to determine themissing reaction kinetics of nonaqueous solvent regeneration of CO2to help develop the model. The predicted gas concentration,axial velocity, energy consumption, and desorption efficiency agreedwell with the stripper experimental data. A parametric analysis wasconducted to investigate the effects of temperature, pressure, leansolvent loading, gas/liquid ratio, packing, and internals on the energyconsumption and desorption efficiency. All analyses were performedunder three defined desorption conditions: N2, methanolvapor, and steam as purge gases. Major energy savings were clearlyidentified because of feasible desorption temperatures below 373 Kunder nonaqueous desorption conditions. N2purge gas desorptionconditions offered the minimum energy consumption of 2.28 GJ/t, being24% below the typical value of 3.0 GJ/t. Additionally, it was foundthat the nonaqueous environment improved the desorption efficiencyby 10% compared to that obtained by typical aqueous solution regeneration. [ABSTRACT FROM AUTHOR]

Weperformed molecular dynamics (MD) simulations on multiaminesolutions of CO2capture to optimize the conventional aminesolvents (MEA, MDEA, DEA, AMP, and TEA). A synergy molecular dynamicsmodel (SMD) was developed for the CO2and amine solutions,in which the molecular synergy number (MSN) was introduced to quantifyinteractions between diffusion and molecule motion. The SMD modelinvolved with the force field was validated with experimental datafrom CO2, amine, and water systems. The best synergy forthe MDEA-DEA-TEA system was achieved at the ratio of 3:1:1, with aminimum MSN being 3.89. The overall synergy in ternary amine systemswas found to be better than that in quaternary and quintuple aminesystems. Several optimized multiamine solution systems were identified.The MDEA-DEA-TEA solution could simultaneously provide better diffusivityand less drag force with mass transfer coefficient being 33.33 % higherthan that of AMP. The MEA-MDEA-DEA-TEA solution could improve CO2transport by increasing 18 % of diffusivity when varyingthe ratio from 1:1:1:1 to 2:1:1:1. All of the results above provideda benchmark to optimize the amine mixing solution design for CO2capture. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a simplified multi-scale modeling approach to multi-component adsorption is developed. A number of binary gas systems involving CO2, CH4 and N2 adsorbed on carbon pores are analyzed in three scales. Comprehensive molecular simulations at the microscopic level using the GCMC method are the basis for the validation of the simplified (mesoscopic-level) models for isotherms of homogenous adsorbent. The macroscopic models are then formulated through the integration of the smaller scale models. Three contributions are made in this work. Firstly, it is demonstrated that the form of extended Langmuir equation can represent adsorption isotherms, developed by GCMC simulation in homogeneous micro-pores under mono-layer adsorption. Secondly, the methodology for the estimation of transferable pore-size distributions using optimization algorithms is successfully provided that more than one single component adsorption isotherm is used in computations. Finally, the extended dual-site Langmuir equation is justified as a suitable macroscopic model for multi-component adsorption on heterogeneous porous media with parameters estimated from small-scale models. [Copyright &y& Elsevier]

Two genera new to China, Fibigia and Pachyneurum and 10 species found in China for the first time, Puccinellia kalininae, Stellaria pulvinata, Nanophyton mongolicum, Capsella orienalis, Pachyneurum grandiflorum, Fibigia spathulata, Craniospermum tuvinicum, Euphrasia schischkinii, E. syreitschikovii, Veronica schmakovii along with 3 species previously unknown in Xinjiang, Rorippa indica, Acalypha australis, and Phalaris canariensis, found in northwest Xinjiang are reported. In addition, the distribution of two species in China is corrected: Lepidium densiflorum is firstly reported for Nei Mongol while the occurrence of Draba sibirica in Gansu is not confirmed. Results of floristic studies by the Chinese-Russian Altai expedition during 2004-2007 are also summarized including 34 species and 1 subspecies revealed as new for China; 7 species confirmed to occur in China; one genus and 5 species not confirmed for China, as well as a number of new records for various provinces, mostly Xinjiang. [ABSTRACT FROM AUTHOR]

