| 1. |
- Can, Quan, et al.
(författare)
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Carotenoids particle formation by supercritical fluid technologies
- 2009
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 17:2, s. 344-349
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Tidskriftsartikel (refereegranskat)abstract
- Based on the solubility in supercritical CO2, two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies. The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 μm can be made via solution enhanced dispersion by supercritical fluids (SEDS) process, in which CO2 worked as turbulent anti-solvent; while for astaxanthin, micronized particles with mean particle size of 0.3-0.8 μm were also made successfully by rapid expansion supercritical solution (RESS) process.
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| 2. |
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| 3. |
- Ji, Yuanhui, et al.
(författare)
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Progress in the study on the phase equilibria of the CO2-H2O and CO2-H2O-NaCl systems
- 2007
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 15:3, s. 439-448
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Tidskriftsartikel (refereegranskat)abstract
- To study the feasibility of CO2 geological sequestration, it is needed to understand the complicated multiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological conditions (273.15-473.15 K, 0-60 MPa), which are also essential for designing separation equipments in chemical or oil-related industries. For this purpose, studies on the relevant phase equilibria and densities are reviewed and analyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable predictions in a wide temperature and pressure range. Besides, three different models (the electrolyte non random two-liquid (ELECNRTL), the electrolyte NRTL combining with Helgeson model (ENRTL-HG), Pitzer activity coefficient model combining with Helgeson model (PITZ-HG)) are used to calculate the vapor-liquid phase equilibrium of CO2-H2O and CO2-H2O-NaCl systems. For CO2-H2O system, the calculation results agree with the experimental data very well at low and medium pressure (0-20 MPa), but there are great discrepancies above 20 MPa. For the water content at 473.15 K, the calculated results agree with the experimental data quite well. For the CO2-H2O-NaCl system, the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52 mol•L-1. Bur for the NaCl concentration of 3.997 mol•L-1, using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model. It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers. More experimental data and more accurate thermodynamic calculations are needed in high temperature and pressure ranges (above 398.15 K and 31.5 MPa).
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| 4. |
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| 5. |
- Dai, Zhengxing, et al.
(författare)
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Prediction and verification of heat capacities for pure ionic liquids
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 169-176
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Tidskriftsartikel (refereegranskat)abstract
- The heat capacity of ionic liquids is an important physical property, and experimental measuring is usually used as a common method to obtain them. Owing to the huge number of ionic liquids that can be potentially synthesized, it is desirable to acquire theoretical predictions. In this work, the Conductor-like Screening Model for Real Solvents (COSMO-RS) was used to predict the heat capacity of pure ionic liquids, and an intensive literature survey was conducted for providing a database to verify the prediction of COSMO-RS. The survey shows that the heat capacity is available for 117 ionic liquids at temperatures ranging 77.66-520 K since 2004, and the 4025 data points in total with the values from 76.37 to 1484 J·mol-1·K-1 have been reported. The prediction of heat capacity with COSMO-RS can only be conducted at two temperatures (298 and 323 K). The comparison with the experimental data proves the prediction reliability of COSMO-RS, and the average relative deviation (ARD) is 8.54%. Based on the predictions at two temperatures, a linear equation was obtained for each ionic liquid, and the heat capacities at other temperatures were then estimated via interpolation and extrapolation. The acquired heat capacities at other temperatures were then compared with the experimental data, and the ARD is only 9.50%. This evidences that the heat capacity of a pure ionic liquid follows a linear equation within the temperature range of study, and COSMO-RS can be used to predict the heat capacity of ionic liquids reliably.
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| 6. |
- Fan, Tengteng, et al.
(författare)
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CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 24:11, s. 1513-1521
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Tidskriftsartikel (refereegranskat)abstract
- The high price and toxicity of ionic liquids (ILs) have limited the design and application of supported ionic liquid membranes (SILMs) for CO2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200 (PEG200) mixtures were selected to prepare novel SILMs because of their green and cost-effective characterization, and the CO2/N2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO2 permeability ranged in 343.3-1798.6 barrer and high CO2/N2 selectivity from 7.9 to 34.8. It was also found that the CO2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to 38 mPa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.
