共查询到20条相似文献，搜索用时 15 毫秒
1.
Removal of chromium (VI) dissolved in water by intermittent foam separation was implemented with cetyl trimethy-ammonium bromide
as surfactant. The influence of various factors on removal efficiency was systematically studied. The removal efficiency has
a maximum value near pH 4.0; thus, most experiments were carried out at pH 4.0. The orthogonal experiment was conducted to
confirm the optimal operating parameters. The orthogonal experimental results show that when the liquid feed concentration
is 10 mg/L, the pH value of feed solution is 4.00, air flow rates 0.9 L/min, surfactant dosage is 300 mg/L, the maximum removal
efficiency of chromium (VI) reaches 97.80%, and condense multiple reaches 1 711. The kinetic test indicates that the foam
separation of chromium is a first-order process. The equivalent rate constant calculated from the slope is 0.406 4, and the
equivalent rate equation is obtained. 相似文献
2.
Chromatograms of tocopherol homologues were obtained by a column of analytical size （inner diameter （ID） 0.46 cm cm×10 cm） packed with silica gel. Adsorption isotherms and film mass-transfer coefficient were estimated from the chromatograms by using a general rate model, which considers axial dispersion, external mass-transfer and intraparticle diffusion. Based on the obtained isotherms and mass-transfer coefficient, the separation process of tocopherol homologues on simulated moving bed （SMB） was simulated using the same model. According to the simulated results, a mixture of α-, γ-, δ-tocopherols and other impurities was separated on an SMB equipment. The SMB equipment was composed of 8 columns of ID 2 cm× 1 0 cm, with 2 columns in each section. The solid phase was silica gel, and the mobile phase was n-hexane/2-propanol （99/1 by volume）. γ- and δ-tocopherols of purity greater than 98% were obtained with recovery greater than 98%. The effects of operating conditions （flow rates and switching time） on the performance of SMB were studied by both simulation and experiments. It was found that all the simulation results were quite close to the experimental results. We conclude that process development and optimization of operating conditions of SMB by simulation are feasible. 相似文献
3.
DMF与CHCl_3混合液精馏分离工艺的研究 总被引：1，自引：0，他引：1
采用模拟的二甲基甲酰胺(DMF)与三氯甲烷(CHCl3)混合液(DMF质量分数为47%),通过精馏塔进行分离。当进料量为2L·h-1时,得出最佳的操作条件如下:进料状态为泡点进料,加料位置为第七块塔板进料,回流比为4。最终结果为:理论塔板数为4.5块,塔板效率为37.5%,塔顶产品DMF质量分数低于0.01%,塔底产品DMF质量分数达到96.03%。该新方法与传统的直接精馏法相比既能减少精馏能耗,又能回收利用DMF,还可使萃取剂CHCl3重复使用,对环境友好不造成污染。 相似文献
4.
Removal of chromium (Ⅵ) dissolved in water by intermittent foam separation was implemented with cetyl trimethy-ammonium bromide as surfactant. The influence of various factors on removal efficiency was systematically studied. The removal efficiency has a maximum value near pH 4.0; thus, most experiments were carried out at pH 4.0. The orthogonal experiment was conducted to confirm the optimal operating parameters. The orthogonal experimental results show that when the liquid feed concentration is 10 mg/L, the pH value of feed solution is 4.00, air flow rates 0.9 L/min, surfactant dosage is 300 mg/L, the maximum removal efficiency of chromium (Ⅵ) reaches 97.80%, and condense multiple reaches 1711. The kinetic test indicates that the foam separation of chromium is a first-order process. The equivalent rate constant calculated from the slope is 0.406 4, and the equivalent rate equation is obtained. 相似文献
5.
庆大霉素发酵液的分离提取 总被引：1，自引：0，他引：1
建立从发酵液中提取庆大霉素的方法,获得具有一定纯度的庆大霉素分析样品。采用732阳离子交换树脂,利用离子交换法从发酵液中提取庆大霉素,探讨不同条件对庆大霉素收率的影响。确定最优的提取条件为:发酵液pH2～3,吸附时间2 h,解吸剂浓度5%,解吸剂流速0.4 mL/min。经HPLC测定,发酵液通过离子交换法分离提取后,庆大霉素纯度由50.7%提高到92.5%。离子交换法适用于庆大霉素发酵液的分离提取,提取液纯度达到药物分析的要求。 相似文献
6.
The desalination of brackishor sea wateris widelyap-plied to the water supply in China and around theworld[1—4]. The common desalination methods , such asmultistage flesh, multi-effect distillation and reverse osmo-sis, usually require high initial costs and skill oper-ation[5 ,6]. For this reason,these desalination techniquesare mostlyreliable for large capacity of fresh water produc-tion but not economical in the water-shortage areas wherewater demand is decentralized or proper infrastructu… 相似文献
7.