Abstract: Adsorption isotherms are the foundation of gas storage and separation operations. The isotherm models are classified into three scale levels with empiricisms in macroscopic level, requirements of long computing time and idealized conditions in microscopic level, as well as gaps in knowledge between these two levels. A multi-scale modeling methodology is developed in this paper in order to reduce the identified limitations. Microscopic molecular simulations (MS) based on the grand canonical Monte Carlo (GCMC) method are carried out followed by the development of the localized adsorption isotherms defined as the intermediate level models. They are represented by the Boltzmann factor and the local Langmuir equations. The macroscopic models are then formulated through the integration of small scale models. The following three contributions are achieved in the paper. First of all, guidelines for the validity of the Boltzmann factor are established, showing its practical significance, and the local Langmuir isotherm is justified as a good approximation to the results from microscopic simulations. Secondly, it is demonstrated that the pore size distributions can be determined using GCMC simulations coupled with the measured adsorption isotherms as exemplified by a case study on a coal specimen. Finally, using the measurement data reported by for carbon dioxide adsorption on coal, we show that the overall adsorption isotherms can be determined from the multi-scale approach through the integration of smaller scale models with pore size distributions without the empiricism, indicating the success of the methodology. Further work is needed to improve the prediction accuracy for methane adsorption on coal specimens. [Copyright &y& Elsevier]

Abstract: Pore structure changing of coal during the CO2 geo-sequestration is one of the key issues that affect the sequestration process significantly. To address this problem, the CO2 sequestration process in an anthracite coal was replicated using a supercritical CO2 (ScCO2) reactor. Different coal grain sizes were exposed to ScCO2 and water at around 40°C and 9.8MPa for 72h. Helium pycnometer and mercury porosimetry provide the density, pore size distribution and porosity of the coal before and after the ScCO2 treatment. The results show that after exposure to the ScCO2–H2O reaction, part of the carbonate minerals were dissolved and flushed away by water which made the true density increased as well as total pore volume and porosity most importantly in the micro-pore range. Hysteresis between mercury intrusion and extrusion was observed. Ink bottle shaped pores can be either damaged or created compared with the ScCO2 treated coal samples. This suggests that the ScCO2 treatment most likely increase the volumes of pores in anthracite coal, which also contributed to the increase in porosity of the treated samples. Therefore the CO2 sequestration into coal appears to have the potential to increase significantly the anthracite microporosity which is very advantageous for CO2 storage. [Copyright &y& Elsevier]

Abstract: Metal hydride heat pump (MHHP) can be utilized in a variety of applications and shows great potential in recovery of low-grade heat. Being its kernel component, the reactors should facilitate good heat and mass transfer to achieve satisfactory system performance. In this paper, the influences of certain heat transfer enhancement measures for the reactors were investigated by numerical simulation and thermodynamic analysis. Three types of reactors packed with metal hydride powder, metal hydride powder/Al foam and metal hydride compact were taken for discussion. As shown in the simulation results, for the MHHP adopting heat transfer enhancement, the coefficient of performance tends to reduce slightly while the specific heating power increases remarkably. Therefore, these measures work positively and are recommended for use in heat pump applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents experimental investigations on CO2/CH4 binary gas flow in bulk coal under controllable stress conditions, focusing on sorption-induced swelling/shrinkage and gas permeability associated with CO2-sequestration enhanced coalbed methane (CO2-ECBM) recovery. The gas flush tests with carbon dioxide were conducted on a specially designed true tri-axial stress coal permeameter (TTSCP) using a large coal sample pre-adsorbed methane. These tests simulate the in-situ conditions of CO2-ECBM recovery from coal and provided experimental information for better understanding of the gas transport in coals. The swelling/shrinkage coefficients of coal associated with CO2-ECBM process have been evaluated using the experimental data. The results show that adsorption and desorption of gases CH4 and CO2 can significantly affect the volumetric change of micro- and macropores in coal, leading to coal swelling/shrinkage and fluctuation of permeability, and hence controlling the transport and flow of gases through coal. [Copyright &y& Elsevier]