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| 7. |
- Gao, Qingwei, et al.
(författare)
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Effect of dimethyl carbonate on the behavior of water confined in carbon nanotube
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 177-185
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Tidskriftsartikel (refereegranskat)abstract
- The dehydration of water by dimethyl carbonate (DMC) is of great significance for its application in electrochemistry and oil industry. With the rapid development of nanomaterial, one-dimensional (e.g. carbon nanotube (CNT)) and two-dimensional (e.g. lamellar graphene) materials have been widely used for molecular sieving. In this work, the molecular behavior of dimethyl carbonate/water mixture confined in CNT with varying diameters was studied based on molecular dynamics simulation. Due to different van der Waals interactions for the components in the mixtures with the solid surface, DMC molecules are preferentially adsorbed on the inner surface of the pore wall and formed an adsorption layer. Comparing with the pure water molecules confined in CNT, the adsorption DMC layer shows notable effect on the local compositions and microstructures of water molecules under nanoconfinement, which may result in different water mobility. Our analysis shows that the surface-induced DMC molecules can destroy the hydrogen bonding network of water molecules and result in an uniform and dispersed distribution of water molecules in the tube. These clear molecular understandings can be useful in material design for membrane separation.
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| 8. |
- He, Hanbing, et al.
(författare)
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Kinetics for Preparation of K2Ti2O5 Using TiO2 Microparticles and Nanoparticles as Precursors
- 2014
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 22:10, s. 1105-1110
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Tidskriftsartikel (refereegranskat)abstract
- The formation mechanism of K2Ti2O5 was investigated with TiO2 microparticles and nanoparticles as precursors by thermogravimetric (TG) technique. A method of direct multivariate non-linear regression was applied for simultaneous calculation of solid-state reaction kinetic parameters from TG curves. TG results show more regular decrease from initial reaction temperature with TiO2 nanoparticles as raw material compared with TiO2 microparticles, while mass losses finish at similar temperatures under the experimental conditions. From the mechanism and kinetic parameters, the reactions with the two materials are complex consecutive processes, and reaction rate constants increase with temperature and decrease with conversion. The reaction proceedings could be significantly hindered when the diffusion process of reactant species becomes rate-limiting in the later stage of reaction process. The reaction active sites on initial TiO2 particles and formation of product layers may be responsible to the changes of reaction rate constant. The calculated results are in good agreement with experimental ones.
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| 9. |
- Huang, Xianzhu, et al.
(författare)
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Flow-resistance analysis of nano-confined fluids inspired from liquid nano-lubrication: A review
- 2017
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 25:11, s. 1552-1562
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Tidskriftsartikel (refereegranskat)abstract
- How to reduce flow resistance of nano-confined fluids to achieve a high flux is a new challenge for modern chemical engineering applications, such as membrane separation and nanofluidic devices. Traditional models are inapplicable to explain the significant differences in the flow resistance of different liquid–solid systems. On the other hand, friction reduction in liquid nano-lubrication has received considerable attention during the past decades. Both fields are exposed to a common scientific issue regarding friction reduction during liquid–solid relative motion at nanoscale. A promising approach to control the flow resistance of nano-confined fluids is to reference the factors affecting liquid nano-lubrication. In this review, two concepts of the friction coefficient derived from fluid flow and tribology were discussed to reveal their intrinsic relations. Recent progress on low or ultra-low friction coefficients in liquid nano-lubrication was summarized based on two situations. Finally, a new strategy was introduced to study the friction coefficient based on analyzing the intermolecular interactions through an atomic force microscope (AFM), which is a cutting-point to build a new model to study flow-resistance at nanoscale.
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| 10. |
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| 11. |
- Khodabandeh, E., et al.
