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Table of Content
28 February 2019, Volume 27 Issue 2
    Review on application of nanoparticles for EOR purposes: A critical review of the opportunities and challenges
    Yousef Kazemzadeh, Sanaz Shojaei, Masoud Riazi, Mohammad Sharifi
    2019, 27(2):  237-246.  doi:10.1016/j.cjche.2018.05.022
    Abstract ( 658 )   PDF (1832KB) ( 578 )  
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    Nanoparticles have already gained attentions for their countless potential applications in enhanced oil recovery. Nano-sized particles would help to recover trapped oil by several mechanisms including interfacial tension reduction, impulsive emulsion formation and wettability alteration of porous media. The presence of dispersed nanoparticles in injected fluids would enhance the recovery process through their movement towards oil- water interface. This would cause the interfacial tension to be reduced. In this research, the effects of different types of nanoparticles and different nanoparticle concentrations on EOR processes were investigated. Different flooding experiments were investigated to reveal enhancing oil recovery mechanisms. The results showed that nanoparticles have the ability to reduce the IFT as well as contact angle, making the solid surface to more water wet. As nanoparticle concentration increases more trapped oil was produced mainly due to wettability alteration to water wet and IFT reduction. However, pore blockage was also observed due to adsorption of nanoparticles, a phenomenon which caused the injection pressure to increase. Nonetheless, such higher injection pressure could displace some trapped oil in the small pore channels out of the model. The investigated results gave a clear indication that the EOR potential of nanoparticle fluid is significant.
    Fluid Dynamics and Transport Phenomena
    Drawdown mechanism of light particles in baffled stirred tank for the KR desulphurization process
    Meng Li, Yangbo Tan, Jianglong Sun, De Xie, Zeng Liu
    2019, 27(2):  247-256.  doi:10.1016/j.cjche.2018.05.019
    Abstract ( 502 )   PDF (10649KB) ( 26 )  
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    To improve the efficiency of the desulfurization process, the drawdown mechanism of light particles in stirred tank is studied in this paper. For both up and down pumping modes, the just drawdown speeds (Njd) of floating particles in transformative Kanbara Reactor (KR) are measured in one and four baffled stirred tanks experimentally. Then numerical simulations with standard k-ε model coupled with volume of fluid model (VOF) and discrete phase model (DPM) are conducted to analyze the flow field at the just drawdown speed Njd. The torques on the impeller obtained from experiments and simulations agree well with each other, which indicates the validity of our numerical simulations. Based on the simulations, three main drawdown mechanisms for floating particles, the axial circulation, turbulent fluctuation and largescale eddies, are analyzed. It's found that the axial circulation dominates the drawdown process at small submergence (S=1/4T and 1/3T) and the large-scale eddies play a major role at large submergence (S=2/3T and 3/4T). Besides, the turbulent fluctuation affects the drawdown process significantly for up pumping mode at small submergence (S=1/4T and 1/3T) and for down pumping mode at large submergence (S=2/3T and 3/4T). This paper helps to provide a more comprehensive understanding of the KR desulphurizer drawdown process in the baffled stirred tank.
    Optical inline analysis and monitoring of particle size and shape distributions for multiple applications: Scientific and industrial relevance
    Jörn Emmerich, Qiao Tang, Yundong Wang, Peter Neubauer, Stefan Junne, Sebastian Maaß
    2019, 27(2):  257-277.  doi:10.1016/j.cjche.2018.11.011
    Abstract ( 412 )   PDF (11205KB) ( 28 )  
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    Particles occur in almost all processes in chemical and life sciences. The particle size and shape influence the process performance and product quality, and in turn they are influenced by the flow behavior of the particles during production. Monitoring and controlling such characteristics in multiphase systems to obtain sufficient qualities will greatly facilitate the achievement of reproducible and defined distributions. So far, obtaining this information inline has been challenging, because existing instruments lack measurement precision, being unable to process overlapping signals from different particle phases in highly concentrated multiphase systems. However, recent advances in photo-optics made it possible to monitor such features (particle size distribution (PSD), aspect ratio and particle concentration) with advanced image analysis (IA) in real-time. New analysis workflows as well as single feature extractions from the images using multiple image analysis algorithms allowed the precise real-time measurements of size, shape and concentration of particle collectives even separated from each other in three phase systems. The performances, advantages and drawbacks with other non-photo-optical methods for assessing the particle size distribution are compared and discussed.
    Experimental study of power consumption, local characteristics distributions and homogenization energy in gas–liquid stirred tank reactors
    Facheng Qiu, Zuohua Liu, Renlong Liu, Xuejun Quan, Changyuan Tao, Yundong Wang
    2019, 27(2):  278-285.  doi:10.1016/j.cjche.2018.10.011
    Abstract ( 436 )   PDF (3253KB) ( 52 )  
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    In this paper, the power consumption, the vertical local void fraction and the local gas-liquid interfacial area are investigated in the aerated stirred tank reactors (STRs) equipped with a rigid-flexible impeller. Meanwhile, the regressive correlation based on power consumption and interfacial area is proposed. Then a novel homogenization energy (HE=RSDPtm) expression based on power consumption and local interfacial area is redefined and used to indicate the mixing efficiency. The optimal operating mode is selected based on the change of the HE value. This paper can provide research ideas for structural optimization of stirred reactors.
