应用响应曲面优化交联淀粉微球的合成工艺

为了优化采用反相悬浮法合成的交联淀粉微球(CSM)的工艺,采用响应曲面法(RSM)分析了交联剂质量分数、反应温度和引发剂浓度对于CSM品质(溶胀度、平均粒径)的影响,并建立了相应的预测模型。方差分析的结果表明:交联剂质量分数、反应温度和引发剂浓度对于CSM溶胀度和平均粒径这2项指标都有着极为显著的影响。优化所得的较优工艺参数:交联剂质量分数为0.5%,交联温度为48℃,引发剂浓度为3.7 mmol/L。对应的CMS溶胀度及平均粒径的预测值分别为246%和16.5μm。经实验证明:应用响应曲面法所得到的CMS合成工艺参数是可行的。     

Optimization of biodiesel production from trap grease via acid catalysis

As a kind of waste collected from restaurants, trap grease is a chemically challenging feedstock for biodiesel production for its high free fatty acid (FFA) content. A central composite design was used to evaluate the effect of methanol quantity, acid concentration and reaction time on the synthesis of biodiesel from the trap grease with 50% free fatty acid, while the reaction temperature was selected at 95 °C. Using response surface methodology, a quadratic polynomial equation was obtained for ester content by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. To achieve the highest ester content of crude biodiesel (89.67%), the critical values of the three variables were 35.00 (methanol-to-oil molar ratio), 11.27 wt% (catalyst concentration based on trap grease) and 4.59 h (reaction time). The crude biodiesel could be purified by a second distillation to meet the requirement of biodiesel specification of Korea.     

Enhancing Biodegradability of Textile Wastewater by Ozonation Processes: Optimization with Response Surface Methodology

ABSTRACT

In this study, an ozonation process was used to increase biodegradability of textile wastewater by considering chemical oxygen demand (COD) and color removal. Response surface methodology was applied in order to determine the significance of independent variables which are initial pH, reaction time and ozone dose. While a biological oxygen demand (BOD)/COD rate of 0.315 was obtained at optimum conditions, which are pH 9, 75 min of reaction time and 26 mg/L ozone dose, color and COD removal was obtained at 74% and 39%, respectively. BOD/COD ratio value increased from 0.18 to 0.32 by ozonation process. In addition, k coefficient for BOD also increased from 0.21 to 0.30 d^?1.     

Separation of chalcopyrite and pyrite from a copper tailing by ammonium humate

Copper tailings constitute a large proportion of mine wastes. Some of the copper tailings can be recycled to recover valuable minerals. In this paper, a copper tailing was studied through the chemical analysis method, X-ray diffraction and scanning electron microscope-energy dispersive spectrum. It turned out that chalcopyrite (Cu) and pyrite (S) were the main recoverable minerals in the tailing. In order to separate chalcopyrite from pyrite in low pulp pH, ammonium humate (AH) was singled out as the effective regulator. The depression mechanism of AH on the flotation of pyrite was proved by FTIR spectrum and XPS spectrum, demonstrating that there was a chemical adsorption between AH and pyrite. By Response Surface Methodology (RSM), the interaction between AH, pulp pH and iso-butyl ethionine (Z200) was discussed. It was illustrated that the optimal dosage of AH was 1678 g·t^-1 involving both the recovery of Cu and S. The point prediction by RSM and the closed-circuit flotation displayed that the qualified Cu concentrate and S concentrate could be obtained from the copper tailing. The study indicated that AH was a promising pyrite depressor in the low pulp pH from copper tailings.     

星点设计-效应面法优化盐酸川芎嗪眼用温度敏感型原位凝胶的处方

探讨星点设计-效应面法优化盐酸川芎嗪眼用温度敏感型原位凝胶的处方。采用泊洛沙姆407和泊洛沙姆188为温敏材料,以模拟泪液稀释前后的溶液-凝胶相转变温度为考察指标,采用星点设计-效应面法对处方进行优化并进行验证。经过优化的处方组成为22.5%泊洛沙姆407和5%泊洛沙姆188;优化处方制备的凝胶在26.9℃为自由流动的液体,经模拟泪液稀释后在32.5℃转变为凝胶。星点设计-效应面法适用于盐酸川芎嗪眼用温度敏感型原位凝胶的处方优化,所建立的模型预测性良好,该眼用温敏凝胶符合眼部应用要求。     