(författare)
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CFD study of non-premixed swirling burners : Effect of turbulence models
- 2020
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 28:4, s. 1029-1038
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Tidskriftsartikel (refereegranskat)abstract
- This research investigates a numerical simulation of swirling turbulent non-premixed combustion. The effects on the combustion characteristics are examined with three turbulence models: namely as the Reynolds stress model, spectral turbulence analysis and Re-Normalization Group. In addition, the P-1 and discrete ordinate (DO) models are used to simulate the radiative heat transfer in this model. The governing equations associated with the required boundary conditions are solved using the numerical model. The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities. Among different models proposed in this research, the Reynolds stress model with the Probability Density Function (PDF) approach is more accurate (nearly up to 50%) than other turbulent models for a swirling flow field. Regarding the effect of radiative heat transfer model, it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior. This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion.
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| 12. |
- Li, Fangfang, et al.
(författare)
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Ionic liquids for CO2 electrochemical reduction
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 75-93
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Forskningsöversikt (refereegranskat)abstract
- Electrochemical reduction of CO2 is a novel research field towards a CO2-neutral global economy and combating fast accelerating and disastrous climate changes while finding new solutions to store renewable energy in value-added chemical and fuels. Ionic liquids (ILs), as medium and catalysts (or supporting part of catalysts) have been given wide attention in the electrochemical CO2 reduction reaction (CO2RR) due to their unique advantages in lowering overpotential and improving the product selectivity, as well as their designable and tunable properties. In this review, we have summarized the recent progress of CO2 electro-reduction in IL-based electrolytes to produce higher-value chemicals. We then have highlighted the unique enhancing effect of ILs on CO2RR as templates, precursors, and surface functional moieties of electrocatalytic materials. Finally, computational chemistry tools utilized to understand how the ILs facilitate the CO2RR or to propose the reaction mechanisms, generated intermediates and products have been discussed.
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| 13. |
- Li, Jiahui, et al.
(författare)
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Extra low friction coefficient caused by the formation of a solid-like layer : A new lubrication mechanism found through molecular simulation of the lubrication of MoS2 nanoslits
- 2018
-
Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 26:12, s. 2412-2419
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Tidskriftsartikel (refereegranskat)abstract
- Monolayer molybdenum disulfide (MoS2) is a novel two-dimensional material that exhibits potential application in lubrication technology. In this work, molecular dynamics was used to investigate the lubrication behaviour of different polar fluid molecules (i.e., water, methanol and decane) confined in monolayer MoS2 nanoslits. The pore width effect (i.e., 1.2, 1.6 and 2.0 nm) was also evaluated. Results revealed that decane molecules exhibited good lubricating performance compared to the other two kinds of molecules. The friction coefficient followed the order of decane < methanol < water, and decreased evidently as the slit width increased, except for decane. Analysis of the spatial distribution and mobility of different confined fluid molecules showed that a solid-like layer was formed near the slit wall. This phenomenon led to the extra low friction coefficient of confined decane molecules
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| 14. |
- Li, Zheng, et al.
(författare)
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Experimental studies of air-blast atomization on the CO2 capture with aqueous alkali solutions
- 2020
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 27:10, s. 23901-2396
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Tidskriftsartikel (refereegranskat)abstract
- In this work, an air-blast atomizing column was used to study the CO2 capture performance with aqueous MEA (mono-ethanol-amine) and NaOH solutions. The effects of gas flow rate, the liquid to gas ratio (L/G), the CO2 concentration on the CO2 removal efficiency (η) and the volumetric overall mass transfer coefficient (KGav) were investigated. The air-blast atomizing column was also compared with the pressure spray tower on the studies of the CO2 capture performance. For the aqueous MEA and NaOH solutions, the experimental results show that the ηdecreases with increasing gas flow rate and CO2 concentration while it increases with increasing L/G. The effects on KGav are more complicated than those for η. When the CO2 concentration is low (3 v/v%), KGav increases with increasing gas flow rate while decreases with increasing L/G. However, when the CO2 concentration is high (9.5 v/v%), as the gas flow rate and L/G increases, KGav increases first and then decreases. The aqueous MEA solution achieves higher η and KGav than the aqueous NaOH solution. The air-blast atomizing column shows a good performance on CO2 capture.
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| 15. |
- Liu, Chang, et al.