    Molecular simulation of penetration separation for ethanol/water mixtures using two-dimensional nanoweb graphynes
    Wei Zhang, Zhijun Xu, Xiaoning Yang
    2019, 27(2):  286-292.  doi:10.1016/j.cjche.2018.02.028
    Abstract ( 371 )   PDF (3289KB) ( 65 )  
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    Graphyne is expected to be a new-class of highly-efficient sieving membranes due to its controllable uniform pore structure and ultrathin single-atom thickness. Herein, we computationally investigate the permeation performance of liquid ethanol-water mixtures across polyporous two-dimensional γ-graphyne sheets. It was found that, in the mixture, ethanol with larger molecular diameter permeates faster through the graphyne pores than water. The simulations demonstrate that pristine graphynes could act as highly-efficient ethanol-permselective membranes for separation of ethanol-water mixtures, with ethanol permeability remarkably higher than conventional membranes. This separation mechanism is distinctly different from the molecular-size dependent sieving process. The stronger hydrophobic interfacial affinity between graphyne and ethanol makes ethanol molecules preferentially adsorb on graphyne surface and selectively penetrate through graphyne pores. This penetration mechanism provides new understanding of molecular transport through atomically thick two-dimensional nanoporous membranes and this work is expected to be valuable in the potential development of highly-efficient membranes for liquid-phase mixture separation.
    Chaotic characteristics of pseudoplastic fluid induced by 6PBT impeller in a stirred vessel
    Deyu Luan, Yiming Chen, Hong Wang, Yue Wang, Xing Wei
    2019, 27(2):  293-297.  doi:10.1016/j.cjche.2018.06.001
    Abstract ( 380 )   PDF (1605KB) ( 80 )  
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    Xanthan gum solutions with different mass concentrations were used to study the chaotic characteristics induced by the impeller of perturbed six-bent-blade turbine (6PBT) in a stirred vessel. Based on the velocity time series obtained by the experiment of particle image velocimetry (PIV), with the software MATLAB (R2016a), the distributions of the largest Lyapunov exponent (LLE) and Kolmogorov entropy (K entropy) of the system, as two important parameters for characterizing the chaotic degree, were investigated respectively. Results showed that both of the LLE and K entropy increased with the increasing speed at the beginning. As the speed was up to 200 r·min-1, the two parameters reached the maximal values meanwhile, corresponding to 0.535 and 0.834, respectively, which indicated that the chaotic degree of the flow field was up to the highest level. When the speed was increased further, both of the LLE and K entropy decreased on the contrary, which meant that the chaotic degree was decreasing. It was also observed that the chaotic characteristics of flow field were hardly affected by the fluid rheology and the detecting positions. The research results will enhance the understanding of the chaotic mixing mechanism and provide a theoretical reference for optimizing impeller structure.
    Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit
    Eduard Manek, Juma Haydary
    2019, 27(2):  298-304.  doi:10.1016/j.cjche.2018.06.023
    Abstract ( 454 )   PDF (839KB) ( 131 )  
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    One of the commercial means to convert heavy oil residue is hydrocracking in an ebullated bed. The ebullated bed reactor includes a complex gas-liquid-solid backmixed system which attracts the attention of many scientists and research groups. This work is aimed at the calculation of the internal recycle flow rate and understanding its effect on other parameters of the ebullated bed. Measured data were collected from an industrial scale residual hydrocracking unit consisting of a cascade of three ebullated bed reactors. A simplified block model of the ebullated bed reactors was created in Aspen Plus and fed with measured data. For reaction yield calculation, a lumped kinetic model was used. The model was verified by comparing experimental and calculated distillation curves as well as the calculated and measured reactor inlet temperature. Influence of the feed rate on the recycle ratio (recycle to feed flow rate) was estimated. A relation between the recycle flow rate, pump pressure difference and catalyst inventory has been identified. The recycle ratio also affects the temperature gradient along the reactor cascade. Influence of the recycle ratio on the temperature gradient decreased with the cascade member order.
