Concentration of glycerol from dilute glycerol wastewater using sweeping gas membrane distillation

In this work, experimental results for the concentration of dilute glycerol wastewater using membrane distillation (MD) with a microporous hydrophobic flat-sheet PTFE membrane are reported. Experiments were performed using the sweeping gas mode of the MD (SGMD) process. The effects of various operating variables, such as feed temperature, glycerol concentration in aqueous phase, feed flow rate and sweeping gas flow rate were studied. A Taguchi analysis has been performed on the experimental results which determined the effects and contribution of each of the factors on the distillate flux and the interactions between the operating variables. Results showed that the most influential factor was feed temperature. The second significant contribution was observed for the sweeping gas flow rate. Feed concentration had a negative effect on the distillate flux. At optimum conditions (i.e. 65 °C, 400 mL/min, 1 mass%, and 0.453 Nm³/h), the Taguchi model predicted the value of the response (the distillate flux) as 20.93 L/m² h, which had good agreement with the experimental results.     

Optimization of environmental impact reduction and economic feasibility of solvent waste recovery using a new software tool

The environmental impact reduction and operating costs savings associated with the purification and recovery of solvent waste in the manufacture of active pharmaceutical ingredients (API's) were investigated. A software toolbox has been developed that combines Aspen Plus^® process simulation with SimaPro^® and Ecosolvent life cycle assessment (LCA) databases. A LCA approach was used in order to consider the environmental impact beyond pharmaceutical production plant boundaries. The feasibility of a relatively small flexible equipment-skid capable of recovering multiple solvent waste streams was evaluated. Distillation and pervaporation were considered to separate binary waste solvent mixtures. Optimum distillation reflux ratio and feed stage were determined to maximize the environmental impact reductions and operating cost savings. The optimum reflux ratio was significantly higher than 1.2 times the minimum reflux ratio suggested by traditional heuristics. The emissions and cost reductions obtained were as much as 49% and 56% higher, respectively, as compared to using the conventional optimum reflux ratio. A comprehensive cash flow analysis showed that the recovery of low volume solvent waste streams is economically feasible, despite traditional thinking. Three case studies from Pfizer are presented to show how our software tool can aid in green engineering decision making.     

乙醇脱水反应的动力学研究

在管式固定床反应器中,采用改性的分子筛催化剂,在温度195～220℃、乙醇浓度30～70 wt%、乙醇液时空速0.08～0.17 mol/g-cat./h的范围内,对乙醇脱水反应的本征动力学进行了研究。动力学研究结果表明,在实验条件范围内,乙醇脱水生成乙烯和乙醚的反应属于平行反应,符合Langmuir-Hinshelwood机理模型,表面反应为速率控制步骤。     

一种新型环保型污泥脱水絮凝剂的研制与应用

以虾蟹壳和累托石为主要原料,制备出一种新型环保型污泥脱水絮凝剂,该絮凝剂的最佳配比为m(天然有机高分子)∶m(改性累托石)=1∶6,它与传统絮凝剂聚丙烯酰胺相比,污泥脱水率提高了547%,污泥沉降时间缩短了33.33%,吨污泥单耗絮凝剂成本下降了4%,且处理过程中的二次污染大大减少.还对该絮凝剂的制备过程及絮凝机理等进行了阐述.     

复合处理剂FYS-1在油田注聚采出液处理中的应用

复合处理剂FYS-1是针对油田采出液中聚合物含量高、粘度高和油水乳化严重等特点而研制开发的一种非离子型高分子产品.室内和现场试验结果表明,该药剂具有优良的综合处理能力,一剂多用,在油田注聚采出液处理领域具有推广应用前景.     

基于液相掺杂的低损耗近等厚芯层掺稀土光纤

过高的纤芯损耗和纤芯折射率非均匀性严重制约了掺稀土光纤在高功率光纤激光器中的应用,提出一种基于液相掺杂的低损耗近等厚芯层掺稀土光纤的工艺方法.结合改良的化学气相沉积(MCVD)溶液掺杂法制备了含有多层疏松层的掺稀土光纤预制棒,理论分析了光纤预制棒缩棒前、后芯层差的变化原理,采用流量递减沉积工艺降低了缩棒后不同芯层之间的...     

Quantification of Mixtures of C2 and C3 Hydroxy Acids and Products of Glycerol Oxidation by High-Performance Liquid Chromatography and Quantitative 13C NMR

The aim of this study was to develop an improved general method for detecting and quantifying mixtures of hydroxy acids and other products of glycerol oxidation in aqueous media, to prevent the confusions that can occur due to similarities and interactions between these compounds depending on media conditions. Standard potential products of glycerol oxidation—glycerol, glyceraldehyde, dihydroxyacetone, glyceric acid, lactic acid, glycolic acid, glyoxylic acid, oxalic acid, tartronic acid, and mesoxalic acid—were analyzed by high-performance liquid chromatography (HPLC) and quantitative ¹³C nuclear magnetic resonance (NMR), in mixtures of known composition. The results obtained were concordant with the known compositions tested. HPLC was more accurate than quantitative ¹³C NMR for simple mixtures, but ¹³C NMR was required for complex mixtures containing dihydroxyacetone and glycerol, oxalic acid and mesoxalic acid, or glyoxylic acid and tartronic acid, pairs of compounds not well separated or detected by HPLC. As proof-of-concept, an unknown mixture generated by glycerol oxidation was analyzed by HPLC and quantitative ¹³C NMR. The results obtained were concordant and allowed accurate determination of the composition of the sample, which contained mesoxalic acid as the major product, with oxalic acid, tartronic acid, and glyceric acid as by-products.     

圆筒织物的连续脱水开布

详细描述了Suvac Cut脱水开幅机.与离心脱水开幅机相比,叙述了这一连续工艺的优点.利用真空脱水技术,阔幅圆筒织物可在连续工艺中脱水和开幅,     

对乙烯基苯甲酸的合成

以对溴苯甲酸为原料,经格氏试剂交换反应得到格氏试剂,然后与乙醛加成合成对羟乙基苯甲酸,再经脱水反应合成了标题化合物。产品总收率47.0%,产品纯度99.4%。通过1HMNR对产品进行了表征。     

2-甲基-2-噁唑啉的合成研究

以N-(2-羟基乙基)乙酰胺为原料,在二水乙酸锌的催化作用下,脱水缩合生成2-甲基-2-噁唑啉,考察了温度、催化剂用量、压力、时间对反应的影响。最佳工艺条件为:m(催化剂):m(N-(2-羟基乙基乙酰胺))=0.15∶1,反应温度为185℃,压力为0.01 MPa,反应时间为2 h,收率可达到95%。并考察了催化剂的重复使用情况。产物经质谱进行了结构表征。