Table of Content

20 April 2010, Volume 10 Issue 2

Previous Issue    Next Issue

流动与传递

Characteristics of Flow Field in a Multi-layered Radial Reactor

LI Rui-jiang CUI Chun-xia WU Yong-qiang ZHI Zi-bin

. 2010, 10(2):  209-214. 

Asbtract ( )   PDF (563KB) ( )  

Related Articles | Metrics

Pressure profiles in the flow channels and beds in a F3000 mm′7000 mm cold model of multi-layered radial flow reactor were measured and the flow properties of multi-layered radial reactor investigated. The results showed that when the mean square root of the pressure difference between distributing and collecting channels was smaller than 1%, the mean square root of the pressure difference between beds and maximum deviation of radial velocity along the axial direction of the beds were smaller than 5%. But when that of the pressure difference between the channels was greater than 10%, radial velocity along the axial direction of the beds became nonuniform. The flow maldistribution of the bed near the flow channel with the large change of pressure gradient was the biggest and the deviation of radial velocity on the top and the bottom of the bed was greater than 70%. The P-type flow gives the best flow distribution for the momentum recovery radial reactor and proper design of the pressure difference between distributing and collecting channels can ensure a uniform distribution in a multi-layered radial reactor.

Circulating Granular Flow Partition in Pyrolytic Topping of Coal with a Circulating Fluidized Bed

JI Wen-feng; DONG Li WANG Yin; NIE Wei XU Guang-wen

. 2010, 10(2):  215-220. 

Asbtract ( )   PDF (240KB) ( )  

Related Articles | Metrics

The pressure difference between two particle-circulation loops in a circulating fluidized bed (CFB) for coal pyrolysis topping process was investigated to examine its effect on the partition of circulated particles. Experiments were conducted in a laboratory CFB of 12 m in height and 0.09 m in i.d. of its riser. The results demonstrated that raising the flow resistance in one side of the particle partition valve reduced the flow rate of particles into this side, implying that the pressure difference between the two circulation loops was one of the important factors affecting the performance of particle partition valve. A proposal was made and verified experimentally on how to control the pressure difference to optimize the particle partition in the valve. The realized particle partition to the low-pressure side of the partition valve varied in 0~52.4% under a total particle circulation rate of 126.9 kg/(m2×s).

Fluidization Properties and Tanks-in-series Model of Silica Nanoparticles in a Horizontal Rectangular Fluidized Bed

LUO Mei-fang HU Yan-jie ZHAO Ying-hong LI Chun-zhong

. 2010, 10(2):  221-225. 

Asbtract ( )   PDF (321KB) ( )  

Related Articles | Metrics

The fluidization characteristics of silica nanoparticles were investigated in a large-scale fluidized bed. The experimental results indicated that silica nanoparticles could be smoothly and uniformly fluidized, the incipient fluidization velocity was about 2 cm/s and the expansion ratio of bed could reach above 3. The backmixing characteristics and residence time distributions of silica nanoparticles in the horizontal rectangular fluidized bed were affected by the number of baffles, flow rate of SiO2 particles, etc. The results also showed that when two equidistant baffles were located in the horizontal rectangular fluidized bed, the solids flow pattern was apparently close to plug flow and the model parameter of tanks-in-series approached 4. On the basis of experimental results, a large horizontal rectangular fluidized bed was designed.

Rheological Property of SiC-based Slurry

ZHANG Zhi LU Xu-chen YAN Yan WANGTi-zhuan;

. 2010, 10(2):  226-230. 

Asbtract ( )   PDF (289KB) ( )  

Related Articles | Metrics

The effects of pH value, silica sol dispersant content and solid content on the rheological property of SiC-based ceramic slurry were investigated. The research results showed that Zeta potential of ceramic particles in silica sol changed significantly in comparison with that of ceramic particles in deionized water. This was caused by the adsorption of silica colloidal particles with negative charges on the surface of ceramic particles. Silica sol-dispersed slurry showed a minimum in viscosity and shear stress when pH value was around 11 and silica sol content 10%(w). The ceramic slurry showed high thixotropic behavior when solid content reached 69%(w).

An Investigation on Measurement of Nanoparticle Size Distribution Using Non-invasive Method

DONG Xue-jin SU Ming-xu CAI Xiao-shu HU Jian HAN Xiao-lin

. 2010, 10(2):  231-235. 

Asbtract ( )   PDF (365KB) ( )  

Related Articles | Metrics

A non-invasive method with high and broad frequencies acoustic attenuation spectra to measure nano-particle size distribution in solid-liquid two-phase system was investigated. Through theoretical analysis and numerical calculation, ECAH (Epstein-Carharts- Allegra-Hawley) model was presented for the theoretical model of inversion calculation. Nano-silver particle suspensions with volume fraction of 1% were used for experimental samples. Using an ultrasonic transducer with center frequency of 50 MHz, the variable path-length and pulse-echo methods were employed to carry out experimental measurements, in which sound attenuation spectra of high and wide frequencies (10~50 MHz) were obtained, and combined with theoretical model and optimal regularization technique to inverse nano-particle size distribution. Experimental results compared with those from the transmission electron microscopy method and the high-speed centrifugal sedimentation method demonstrated that the method could be used for measurement of nano-particle size distribution in solid-liquid two-phase system.

Effects of Superficial Gas Velocity on Electrical Conductivity and Phase Holdup in Three-phase Fluidized Bed

LI Hong-li LI Deng-xin LIU Guang-tao; DUAN Guang-jie

. 2010, 10(2):  236-239. 