    Separation Science and Engineering
    Superior adsorption performance of graphitic carbon nitride nanosheets for both cationic and anionic heavy metals from wastewater
    Gang Xiao, Yaoqiang Wang, Shengnan Xu, Peifeng Li, Chen Yang, Yu Jin, Qiufeng Sun, Haijia Su
    2019, 27(2):  305-313.  doi:10.1016/j.cjche.2018.09.028
    Abstract ( 454 )   PDF (6274KB) ( 170 )  
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    Water pollution caused by highly toxic Cd(Ⅱ), Pb(Ⅱ), and Cr(VI) is a serious problem. In the present work, a green and low-cost adsorbent of g-C3N4 nanosheets was developed with superior capacity for both cationic and anionic heavy metals. The adsorbent was easily fabricated through one-step calcination of guanidine hydrochloride with thickness less than 1.6 nm and specific surface area of 111.2 m2·g-1. Kinetic and isotherm studies suggest that the adsorption is an endothermic chemisorption process, occurring on the energetically heterogeneous surface based on a hybrid mechanism of multilayer and monolayer adsorption. The tri-s-triazine units and surface N-containing groups of g-C3N4 nanosheets are proposed to be responsible for the adsorption process. Further study on pH demonstrates that electrostatic interaction plays an important role. The maximum adsorption capacity of Cd(Ⅱ), Pb(Ⅱ), and Cr(VI) on g-C3N4 nanosheets is 123.205 mg·g-1, 136.571 mg·g-1, and 684.451 mg·g-1, respectively. The better adsorption performance of the adsorbent than that of the recently reported nanomaterials and low-cost adsorbents proves its great application potential in the removal of heavy metal contaminants from wastewater. The present paper developed a promising adsorbent which will certainly find applications in wastewater treatment and also provides guiding significance in designing adsorption processes.
    Performance investigation of Fe3O4 blended poly (vinylidene fluoride) membrane on filtration and benzyl alcohol oxidation: Evaluation of sufficiency for catalytic reactors
    Huseyin Gumus
    2019, 27(2):  314-321.  doi:10.1016/j.cjche.2018.05.006
    Abstract ( 461 )   PDF (2078KB) ( 75 )  
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    Fe3O4-PVDF membranes were prepared by blending of magnetic Fe3O4 powders with polyvinylidene fluoride to investigate whether those were usable or not in catalytic membrane reactors. Filtration performances and catalytic activity of membranes in microwave conditions were measured in separate processes. Composite Fe3O4-PVDF membranes were characterized by TG-DTA, FTIR, XRD, SEM and contact angle techniques. Disappearing of α-phases at PVDF was observed with increasing amount of additives from XRD diffraction patterns. Decomposition of polymer fastened due to catalytic effect of Fe3O4. Finger-like structures and large number of small pores were observed at the SEM images. Those provided effective transportation of substrate among the active sites of catalyst. At the experiments conducted in batch reactor, 51%, 77%, 66% and 63% benzyl alcohol conversion were recorded for 2%, 4%, 6% and 8% Fe3O4-PVDF composite pieces respectively. Catalyst were separated magnetically and reused several times. On the other hand Fe3O4 blended PVDF membranes provided improved flux and BSA rejection compared with performance of bare PVDF membrane; 41.6% BSA rejection was obtained with 4% Fe3O4-PVDF whereas it was only 6.7% for PVDF. Fe3O4-PVDF composites performed high activity for the benzyl alcohol oxidation in batch reactor and also better filtration at filtration cell. These results promise to obtain practical and low cost membrane material for catalytic reactors usable in microwave support to get fast results.
    Special Issue of Membranes and Membrane Processes based on Confined Mass Transfer
    Polyurethane-SAPO-34 mixed matrix membrane for CO2/CH4 and CO2/N2 separation
    Gholamhossein Sodeifian, Mojtaba Raji, Morteza Asghari, Mashallah Rezakazemi, Amir Dashti
    2019, 27(2):  322-334.  doi:10.1016/j.cjche.2018.03.012
    Abstract ( 430 )   PDF (7326KB) ( 18 )  
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    SAPO-34 nanocrystals (inorganic filler) were incorporated in polyurethane membranes and the permeation properties of CO2, CH4, and N2 gases were explored. In this regard, the synthesized PU-SAPO-34 mixed matrix membranes (MMMs) were characterized via SEM, AFM, TGA, XRD and FTIR analyses. Gas permeation properties of PU-SAPO-34 MMMs with SAPO-34 contents of 5 wt%, 10 wt% and 20 wt% were investigated. The permeation results revealed that the presence of 20 wt% SAPO-34 resulted in 4.45%, 18.24% and 40.2% reductions in permeability of CO2, CH4, and N2, respectively, as compared to the permeability of neat polyurethane membrane. Also, the findings showed that at the pressure of 1.2 MPa, the incorporation of 20 wt% SAPO-34 into the polyurethane membranes enhanced the selectivity of CO2/CH4 and CO2/N2, 14.43 and 37.46%, respectively. In this research, PU containing 20 wt% SAPO-34 showed the best separation performance. For the first time, polynomial regression (PR) as a simple yet accurate tool yielded a mathematical equation for the prediction of permeabilities with high accuracy (R2>99%).
    Separation Science and Engineering
    Selective recovery of lithium from simulated brine using different organic synergist
    Huifang Li, Lijuan Li, Xiaowu Peng, Lianmin Ji, Wu Li
    2019, 27(2):  335-340.  doi:10.1016/j.cjche.2018.04.010
    Abstract ( 414 )   PDF (2252KB) ( 26 )  
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    The organic synergists, including Octanol, ethyl acetate (EA), butyl acetate (BA), methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), N,N-bis(2-ethylhexyl) acetamide (N523) and 8-hydroxylquiolate, were added to the TBP-FeCl3 extraction system to extract lithium from brine. The effects of concentration of organic synergist and total organic extractant, molar ratio of Fe/Li, phase ratio, counter-current extraction and the acidity of stripping agent on lithium extraction were investigated to optimize the extraction conditions. Under the optimize conditions, the results of counter-current extraction showed the mixed extraction system was the preponderance on the lithium extraction. Especially the separation of lithium in organic phase and aqueous phase and the separation mass ratio of Mg/Li increased greatly. An extraction mechanism was proposed based on the analysis of FT-IR spectra and Raman spectra.