(författare)
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The biomethane producing potential in China : A theoretical and practical estimation
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 24:7, s. 920-928
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Tidskriftsartikel (refereegranskat)abstract
- Biomethane has been developed rapidly in many countries as a renewable energy which upgraded from biogas. China also began to pay attention to it even though we still at a initial stage, primarily, understanding the biomethane potential and development prospect, choosing appropriate biomass as the biomethane source is very important. In this work, the theoretical and practical biomethane producing potential from five main biomass resources in China were estimated with appropriate methods based on the data collected, and during calculation, two appropriate energy crops were assumed to be planted on marginal lands for biomethane production. Our estimation showed that the theoretical and practical biomethane potentials in China can reach to 888.78 and 316.30 billion m3 per year, agricultural waste should be the preferential development biomass, and planting energy crops on marginal lands is the most promising way to enhance biomethane production in China. When compared with natural gas, Chinese natural gas consumption in 2013 only account for 48.15 % of the practical biomethane potential.
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| 16. |
- Liu, C, et al.
(författare)
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The study of dissolution kinetics of K2SO4 crystal in aqueous ethanol solutions with a statistical rate theory
- 2004
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 12, s. 128-130
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Tidskriftsartikel (refereegranskat)abstract
- Dissolution kinetics of K2SO4 crystal in aqueous ethanol solutions was studied on-line with ion selective electrode. The concentration of K2SO4 was calculated from the determined electromotive force in which the activity coefficient of components in the liquid phase was calculated with the Pitzer equation. Dissolution kinetic parameters in the modified statistical rate theory were regressed. The correlation results show that dissolution rate of K2SO4 is slower in aqueous ethanol solutions than that in aqueous solutions. The two most important reasons are as follows: (1) The solubility Of K2SO4 in aqueous ethanol solutions is lower than that in aqueous solutions, which causes a decrease of the driving force of mass transfer. (2) The process of surface reaction Of K2SO4 became slower due to the addition of ethanol, so that the whole process is mainly dominated by the surface reaction instead of mass transfer.
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| 17. |
- Lu, Shan, et al.
(författare)
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Modeling and optimization methods of integrated production planning for steel plate mill with flexible customization
- 2015
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 2210-321X .- 1004-9541. ; 23:12, s. 2037-2047
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Tidskriftsartikel (refereegranskat)abstract
- With diversified requirements and varying manufacturing environments, the optimal production planning for a steelmill becomes more flexible and complicated. The flexibility provides operators with auxiliary requirements through an implementable integrated production planning. In this paper, a mixed-integer nonlinear programming (MINLP) model is proposed for the optimal planning that incorporates various manufacturing constraints and flexibility in a steel plate mill. Furthermore, two solution strategies are developed to overcome the weakness in solving the MINLP problem directly. The first one is to transform the original MINLP formulation to an approximate mixed integer linear programming using a classic linearization method. The second one is to decompose the original model using a branch-and-bound based iterative method. Computational experiments on various instances are presented in terms of the effectiveness and applicability. The result shows that the second method performs better in computational efforts and solution accuracy. (C) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.
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| 18. |
- Nawaz, Muhammad, et al.
(författare)
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Improved process monitoring using the CUSUM and EWMA-based multiscale PCA fault detection framework
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 29:1, s. 253-265
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Tidskriftsartikel (refereegranskat)abstract
- Process monitoring techniques are of paramount importance in the chemical industry to improve both the product quality and plant safety. Small or incipient irregularities may lead to severe degradation in complex chemical processes, and the conventional process monitoring techniques cannot detect these irregularities. In this study to improve the performance of monitoring, an online multiscale fault detection approach is proposed by integrating multiscale principal component analysis (MSPCA) with cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts. The new Hotelling’s T2 and square prediction error (SPE) based fault detection indices are proposed to detect the incipient irregularities in the process data. The performance of the proposed fault detection methods was tested for simulated data obtained from the CSTR system and compared to that of conventional PCA and MSPCA based methods. The results demonstrate that the proposed EWMA based MSPCA fault detection method was successful in detecting the faults. Moreover, a comparative study shows that the SPE-EWMA monitoring index exhibits a better performance with lower values of missed detections ranging from 0 - 0.80% and false alarms ranging from 0 - 21.20%.