A virtual prototyping environment for a robust design of an injection moulding process

This paper proposes a new approach that enables a robust optimisation of the injection moulding process, based on the integration of numerical simulations, Response Surface Methodology and stochastic simulations in a type of integrated environment known as a virtual prototyping environment (VPE). The principal aim of the proposed approach is to include in the numerical setup of injection moulding the effects of fluctuations of process parameters.To clarify the proposed methodology, the paper details its application to the injection moulding process for the production of an engine cover. The moulded part presents some critical tolerances on different dimensions because of sealing and assembly requirements and the application of the VPE makes it possible to perform a robust setup taking into account the process fluctuations. The numerical prediction was confirmed by real production measurements on small pre-production runs performed adopting the moulding window explored in the virtual setup.     

Optimization of Ultrasonic Enhanced Salt‐Containing Hydrodistillation by Response Surface Methodology

An ultrasonic enhanced salt‐containing hydrodistillation (UESHD) method for separating essential oil from lavender (Lavandula angustifolia) flowers was investigated using response surface methodology (RSM). The experimental data obtained from a 27‐run experiment were fitted to a second‐order polynomial equation. The optimal conditions were determined by the 3D response surface and the contour plots derived from the models. The efficiency of UESHD and conventional hydrodistillation (HD) was compared. The extraction yield of UESHD was two‐fold higher than that of HD. In addition, GC‐MS results indicated some differences in composition and content between the two essential oils from UESHD and HD.     

二次正交旋转组合设计优化猪源罗伊乳杆菌冷冻干燥保护剂

目的优化猪源罗伊乳杆菌冷冻干燥的保护剂配方,提高冻干后的菌体存活率。方法应用SASV8.0统计分析软件中的二次正交旋转组合设计方案,进行冷冻干燥保护剂组分配比优化的试验设计,并通过响应面法分析各因素对响应值的效应关系。应用优化的冻干保护剂配方进行3次重复冻干试验,验证预测结果的准确性。结果经优化后,保护剂各组分最佳配比为:蔗糖15%,甘油3%,山梨醇15%,脱脂乳15%。应用优化保护剂进行的3次重复冻干试验,菌体冻干存活率的平均值为71.6%,与预测值(73.6%)基本相符。结论应用二次正交旋转组合设计结合响应面法,优化了猪源罗伊乳杆菌的冷冻干燥保护剂组分。     

Development of a Coconut- and Palm-Based Fat Blend for a Cookie Filler

Thirteen fat blends intended for cookie filler (CF) production that consist of 20–70 % palm mid-fraction (PMF), 20–70 % virgin coconut oil (VCO), and 0–10 % palm stearin (POs) were developed based on the solid fat contents (SFC) of the fat portions extracted from five commercial CF samples: A, B, C, D, and E. A mixture design was applied for fat blend optimization, and the combination that best approached the target SFC values was composed of 70 % PMF, 20 % VCO, and 10 % POs. The optimized coconut- and palm-based fat blend (O-CP) exhibited a steeper SFC profile, with 8.2 % (±0.2) SFC at 25 °C (room temperature) and 0.2 % (±0.2) SFC at 37 °C (body temperature); lower slip melting point of 34.0 °C (±0.0); and a lower iodine value (IV) of 40.25 g/100 g (±1.04). In addition, O-CP contained higher proportions of medium-chain fatty acids (MCFA) and lauric acid (C12:0) of 3.2 % (±0.18) and 9.7 % (±0.43), respectively. In terms of its thermal profile, O-CP showed no significant difference in terms of its crystallization range, 49.7 °C (±2.66) with the exception of sample C, but it exhibited a smaller melting range, 65.8 °C (±1.47), compared to the fat portions of the commercial samples. The ranges represented the span between the onset and offset temperatures of both crystallization and melting profiles as determined by differential scanning calorimetry.     