Asbtract ( )   PDF (196KB) ( )  

Related Articles | Metrics

The effects of superficial gas velocity on electrical conductivity and local gas holdup in three-phase fluidized bed (TPFB) were examined in a 90 mm diameter column by the conductivity probe method. The experiments were carried out with glass beads in the diameter of 5~6 mm, and density of 2.6 g/cm3 as solid phase, and water and air as the liquid and gas phases respectively. Experimental results show that except test hole 1, in the radial direction, the more close the distance to the center of TPFB, the lower the electrical conductivity; in the axial direction, the greater the distance from the gas distributor, the lower electrical conductivity and the more uniform distribution of electrical conductivity. When Ug was 0.81 and 2.82 m/s respectively, gas hold-up eg was large in central area of TPFB, and it reduced near the side wall, with Ug increasing, eg increased, the radial distribution of eg became uneven. In the axial direction, the more upward, the greater eg became. With Ug increasing, eg increased, the radial distribution of eg became uneven.

Effect of Rare Earth Ce on Microstructure and Properties of X65 Pipeline Steels

SUN Hao; JI Yun-ping; CHEN Lin;

. 2010, 10(2):  240-244. 

Asbtract ( )   PDF (380KB) ( )  

Related Articles | Metrics

X65 pipeline steel was smelted by vacuum induction furnace. Metalloscope and scanning electron microscope were used to observe its microstructure. Electronic universal tester and electronic pendulum impact testing machine were used to measure its mechanical properties. The effect of rare earth element Ce addition on microstructure and mechanical property of X65 pipeline steel was studied. The results showed that Ce had obvious metamorphism on molten steel. The included foreign substance changed into globular rare earth compounds inclusion and the crystal grains were refined, and then the mechanical properties were improved. After different heat treatment processes, it was found that the process of finishing rolling at 860℃ and air cooling could promote the mechanical properties of X65 pipeline steel.

Study on Additive of Pulverized Coal in Blast Furnace by Thermogravimetry

ZHANG Jian-liang GONG Bi-xia; ZHANG Xi-dong; Cheng-lin;

. 2010, 10(2):  245-248. 

Asbtract ( )   PDF (288KB) ( )  

Related Articles | Metrics

The effects of nine kinds of additives on combustion characteristics of pulverized coal were studied by thermogravimetry method. The combustion efficiency under different temperatures, the intense combustion starting temperature and the maximum reaction rate of the coal samples with different additives were analyzed by thermogravimetric and differential thermogravimetric curves. Their average combustion rates were studied by TG fitting curves. On the basis of the above analysis, the comprehensive combustion performance of No.5 coal samples with additive was superior to raw coal without any additive. Compared with the raw coal, the intense combustion starting temperature of No.5 coal sample was decreased by 14℃, the combustion efficiency under 600℃ was increased by 11.94% and the average combustion rate increased by 8.7%. So it was considered that the additive added into No.5 coal sample could be used as combustion-supporting agent of pulverized coal.

反应与分离

Capture of CO2 from Flue Gases by a Combined Process of Vacuum and Temperature Swing Adsorption Using 13X-APG Zeolite

LIANG Hui LIU Zhen WANG Lu LI Ping YU Jian-guo;

. 2010, 10(2):  249-255. 

Asbtract ( )   PDF (421KB) ( )  

Related Articles | Metrics

The combined process of vacuum and temperature swing adsorption (VTSA) was developed to capture CO2 from the flue gases using 13X-APG zeolite, in which a five-step cyclic adsorption-desorption procedure was involved. The regeneration efficiency of adsorbents, the recovery rate of CO2 from the flue gas, CO2 purity in product gas and productivity of product gas were measured for CO2 capture from the flue gas at ambient pressure and room temperature. The experimental results were compared with those obtained by both conventional vacuum swing adsorption (VSA) process and temperature swing adsorption (TSA) process. In the VTSA process, the adsorbents could be regenerated better at the milder vacuum pressure (3′103 Pa) with the heating help (110~150℃), an excellent capture efficiency could be reached, with 97% regeneration efficiency of adsorbents, 98% of CO2 recovery rate, 90% of CO2 purity in product gas, and 1.8 mol/kg of productivity of CO2 in product gas, where the productivity double the result captured by the VSA process.

Microwave Activation Pretreatment and Pressure Leaching of Complex Copper Sulfide Concentrate

XU Zhi-feng LI Qiang WANG Chen-yan

. 2010, 10(2):  256-262. 

Asbtract ( )   PDF (237KB) ( )  

Related Articles | Metrics

The microwave activation-pressure leaching technique of complex copper sulfide concentrate with tetrahedrite as the main mineral is studied. The results show that the leaching of complex copper sulfide concentrate is greatly improved after the microwave activation pretreatment under the following conditions: microwave power of 82 W, batch concentrate weight of 95 g, and handling time of 120 s. No loss of lead, zinc, sulfur and arsenic in the concentrate occurs during the pretreatment. The pressure leaching conditions of activated copper concentrate are further determined as follows: temperature of 453 K, oxygen partial pressure of 0.6 MPa, initial sulfuric acid concentration of 1.23 mol/L, ratio of liquid to solid of 5 mL/g, calcium lignosulphonate dosage of 1.25%(w) of the concentrate, leaching time of 2.0 h, and agitation speed of 500 r/min. Under these conditions, the extraction rate of copper, zinc and iron is achieved at 86.36%, 92.33% and 27.64% respectively. The leaching residues may return to the rationing of leaching materials for high recovery of copper and zinc after the residues are processed by high-temperature kerosene for deprivation of elemental sulfur.

Pressure Leaching of Alkali-pretreated Limonitic Laterite Ore

ZHANG Yong-lu WANG Chen-yan XU Zhi-feng

. 2010, 10(2):  263-269. 