    Zeolite P synthesis based on fly ash and its removal of Cu(Ⅱ) and Ni (Ⅱ) ions
    Yong Liu, Guodong Wang, Lu Wang, Xianlong Li, Qiong Luo, Ping Na
    2019, 27(2):  341-348.  doi:10.1016/j.cjche.2018.03.032
    Abstract ( 413 )   PDF (1941KB) ( 146 )  
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    Zeolite P was synthesized through hydrothermal method based on a kind of Class C fly ash (FA). X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) were used to analyze and characterize the synthetic sample. The kinetics and thermodynamics of copper and nickel ions removed by the zeolite samples were experimentally explored in detail. The results of kinetic treatment showed the second-order exchange second-order saturation model (SESSM) can well describe the removal process of copper ions, while the first-order empirical kinetic model (FEKM) is the best kinetic model for nickel ions. Langmuir and Freundlich isotherms were used to fit the equilibrium concentration of Cu(Ⅱ) or Ni(Ⅱ) under certain conditions. Whether for copper or nickel ion, the Langmuir model is in good agreement with the experimental equilibrium concentration. The apparent theoretical removal capacities for Cu(Ⅱ) and Ni(Ⅱ) can reach to 138.1 mg·g-1 and 77.0 mg·g-1, respectively.
    Catalysis, kinetics and reaction engineering
    Synergistic interaction of metal–acid sites for phenol hydrodeoxygenation over bifunctional Ag/TiO2 nanocatalyst
    Andrew Ng Kay Lup, Faisal Abnisa, Wan Mohd Ashri Wan Daud, Mohamed Kheireddine Aroua
    2019, 27(2):  349-361.  doi:10.1016/j.cjche.2018.08.028
    Abstract ( 394 )   PDF (10538KB) ( 20 )  
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    The use of silver metal for hydrodeoxygenation (HDO) applications is scarce and different studies have indicated of its varying HDO activity. Several computational studies have reported of silver having almost zero turnover frequency for HDO owing to its high C-O bond breaking energy barrier and low carbon and oxygen binding energies. Herein this work, titania supported silver catalysts were synthesized and firstly used to examine its phenol HDO activity via experimental reaction runs. BET, XRD, FESEM, TEM, EDX, ICP-OES, Pyridine-FTIR, NH3-TPD and H2-TPD analyses were done to investigate its physicochemical properties. Phenomena of hydrogen spillover and metal- acid site synergy were examined in this study. With the aid of TiO2 reducible support, hydrogen spillover and metal-acid site interactions were observed to a certain extent but were not as superior as other Pt, Pd, Ni-based catalysts used in other HDO studies. The experimental findings showed that Ag/TiO2 catalyst has mediocre phenol conversion but high benzene selectivity which confirms the explanation from other computational studies.
    Ternary phase diagrams and solvate transformation thermodynamics of omeprazole sodium in different solvent mixtures
    Meitang Jin, Zhao Xu, Ying Bao, Long Li, Liping Wang, Haijiao Lu, Chuang Xie, Hongxun Hao
    2019, 27(2):  362-368.  doi:10.1016/j.cjche.2018.07.016
    Abstract ( 440 )   PDF (3500KB) ( 61 )  
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    Omeprazole sodium (OMS), a typical non-hydrogen bond donors API, is only available in solvates so far, including monohydrate, ethanol solvate and methanol solvate. The methanol solvate was found for the first time. Solvate transformation thermodynamics of OMS was studied in this paper. First, the ternary phase diagrams forming two solvates for OMS in binary solvent mixtures including methanol + water, ethanol + water, and methanol + ethanol were measured at temperature ranging of T=(278.15 to 313.15) K under atmospheric pressure. Further, the standard equilibrium constants of the solvate transformation reactions were evaluated according to the chemical reaction isothermal equation. The standard molar Gibbs free energy, the standard molar enthalpy, and the standard molar entropy of solvate transformation reactions were then calculated based on van't Hoff equation. Moreover, the thermodynamic stability of the OMS solvate was analyzed based on phase diagram. The results are of great importance to develop a crystallization process for manufacturing OMS solvate, and could be helpful to other solvate transformation research.