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| 19. |
- Ren, Jiajia, et al.
(författare)
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Supported ionic liquid sorbents for CO2 capture from simulated flue-gas
- 2018
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Ingår i: Chinese Journal of Chemical Engineering. - : Chemical Industry Press. - 1004-9541 .- 2210-321X. ; 26:11, s. 2377-2384
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Tidskriftsartikel (refereegranskat)abstract
- Supported ionic liquid (IL) sorbents for CO2 capture were prepared by impregnating tetramethylammonium glycinate ([N1111][Gly]) into four types of porous materials in this study. The CO2 adsorption behavior was investigated in a thermogravimetric analyzer (TGA). Among them, poly(methyl methacrylate) (PMMA)-[N1111][Gly] exhibits the best CO2 adsorption properties in terms of adsorption capacity and rate. The CO2 adsorption capacity reaches up to 2.14 mmol·g− 1 sorbent at 35 °C. The fast CO2 adsorption rate of PMMA-[N1111][Gly] allows 60 min of adsorption equilibrium time at 35 °C and much shorter time of 4 min is achieved at 75 °C. Further, Avrami's fractional-order kinetic model was used and fitted well with the experiment data, which shows good consistency between experimental results and theoretical model. In addition, PMMA-[N1111][Gly] remained excellent durability in the continuous adsorption–desorption cycling test. Therefore, this stable PMMA-[N1111][Gly] sorbent has great potential to be used for fast CO2 adsorption from flue-gas.
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| 20. |
- Song, Junping, et al.
(författare)
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Modified graphite filled natural rubber composites with good thermal conductivity
- 2015
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 2210-321X .- 1004-9541. ; 23:5, s. 853-859
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Tidskriftsartikel (refereegranskat)abstract
- The rubber composites with good thermal conductivity contribute to heat dissipation of tires. Graphite filled natural rubber composites were developed in this study to provide good thermal conductivity. Graphite was coated with polyacrylate polymerized by monomers including methyl methacrylate, n-butyl acrylate and acrylic acid. The ratios between a filler and acrylate polymerization emulsion and those between monomers were varied. Eight types of surface modification formulas were experimentally investigated. Modification formula can affect coating results and composite properties greatly. The best coating type was achieved by a ratio of 1:1 between methyl methacrylate and n-butyl acrylate. The coating of graphite was thermally stable in a running tire. Filled with modified graphite, the tire thermal conductivity reached up to 0.517-0.569 W . m(-1) . K-1. In addition, the mechanical performance was improved with increased crosslink density, extended scorch time and short vulcanization time.
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| 21. |
- Sun, Licheng, et al.
(författare)
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Multi-objective fuzzy optimization algorithm for separation-recycle system
- 2004
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 12:2, s. 221-226
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Tidskriftsartikel (refereegranskat)abstract
- Separation-recycle system is an important part in chemical process, and its optimization is a multi-objective problem. In this paper the process optimization procedure is proposed. The fuzzy optimization algorithm with the concept of relative importance degree (RID) is utilized to transfer multi-objective optimization (MO-O) model into a single-objective optimization (SO-O) framework. The treatment of process condensate in synthesis ammonia plant is taken as example to illustrate the optimization procedure, and the satisfactory result demonstrates feasibility and effectiveness of the suggested method.
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| 22. |
- Tian, Shuangshuang, et al.
(författare)
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Transformation mechanism of nutrient elements in the process of biochar preparation for returning biochar to soil
- 2017
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 25:4, s. 477-486
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Tidskriftsartikel (refereegranskat)abstract
- Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned to soil, thereby seriously undermining biochar's efficacy. Therefore, the transformation mechanisms of biochar pH, mass, nutrients and metals during pyrolysis under different atmospheres and temperatures were studied such that the best method for biochar preparation could be developed. Several conclusions can be reached: (1) a CO2 atmosphere is better than a N2 atmosphere for biochar preparation, although preparation in a CO2 atmosphere is not a common practice for biochar producers; (2) 350 °C is the best temperature for biochar preparation because the amount of nutrient loss is notably low based on the premise of straw transferred into biochar; and (3) transforming mechanisms of pH, N, P and K are also involved in the biochar preparation process.