Asbtract ( )   PDF (286KB) ( )  

Related Articles | Metrics

The pressure leaching of low grade alkali-pretreated limonitic laterite ore by a mixed acid was investigated. After alkali-pretreatment, iron exists in the form of amorphous iron oxide while nickel is adsorbed on the surface of iron oxides in the form of nickel oxide. The preferable pressure-leaching conditions of alkali-pretreated limonitic laterite ore are determined as follows: leaching temperature of 458 K, initial acidity of leaching system with cI=2.44 mol/L, leaching time of 60 min, ratio of liquid to solid of 2:1 mL/g, and agitation speed of 500 r/min. This pressure-leaching technique is proved to be effective and stable. Under the above conditions, the extraction rates of nickel and cobalt are kept about 95% and 80% respectively while that of iron is as lower as 1%. The content of nickel and cobalt in the leaching residues is as low as 0.028% and 0.007% respectively. The valuables of nickel and cobalt can be efficiently separated from the impurity of iron. After the pressure leaching of alkali-pretreated laterite ore, iron is finally hydrolyzed and precipitated in the form of hematite which can be further reclaimed. The iron minerals in the leaching residues rarely contain nickel.

Bacteria-assisted Leaching of Arsenic-rich Gold Concentrate with Fe2(SO4)3 Solution

TAO Min-hui YANG Shao-bin ZHANG Guang-ji YUAN Qiu-hong CAO Jun-ya WANG Yue-hu HAN Bao-ling

. 2010, 10(2):  270-275. 

Asbtract ( )   PDF (317KB) ( )  

Related Articles | Metrics

Fe3+ solution leaching of an arsenic-rich gold concentrate has been studied by shake-flask tests. The effects of temperature, concentration of Fe3+ and high density of bacteria (separately Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Sulfobacillus sibiricu) have been investigated. Compared with bioleaching, Fe3+ solution chemical leaching leads to a higher dissolving rate of arsenic-rich gold concentrate. Higher temperature is favorable for the leaching, and the leaching rate of As is improved with increasing of temperature before reaching at 80. Fe3+ concentration has little effect on the leaching rate of As at the beginning of leaching, high Fe3+ concentration leads to high leaching rate of As when the concentration is lower than 40 g/L, but the leaching rate of As decreases when higher Fe3+ concentration is used due to the production of jarosite. In continuous operation, a higher leaching rate can be achieved under lower but constant Fe3+ concentration. In comparison with bioleaching experiments, increasing pulp density has an obviously negative effect on the bacteria, while the high density of bacteria can be helpful to relieve the effect, at the same time be better for Fe3+ solution chemical leaching for they can keep higher density of Fe3+ and lower S.

Desalination of Ammonium Sulfate Solution by Multi-stage Counter-current Electrodialysis

YANG Xiao-li; WANG Qian; ZHANG Li-ye; CONG Wei

. 2010, 10(2):  276-281. 

Asbtract ( )   PDF (249KB) ( )  

Related Articles | Metrics

Single-stage electrodialysis and multi-stage counter-current electrodialysis were used, respectively, to desalinate ammonium sulfate solution at the concentration of 0.52 mol/L under current-constant condition. The results showed that the phenomena of concentration diffusion and water leakage were obviously alleviated by using a multi-stage counter-current electrodialysis, while they were severe in the end period by using single-stage electrodialysis. Comparing two-stage electrodialysis and three-stage electrodialysis with single-stage one, the removal amount of salt in dilute cell was increased by 7.9% and 22.5%, the concentration of salt in concentrated cell increased by 1.6% and 6.5%, the flux increased by 7.0% and 18.5%, and the energy consumption reduced by 12.0% and 32.0%, respectively.

Decomposition Kinetics of CO2 Gas Hydrate in H2O-H2O2-CO2 System at High Pressure and Low Temperature

LIU Hai-bin CAO Ji-lin GUO Kang-ning

. 2010, 10(2):  282-286. 

Asbtract ( )   PDF (181KB) ( )  

Related Articles | Metrics

In order to develop a new method for separation of peroxide hydrogen and water system by gas hydrate, the decomposition kinetics of gas hydrate formed from H2O-H2O2-CO2 system was studied. Solution compositions in the decomposition process of CO2 gas hydrate were measured at high pressure and low temperatures, 273.15, 274.15 and 276.15 K. Based on the experimental data, the decomposition kinetics model of CO2 gas hydrate in this ternary system was established. The calculated values were in good agreement with the experimental data. The decomposition rate constant of CO2 gas hydrate decomposition reaction was determined at the above temperatures. The activation energy of decomposition reaction of CO2 gas hydrate was 97.17 kJ/mol.

Ion Exchange Equilibria between the Modified Clinoptilolite and Aqueous Solutions of Na+-Ca2+-Mg2+ and NH4+-Ca2+-Mg2+ Systems

YUAN Jun-sheng YANG Lei

. 2010, 10(2):  287-291. 