    Pt-Re/rGO bimetallic catalyst for highly selective hydrogenation of cinnamaldehyde to cinnamylalcohol
    Zuojun Wei, Xinmiao Zhu, Xiaoshuang Liu, Haiqin Xu, Xinghua Li, Yaxin Hou, Yingxin Liu
    2019, 27(2):  369-378.  doi:10.1016/j.cjche.2018.04.022
    Abstract ( 507 )   PDF (3279KB) ( 49 )  
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    In the present work, a series of Pt-based catalysts, alloyed with a second metal, i.e., Re, Sn, Er, La, and Y, and supported on activated carbon, ordered mesoporous carbon, N-doped mesoporous carbon or reduced graphene oxide (rGO), have been developed for selective hydrogenation of cinnamaldehyde to cinnamylalcohol. Re and rGO were proved to be the most favorable metal dopant and catalyst support, respectively. Pt50Re50/rGO showed the highest cinnamylalcohol selectivity of 89% with 94% conversion of cinnamaldehyde at the reaction conditions of 120℃, 2.0 MPa H2 and 4 h.
    Catalytic performance of perovskite-like oxide doped cerium (La2-xCexCoO4±y) as catalysts for dry reforming of methane
    Yukun Bai, Yuqi Wang, Weijian Yuan, Wen Sun, Guoxia Zhang, Lan Zheng, Xiaolong Han, Lifa Zhou
    2019, 27(2):  379-385.  doi:10.1016/j.cjche.2018.05.016
    Abstract ( 428 )   PDF (3243KB) ( 81 )  
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    A series of oxides (La2-xCexCoOy) with perovskite-like structure were prepared by the Pechini sol-gel method for dry reforming of methane reaction (DRM). The prepared catalysts were characterized by BET, XRD, TGA, H2-TPR and SEM. Experimental results indicate that the addition of Ce can impact both sample morphology and catalytic performance significantly compared with La2CoO4 catalyst, and LaCeCoO4 presented the highest catalytic ability among all the samples. The Ce addition tends to increase the specific surface area of La2-xCexCoOy from 0.2 to 8.5 m2·g-1, suggesting that LaCeCoO4 catalyst contained more well-dispersed active sites and more space to reaction. Moreover, the catalytic performance and anti-coking ability were substantially improved after Ce addition during DRM, which may be attributed to the decrease of LaCoO3 particle size and growth of oxygen storage capacity, respectively.
    The influence mechanism of solvent on the hydrogenation of dimethyl oxalate
    Shi Yin, Lingjun Zhu, Xiaoliu Wang, Yingying Liu, Shurong Wang
    2019, 27(2):  386-390.  doi:10.1016/j.cjche.2018.04.029
    Abstract ( 416 )   PDF (1289KB) ( 37 )  
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    The hydrogenation of dimethyl oxalate (DMO) for the producing of C2-C4 alcohols with methanol as solvent was researched at the temperature of 270℃ to 310℃. Ethylene glycol (EG) was the main product at low temperature and the selectivity of which was 61.9% at 230℃. However, EG selectivity decreased sharply with the increase of temperature while ethanol became the main liquid products with the selectivity of 43.5% at 270℃. It can be ascribed to a thorough hydrogenation of DMO at a high temperature. In addition, the promotion of Guerbet reaction led to the production of propanol and butanol. Simultaneously, the amount of gas products including CO, CO2 and dimethyl ether (DME) also increased, which became a competition factor in the conversion of DMO to liquid products including C2-C4 alcohols. The blank test was carried out with pure methanol as feedstock with and without Cu/SiO2 catalyst, which revealed that methanol was involved in the formation of gas products and higher alcohols on Cu-based catalyst, and the main gas product was CO.
    Chemical Engineering Thermodynamics
    Liquid phase equilibrium of phenol extraction from bio-oil produced by biomass pyrolysis using thermodynamic models
    Dewi Selvia Fardhyanti, Bayu Triwibowo, Heri Istanto, Muhammad Khusni Anajib, Amalia Larasati, Windy Oktaviani
    2019, 27(2):  391-399.  doi:10.1016/j.cjche.2018.08.011
    Abstract ( 441 )   PDF (1605KB) ( 102 )  
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    Utilization of biomass as a new and renewable energy source is being actively conducted by various parties. One of the technologies for utilizing or converting biomass as an energy source is pyrolysis, to convert biomass into a more valuable product which is bio-oil. Bio-oil is a condensed liquid from the vapor phase of biomass pyrolysis such as coconut shells and coffee shells. Biomass composition consisting of hemicellulose, cellulose, and lignin will oxidize to phenol which is the main content in bio-oil. The total phenolic compounds contained in bio-oil are 47.03% (coconut shell) and 45% (coffee shell). The content of phenol compounds in corrosive bio-oils still quite high, the use of this bio-oil directly will cause various difficulties in the combustion system due to high viscosity, low calorific value, corrosivity, and instability. Phenol compounds have some benefits as one of the compounds for floor cleaners and disinfectants which are contained in bio-oil. The correlation between experimental data and calculations shows that the UNIQUAC Functional-group Activity Coefficients (UNIFAC) equilibrium model can be used to predict the liquid-liquid equilibrium in the phenol extraction process of the coconut shell pyrolysis bio-oil. While the Non-Random Two Liquid (NRTL) equilibrium model can be used to predict liquid-liquid equilibrium in the extraction process of phenol from bio-oil pyrolysis of coffee shells.
