Mass transfer process of peanut protein extracted by bis(2-ethylhexyl)sodium sulfosuccinate reverse micelles

The liquid-liquid extraction method using reverse micelles can simultaneously extract lipid and protein of oilseeds,which have become increasingly popular in recent years.However,there are few studies on mass transfer processes and models,which are helpful to better control the extraction process of oils and proteins.In this paper,mass transfer process of peanut protein extracted by bis(2-ethylhexyl)sodium sulfosuccinate(AOT)/isooctane reverse micelles was investigated.The effects of stirring speed(0,70,140,and 210 r/min),temperature of extraction(30,35,40,45,and 50℃),peanut flour particle size(0.355,0.450,0.600,and 0.900 mm)and solidliquid ratio(0.010,0.0125,0.015,0.0175,and 0.020 g/mL)on extraction rate were examined.The results showed that extraction rate increased with temperature rising,particle size reduction as well as solid-liquid ratio increase respectively,while little effect of stirring speed(P>0.05)was observed.The apparent activation energy of extraction process was calculated as 10.02 kJ/mol and Arrhenius constant(A)was 1.91 by Arrhenius equation.There was a linear relationship between reaction rate constant and the square of the inverse of initial particle radius(1/r_(0)^(2))(P<0.05).This phenomenon and this shrinking core model were anastomosed.In brief,the extraction process was controlled by the diffusion of protein from the virgin zone interface of particle through the reacted zone and it was in line with the first order reaction.Mass transfer kinetics of peanut protein extracted by reverse micelles was established and it was verified by experimental results.The results provide an important theoretical guidance for industrial production of peanut protein separation and purification.

Numerical Analysis of Blast Furnace Performance Under Charging Iron-Bearing Burdens With High Reducibility

The reducibility of iron-bearing burdens was emphasized for improving the operation efficiency of blast furnace. The blast furnace operation of charging the burdens with high reducibility has been numerically evaluated using a multi-fluid blast furnace model. The effects of reaction rate constants and diffusion coefficients were investigated separately or simultaneously for clarifying the variations of furnace state. According to the model simulation results, in the upper zone, the indirect reduction of the burdens proceeds at a faster rate and the shaft efficiency is enhanced with the improvement under the conditions of interface reaction and intra-particle diffusion. In the lower zone, direct reduction in molten slag is restrained. As a consequence, CO utilization of top gas is enhanced and the ratio of direct reduction is decreased. It is possible to achieve higher energy efficiency of the blast furnace, and this is represented by the improvement in productivity and the decrease in consumption of reducing agent. The use of high-reducibility burdens contributes to a better performance of blast furnace. More efforts are necessary to develop and apply highreducibility sinter and carbon composite agglomerates for practical application at a blast furnace.

Kinetics of Silver Dissolution in Nitric Acid from Ag-Au_(0.04)-Cu_(0.10) and Ag-Cu_(0.23) Scraps

Kinetics of dissolution of silver present in precious metal 26～85℃. Dissolution rate of silver was much faster than scraps in HNO3 was studied in temperature range of that of copper at all temperatures. Effects of particle size, stirring speed, acid concentration and temperature on the rate of dissolving of silver were evaluated. Dissolution rate decreases with particle size and increases with temperature. Dissolving was accelerated with acid concentrations less than 10 mol/L. Concentrations greater than 10 mol/L resulted in slowing down of the dissolution rate. Shrinking core model with internal diffusion equation t/τ=1-3（1-x）^2/3＋2（1-x） could be used to explain the mechanism of the reaction. Silver extraction resulted in activation energies of 33.95 kJ/mol for Ag-Au0.04-Cu0.10 and 68.87 kJ/mol for Ag-Cu0.23 particles. Inter-diffusion of silver and nitrate ions through the porous region of the insoluble alloying layer was the main resistance to the dissolving process. Results were tangible for applications in recycling of the material from electronic silver-bearing scraps, dental alloys, jewelry, silverware and anodic slime precious metal recovery.