Systematic retrofit design with Response Surface Method and process integration techniques: A case study for the retrofit of a hydrocarbon fractionation plant

This paper demonstrates the Retrofit Design Approach (RDA) and Response Surface Methodology (RSM) for the retrofit of industrial plants in which assessment of design options for improving existing processes in a site-wide and integrated manner is not straightforward, due to complex design interactions in the process. The design methodology applied in this study is based on the systematic use of a process simulator which is used to identify promising variables through sensitivity analysis. Hence, the most important factors are determined and a reduced model is constructed based on RSM. An optimization framework is then built using the reduced model based on key selected variables, which is optimized to find optimal conditions and performance of the process. This design methodology provides strategic guidelines for determining the most cost-effective design options. The retrofit of a hydrocarbon fractionation plant is presented as an industrial case study. This includes a large number of design options with different process configurations and operating conditions due to the interconnection of distillation columns in sequence and the integrated heat recovery within the plant. The case study results demonstrate the applicability of the proposed approach which is able to effectively deal with a large retrofit problems. This is possible with the aid of process simulation and RSM producing a reduced model which requires considerably less computational effort to solve.     

Optimization of Solvent Extraction of Moringa (Moringa Oleifera) Seed Kernel Oil Using Response Surface Methodology

Extraction of seed kernel oil from moringa (Moringa oleifera) was investigated with hexane, petroleum ether and acetone as the first extraction medium at various kernel particle size, extraction temperature and residence time, which were called as independent variables. Central composite rotatable design (CCRD) of experiments was used to study the effect of solvent type, particle size, extraction temperature and residence time of solvent on the oil yield, which was called as dependent variable. The maximum oil yield of 33.1% for hexane, 31.8% for petroleum ether and 31.1% for acetone was obtained. Among the three solvents, hexane yielded the maximum oil from moringa seed kernels. Among three process parameters studied, particle size had the most significant effect on the oil yield followed by extraction temperature and time for all the solvents. Response surface methodology technique was used to optimize the independent variables for maximum oil extraction. From the optimized values of particle size (0.62 mm), extraction temperature (56.5°C) and residence time (7 h), maximum oil yield obtained was 33.5%, using hexane. Optimized values of independent variables for maximum yield were varied for other two solvents. This protocol provides improved opportunities for the medicinal use of moringa oil in addition to its popularity as a vegetable in south Asia.     

Optimization of Nannochloropsis oculata growth using the response surface method

Optimization of Nannochloropsis oculata growth was undertaken using the response surface method. A central composite design was defined to study the effects of temperature, pH, incident light intensity and aeration rate on the maximum growth rate of the microalga. Using statistical analysis, the first model calculated to fit results was twice improved. The final model obtained was used to clarify the effects of each factor and their interactions on the growth of Nannochloropsis oculata. The optimum growth conditions of this microorganism were also estimated as 21 °C, 52 µmol photons m^?2 s^?1, pH 8.4 and 14.7 VVH of aeration rate. These conditions were tested and validated experimentally since the maximum growth rate achieved with these parameters, 0.0359 h^?1, is the best reported in this study. Copyright © 2006 Society of Chemical Industry     

Effect of interaction of operation parameters on elutriation behavior in a vortexing fluidized bed

A systematic investigation on elutriation behavior conducted in a vortexing fluidized bed (VFB) cold model is studied. The effects of various parameters on the elutriation are investigated from the data obtained by using ‘response surface methodology’ (RSM) to determine the relationship between elutriation rate and operating conditions. The results show that all the interactions among primary air flow rate, secondary air flow rate, fine particle size, secondary air inlet diameter, and imaginary circle diameter had significant influences on elutriation behavior in the VFB. The modified regression models of the ‘specific elutriation rate constant’ (K*) were also submitted in this study.     

Optimization of transesterification of castor oil with ethanol using a central composite rotatable design (CCRD)

In the present study, the synthesis of fatty acid esters from castor oil using an alkaline catalyst was optimized. The variables reaction time, catalyst amount and oil:ethanol molar ratio were studied using a central composite rotatable design. The effects and significance of the models on the response variable and on ethyl biodiesel yield derived from pure castor oil were evaluated using a response surface curve and analysis of variance. All the variables significantly affected the reaction yield, the amount of catalyst being the most effective. The highest yield was obtained using an oil:ethanol molar ratio of 1:11, 1.75% KOH and a reaction time of 90 min.     