    Solubility of the silver nitrate in supercritical carbon dioxide with ethanol and ethylene glycol as double cosolvents: Experimental determination and correlation
    Hongrui Ren, Jibin Song, Qinqin Xu, Jianzhong Yin
    2019, 27(2):  400-404.  doi:10.1016/j.cjche.2018.06.011
    Abstract ( 388 )   PDF (325KB) ( 43 )  
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    Solubility of the silver nitrate in the supercritical carbon dioxide containing ethanol and ethylene glycol as double cosolvents was measured under certain pressure and temperature range (10-25 MPa, 323.15-333.15 K). The impact of the pressure and temperature on the solubility was also investigated. Based on the experiment data, a correlation model concerning solid's solubility in supercritical fluids was established by combining the solubility parameter with the thermodynamic equation when a binary interaction parameter and a mixed solvent solubility parameter were defined. Experiments show the solubility of AgNO3 increases with the pressure at a certain temperature. However, the influence of temperature is related to a pressure defined as the turnover pressure (12.3 MPa). When the pressure is higher (or lower) than this turnover pressure, silver nitrate's solubility shows increasing (or decreasing) trend as the temperature rises. Satisfactory accuracy of our presented model was revealed by comparing experimental data with calculated results.
    Influence factors of methane hydrate formation from ice: Temperature, pressure and SDS surfactant
    Weiguo Liu, Yanghui Li, Xiaohu Xu
    2019, 27(2):  405-410.  doi:10.1016/j.cjche.2018.03.033
    Abstract ( 390 )   PDF (3291KB) ( 115 )  
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    A series of experiments of forming hydrate from ice powders in different conditions have been carried out with constant volume method to evaluate the influence factors such as pressure, temperature, and SDS surfactant. The change of temperature and pressure were collected as a function of elapsed time, which were used to calculate the gas consumption and hydrate saturation during hydrate formation (pVT method). Based on the experimental results and the analysis, it is concluded that:(1) Both initial pressure and temperature have effect on the hydrate formation and temperature plays a more important role in the process; (2) heating and secondary pressurization will promote the gas hydrate formation and enhance the hydrate saturation as a result. Meanwhile, the promotion of heating seems to be more obvious than that of secondary pressurization; (3) different concentrations of SDS surfactant have clearly influence on the saturation of gas hydrate and there is an optimal concentration to promote the hydrate formation.
    Biotechnology and Bioengineering
    n-Hexadecane and pyrene biodegradation and metabolization by Rhodococcus sp. T1 isolated from oil contaminated soil
    Xiaoqiang Jia, Yun He, Lei Huang, Dawei Jiang, Wenyu Lu
    2019, 27(2):  411-417.  doi:10.1016/j.cjche.2018.03.034
    Abstract ( 325 )   PDF (1106KB) ( 51 )  
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    The high-molecular weight polycyclic aromatic hydrocarbons (PAHs) pyrene and typical long chain alkane n-hexadecane are both difficult to degrade. In this study, n-hexadecane and pyrene degrading strain Rhodococcus sp. T1 was isolated from oil contaminated soil. Strain T1 could remove 90.81% n-hexadecane (2 vol%) and 42.79% pyrene (200 mg·L-1) as a single carbon within 5 days, respectively. Comparatively, the degradation of pyrene increased to 60.63%, but the degradation of n-hexadecane decreased to 87.55% when these compounds were mixed. Additionally, identification and analysis of degradation metabolites of Rhodococcus sp. T1 in the above experiments showed that there were significant changes in alanine, methylamine, citric acid and heptadecanoic acid between sole and dual substrate degradation. The optimal conditions for degradation were then determined based on analysis of the pH, salinity, additional nutrient sources and liquid surface activity. Under the optimal conditions of pH 7.0, 35℃, 0.5% NaCl, 5 mg·L-1 of yeast extract and 90 mg·L-1 of surfactant, the degradation increased in single or dual carbon sources. To our knowledge, this is the first study to discuss metabolite changes in Rhodococcus sp. T1 using sole substrate and dual substrate to enhance the long-chain alkanes and PAHs degradation potential.