Abstract: Two Australian Permian coals of similar rank but different texture, one predominantly dull and the other predominantly bright, were investigated in laboratory experiments to assess changes in reservoir properties following exposure to supercritical CO2 (SCCO2) and water. Both powdered coal (0.180–0.220mm) and small cubes (15mm to a side) were tested in a high-pressure (HP) batch reactor for up to 120h. Two reaction fluids were used, each on separate sister coal samples: de-ionised water (DH2O) only, and a SCCO2 and DH2O mixture. Properties were measured before and after treatment with: high-pressure CO2 adsorption isotherms (storage capacity); helium pycnometry, mercury porosimetry and low-pressure (LP) CO2 adsorption (density, porosity and PSD effects); leachate chemical analysis for dissolved mineral matter; and water and CO2 permeabilities at in situ conditions during core flood experiments on an 80mm cube. Micro and meso porosities for both coals showed significant increases after reactions with the SCCO2 and DH2O mixture. The macroporosity decreased significantly for the dull coal, but increased marginally for the bright coal. Total accessible porosity for dull coal showed virtually no change (0.5%); the bright coal exhibited 3.4% increase from a pre-treatment total porosity of 11.0%. On powdered samples reacted with the mixture, 80%+ increases in internal surface areas, measured using LP CO2 sorption at 0°C, were noted for both coals. The HP CO2 excess adsorption isotherms on both coals increased after treatment, varying with pressure level, coal type and coal texture. The core flood tests indicated the permeability to CO2, after a waterflood stage, increased significantly. The second stage waterflood exhibited an over 600% increase on the pre-CO2 first stage waterflood permeability. These combined results indicate that mineral matter in Permian coals is dissolved and mobilized by the carbonic acid formed during CO2 dissolution in water, leading to increased porosity, permeability and HP CO2 excess adsorption. [Copyright &y& Elsevier]

Abstract: Carbon dioxide capturing from the flue gas of power stations is an effective way to mitigate the global warming. In order to predict the performance from startup to stable operation in CO2 absorption process, a multi-field synergy model was developed based on CO2 capture process in a packed column by means of monoethanolamine (MEA). The model suggests that the integral diffusion–reaction coefficient plays an important role in the diffusion, fluid flow, heat transfer and chemical reaction processes. The influences of the fluid flow, heat transfer and chemical reaction can be justified using corresponding synergy numbers, quantifying multi-field interactive dynamic characteristics of the CO2 capture process. The simulation shows a good agreement compared with data in the literature. The results show that the packing Reynolds number can be used as a criterion to choose the proper packing. The less the Reynolds number is, the more efficient the reaction absorption is. The average synergy number Fdc would be decreased by 20% with 6K temperature drop and be descended by 7% with the 2.5% solvent weight percentage increment, which improved the efficiency of CO2 capture by about 5% and 14%, and lowered the energy consumption by about 5%. The average synergy number Fdh would be decreased by about 8% with the 0.062mol/molMEA lean solvent loading increment, which improved the efficiency by about 15% and lowered the energy consumption by 5%. After comparing with CMR-2, Raschig rings, Berl saddles and Pall rings, the 33% less average synergy number F df of the CMR-2 packing with about 5% drop in energy consumption yields the highest efficiency of 71%, which is 10% higher than that of the Berl saddle packing. The results indicate that the proposed multi-field synergy model is an effective way to intensify the capture process as a guideline with the priority of precision and simplicity. [Copyright &y& Elsevier]

