玉米粉吸附乙醇蒸气中的水

玉米粉能从乙醇蒸气中选择性地吸附水分,得到无水乙醇,并可在90～120℃的空气中再生,反覆循环使用,性能稳定。吸附穿透时间和床层高度关系符合Bohart Adams公式。     

乙醇-水体系分离提纯过程新技术的研究

首先拟合了Aspen Plus中乙醇-水的二元交互参数,使其计算结果更符合实际。其次通过分析乙醇-水精馏二塔(C31103)与新型吸附系统工艺流程,计算了C31103与吸附系统的主要能耗,得到了二者关于C31103塔顶采出中乙醇质量分数x_D的关系式。并计算得到淡酒量和塔顶采出量关于x_D的关系式。运用Aspen Plus软件对C31103进行稳态优化,计算出x_D在0.945～0.88之间时的能耗与x_D的关系,确定最适宜x_D为0.9～0.92,并通过模拟得到各x_D下的淡酒量和塔顶采出量等结果,比较淡酒量的计算结果和模拟结果,得到相对误差小于4%,证实了能耗模型的准确性。     

苯-水混合蒸气在活性炭上的二元吸附平衡

Adsorption equilibrium isotherms of benzene in the concentration range of 500-4000 mg·@m-3 on two commercial activated carbons were obtained using long-column method under 30℃ and different humidity conditions. Results show that the benzene and water vapors have depression effects upon the adsorption of each other and that the unfavorable effect of water vapor resembles its single-component isotherm on activated carbon. A competitive adsorption model was proposed to explore the depression mechanisms of the non-ideal, non-similar binary adsorption systems. A modified Polanyi-Dubinin equation was set up to correlate the binary adsorption equilibrium and to calculate the isotherms of benzene on activated carbon in presence of water vapor with considerable precision.     

1,3-丙二醇与水、乙醇二元混合体系超额体积

测定了常压下1,3-丙二醇-水和1,3-丙二醇-乙醇两个二元混合体系纯组分及混合液在328.15～348.15 K温度内全浓度范围的密度,计算了体系的超额摩尔体积等性质。两个二元混合体系的超额摩尔体积在所测定的温度和全浓度范围内均呈负偏差。体积数据说明1,3-丙二醇-水、乙醇混合体系中不同分子间的交叉缔合强于同分子间的自缔合,同时组分间分子大小的不对称产生填充效应。     

渗透汽化膜分离乙醇水混合物

以自制的壳聚糖／聚丙烯腈透水复合膜，对乙醇水实行渗透汽化分离，分离因子可达１４０～２５００，含水８．９％～３４．６％（质）的溶液，透过液中含水高达９３％～９９．８％（质），渗透总通量为０．１５～１．２５ｋｇ／ｍ￣２·ｈ。     

乙醇-水体系在马铃薯粉吸附剂上的气相吸附过程研究

利用固定床吸附柱(φ25 mm×900 mm)对乙醇-水体系在马铃薯粉吸附剂中的气相吸附过程进行了研究,研究了不同条件下乙醇-水体系在马铃薯粉中吸附的透过曲线。结果表明,在本试验条件下,生产能力和透过时间随温度降低、粒径变小、进料流量降低和床层高度增加而增大。在乙醇-水体系进料流量为3 mL/min左右、床层温度80℃、吸附剂粒径245～350μm、床层高度700 mm和进料乙醇体积分数94.5%条件下,每1 000 g马铃薯粉吸附剂可脱水得到无水乙醇205.1 g。马铃薯粉吸附性能良好,再生容易,具备作为生物质吸附剂制备无水乙醇的潜力。     

乙醇-水体系双效精馏过程模拟

利用ASPEN-PLUS模拟乙醇.水体系分离过程,考察并流型、平流型,逆流型三种双效精馏流程.在相同的设计基础和要求下,从设备投资和节能效果两方面对三种双效精馏流程和单塔流程进行比较.结果显示,并流型双效精馏流程更具优势.     