Asbtract ( )   PDF (304KB) ( )  

Related Articles | Metrics

The ion exchange equilibria between the modified clinoptilolite and the ternary solution systems of Na+-Ca2+-Mg2+ and NH4+-Ca2+-Mg2+ were investigated. The ion exchange equilibrium data of the above systems were measured respectively. Based on the experimental results, the ion exchange isothermic surfaces were constructed using three-dimensional coordinates, and the ternary separation factors of the systems calculated. The results show that the separation factors of Na+ is over 10, Ca2+ between 0.4 and 10, and Mg2+ below 0.4 in the Na+-Ca2+-Mg2+ system, therefore the ion exchange selective sequences of the clinoptilolite is Na+>Ca2+>Mg2+, and higher temperature is in favor of the selectivity of the zeolite to Ca2+ and Mg2+, but lower temperature is propitious to the adsorption of the zeolite to Na+. The separation factor of NH4+ is over 15, Ca2+ between 0.2 and 1.5, and Mg2+ below 0.2 in the NH4+-Ca2+-Mg2+ system, so the ion exchange selective sequences of the clinoptilolite is NH4+>Ca2+>Mg2+, and higher temperature is in favor of the selectivity of the zeolite to Ca2+ and Mg2+, otherwise lower temperature is propitious to the adsorption of the zeolite to NH4+.

过程与工艺

Optimization on Production Process of Furfural by High-temperature Dilute-acid Hydrolysis of Corncobs

GAO Li-fang XU Hong-bin WANG Shao-na CAO Hong-bin

. 2010, 10(2):  292-297. 

Asbtract ( )   PDF (235KB) ( )  

Related Articles | Metrics

To resolve the problems of low resource utilization efficiency in China's current furfural manufacturing industry, the production process of furfural by high-temperature dilute-acid hydrolysis of corncobs was optimized through single factor and orthogonal experiments, with injecting water into an autoclave by a constant-flux pump. The effects of residence time, sulfuric acid concentration, temperature, interaction of sulfuric acid concentration and temperature, and ratio of liquid to solid on the yield of furfural were investigated. The results indicated that the order of influential factors on the yield of furfural within the experimental range was obtained as follows: residence time>temperature>ratio of liquid to solid>sulfuric acid concentration. The optimal conditions were obtained with the yield of furfural and the consumption of water as the objective function. Under the optimized conditions of residence time 100 min, temperature 180℃, sulfuric acid concentration 0.5%, and ratio of liquid to solid 8:1, the consumption of sulfuric acid was lower, and the yield of furfural reached as high as 75.27%, 15%~20% higher than that of the current industrial process.

Thermal Decomposition Behavior of ZrH2 Particles and Its Effect on Distributions of Elements in Aluminum Foam

LI Da-wu; WANG Ke SUN Ting YAO Guang-chun LI Jie

. 2010, 10(2):  298-303. 

Asbtract ( )   PDF (322KB) ( )  

Related Articles | Metrics

Thermal decomposition behavior of zirconium hydride was studied by using temperature-programmed thermogravimetry. The thermodynamic and kinetic characteristics and potential reactions in the foaming process were analyzed. The aluminum foam with small pore diameter was prepared. The effect of ZrH2 particles dispersion on elemental distributions in aluminum foam was investigated. The results indicated that decomposition behavior of ZrH2 was controlled by chemical reaction process under low heating rate, but controlled by diffusion of solid product under high heating rate. The distributions of metal elements were impacted by thermal decomposition of ZrH2, the bubbles floating upward led to the non-uniform distribution of Zr and Ca elements.

Effects of Solvents on Catalytic Hydrogenation Process of m-Dinitrobenzene to Produce m-Phenylenediamine

ZHANG Xin-bo XU Li-yong YUAN Jun-feng XIANG Yi-zhi

. 2010, 10(2):  304-308. 

Asbtract ( )   PDF (209KB) ( )  

Related Articles | Metrics

The effects of solvent benzene and ethanol on catalytic process of hydrogenation m-dinitrobenzene to produce m-phenylenediamine were studied. The solubility of intermediates in solvents has significant effect on its selectivity, and intermediate m-nitoso-nitrobenzene in benzene is less than that in ethanol. With the reaction temperature increasing from 50 to 90℃ (at 2 MPa), the reaction time is reduced from 350 to 75 min in benzene, while from 120 to 35 min in ethanol. With the reaction pressure increasing 0.4 to 2.8 MPa, the reaction time is reduced from 250 to 85 min in benzene, while from 70 to 40 min in ethanol. The solubility of hydrogen and organic product, and the adsorption behaviors of hydrogen and organic product on catalysts in different solvents have significant effects on reaction rate.

Experimental Study on Formation of Carbon Dioxide Hydrate in a Water Spraying Reactor

ZHONG Dong-liang YANG Chen LIU Dao-ping WU Zhi-min

. 2010, 10(2):  309-313. 

Asbtract ( )   PDF (508KB) ( )  

Related Articles | Metrics

Experiments of CO2 hydrate formation were carried out in a water spraying reactor. The growth process was visually observed and photographed. Crystallization supersaturation was employed as the driving force to investigate the growth characteristics of CO2 hydrate. The results indicate that the amount of generated CO2 hydrate increases with the rising of driving force. The lower the system temperature is, the more the CO2 hydrate forms. The growth rate of CO2 hydrate is 0.531~9.53 mmol/s, which is in accordance with the reported result from static reactor in the literature, implying that the function of water spraying reactor to promote the growth of CO2 hydrate needs to be improved. Due to low driving force and incomplete hydrate formation, the obtained gas storage rate of CO2 hydrate is 14~24 m3/m3.

系统与集成

Life Cycle Assessment of Resource and Energy Consumption for Production of Biodiesel

XING Ai-hua MA Jie ZHANG Ying-hao WANG Yao JIN Yong

. 2010, 10(2):  314-320. 