Abstract: The metal hydride reactors are widely used in many industrial applications, for example, hydrogen storage, heat pump, thermal compression, gas separation, etc. The performance of the reactor is greatly affected by its design, which deserves careful study. Given the complicated nature of the hydride formation/decomposition processes, a series of technical issues are involved in the design of metal hydride reactors, such as primary configuration, thermal management, hydrogen transfer and mechanistic strength. These issues should be well addressed to fulfil the requirement of specific application. In this paper, the representative achievements with regards to the design issues so far were reviewed in detail, and some comments were made accordingly. It was concluded that an optimized reactor design comes from integrated considerations of numerous factors, particularly requirements for the applications and characteristics of the metal hydride system. The analytic hierarchy process was recommended for use in the selection of the optimum reactor scheme. [Copyright &y& Elsevier]

Abstract: Nitroalkene fatty acid derivatives manifest a strong electrophilic nature, are clinically detectable, and induce multiple transcriptionally regulated anti-inflammatory responses. At present, the characterization and quantification of endogenous electrophilic lipids are compromised by their Michael addition with protein and small-molecule nucleophilic targets. Herein, we report a trans-nitroalkylation reaction of nitro-fatty acids with β-mercaptoethanol (BME) and apply this reaction to the unbiased identification and quantification of reaction with nucleophilic targets. Trans-nitroalkylation yields are maximal at pH 7 to 8 and occur with physiological concentrations of target nucleophiles. This reaction is also amenable to sensitive mass spectrometry-based quantification of electrophilic fatty acid–protein adducts upon electrophoretic resolution of proteins. In-gel trans-nitroalkylation reactions also permit the identification of protein targets without the bias and lack of sensitivity of current proteomic approaches. Using this approach, it was observed that fatty acid nitroalkenes are rapidly metabolized in vivo by a nitroalkene reductase activity and mitochondrial β-oxidation, yielding a variety of electrophilic and nonelectrophilic products that could be structurally characterized upon BME-based trans-nitroalkylation reaction. This strategy was applied to the detection and quantification of fatty acid nitration in mitochondria in response to oxidative inflammatory conditions induced by myocardial ischemia–reoxygenation. [Copyright &y& Elsevier]

This paper presents an alternative model of multicomponent gas diffusion and flow in bulk coals, focusing on counter-diffusion associated with -sequestration enhanced coalbed methane (-ECBM) recovery. The model was developed based on the bidisperse diffusion mechanism and the Maxwell–Stefan (MS) diffusion theory, which provides an improved simulation of multicomponent gas diffusion dynamics. The model was firstly validated under the condition of pure gas diffusion by comparing with the analytical solutions of a bidisperse diffusion model and the experimental data obtained from pure-gas sorption kinetic tests. Then it was numerically solved by considering counter-diffusion and flow in a large coal sample to simulate a laboratory -injection core flush experiment. The simulation shows an excellent agreement with the flush experiment. A quantitative description of the relationship between micropore diffusivity and concentration has been achieved, which is a deficiency in currently available CBM/ECBM models. The concentration-dependent diffusivities need to be taken into account in modeling the coalbed methane (CBM) recovery, in particular for simulation of ECBM production from and sequestration in coal seams. [Copyright &y& Elsevier]

Effective recovery of residual methane from coal seams after major extraction operations is an important but difficult task due to the small driving forces and low mass transfer coefficients. An obvious option to achieve nearly complete methane recovery is the depressurization technique. In this communication, we develop a model for the prediction of mass transfer dynamics between coal matrix and fractures under depressurization conditions. The fluid flow in fractures is modeled using Darcy''s law described by partial differential equations, whereas the variations of gas and adsorbed phase concentrations within the coal matrix are represented by a lumped parameter model represented by ordinary differential equations. Key parameters are estimated using well-established methods from the general literature. The model is validated using a true tri-axial stress coal permeameter (TTSCP), which provides accurate dynamic measurements of system properties under a series of controlled pressure reductions. The model provides physical insights into the observed behavior. The relative importance of the convective and diffusive flows is quantified through numerical simulations, which is essential to the design of depressurization operations. [Copyright &y& Elsevier]