丙烷-乙醇-水体系相平衡研究

提出了改进的DDLC-MH(81)状态方程,用于丙烷-乙醇-水体系二元汽液平衡数据的关联计算,其模型参数与温度有良好的线性关系.并用汽相循环法测定了该体系在不同温度下的二元及三元VLE数据,结果与模型的推算值取得良好的一致.并用模型预测了超临界丙烷条件下的三元相平衡数据.结果表明,在液相乙醇浓度高于0.2的情况下,超临界丙烷比超临界二氧化碳有更高的乙醇溶解度和选择性.     

Aspen模拟乙醇-水体系的共沸精馏

针对某化工厂生产的质量分数为15％乙醇水溶液的提纯,提出共沸精馏的方法进行脱水处理.利用Aspen模拟工艺流程,首先对该股物料进行普通蒸馏处理,得到质量分数为95％的乙醇-水共沸物.然后,以苯为共沸剂,优化工艺参数,塔底得到质量分数为99.67％的无水乙醇,塔顶得到乙醇-苯-水共沸物.塔顶物料静置后分层,上层苯液可经过...     

Binary Adsorption Isotherms of Water and Ethyl Acetate Vapor for Materials Contained in a Box of a Tobacco Product

ABSTRACT

An experimental study has been carried out on the characteristics of binary adsorption isotherms of water and volatile flavor for typical materials used in a box of a tobacco product or cigarettes. Ethyl acetate chosen as a model for water–soluble volatile flavor. Binary adsorption isotherms for the tobacco, papers, filters, and activated carbons were measured with a flow–type multi–component adsorption system under the canstant conditions of temperature a t 303 K and vapor pressure of water a t 2.5 kPain the vapor pressure range of ethyl acetate from 0 to 4.2 kPa. A linear equation was applied to express the binary adsorption isotherms for the tobacco, papers and filters, while a Dubinin–Astakhov equation was applied for the activated carbons. The binary adsorption was characterized into three groups, depending on the selectivity as well as the mechanism of adsorption; i.e.(l) for tobacco and papers, water was adsorbed much greater rather than ethyl acetate, (2) for filters, ethyl acetate was adsorbed on the surface as great as water, (3) for activated carbons, ethyl acetate was adsorbed much greater onto their micropores rather than water. The results showed that ethyl     

由吸附等温线分析膨润土的分形孔隙

膨润土是一种多孔的粘土材料，对气相和液相中的污染物均有很好的净化效果。为了了解其对气体的吸附性能，用氮气吸附等温线分析了2种膨润土和1种活性白土的BET比表面积和孔隙分布，并应用基于FHH模型的方法计算了它们的分形维数。结果表明，普通膨润土的分形维数接近2，而活性白土的达到了2．59。讨论了孔隙度、比表面积以及分形维数等参数与吸附量的关系，表明分形维数更能反映膨润土对气体的吸附性能。     

Binary Adsorption in a Fixed-Bed Column Packed with an Ion-Exchange Resin

Abstract

A mathematical model was adopted to analyze a binary fixed-bed adsorption column packed with an ion-exchange resin. Two pairs of organic compounds, o-cresol-benzoic acid and p-chlorophenol-p-nitrophenol, were employed as the adsorbates. A modified Langmuir isotherm with interaction factors η _i was found suitable for representing the adsorption equilibrium. Scale-up of the binary adsorption column with respect to column length was effective based on the proposed mathematical model and corresponding methods for estimating the model parameters. The significance of excess concentration in the breakthrough curve was related to inlet concentration, column length, and the difference in adsorption affinity.     

聚醚型螯合树脂的合成及其等温吸附性能

通过接枝反应制备了一系列以聚环氧氯丙烷为主链,侧链末端含吡咯配位基的HPnCP(n=6,4,2)螯合树脂,各步产物的化学结构经IR和1H NMR检测得以确认。静态吸附实验及等温吸附实验结果表明:该类树脂对Cu(Ⅱ)和Hg(Ⅱ)有着较好的吸附性能(大于1.0mmol/g);对Co(Ⅱ)和Cd(Ⅱ)达到饱和吸附时的平衡浓度约为0.06～0.07mol/l;HP_4CP对Co(Ⅱ)和Cd(Ⅱ)以及HP_2CP对Co(Ⅱ)的等温吸附既可用Langmuir方程描述也可用Freundlich方程描述;但HP_2CP对Cd(Ⅱ)的等温吸附不符合Langmuir方程,只可用Freundlich方程描述。     