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| 23. |
- Tong, Fei, et al.
(författare)
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Transparent and anti-fogging AlPO4-5 films constructed by oblique oriented nano-flake crystals
- 2022
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 44, s. 332-340
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, transparent and anti-fogging AlPO4-5 films were prepared on glass substrates using a novel developed process. The process entails a simple in-situ sol-gel followed by vapor phase transport. The in-situ sol-gel process was implemented by coating the precursor sols for the synthesis of AlPO4-5 on the glass substrates successively using the spin-coating method. The films and powders scribed from the films were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The unique films were composed of oblique oriented nano-flake AlPO4-5 crystals with the thickness of about 20 nm. The formation of nano-flake crystals can be ascribed to the high concentration of the precursors, resulting in the formation of a supersaturation system. The obtained films showed high antifogging performance due to the superhydrophilicity with a water contact angle of lower than 1.0°. The silicone oil contact angle was also low about 8.2°. In addition, heteroatom-substituted AlPO4-5 films showing different colors can be obtained easily by simply adding transition metal ions in the phosphate acid solution during the preparation that can extend the application of the method for different coating demand.
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| 24. |
- Wu, Nanhua, et al.
(författare)
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Thermodynamic analysis and modification of Gibbs–Thomson equation for melting point depression of metal nanoparticles
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 198-205
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal melting point depression of metal nanoparticles often occurs in heterogeneous catalytic reactions, which leads to a reduction in the stability of reactive nanoclusters. To study this abnormal phenomenon, the original and surface-energy modified Gibbs–Thomson equations were analyzed in this work and further modified by considering the effect of the substrate. The results revealed that the original Gibbs–Thomson equation was not suitable for the particles with radii smaller than 10 nm. Moreover, the performance of the surface-energy modified Gibbs–Thomson equation was improved, and the deviation was reduced to (-350 ∼ 100) K, although further modification of the equation by considering the interfacial effect was necessary for the small particles (r < 5 nm). The new model with the interfacial effect improved the model performance with a deviation of approximately -50 to 20 K, where the interfacial effect can be predicted quantitatively from the thermodynamic properties of the metal and substrate. Additionally, the micro-wetting parameter αw can be used to qualitatively study the overall impact of the substrate on the melting point depression.
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| 25. |
- Zhang, Yumeng, et al.
(författare)
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Progress in molecular-simulation-based research on the effects of interface-induced fluid microstructures on flow resistance
- 2019
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 27:6, s. 1403-1415
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Tidskriftsartikel (refereegranskat)abstract
- In modern chemical engineering processes, solid interface involvement is the most important component of process intensification techniques, such as nanoporous membrane separation and heterogeneous catalysis. The fundamental mechanism underlying interfacial transport remains incompletely understood given the complexity of heterogeneous interfacial molecular interactions and the high nonideality of the fluid involved. Thus, understanding the effects of interface-induced fluid microstructures on flow resistance is the first step in further understanding interfacial transport. Molecular simulation has become an indispensable method for the investigation of fluid microstructure and flow resistance. Here, we reviewed the recent research progress of our group and the latest relevant works to elucidate the contribution of interface-induced fluid microstructures to flow resistance. We specifically focused on water, ionic aqueous solutions, and alcohol–water mixtures given the ubiquity of these fluid systems in modern chemical engineering processes. We discussed the effects of the interface-induced hydrogen bond networks of water molecules, the ionic hydration of ionic aqueous solutions, and the spatial distributions of alcohol and alcohol–water mixtures on flow resistance on the basis of the distinctive characteristics of different fluid systems.
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| 26. |
- Daniel, Geoffrey, et al.