Optimization of a continuous ultrasound assisted oxidative desulfurization (UAOD) process of diesel using response surface methodology (RSM) considering operating cost

A continuous-flow ultrasound-assisted oxidative desulfurization(UAOD) of partially hydro-treated diesel has been investigated using hydrogen peroxide-formic acid as simple and easy to apply oxidation system. The effects of different operating parameters of oxidation stage including residence time(2–24 min), formic acid to sulfur molar ratio(10–150), and oxidant to sulfur molar ratio(5–35) on the sulfur removal have been studied using response surface methodology(RSM) based on Box–Behnken design. Considering the operating costs of the continuous-flow oxidation stage including chemical and electrical energy consumption, the appropriate values of operating parameters were selected as follows: residence time of 16 min, the formic acid to sulfur molar ratio of 54.47, and the oxidant to sulfur molar ratio of 8.24. In these conditions, the sulfur removal and the volume ratio of the hydrocarbon phase to the aqueous phase were 86.90% and 4.34, respectively. By drastic reduction in the chemical consumption in the oxidation stage, the volume ratio of the hydrocarbon phase to the aqueous phase was increased up to 10. Therefore, the formic acid to sulfur molar ratio and the oxidant to sulfur molar ratio were obtained 23.64 and 3.58, respectively, which lead to sulfur removal of 84.38% with considerable improvements on the operating cost of oxidation stage in comparison with the previous works.     

产L-乳酸的鼠李糖乳杆菌发酵培养基的优化

采用Plackett-Burman试验设计优化了鼠李糖乳杆菌产L-乳酸的发酵培养基,筛选出对L-乳酸产量有显著性影响的因素,即葡萄糖、柠檬酸氢二铵、乙酸钠、酵母膏,对这四个显著性因素,用中心组合试验优化得到最佳发酵培养基。结果表明:当培养基组成为:葡萄糖138.8 g/L、柠檬酸氢二铵2.19 g/L、乙酸钠6 g/L、酵母膏为7.56 g/L、蛋白胨0.50 g/L时,L-乳酸的产量为104.40 g/L。     

固体推进剂配方优化设计方法及其软件系统

概述了固体推进剂配方优化设计的进展及常用的优化方法,重点介绍了模式搜索法和遗传算法优化原理,通过一些典型实例介绍了具体优化计算方法。该优化方法和优化设计软件包(SPOD)可用于火炸药、化学及高分子材料配方优化设计中。附参考文献41篇。     

Optimization of silver cementation yield in fixed bed reactor using factorial design and central composite design

This work deals with cementation of silver onto iron grid in fixed bed reactor. The influence of several parameters is studied namely: initial concentration of silver [Ag⁺]₀, flow rate, solution pH, and mass of iron. Moreover, their influence on the yield of the reaction of cementation is investigated statistically by the experimental design in view of industrial application. The estimation and the comparison of the parameter's effects are realised by using two‐level factorial design. The analysis of these effects permits to state that the most influential factor is the mass of iron with an effect of (+5.642), the second in the order is the initial concentration of silver ions (Ag⁺) with an effect of (+4.005), the third is the flow rate of the electrolytic solution with an effect of (+3.824). A central composite design methodology is employed to determine the optimum conditions for a silver cementation yield onto iron grid. For this end, the experimental results were approximated by a second‐order model as well as the surface contour plots and surface responses are drowned. The optimal conditions found for initial silver concentration, such as a flow rate, pH of the solution and mass of iron, are respectively: 21.25 mg/L, 4.43 L/min, 3.6 and 50 g. Under these conditions, the obtained silver cementation yield is 96.851%.     

中心复合实验优化竹黄半纤维素水解的工艺研究

以戊糖收率和水解底物失重率为评价指标,采用中心复合实验设计法对酸性亚硫酸氢钠(ASB)预水解竹黄制备戊糖工艺进行了优化.研究结果表明,各因素对戊糖收率的影响显著性顺序为硫酸质量浓度(X3)＞亚硫酸氢钠质量浓度(X4)＞反应时间(X2)＞反应温度(X1);对水解底物失重率的影响显著性顺序为反应温度(X1)＞硫酸质量浓度(X3)＞反应时间(X2)＞亚硫酸氢钠质量浓度(X4).当固液比(W/V)为1∶5时,ASB预水解最佳工艺条件为:水解温度为171.1℃,水解时间为37 min,硫酸质量浓度为13.92 g/L,亚硫酸氢钠质量浓度为13.84 g/L,在此条件下得到的戊糖收率为83.93％,底物失重率为29.36％.通过验证实验表明,该设计模型具有良好预测性.