Asbtract ( )   PDF (236KB) ( )  

Related Articles | Metrics

Life cycle assessment (LCA) was performed for a biodiesel production process of 30000 t/a that took into account of resource utilization, energy consumption. The land use, water and energy consumption were calculated and evaluated for three feedstocks, namely, rape seed oil, Jatropha curcas L. oil and waste oil. For rape seed oil and Jatropha curcas L. oil the LCA included the planting, harvesting and transportation, pretreatment, biodiesel production, distribution and consumption, while for the waste oil, there was no planting and waste collection occupying the place of harvesting. The land areas required were 13132, 3333 and 5 m2/t, the amounts of water consumed were 9063.55, 12306.62 and 1.97 m3/t, and amounts of fossil energy consumed were 0.9, 0.67 and 0.25 MJ/t for rape seed oil, Jatropha curcas L. oil, and waste oil based biodiesel, respectively. The results showed that the planting and production processes used most of the resources and energy. Waste oil and Jatropha curcas L. oil should be developed as biodesel feedstock in China. The effective way to decrease biodiesel life cycle resource utilization, energy consumption would be to cultivate high quality oil plants, improve the catalyst activity and develop a better transesterification process.

Life Cycle Environmental Impact Assessment of Pyrometallurgical Separation Process of Paigeite Ore

AN Jing XUE Xiang-xin JIANG Tao

. 2010, 10(2):  321-326. 

Asbtract ( )   PDF (240KB) ( )  

Related Articles | Metrics

A life cycle impact assessment method was applied to analyze the environmental impacts resulting from the process of pyrometallurgical separation of paigeite ore quantitatively. The correlative environmental impacts include climate change, acidification, photochemical ozone formation, nutrient enrichment, human toxicity, mineral depletion, fossil energy depletion, water depletion and land occupation, and the impact scores are expressed as mining and processing of 10000 t paigeite ore. The results showed that climate change score is 1.45′107 kg CO2-eq, acidification score 3.61′104 kg SO2-eq, photochemical ozone formation score 7.16′102 kg C2H4-eq, nutrient enrichment score 30.41 kg PO43--eq, human toxicity score 2.43′104 kg C6H4Cl2-eq, mineral depletion and fossil energy depletion scores are 7.72′103 kg Sb-eq and 3.68′10-1 kg Sb-eq respectively, water depletion score 1.24′105 m3 and land occupation score 7.98′106 kg solid waste. In view of the production link, water depletion and land occupation resulting from material production is dominant, the scores of climate change, photochemical ozone formation, nutrient enrichment, mineral depletion and fossil energy depletion resulting from smelting by blast furnace are larger than that from other production link, and borax production holds a very important place in acidification and human toxicity. From the source of each environmental impact, the impacts resulting from energy production are larger than that from production process for all impact categories expect mineral depletion, water depletion, energy depletion and land occupation.

Simulation for Separation of Water-Isopropanol-Diiospropylamine by Heat Integration Pressure Swing Distillation

YANG De-ming GAO Xiao-xin

. 2010, 10(2):  327-331. 

Asbtract ( )   PDF (195KB) ( )  

Related Articles | Metrics

Heat integration pressure swing distillation (HIPSD) for separation of water-isopropanol-diiospropylamine was investigated based on the dependency of the azeotropic composition on the system pressure is sensitive. The UNIQUAC-RK equation was used for calculating vapor-liquid equilibrium data of water-isopropanol-diiospropylamine system, and the binary interaction parameters of UNIQUAC equation were corrected against the experimental data in the range of 0.004~1.0 MPa. Simulations of HIPSD were performed by ASPEN PLUS software with RADFRAC module, and the optimum conditions, composition profiles of vapors and liquids in column including column parameters were determined. The simulation results show that HIPSD can save energy by 34.3% compared with PSD.

生化工程专栏

Storage Stability of Alpha-Lipoic Acid-loaded Lipid Nanoparticles

TANG Jin-guo; XIA Qiang LIU Guang-yu

. 2010, 10(2):  332-338. 

Asbtract ( )   PDF (420KB) ( )  

Related Articles | Metrics

Alpha-lipoic acid-loaded lipid nanoparticles (ALA-LNs) were prepared by high pressure homogenization method. The influences of storage conditions such as time and temperature on the physical and chemical storage stability of ALA-LNs were studied in details. The stability was evaluated by particle size and polydispersity index, morphology of ALA-LNs, and capacity of ALA loading. The dilution and pH stability of ALA-LNs suspensions were also studied. After three months storage, the mean size of ALA-LNs at 4 and 40℃ was increased by 2.68% and 3.62% compared with the original size, respectively. ALA-LNs stored at 40℃ had ellipsoid shape and the mean size was about 152 nm (SD=23.6). The loading capacity of ALA at 40℃ was much higher than those stored at other two temperatures. The good dilution and pH stability were also demonstrated. The sample had good fluidity even at 4℃.

Impact of Surfactants on Asymmetric Bioreduction of 2-Octanone by Saccharomyces cerevisiae

SHI Xian-ai; LI Cong-ying; FU Juan; MENG Chun; GUO Yang-hao LOU Wen-yong; WU Hong; Min-hua;

. 2010, 10(2):  339-343. 

Asbtract ( )   PDF (249KB) ( )  

Related Articles | Metrics

In aqueous buffer system containing surfactants of SDS, CTAB and Emulsifier OP-6, the asymmetric reduction of 2-octanone to (S)-2-octanol with Saccharomyces cerevisiae cells was studied. The results indicated that the yield and product e.e. were disappointingly low due to the serious reverse reaction and side reaction in the surfactant-free system. Particularly, at the substrate concentration of 10 mmol/L, they were 77.4% and 78.8% for 96 h reaction. With addition of surfactants to the system, the rates of reverse and side reactions were decreased by Emulsifier OP-6 and CTAB, with the effective increase of the average positive reaction rate. In the systems containing 0.4 mmol/L Emulsifier OP-6 or 0.04 mmol/L CTAB, the yield and e.e. value were 88.4%, 91.1% and 97.0%, 94.5%, respectively, obviously higher than those in the reaction system without surfactant. The further work showed that the enhancement of efficiency and enantioselectivity of the asymmetric reduction resulted from the effect of the surfactants on the cell characteristics such as growth, membrane penetrability, etc. Among the surfactants investigated, Emulsifier OP-6 performed best.