(författare)
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Inocula selection in microbial fuel cells based on anodic biofilm abundance of Geobacter sulfurreducens
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541. ; 24, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- Microbial fuel cells (MFCs) rely on microbial conversion of organic substrates to electricity. The optimal performance depends on the establishment of a microbial community rich in electrogenic bacteria. Usually this microbial community is established from inoculation of the MFC anode chamber with naturally occurring mixed inocula. In this study, the electrochemical performance of MFCs and microbial community evolution were evaluated for three inocula including domestic wastewater (DW), lake sediment (LS) and biogas sludge (BS) with varying substrate loading (L-sub) and external resistance (R-ext) on the MFC. The electrogenic bacterium Geobacter sulfurreducens was identified in all inocula and its abundance during MFC operation was positively linked to the MFC performance. The LS inoculated MFCs showed highest abundance (18%+/- 1%) of G. sulfurreducens, maximum current density [I-max = (690 +/- 30) mA.m(-2)] and coulombic efficiency (CE = 29% +/- 1%) with acetate as the substrate. I-max and CE increased to (1780 +/- 30) mA.m(-2) and 58% +/- 1%, respectively, after decreasing the R-ext from 1000 Omega to 200 Omega, which also correlated to a higher abundance of G. sulfurreducens (21% +/- 0.7%) on the MFC anodic biofilm. The data obtained contribute to understanding the microbial community response to L-sub and R-ext for optimizing electricity generation in MFCs. (c) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.
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| 27. |
- Johansson, Inge, et al.
(författare)
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Volatile organic compound emissions when drying wood particles at high dewpoints
- 2004
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Ingår i: Chinese Journal of Chemical Engineering. - 2210-321X. ; 12:6, s. 767-772
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Tidskriftsartikel (refereegranskat)abstract
- Emission of volatile org. compds. (VOCs) during drying of wood particles for particleboard manuf., or for prodn. of refined biofuels, is a potential environmental problem. The aim of this work is to study the emissions of VOCs during drying, and the influence on the emissions by different drying parameters. The expts. have mainly been done in a batch fluidized bed dryer, but measurements have also been done in a, pilot scale, continuous fluidized bed dryer. The parameters studied are air flow rate through the bed, air temp., air dew point, and bed height. Since the present trend in biofuels and particle drying is towards very high dew points during drying, some measurements were made at dew points up to 95°, corresponding to a water content of 3.2 kg water per kg dry air. The emissions were measured in two different ways, online during drying with a flame ionization detector and through wood analyses of the terpene content in the wood particles before and after drying. Substantial work was made in developing the latter method as well as developing the drying equipment to be able to produce a wide range of conditions of the drying medium. It was shown that the VOCs emitted, during wood particle drying, mainly consist of terpenes. The behavior of the emissions was typical, at first contact with the drying gas a sharp peak in the release rate was detected. After that, the release rate stabilizes and declines slowly to a point where the material temp. increases and results in a second small peak in the release rate. Typically 80%-90% of the initial terpene content in the material was emitted during drying to low moisture content and it is not possible to significantly influence this release by changing the drying conditions. Up to 50% of the emitted terpenes are released during a very short period after contact with the drying medium. This fact could be utilized by employing a 2-step drying process. The fact that the VOC concn. in the inert gas gets much higher when drying at higher dew points could be taken into consideration when dealing with closed loop applications where the inert gas after the dryer is burnt.
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| 28. |
- Lu, Shan, et al.
(författare)
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Modelling and Optimization Methods of Integrated Production Planning for Steel Plate Mill with Flexible Customization
- 2015
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Ingår i: Chinese Journal of Chemical Engineering. - 2210-321X.
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Tidskriftsartikel (refereegranskat)abstract
- With diversified requirements and varying manufacturing environments, the optimal production planning encountered in a steel mill became more flexible and also complicated. The flexibility can provide the operators with auxiliary requirements through an implementable integrated production planning. In this paper, a mixed-integer nonlinear programming (MINLP) model is formulated for the optimal planning that incorporates various manufacturing constraints and the flexibility in a steel plate mill. Furthermore, two solution strategies are developed to overcome the weakness of solving MINLP problem directly. The first one is to transform the original MINLP formulation to an approximate mixed integer linear programming (MILP) using a classic linearization method. The second one is to decompose the original model using a branch-and-bound based iterative method. Computational experiments on various problem instances are presented in terms of the effectiveness and applicability. The result shows that the proposed second method performs better in computational efforts and solution accuracy.
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