选用１日龄樱桃谷肉鸭３００只,随机分成三组,每组１００只;对照组（ＣＫ）仅喂基础日粮（玉米－豆饼－麦麸型）,试验Ⅰ（ＤＥ１）和Ⅱ（ＤＥ２）组分别添加０．１％以β葡聚糖酶、木聚糖酶、蛋白酶与果胶酶为主的酶制剂Ⅰ和以淀粉酶、木聚糖酶与蛋白酶为主的酶制剂Ⅱ,进行４７天的饲养对比试验。结果显示,与未加酶ＣＫ组相比,ＤＥ１和ＤＥ２组肉鸭日增重分别提高５．５７％（Ｐ＜０．０５）和４．５９％（Ｐ＜０．０５）,料重比分别下降６．９７％（Ｐ＜０．０５）和４．８３％（Ｐ＜０．０５）,两组稀粪率也均下降显著,各组死亡率未见明显差异;表明酶制剂Ⅰ为最适酶配方组。 相似文献
8.
9.
对单级和多级ＣＡＲＥ过程分别进行了最优化分析．单级过程的优化目标函数（Ｆ１）为ＲＥＣ和ＰＦ的积，而多级过程则将获得一定纯度的目标组分情况下的回收率和ＣＡＲＥ级数之比为优化目标函数Ｆ２．结果表明，当膜对目标和杂质组分的截留率相等时，在一定的洗脱液流速ｒｅ范围内，对于每一个ｒｅ均存在一对应的循环流速ｒｅ，使Ｆ１和Ｆ２最大，并且最大值相等；当ｒｅ一定时，最佳ｒｒ随膜的截留率和亲和载体对目标组分的结合分率的增大而降低．对于多级过程，当膜对杂质的截留小于对目标组分的截留时，只存在一组最佳的操作条件（即ｒｅ和ｒｒ）． 相似文献
10.
A continuous-time nonlinear model predictive controller （NMPC） was designed for a boiler-turbine unit. The controller was designed by optimizing a receding-horizon performance index, with the nonlinear system approximated by its Taylor series expansion with a certain order, the magnitude saturation constraints on the inputs satisfied by increasing the predictive time, and the rate saturation conditions on the actuators satisfied by tuning the time constant of the reference trajectories in a reference governor. Simulation results showed that the controller can drive the drum pressure and output power of the nonlinear boiler-turbine unit to follow their respective reference trajectories throughout a varying operation range and keep the water level deviation within tolerances. Comparison of the NMPC scheme with the generic model control （GMC） scheme indicated that the responses are slower and there are more oscillations in the responses of the water level, fuel flow input and feed water flow input in the GMC scheme when the boiler-turbine unit is operating over a wide range. 相似文献
11.
Wang Zhanyuan 《大连大学学报》1992,(1)
用拟均相一维和二维模型对乙苯脱氢制苯乙烯绝热固定床催化反应器进行数学模拟,模拟计算结果同生产实测数据甚为接近。这一反应的热效应(140KJ/mol)不大,一维和二维模型的计算结果也甚为接近。在一定操作条件下:进料比(水/2苯)为2.5;进料温度为630℃;应器压力,一段为1.7Qtm,二段为1.5Qtm;乙苯的转化率在一段反应器可达到41%(mol),二段反应器可达到63%(mol)。 相似文献
12.
Jun Li Nan Gao Guang-yi Cao Heng-yong Tu Ming-ruo Hu Xin-jian Zhu Jian Li 《浙江大学学报(A卷英文版)》2010,11(1):61-70
In this paper, an application of a nonlinear predictive controller based on a self recurrent wavelet network （SRWN） model for a direct internal reforming solid oxide fuel cell （DIR-SOFC） is presented. As operating temperature and fuel utilization are two important parameters, the SOFC is identified using an SRWN with inlet fuel flow rate, inlet air flow rate and current as inputs, and temperature and fuel utilization as outputs. To improve the operating performance of the DIR-SOFC and guarantee proper operating conditions, the nonlinear predictive control is implemented using the off-line trained and on-line modified SRWN model, to manipulate the inlet flow rates to keep the temperature and the fuel utilization at desired levels. Simulation results show satisfactory predictive accuracy of the SRWN model, and demonstrate the excellence of the SRWN-based predictive controller for the DIR-SOFC. 相似文献
13.
山苍子油多段连续减压精馏提取柠檬醛工艺 总被引：1，自引：0，他引：1
研究多段连续减压精馏山苍子油提取柠檬醛的生产工艺,通过正交实验分析不同操作条件（回流比、塔顶温度和塔釜温度）下所得柠檬醛产品的浓度与得率,得出了该实验流程精馏塔系统的塔顶温度和回流比的控制对产品纯度有显著影响.维持较高的系统绝压为666.612～2 666.447Pa时,阻聚剂和抗氧化剂的添加量最少应达0.3%,可获得该实验系统提取柠檬醛的较佳工艺条件.基于该文原料油生产的柠檬醛纯度最高达95%,得率65%. 相似文献
14.