Modelling and numerical simulation of isothermal oxidation of an individual magnetite pellet based on computational fluid dynamics

A mathematical model based on the computational fluid dynamics method,heat and mass transfer in porous media and the unreacted shrinking core model for the oxidation reaction of an individual magnetite pellet during preheating was established.The commercial software COMSOL Multiphysics was used to simulate the change in the oxidation degree of the pellet at different temperatures and oxygen concentrations,and the simulated results were compared with the exper-imental results.The model considered the influence of the exothermic heat of the reaction,and the enthalpy change was added to calculate the heat released by the oxidation.The results show that the oxidation rate on the surface of the pellet is much faster than that of the inside of the pellet.Temperature and oxygen concentration have great influence on the pellet oxidation model.Meanwhile,the exothermic calculation results show that there is a non-isothermal phenomenon inside the pellet,which leads to an increase in temperature inside the single pellet.Under the preheating condition of 873-1273 K(20%oxygen content),the heat released by the pellet oxidation reaction in a chain grate is 7.8×10^(6)-10.8×10^(6) kJ/h,which is very large and needs to be considered in the magnetite pellet oxidation modelling.

Adsorptive separation of La(Ⅲ)from aqueous solution via the synthesized[Zn(bim)_(2)(bdc)]_(n) metal-organic framework

Lanthanum is one of the rare earth metals which due to specific chemio-physical properties,has wide applications in different industries.In this research,the ability of the synthesized metal-organic framework(MOF),[Zn(bim)_(2)(bdc)]_(n)(ZBB) for the removal of lanthanum ions from the aqueous stream was investigated in the batch and column processes.The synthesized MOF was characterized by using scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET),Fourier transform infrared spectroscopy(FTIR) and thermogravimetric analysis(TGA).The effect of pH on lanthanum ions adsorption was evaluated in the range from 1 to 7.Moreover,isothermal,kinetic,and thermodynamic parameters for adsorption of La(Ⅲ) ions onto the synthesized MOF were evaluated.The adsorption capacity of lanthanum ions onto the synthesized MOF was calculated to be about 130 mg/g.Thermodynamic studies demonstrate the endothermic and chemical nature of lanthanum adsorption,while kinetic studies suggest the pseudo-first-order of reaction.In column mode,the effect of solution flow rate passing through the fixed-bed was studied.Experimental data confirm that increasing the bed flow rate causes a decrease in the adsorption capacity of lanthanum ions on the synthesized MOF.

Effect of pressure on gasification reactivity of three Chinese coals with different ranks

The gasification reactivities of three kinds of different coal ranks(Huolinhe lignite,Shenmu bituminous coal,and Jincheng anthracite)with CO_(2) and H_(2)O was carried out on a self-made pressurized fixed-bed reactor at increased pressures(up to 1.0 MPa).The physicochemical characteristics of the chars at various levels of carbon conversion were studied via scanning electron microscopy(SEM),X-ray diffraction(XRD),and BET surface area.Results show that the char gasification reactivity increases with increasing partial pressure.The gasification reaction is controlled by pore diffusion,the rate decreases with increasing total system pressure,and under chemical kinetic control there is no pressure dependence.In general,gasification rates decrease for coals of progressively higher rank.The experimental results could be well described by the shrinking core model for three chars during steam and CO_(2) gasification.The values of reaction order n with steam were 0.49,0.46,0.43,respectively.Meanwhile,the values of reaction order n with CO_(2) were 0.31,0.28,0.26,respectively.With the coal rank increasing,the pressure order m is higher,the activation energies increase slightly with steam,and the activation energy with CO_(2) increases noticeably.As the carbon conversion increases,the degree of graphitization is enhanced.The surface area of the gasified char increases rapidly with the progress of gasification and peaks at about 40%of char gasification.