A semicontinuous approach for heterogeneous azeotropic distillation processes

The separation of azeotropes has substantial energy and investment costs, and the available methods require high capital costs for reconstruction of process plants. As an alternative, a semicontinuous configuration that utilizes an existing plant with minor modifications has been explored. In this paper, a semicontinuous, heterogeneous azeotropic distillation process is proposed and acetic acid dehydration process is used as a case study. To carry out the simulation work, Aspen HYSYS^® simulation software is used along with MATLAB^® and an interface program to handle the mode-transition of the semicontinuous process. Sensitivity analyses on operating parameters are performed to identify the process limits. Comparisons are made to conventional heterogeneous azeotropic distillation, and dividing-wall distillation column on the annual cost. The results proved that the semicontinuous system is the best setup in terms of total annual costs and energy requirements.     

A new efficient method for one‐pot conversions of aryl carboxylic acids into nitriles without solvent

A new efficient method for synthesising nitriles, important organic reagents, is reported in this paper. In an environmentally benign solvent‐free system, aryl carboxylic acids were converted into the corresponding nitriles via one‐pot reactions, by amidation with ethyl carbamate followed by dehydration with thionyl chloride, in excellent yields. The results showed that the method has the advantages of lower cost, higher yield, less pollution and greater ease of work‐up. Copyright © 2008 Society of Chemical Industry     

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本文介绍了采用复合吸收剂净化天然气的试验结果,在现有三甘醇等脱水剂中添加单乙醇胺,在脱水的同时脱除H_2S,在保证净化气露点低于-21℃的条件下,使净化气中H_2S含量亦低于5mg/m～3。     

航空油品高频/高压电脱水微观机理

设计并建立了一套高压电物理化学显微分析装置，为研究高压电物理化学领域的微观机理提供了一种新的技术途径。采用该技术，研究了胜利稠油经6％加氢裂解柴油稀释的原料油的高频／高压电脱水的微观机理。该原料的脱水率达96．7％，高于传统的电脱水方法。     

酸催化二甘醇脱水环化反应研究

以硫酸、磷钨酸、ZRP-5分子筛为催化剂,研究了二甘醇(DEG)脱水环化的反应规律。结果表明,DEG发生分子内脱水环化反应,生成1,4-二氧六环(DOX),DEG分子间脱水不仅可以生成四甘醇、六甘醇等,同时可生成三甘醇、五甘醇等一系列的多甘醇(PEG)。不仅DEG可以脱水环化生成DOX,在反应中生成的PEG也同样可以进行生成DOX的反应。对于二甘醇(DEG)脱水环化反应,硫酸是性能优良的催化剂,反应可以在较低的温度下进行,馏出产物中DOX选择性大于95％。     

雅克拉凝析气田高压脱水工艺的成功应用

雅克拉凝析气田位于新疆阿克苏境内，2005年11月29日建成投运的260×10⁴m³/d雅克拉集气处理站是目前中石化最大的高压凝析气处理装置。该站的高压分子筛脱水工艺为两塔流程，采用差压再生（吸附压力5.9 MPa、再生压力2.8 MPa）、再生气自动回收工艺技术，并采用时序控制程序自动切换，具有工艺简单可靠、自动化程度高、热能利用率高、脱水露点深度高、操作维护简单、投资较少、运行成本低等优点，自建成投产以来运行稳定，效果十分显著。该工艺装置的成功应用，对类似脱水装置设计、操作具有一定参考价值。     

坨五站中间乳化层快速增长原因及治理方案

胜利采油厂坨五站高含水(95％)原油化学预脱水中，二级沉降罐内油水相之间的中间乳化层增长迅速，引起了一系列问题。现场调查和大量室内测试结果表明，产生这一现象的原因有：油溶性破乳剂WD-1加入点不合理。有2／3的含水原油在通过油水分离器之后才与破乳剂混合；二级沉降罐进油口伸入油相内，油流的冲击达不到中间层；WD-1对坨五站混合原油中的稠油破乳脱水性能欠佳，不能适应坨五站混合原油组成和含水的变化。针对上述各种原因筛选出了性能更好的一种破乳剂1916。根据确定的几种原因采取了相应的措施：将破乳剂加入点改在3个并联油水分离器之前；将二级沉降罐的进油口移到水相内；改用筛选出的破乳剂1916，结果使中间乳化层的增长受到了抑制。图2表4参2。     

酸化返出液中分离出的原油脱水时电脱水器跳闸原因及对策

海上油井酸化后,油井返排液沉降分离得到含酸原油,后者进入电脱水器后常引起电脱水器跳闸。其原因是含酸原油(油包水型乳状液)的电导率过高,超过了电脱水器的安全工作电导率κw。对于现场所用的电脱水器,由设计参数计算出κw=0.43μS/cm。从某海上油田3口油井酸化后不同时间的返排液共取样40份,随机选出13份,沉降分离后得到13份含酸原油样,测得电导率范围在0.03～10000μS/cm。认为原油的含水率(应<18%)不是引起跳闸的原因,跳闸的主因是含酸原油的高电导率。研制了一种油溶性的碱性添加剂,其化学成份是碱金属、碱土金属氧化物或氢氧化物,以浓溶液形式加入含酸原油中,可使电导率降至κw以下。加入量由实验确定。表2参2。     

The effects of glycol methacrylate as a dehydrating agent on the dimensional changes of liver tissue

The dimensional changes of liver sections during the course of processing with glycol methacrylate (GMA) or with ethanol are described. Tissue processing with ethanol served as a control. During prolonged processing steps (24 h each), linear shrinkage of tissue specimens dehydrated with GMA at room temperature was 13.2%. Subsequent infiltration with GMA resulted in trivial swelling, and polymerization in slight shrinkage (2.3%). In comparison, processing with cold GMA resulted in shrinkage during dehydration (about 10.8%), a slight swelling in pure GMA, followed by shrinkage during polymerization (2.2%). Short routine processing schedules resulted in similar shrinkage/swelling patterns, although precise values differed slightly. In all experiments, ethanolic dehydration resulted in smaller dimensional tissue changes than did GMA dehydration. The dimensional changes of tissue sections during stretching on water, mounting and drying compensated for the major part of the shrinkage manifested during processing.