    Optimizational production of phenyllactic acid by a Lactobacillus buchneri strain via uniform design with overlay sampling methodology
    Jintao Guan, Chaofei Han, Yixin Guan, Songhong Zhang, Junxian Yun, Shanjing Yao
    2019, 27(2):  418-425.  doi:10.1016/j.cjche.2018.04.005
    Abstract ( 449 )   PDF (1889KB) ( 77 )  
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    A Lactobacillus buchneri GBS3 strain isolated from the traditional Chinese pickles was used for the production of 3- phenyllactic acid (PLA), an important compound with antimicrobial activities against a wide species of grampositive and gram-negative bacteria and some fungi. The growth performance of this strain in the de Man, Rogosa and Sharpe (MRS) medium, the production of metabolites of valuable organic acids, and the biosynthesis of PLA using this strain as the whole-cell biocatalyst and phenylpyruvic acid (PPA) as the precursor, were investigated experimentally. The uniform design method with overlay sampling was developed for the optimization of the biotransformation conditions. The results showed that although it produced naturally lactic acid with the maximum concentration of 1.84 g·L-1 and PLA with the concentration of 0.015 g·L-1 after 66 to 72 h cultivation in MRS broth by fermentation, the present strain displayed an effective utilization ability by transforming PPA to PLA. By the uniform design method with overlay sampling for the design and optimization of transformation conditions, a maximum yield of 10.93 g·L-1 PLA with the mole conversion ratio of 83.07% from PPA to PLA was achieved under the optimized condition, i.e., 20 g·L-1 glucose, 270 g·L-1 cells, 13 g·L-1 PPA, pH 8.0 and the reaction time of 15 h, indicating that Lactobacillus buchneri GBS3 was an interesting strain for the biosynthesis of PLA via the microbial transformation. The prediction of PLA yield under different conditions was achieved successfully based on the limited information of only a small number of experiments by the uniform design with overlay sampling. Therefore, the present methodology is effective and helpful for the optimization of the biosynthesis processes of PLA.
    Energy, Resources and Environmental Technology
    Advances in reduction of NOx and N2O1 emission formation in an oxyfired fluidized bed boiler
    Khalid El Sheikh, Mohammad Jakir Hossain Khan, Mahar Diana Hamid, Siddhartha Shrestha, Brahim Si Ali, G.A. Ryabov, Lya A. Dolgushin, Mohd Azlan Hussain, Tatiana V. Bukharkina, Elena A. Gorelova
    2019, 27(2):  426-443.  doi:10.1016/j.cjche.2018.06.033
    Abstract ( 398 )   PDF (3623KB) ( 343 )  
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    Fossil fuel combustion is one of the major means to meet the mounting global energy demand. However, the increasing NOx and N2O emissions arising from fossil fuel combustion process have hazardous effects. Thus, mitigating these gases is vital to attain a sustainable environment. Interestingly, oxy-fuel combustion in fluidized bed for carbon capture and minimized NOx emissions is strongly sustainable compare to the other approaches. It was assessed that NOx formation and fuel-N conversion have significant limitation under oxy-fluidized bed compared to air mode and the mechanism of NOx formation is still deficient and requires further development. In addition, this review paper discussed the potential of primary measure as low emission process with others supplementary techniques for feasible NOx reduction. The influences of combustion mode, operating parameters, and reduction techniques such as flue gas recirculation, oxygen staging, biomass co-firing, catalyst, influence of fluidized bed design and structure, decoupling combustion and their merges are respectively evaluated. Findings show that significant minimization of NOx emission can be achieved through combination of primary and secondary reduction techniques.
    Characterization and analysis of petrochemical wastewater through particle size distribution, biodegradability, and chemical composition
    Xiaoqiang Jia, Dayao Jin, Chen Li, Wenyu Lu
    2019, 27(2):  444-451.  doi:10.1016/j.cjche.2018.04.030
    Abstract ( 394 )   PDF (1070KB) ( 86 )  
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    The centralized treatment method is a widely used form of wastewater treatment that tends to be less effective at removing toxic substances. Therefore, a detailed analysis of the composition of wastewater can provide important information for the design of an effective wastewater treatment process. The objective of this paper was to investigate particle size distribution (PSD), biodegradability, and the chemical composition of the petrochemical wastewater discharges. For this purpose, this project selected the petrochemical wastewater and treated wastewater of China National Offshore Oil Corporation Zhongjie Petrochemical Co, Ltd. as the analysis objects. The step-by-step filtration method, along with a molecular weight classification method, was selected to build the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) fingerprints of petrochemical wastewater and treated wastewater. The results showed that the main pollutants were settleable particles in petrochemical wastewater, which contributed to over 54.85% of the total COD. The colloidal particles with particle sizes in the range of 450-1000 nm had the highest COD value in the treated wastewater, which contributed 34.17% of the total COD of treated wastewater. The results of the BOD analysis showed that the soluble fractions were the main reason that treated wastewaters did not meet the treatment standards. Tests on the organic compounds in petrochemical wastewater found that there were mainly linear paraffins, branched paraffins, benzene series compounds, and some plasticizers in the influent of the petrochemical wastewater. The most abundant pollutants in treated petrochemical wastewater were the adjacent diisobutyl phthalate and the linear alkanes. Fourier transform infrared (FTIR) transmission spectroscopy analysis showed that the settleable particles of petrochemical wastewater and membrane bioreactor (MBR)-treated wastewater contained multiple types of organic substances. The results also indicated that removing the oil-settleable substances, the colloidal particles (450-1000 nm), and the soluble organics will be necessary for the treatment of petrochemical wastewater.