Repeated Fermentation with Variable Feeding for Production of e-Poly-L-lysine by Kitasatospora sp. MY 5-36

ZHANG Yang; ZHANG Quan-jing; FENG Xiao-hai XU Hong

. 2010, 10(2):  344-347. 

Asbtract ( )   PDF (256KB) ( )  

Related Articles | Metrics

Repeated fermentation with variable feeding for production of e-poly-L-lysine (e-PL) by Kitasatospora sp. MY 5-36 was investigated. It was demonstrated that the repeated fermentation in shaking flask had good feasibility and stability. The e-PL production was also studied in a 5 L bioreactor. The maximum e-PL concentration was obtained when 10%(j) fermentation broth was left as the seed for the next batch of repeated fermentation. The feeding should be started when the fermentation broth of residual sugar concentration decreased to 10 g/L. During the repeated fermentation, the glucose concentration was maintained at about 10 g/L with variable flow feeding. A high level of e-PL production capacity still remained after 5 batches of fermentation, with approximate average batch e-PL concentration of 20.0 g/L under a productivity of 0.159 g/(L×h).

材料工程专栏

Morphology of Iron Aluminophosphate Synthesized by Solid-state Chemical Reaction at Low Temperature

LIU Shao-you TANG Wen-hua LONG Bu-ming; YANG Hong-yun

. 2010, 10(2):  348-354. 

Asbtract ( )   PDF (921KB) ( )  

Related Articles | Metrics

Fe(III)-substituted aluminophosphate particles with various morphologies was successfully prepared by solid-state reaction of iron chloride hexahydrate (FeCl3×6H2O), aluminium chloride hexahydrate (AlCl3×6H2O) and sodium dihydrogen phosphate dihydrate (NaH2PO4×2H2O) with cetyltrimethylammonium bromide (CTAB) or sodium dodecyl benzene sulfonate (SDBS) as template. The structural change of the samples was monitored by XRD, FI-IR and N2 absorption-desorption. Meanwhile, the effects of such as template, molar ratio of aluminium to iron (Al/Fe), and calcination temperature on the morphology of iron aluminophosphate (FeAlPO) were investigated. Moreover, catalytic activity of FeAlPO powder with various morphologies was compared. The results show that the iron ions have entered into the frameworks of aluminophosphate. The crystalline structure and morphology of FeAlPO molecular sieve are directly related to the sort of template. When Al/Fe is 1:1, and CTAB acts as a template, the obtained FeAlPO-5 powder is self-assembled by irregular shape nanoparticles. And SDBS acts as a template, the obtained FeAlPO-11 powder is spherical nanoparticles, either FeAlPO-5 or FeAlPO-11 powder is of particle diameter distribution of 80~200 nm. The change of Al/Fe can only enhance or restrain the growth of the crystal planes, but the increase of calcination temperature makes the transformation of FeAlPO-11 into FeAlPO-5 crystalline structure.

Influence of Additives on Pore Size Distributions of Silica Aergels

WANG Cheng-shu; XIE Chao; WANG Tao

. 2010, 10(2):  355-360. 

Asbtract ( )   PDF (439KB) ( )  

Related Articles | Metrics

Silica aerogel is prepared using rice husk ash as silicon source. Several additives are added into the sol under suitable conditions, through the steps of sol-gel, solvent exchange and supercritical carbon dioxide drying. The added amount 15%~20% of glycerol and ethylene glycol have strongly influence on the pore size distributions (PSD). During this process, silica aerogel with smaller pores, more uniform, higher specific surface area and smaller average pore size is produced. High molecular weight polyethylene glycols can shorten the gelation time and the PSD is relatively uniform. Formamide and dimethylformamide have the most significant effect on the samples with 20~40 nm PSD and high specific surface area above 750 m2/g. Polyvinylpyrrolidone can accelerate polymerization rate and the aerogel has more small pores and dense network structure.

Preparation of Organic Functionalized Mesoporous Catalysts and Their Applications to the Self-condensation Reaction of n-Butanal to 2-Ethylhexenal

SU Bo; LANG Wan-zhong; ZENG Qun-ying; LIU Xun-wen YANG Chun-ji; GUO Ya-jun;

. 2010, 10(2):  361-366. 

Asbtract ( )   PDF (285KB) ( )  

Related Articles | Metrics

Three organic amine functionalized MCM-41 solid base catalysts, NH2-MCM, NH2NH-MCM and NR2-MCM, using 3-aminepropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N,N-diethyl-3-aminopropyltriethoxysilane as precursors, were prepared by surface grafting. Anchoring 2-cyanoethyltrimethoxysilane on the surface of NH2-MCM, the acid-base amphoteric bifunctionalized catalyst NH2-MCM-COOH was prepared. The properties of as-synthesized catalysts were analyzed. The as-synthesized catalysts were applied to self-condensation reaction of n-butanal to investigate the catalytic activity. It is shown that NH2-MCM has the best catalytic activity among the three catalysts under the same conditions. With 0.3 mmol amine, the yield of 2-ethylhexenal attains above 70% after 10 h of reaction. Compared with NH2-MCM, NH2-MCM-COOH exhibits excellent catalytic activity, after 10 h of reaction with 0.15 mmol amine，the yield of 2-ethylhexenal nearly doubles that for NH2-MCM. The results reveal that the alkaline organic amine groups and acid groups on the surface of catalysts have obvious synergic effect to promote the self-condensation reaction of n-butanal.