This paper presents an analysis of membrane reactor operation and design for enhanced hydrogen production. Silica derived membranes were used for gas permeation studies and a membrane reactor for the water gas shift reaction. A model of the equilibrium reaction is developed and analysed with respect to operational factors such as temperature and pressure analysed in consideration for production of a 99% pure H2 stream. These factors influence the optimisation of the reaction and permeation rate as well as the equilibrium conversion. It was found that using H2 permeation membranes, the H2 equilibrium could be shifted towards the products. In turn, this provided better conversion at higher temperatures. The cost of H2 production using membrane reactors is dependent upon several engineering process parameters such as reaction rates, permeation, selectivities, temperature and pressure. Silica membranes assembled in membrane reactors out performed conventional reactor systems. Silica membranes were synthesised showing permeations of 5 × 10-8 mol m-2 s-1 Pa-1 and H2/CO selectivities >10. The silica membrane capital cost per kg H2 produced ranged from US$0·25 to 3&middot00 for 10 to 80%H2 separation respectively. [ABSTRACT FROM AUTHOR]

Deep-frying, which consists of immersing a wet material in a large volume of hot oil, presents a process easily adaptable to dry rather than cook materials. A suitable material for drying is sewage sludge, which may be dried using recycled cooking oils (RCO) as frying oil. One advantage is that this prepares both materials for convenient disposal by incineration. This study examines fry-drying of municipal sewage sludge using recycled cooking oil. The transport processes occurring during fry-drying were monitored through sample weight, temperature, and image analysis. Due to the thicker and wetter samples than the common fried foods, high residual moisture is observed in the sludge when the boiling front has reached the geometric center of the sample, suggesting that the operation is heat transfer controlled only during the first half of the process followed by the addition of other mechanisms that allow complete drying of the sample. A series of mechanisms comprising four stages (i.e., initial heating accompanied by a surface boiling onset, film vapor regime, transitional nucleate boiling, and bound water removal) is proposed. In order to study the effect of the operating conditions on the fry-drying kinetics, different oil temperatures (from 120 to 180°C), diameter ( D = 15 to 25 mm), and initial moisture content of the sample (4.8 and 5.6 kg water·kg -1 total dry solids) were investigated. [ABSTRACT FROM AUTHOR]

Abstract: Coal fired power generation will continue to provide energy to the world for the foreseeable future. However, this energy use is a significant contributor to increased atmospheric CO2 concentration and, hence, global warming. Capture and disposal of CO2 has received increased R&D attention in the last decade as the technology promises to be the most cost effective for large scale reductions in CO2 emissions. This paper addresses CO2 transport via pipeline from capture site to disposal site, in terms of system optimization, energy efficiency and overall economics. Technically, CO2 can be transported through pipelines in the form of a gas, a supercritical fluid or in the subcooled liquid state. Operationally, most CO2 pipelines used for enhanced oil recovery transport CO2 as a supercritical fluid. In this paper, supercritical fluid and subcooled liquid transport are examined and compared, including their impacts on energy efficiency and cost. Using a commercially available process simulator, ASPEN PLUS 10.1, the results show that subcooled liquid transport maximizes the energy efficiency and minimizes the cost of CO2 transport over long distances under both isothermal and adiabatic conditions. Pipeline transport of subcooled liquid CO2 can be ideally used in areas of cold climate or by burying and insulating the pipeline. In very warm climates, periodic refrigeration to cool the CO2 below its critical point of 31.1°C, may prove economical. Simulations have been used to determine the maximum safe pipeline distances to subsequent booster stations as a function of inlet pressure, environmental temperature and ground level heat flux conditions. [Copyright &y& Elsevier]