    Shell powder as a novel bio-filler for thermal insulation coatings
    Peigen Zhang, Jingwen Tang, Qiang Tang, Minzhao Zhang, Luwei Shen, Wubian Tian, Yamei Zhang, Zhengming Sun
    2019, 27(2):  452-458.  doi:10.1016/j.cjche.2018.02.006
    Abstract ( 461 )   PDF (3674KB) ( 57 )  
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    The feasibility of employing shell powder as a novel bio-filler to prepare fluorocarbon coating is demonstrated. According to the relevant Chinese standards, the thermal and mechanical properties of the shell powder-filled fluorocarbon coating were evaluated, and compared with those filled by commercial calcium carbonate. All the shell powder-filled coatings can meet the requirements stated in the relevant standards, and with decreasing the particle size of the shell powders, the performance of the thermal insulation coating is enhanced. The coating (SC3) filled by shell powders with an average particle size of 2.81 μm possesses a better thermal insulation performance than the coating (CC) filled by commercial calcium carbonate. The coating SC3 has comparable adhesive force and washing resistance with the coating CC, and in the washing resistance test, after 2000 cycles, the coating SC3 was still able to cover totally their substrates. This work demonstrates a high value-added disposal method for the aquacultural wastes.
    Preparation of new and novel wave like poly(2-anisidine) zirconium tungstate nanocomposite: Thermal, electrical and ion-selective studies
    Anish Khan, Aftab Aslam Parwaz Khan, Mahmoud A. Hussein, Bernaurdshaw Neppolian, Abdullah M. Asiri
    2019, 27(2):  459-466.  doi:10.1016/j.cjche.2018.03.028
    Abstract ( 312 )   PDF (11089KB) ( 39 )  
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    It is necessary to synthesize new material for the advancements of the technology. In this study, new and novel poly (2-anisidine)@zirconium tungstate (P2A/ZrW2O8) was synthesized by simple so-gel method. Physicochemical characterization of P2A/ZrW2O8 was done by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ion exchange and simultaneous four probe dc conductivity studies. The conductivity study revealed its highly semiconducting nature, in the range of 10-1-10-2 S·cm-1. Ion-exchange capabilities of the composite make it applicable for cation-exchange studies. The result of distribution studies (Kd) revealed its selectivity towards Cd2+ compared to other metal ions. This property of the composite was utilized for designing Cd2+ selective membrane electrode. Several important physical parameters of the ion-selective electrode were determined, such as Nernstian slope (32.32 mV·decade-1), working pH range was 2.0-4.0 and response time was found~17 s. The analytical utility of this wave like composite membrane electrode was as, indicator electrode in various potentiometric titrations.
    Materials and Product Engineering
    TIPS behavior for IPP/nano-SiO2 blend membrane formation and its contribution to membrane morphology and performance
    Zhensheng Yang, Zheng Sun, Dongsheng Cui, Pingli Li, Zhiying Wang
    2019, 27(2):  467-475.  doi:10.1016/j.cjche.2018.06.021
    Abstract ( 415 )   PDF (2165KB) ( 39 )  
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    In the present work, the TIPS behavior of isotactic polypropylene (iPP)/di-n-butyl phthalate (DBP)/dioctyl phthalate (DOP)/nano-SiO2 system and the competition relation between liquid-liquid phase separation and polymer crystallization are successfully adjusted by adding nano-SiO2. The liquid-liquid phase separation temperature of the system increases with increasing nano-SiO2 content. Besides, iPP crystallization temperature is also changed after adding nano-SiO2. IPP/nano-SiO2 blend hollow fiber microporous membrane is prepared via TIPS method. SEM photos show that the membrane exhibits mixed morphology combining cellular structure relating to liquid-liquid phase separation and branch structure originating from polymer crystallization. The relative weight of cellular structure first decreases and then increases with the increase of nano-SiO2 content. Furthermore, porosity, connectivity among pores and pure water flux of the membrane first increase and then decrease with increasing nano-SiO2 content. However, mechanical performance of the membrane is improved at all times with increasing nano-SiO2 content.
    Effect of the alkali metal (Li, Na, K) substitution on the geometric, electronic and optical properties of the smallest diamondoid: First principles calculations
    Sriprajak Krongsuk, Nikorn Shinsuphan, Vittaya Amornkitbumrung
    2019, 27(2):  476-482.  doi:10.1016/j.cjche.2018.05.020
    Abstract ( 327 )   PDF (3765KB) ( 61 )  
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    In this study we employed the B3LYP/6-311++G(d,p) method combined with the CIS/6-311++G(d,p) calculation to investigate the effects of the type and the number of alkali metal atoms (Li, Na, K) on the geometric, electronic, and optical properties of alkali metals substituted into adamantanes. Substituting alkali metal (Li, Na, K) atoms caused significant changes in the electronic and optical properties of adamantane. The Ad-1Li, Ad-1Na, and Ad-1K structures showed a dramatically decreased energy gap and ionization potential, while adding more alkali metal atoms slightly decreased these properties. Substituting more alkali metals led to a shift in the maximum absorption wavelength from the visible to the infrared region, depending on the type of alkali metal atom substituted. The magnitude of shift occurred in the following order:Li < Na < K. These characteristics suggest the possibility of tunable electronic structures of this material for optoelectronic device applications.