用于乙醇-水分离的SA-PVA/PSF中空纤维渗透汽化复合膜 总被引：1，自引：1，他引：0
Using polysulfone (PSF) hollow fiber ultrafiltration membranes as the substrate, sodium alginate (SA) and polyvinyl alcohol (PVA) blend solutions as the coating solution, and maleic anhydride (MAC) as the cross-linked agent, SAPVA/PSF hollow fiber composite membranes were prepared for the dehydration of ethanol-water. The effects of different sodium alginate concentration in the coating solutions and different operating temperatures on pervaporation performance were investigated. The experimental results showed that pervaporation performance of the SA-PVA/PSF composite membranes for ethanol-water solution exhibited a high separation factor although they had a relatively low permeation flux. As SA concentration in SA-PVA coating solution was 66.7% and the operating temperature was 40 ℃, SA-PVA/PSF hollow fiber composite membrane (PS4) had a separation factor of 886 and flux of 12.6 g/(m2·h). Besides, SA-PVA/PSF hollow fiber composite membranes (PS3 and PS4) were used for the investigation of the effect of ethanol concentration in the feed solution on pervaporation performance. 相似文献
15.
Lei Li Nai-yun Gao Yang Deng Juan-juan Yao Ke-jia Zhang Hai-jun Li Di-di Yin Hua-se Ou Jian-wei Guo 《浙江大学学报(A卷英文版)》2009,10(11):1660-1669
The degradation of Microcystin-LR （MC-LR） in water by hydrogen peroxide assisted ultraviolet （UV/H2O2） process was investigated in this paper. The UV/H2O2 process appeared to be effective in removal of the MC-LR. MC-LR decomposition was primarily ascribed to production of strong and nonselective oxidant-hydroxyl radicals within the system. The intensity of UV radiation, initial concentration of MC-LR, MC-LR purity, dosages of H2O2, the initial solution pH, and anions present in water, to some extent, influenced the degradation rate of MC-LR. A modified pseudo-first-order kinetic model was developed to predict the removal efficiency under different experimental conditions. 相似文献
16.
Azeotropic liquid mixture cannot be separated by conventional distillation. But extractive distillation or combination of the two can be valid for them. An experiment to separate benzene and cyclohexane by batch extractive distillation was carried out with N,N-dimethylformide (DMF), dimethyl sulfoxide (DMSO) and their mixture as extractive solvent. The effect of the operation parameters such as solvent flow rate and reflux ratio on the separation was studied under the same operating conditions. The results show that the separation effect was improved with the increase of solvent flow rate and the reflux ratio; all the three extractive solvents can separate benzene and cyclohexane, with DMF being the most efficient one, the mixture the second, and DMSO the least. In the experiment the best operation conditions are with DMF as extractive solvent, the solvent flow rate being 12.33 mL/min, and the reflux ratio being 6. As a result, we can get cyclohexane from the top of tower with the average product content being 86.98%, and its recovering ratio being 83.10%. 相似文献
17.
LIU Zuohu LIU Renlong DU Jun TAO Changyuan LI Xiaohong College of Chemistry & Chemical Engineering Chongqing University Chongqing P. R. China College of Resources & Environmental Science Chongqing University Chongqing P. R. Chin 《重庆大学学报(英文版)》2004,3(1):61-64
1.IntroductionPhenolisanimportantchemicalindustrymaterial,butitalsoaboundswithserioushazardtoenvironmentandthreatstohumanhealth.Rigidruleshavebeenmadeoutonthephenoldischargeconcentration.Researchesonthetreatmentofphenolwastewaterwerecarriedoutinvariouscountries[1-5].Membraneseparationmethodsincludingreverseosmosis,ultrafiltrationandpervaporationhaveattractedmuchattentionforphenolwastewatertreatment,withcelluloseacetate(CA)membraneemployedmostly[6].Membranedistillationisanewmembraneseparation… 相似文献
18.
研究了利用乙酰乙酸甲酯、氨基甲酸铵制备3-丁烯酸甲酯的方法,反应收率95.43%,但投料比、蒸馏方式、原料均对反应的收率和纯度有影响.反应的后续蒸馏不仅可以回收溶剂,同时可以回收反应体系中的副产物碳酸氢铵.此方法反应时间短,无污染,分离简便,产品收率高、纯度好. 相似文献
19.
连续精馏实验影响因素关系测定 总被引：1，自引：0，他引：1
采用甲醇-丙酮物系进行实验,通过改变回流比以及进料液流速这两个条件,观察分析分离效果,总结出连续精馏实验影响因素的关系以及实验室连续精馏的最佳操作条件.随回流比的增大,塔顶馏分的浓度的变化关系是先增大再降低.随进料液流速的增大,塔顶馏分的浓度变化是逐步增大,增大到一定值就基本维持平稳不变.最佳操作条件是回流比R=3,进料液流速=6ml/min.在此操作条件下甲醇丙酮的分离效果最佳. 相似文献
20.
将前人提出的连续循环亲和提取（ＣＡＲＥ）过程扩展到利用超滤膜的系统，即考虑超滤膜对料液中各组分的截留作用，建立了该过程的数学模型，对该过程的分离纯化性能──浓缩因子（ＣＦ），纯化因子（ＰＦ）和回收率（ＲＥＣ）──进行理论分析。结果表明：随膜截留率的增大，ＣＦ和ＲＥＣ增大，而ＰＦ降低；增大洗脱液和循环液的流速虽可提高回收率，但却使纯化因子降低，表明存在最佳的操作条件使该过程的分离纯化性能最好。 相似文献