Preparation and Characterization of Interlayer Assembled SiO2-TiO2 Clay Material

ZHANG Ying; CHEN Ai-ping LUO Mei-fang LI Chun-zhong XU Zhen-liang

. 2010, 10(2):  367-372. 

Asbtract ( )   PDF (374KB) ( )  

Related Articles | Metrics

SiO2-TiO2 pillaring agent was synthesized by sol-gel method, and raw clay was added into pillaring agent sol to prepare SiO2-TiO2 pillared montmorillonite. The structural properties of samples were characterized by XRD, N2 adsorption/desorption, TG-DTA and UV-Vis spectrometry techniques. The effects of material ratio and preparation conditions on the structural properties of the final products were investigated. From XRD patterns, the SiO2-TiO2 particles were intercalated into interlayer space of raw clay successfully. When nearly all the SiO2-TiO2 sol not pillared into the clay was removed, the BET speci?c surface area was up to 127.2 m2/g. Thermal stability of the pillared montmorillonite was increased by about 70℃ compared with the raw clay. And the sample with higher content of Si in SiO2-TiO2 particles showed higher thermal stability. Ti was in tetrahedral coordination and octahedral coordination in the pillared montmorillonite calcined below 500℃, and TiO2 was crystallized into anatase at 600℃. Compared with conventional wet method, the new dry method was simpler and more controllable in pillaring reaction process. And the SiO2-TiO2 pillared montmorillonite with regular structure was more easily obtained by the dry method.

Property of Lead-free Low Melting Glass of P2O5-V2O5-B2O3-ZnO System for Electronic Sealing Application

LI Jing; XIE Zhao-hui ZHU Qing-shan TONG Hua WANG Jing-gang PENG Lian;

. 2010, 10(2):  373-378. 

Asbtract ( )   PDF (241KB) ( )  

Related Articles | Metrics

A lead-free low melting glass consisting of P2O5, V2O5, B2O3 and ZnO was studied for electronic sealing application. The effects of V2O5 and B2O3 concentrations on the glass softening temperature (Tf), thermal expansion coefficient and thermal stability were investigated. The results showed that Tf decreased with V2O5 concentration increasing, while as the content of B2O3 increased, Tf first increased and then decreased, which appeared boron abnormal phenomenon. When the glass contained 8%(mol) V2O5 and 15%(mol) B2O3, Tf, thermal expansion coefficient and thermal stability could meet the requirements, but the chemical stability of the glass was poor. But addition of small amounts of Al2O3 and Fe2O3 could greatly improve the chemical stability. Consequently, a glass with molar percentage composition of 26.0P2O5-17.3V2O5-7.7B2O3-45.0ZnO-2.0Al2O3-2.0Fe2O3 with a low transition temperature of 340℃, a thermal expansion coefficient of 7.5×10-6 ℃-1 (25~300℃), and a weight loss of 0.63 mg/cm2 after immersing in 90℃ water for 10 h, was successfully prepared for electronic sealing applications. Its properties were comparable with those of traditional low melting sealing glasses.

Preparation and Characterization of New Bimodal Porous Cobalt-based Catalyst for Fischer-Tropsch Synthesis

JI Ren-shan; XIAO Cui-wei; WANG Nai-ji QIN Guo-tong

. 2010, 10(2):  379-384. 

Asbtract ( )   PDF (517KB) ( )  

Related Articles | Metrics

Bimodal porous support was modified with ZrO2 sols introduced into bigger pores of SiO2 gel pellets directly, then a eggshell cobalt-based catalyst based on the support was prepared. The structure and reduction property of the catalyst were characterized. The pores of obtained supports and catalyst distributed distinctly as two kinds of main pores. The results show that the BET specific surface area and pore volume of bimodal porous support as well as catalyst were increased compared with the original silica gel and catalyst. Bimodal porous support with additive ZrO2 was beneficial to improve dispersing degree, activity and selectivity for C5+ hydrocarbon of catalyst. The CO conversion rate reached 96.6%, and the selectivity for C5+ hydrocarbon was 91.2% under the conditions of temperature 250℃, pressure 2 MPa, and air space speed 500 h-1.

Properties of La Doped Al-substituted α-Ni(OH)2 Electrode Material

LIU Chang-jiu ZHAO Wei-min CHEN Shi-juan;

. 2010, 10(2):  385-389. 

Asbtract ( )   PDF (489KB) ( )  

Related Articles | Metrics

The La doped Al-substituted α-nickel hydroxide electrode material was prepared by homogeneous precipitation method with urea. Its structure and morphology were characterized, and electrochemical performance investigated. The results show that the La doped Al-substituted particles have a sperical shape and their surface is rough. The sample has a relatively larger interlayer distance and better crystallinity compared with the Al-substituted sample. At 0.1 C charge-discharge rate, the discharge specific capacity of La doped sample reaches 403.04 mA×h/g, simultaneously its discharge mediate potential is higher and maintained at 1.29 V. In addition, the discharge specific capacity of the sample reachs 343.47 mA×h/g at 1 C rate, and the capacity still remains 90.31% after 50 cycles. The La doped Al-substituted α-nickel hydroxide has better high-rate discharge performance.

Synthesis, Characterization and Electrochemical Property of New Fluorine-containing Quaternary Ammonium Salt (C4H9)4NAlF4

ZHOU Jun CAO Yan TANG Qing; WANG Shao-na

. 2010, 10(2):  390-394. 