气体吸附等温线回归准确性分析

针对由吸附等温线模型回归气体吸附平衡数据的准确性进行了研究,从实验误差和表面覆盖率两个因素出发,主要考查了它们对回归Langmuir、DR方程两种等温线模型中各参数的影响,并对回归参数的可靠性作了分析。实验误差和表面覆盖率对各模型参数回归的准确性均有影响。对于Langmuir和DR方程,提高测试的表面覆盖率可以更可靠地计算出饱和吸附量以及模型中的其它参数。另外,仅通过减小实验误差来保证模型中所有参数的准确性是不可取的。     

乙醇脱水的木薯粉吸附性能研究

使用恒温固定吸附床对乙醇蒸汽脱水的术薯粉吸附剂的气相选择吸附性能进行研究。乙醇原料液的浓度为75％～95％（质量百分数）,使用干燥过的木薯粉作为吸4;什剂,分别测得吸附床不同位置处、不同表观速率、不同吸附剂粒度和不同温度时的乙醇蒸汽的透过曲线并进行了分析。通过木薯粉吸附最终可获得99．7％（质量百分数）的无水乙醇。     

不同预处理方法对玉米蛋白水解的影响

在没有外加碱的pH值渐变条件下,考察了添加乙醇、添加亚硫酸盐、特殊热处理三种方法对玉米蛋白水解度的影响。并在此基础上通过正交试验进一步优化出水解玉米蛋白的最佳条件：水解温度为60℃,酸性蛋白酶加入量为10%（g/g）,底物浓度为80 g/L,水解时间为8 h。在上述最佳条件下,玉米蛋白的降解率可达36.70%,蛋白质的水解度可达19.85%,水解产物的平均分子量达到1918。结果表明,采用特殊的热处理方法能够显著提高玉米蛋白降解率以及蛋白质水解度。     

Prediction of Gas‐Phase Adsorption Isotherms Using Neural Nets

This study investigated a number of models (the modified Sips', Dubinin‐Astakhov's, VSM theory, the generalized Khan et al.'s model and a simple artificial neural network (ANN)) to predict the effect of temperature on equilibrium adsorption of hydrocarbon gases and vapors on activated carbon. Published data on the adsorption of methane, ethane and propane on activated carbon at 311 K to 505 K were used to estimate the parameters of the conventional models and train the network. Then, the conventional models and the ANN were used to predict the isotherm at a single temperature for each adsorbate, and these results were compared with experimental data. It was found that the ANN model had a lower mean relative error than the conventional models.     

水蒸气等温吸附表征水泥基材料孔隙结构

采用水胶比0.45的净浆、砂浆和混凝土材料,以水蒸气等温吸附法和压汞法为试验方法,以GAB吸附模型为数据分析手段,通过等温吸附曲线、脱附曲线、滞回曲线和孔隙分布,研究使用水蒸气等温吸附法表征水泥基材料的孔隙结构。研究结果表明:骨料对水泥基材料的水蒸气等温吸附曲线几乎没有影响;水泥基材料吸附/脱附滞回曲线出现在整个湿度区域,并在湿度为80%达到最大值;考虑表面吸附层能够提高水蒸气等温吸附计算的孔隙分布精度;水蒸气等温吸附法得到的孔隙率和比表面积与压汞法得到的数值具有正相关性;微孔(r<3nm)中能量不稳定和显孔(r>3nm)中墨水瓶效应是水蒸气等温吸附过程滞回现象的主要原因。     

用FA和ECM方法测定吸附等温线的比较

Adsorption isotherm is the most fundamental information related to chromatography.To calculate the parameters of Langmuir adsorption isotherm of thymidine,fronal analysis(FA)and lution-curve method(ECM)were adopted in reversed-phase high performance liguid chromatography(RP-HPLC).In FA,tha concentration of stationary phase was measured from the elution curves and the isotherm was determined by regression analysis,while the parameters by ECM were obtained by parameter optimization.The adsorption isotherms of thymidine from the two methods were very similar.The superiority of ECM over FA was that the consumption of sample was less and only one or two in jections of sample were required.