Asbtract ( )   PDF (318KB) ( )  

Related Articles | Metrics

Under the protection of nitrogen gas, high purity tetrabutylammonium cation salt with tetrafluoroaluminate anion, which was synthesized from tetrabutyl ammonium hydroxide aqueous solution and ammonium hexafluoroaluminate, was extracted from reacted solution by dichloromethane and dehydrated by entrainer isopropanol. Its structure was characterized by elemental analysis, FT-IR, Raman, 19F-NMR, 1H-NMR and MSI-MS. In addition, thermogravimetric analysis, cyclic voltammetry and other methods were used to examine its physical and electrochemical properties. The results showed that melting point, decomposition temperature, conductivity and electrochemical window of the compound were 204℃, 400℃, 4.67 S/m (220℃) and 4.8 V (220℃) respectively, indicating that it was a potential low-temperature electrolyte with low melting point, high conductivity, good thermal and electrochemical stability.

Effects of Different Hollow Fiber Membrane Modules on Bubbleless Aeration of Methane and Oxygen

DUAN Chang-hong LUO Ming-fang YANG Cheng JIANG Hao YANG Cheng

. 2010, 10(2):  395-399. 

Asbtract ( )   PDF (250KB) ( )  

Related Articles | Metrics

To explore the possibility of bubble-free membrane aeration in the biotransfer of methane safely and efficiently, the effects of hollow fiber membrane modules on the mass transfer rates of methane and oxygen were examined in this work. Three membrane modules, dense silicone membrane (A), hydrophobic microporous polypropylene membrane (B), and hydrophilic microporous poly(ether sulfone) membrane (C), were investigated. The investigation results show that the gas-liquid mass transfer rates of methane and oxygen can be improved significantly for modules A and B. For the bubbleless aeration of methane (for the case that methane is bubbleless aerated), the volumetric mass transfer coefficients (KLa) of methane for modules A and B are 3.19 and 3.78 h-1, respectively, which are 3 times of that for the conventional bubble aeration. For the bubbleless aeration of air (for the case that air is bubbleless aerated), KLa of oxygen for module B is 61.1 h-1, which is 2.6 times of that for module A and 24.8 times of that for the conventional bubble aeration.

Anti-corrosion Performance of Superfine Fly Ash Fiber

ZHANG Ze-wu; CHEN Jian-ding WU Qiu-fang MA Xin-sheng

. 2010, 10(2):  400-404. 

Asbtract ( )   PDF (585KB) ( )  

Related Articles | Metrics

The surface properties of micro fly ash fiber (FAF) were investigated in the corrosive media of water, H2SO4 solution, NaOH solution under the conditions of 100℃ and 3 h. The changes of weight, specific surface area, micro-morphology, composition and structure of FAF before and after corrosion were examined, and composition of residual solution analyzed by ICP. The results showed that weight loss of FAF increased with the decrease of pH value in the corrosive medium, and that the pH of corrosive medium increased by the leached ions at the same time. The surface of FAF was etched in many small potholes and weight lost 12.9% under water corrosion. Its weight lost 4.6% under 0.25 mol/L of NaOH solution corrosion with surface etched to ravines and the surface Si?OH vibration absorption peak significantly declined, meanwhile Si and Al concentrations changed less and specific surface area increased from 0.129 to 5.486 m2/g. Whereas, FAF was broken and weight lost 18.9% with the Si, Al, Ca substantive leaching under 0.25 mol/L H2SO4 solution corrosion, with the FT-IR diagram showing the characteristic peaks of SO42-. It shows that alkali metal ion leaching and network structure with Si component dissolving in the solution are the main corrosion mechanism.

Preparation and Properties of Magnetic Sensitive PVA/Fe2O3 Hydrogel

ZHANG Shu-di; ZHAI Yu-chun ZHANG Zhen-fang;

. 2010, 10(2):  405-408. 

Asbtract ( )   PDF (234KB) ( )  

Related Articles | Metrics

A series of Fe2O3 magnetic-sensitive polyvinly-alcohol (PVA) hydrogels were fabricated using freezing-thawing method, focusing on the mechanical properties, swelling characteristics and magnetic sensibility. The results showed that 1%Fe2O3/PVA hydrogel had the best mechanical properties, swelling rate and loss rate of the poly(vinly alcohol) hydrogel were decreased with the increasing of the magnetic particles content, the change tendency was similar, cross-linking was increased with swelling performance decreasing. PVA and Fe2O3 had better compatibility from the SEM image. Under the 3000 Oe magnetic field strength, water hydrogel reached saturation, showing a strong paramagnetism, and hydrogel had more hysteresis loss, showing that its magnetic susceptibility was better.

综述

Research Progress in Culture Conditions and Fermentation Technology of Bacillus mucilaginosus

WANG Xue YUAN Xiao-fan ZHAO Bing WANG Xiao-dong WANG Yu-chun

. 2010, 10(2):  409-416. 

Asbtract ( )   PDF (353KB) ( )  

Related Articles | Metrics

The research progress of Bacillus mucilaginosus used in the fields of microbial fertilizer, mineral decomposition and wastewater treatment were reviewed. In the light of B. mucilaginosus, the studies on culture media, culture conditions and fermentation in bioreactor for spore yield in microbial fertilizer field, on culture media and conditions of culture and bioflocculation for flocculation ratio in wastewater treatment field and on the conditions of soil and mineral decomposition for decomposing minerals and extracting mineral components in mineral decomposition field were discussed. It is proposed that the control of fermentation progress by establishing fermentation model and investigation into characteristics of rheological behavior, and application of B. mucilaginosus in soil improvement will be the further research directions.