阻垢剂阻垢性能及阻垢机理的研究进展

使用阻垢剂是解决工业水处理系统结垢问题最高效实用的方法之一.对比分析了不同类型阻垢剂的阻垢性能,并从螯合增溶、分散吸附、畸变作用和几何匹配等方面阐述了阻垢剂的阻垢机理,可为未来阻垢剂阻垢性能和阻垢机理的发展提供借鉴.     

天冬氨酸-衣康酸共聚物对碳酸钙阻垢性能研究

为提高聚天冬氨酸(PASP)抑制碳酸钙结垢的性能,改性合成了新型产品天冬氨酸-衣康酸共聚物(PAI)。采用静态阻垢法,考察不同水质条件对PAI阻垢性能的影响,并与改性产品天冬氨酸-赖氨酸共聚物(PAL)和市售PASP进行了对比;初步从动力学角度,考察了PAI、有机膦系阻垢剂PBTCA和PASP在特定条件下阻垢效果的差异。结果表明,相同实验条件下,PAI的阻垢率最高可达90.12%,略优于PAL,明显高于PASP;碳酸钙结晶生长速率常数分别为k(PBTCA)=30.39k(PAI)=34.806k(PASP)=40.557。表明PAI是阻垢性能优异的新型改性产物,适用于水质条件不稳定和水力停留时间较长的用水系统。     

反渗透专用阻垢剂TJRO101的阻垢性能

反渗透专用阻垢剂的阻垢效果可通过反渗透的动态模拟实验来评价.反渗透装置以“周期性浓缩的全循环模式“运行,使浓水侧的饱和指数逐渐增大,碳酸钙和硫酸垢的结垢趋势逐渐增加,RO的总回收率也逐渐提高.碳酸钙和硫酸垢的沉积使得溶液的组成改变,并以此评价阻垢剂的阻垢效果.对新型反渗透专用阻垢剂TJRO101、传统反渗透阻垢剂SHMP及King Lee的PTP2000的动态模拟实验表明,TJRO101对CaCO3,CaSO4,BaSO4,SrSO4垢有极其优良的阻垢性能,是一种多功能的反渗透专用阻垢剂.     

复合缓蚀阻垢剂对模拟循环冷却水中Q235碳钢的缓蚀与阻垢性能

为寻找性能更优的缓蚀阻垢剂,采用静态失重、静态阻垢、电化学测试、X射线粉末衍射(XRD)、扫描电镜(SEM)等方法,研究了聚环氧琥珀酸(PESA)、羟基乙叉二膦酸(HEDP)及其复合物对模拟循环冷却水中Q235碳钢的缓蚀与阻垢性能。结果表明:复合缓蚀阻垢剂对Q235碳钢的缓蚀率和阻垢率均达到90%以上,其缓蚀、阻垢性能明显优于单组分PESA和HEDP;复合缓蚀阻垢剂是以抑制阴极反应为主的缓蚀剂,能很好地发挥各组分间的协同作用,在碳钢表面形成保护膜,抑制其在循环冷却水中发生腐蚀;复合缓蚀阻垢剂有助于Ca CO3垢样的分散和球霰石晶型的形成,起到较好的阻垢分散作用。     

再生水循环冷却系统中缓蚀阻垢剂的优化研究

针对再生水用于循环冷却系统引起的腐蚀结垢问题,采用碳酸钙沉积法、旋转挂片法、表面微观分析技术和电化学方法,结合正交试验设计和动态模拟试验装置,对钼系缓蚀阻垢剂的缓蚀、阻垢性能进行试验研究,确定了钼系配方的最优组成,并探讨了钼系缓蚀阻垢剂的协同作用机理。结果表明:复配药剂的最佳组成为2-膦酸丁烷-1,2,4-三羧酸(PBTCA)5.0 mg/L,丙烯酸-2-丙烯酰胺-2-甲基丙磺酸共聚物(AA/AMPS)5.0 mg/L,钼酸盐8.0 mg/L,锌盐2.0 mg/L,BTA 1.0 mg/L。该复配药剂的阻垢机理包括膦酸基(-PO_3H_2)的晶格畸变、羧基(-COOH)的螯合增溶以及长链结构的分散作用,是一种典型的阳极型缓蚀剂。     

含羧基磺酸类共聚物阻垢剂的合成及其对CaCO_3的阻垢效果

为了解决发动机冷却水箱的结垢问题,采用试剂顺酐(MAH)、丙烯基磺酸钠(ALS)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)和甲基丙烯酸羟乙酯(HEMA),通过水溶液自由基聚合法,合成了含羧基磺酸类四元共聚物PMAAH。按GB/T 16632-2008测试了PMAAH的阻垢性能,探讨了其阻垢效果与投加量、钙离子浓度、时间、水样温度间的关系;将PMAAH与防冻液复配并与防冻液在高温条件下阻碳酸钙垢的效果进行了对比。结果表明:PMAAH具有良好的阻碳酸钙垢的能力,阻垢性能优于传统的阻垢剂和防冻液,适用于发动机冷却系统。     

反渗透阻垢剂在国外的研究与应用

本文概述了近二十年来反渗透阻垢剂在国外的研究与应用。包括阻垢剂的种类,结构、特性、效果;阻垢剂的结构和官能团与其阻垢效果的关系;各种因素,如溶液pH 值,阻垢剂的浓度,阻垢剂(聚电解质)的分子量,其它离子的存在和含量等对阻垢效果的影响。     

三元阻垢剂IA/AA/HEMA的制备与性能

以衣康酸(IA)、丙烯酸(AA)和甲基丙烯酸羟乙酯(HEMA)为单体,采用水溶液聚合法制备三元共聚阻垢剂IA-AA-HEMA,以阻垢率为指标,利用称垢法评价其阻垢效果;利用P-B试验和CCD实验优化阻垢剂制备条件。结果表明IPA投加量15%、KPS投加量8%、单体配比n_(IA)∶n_(AA)∶n_(HEMA)=1∶0.5∶0.3、聚合温度86℃、聚合时间85 min的最优条件下,阻垢率最大可达96.69%,其中聚合温度和单体配比n_(IA)∶n_(AA)对阻垢率的影响极为显著,聚合时间和KPS显著影响次之。红外光谱表征表明IA-AA-HEMA阻垢剂聚合成功,CaCO_3垢样的扫描电镜分析结果表明加入IA-AA-HEMA后CaCO_3垢样结构明显疏松,阻垢效果良好。     

反渗透膜用阻垢剂的研制与应用研究

利用溶液聚合的方法以丙烯酸、丙烯磺酸钠等单体为原料合成了含磺酸基的多元共聚物,并与有机膦酸、低分子量的聚丙烯酸等水处理药剂按一定比例进行复配研制成反渗透阻垢剂TM-1,通过动态实验室阻垢实验和在工业生产反渗透系统中的使用,证明TM-1对CaCO3垢、CaSO4垢,铁盐、硅垢等有很好的阻垢效果.     

快速评价反渗透专用阻垢剂阻垢性能的实验技术

反渗透装置中最重要的给水预处理方法之一是加入阻垢剂,来防止水中难溶盐形成水垢,RO市场上每年都会推出新的阻垢剂．RO装置的技术人员在使用这些阻垢剂前要对其性能进行实验室评估,研究阻垢剂所可能达到的最大回收率及正确的加药量．文章对阻垢剂的实验室快速评价技术进行了研究,使RO装置以周期性浓缩的全循环模式运行,以逐渐提高RO装置浓水侧的结垢趋势,并测定其结垢速率．选择了新型阻垢剂PTP-2000和传统阻垢剂SHMP,对其阻QaCO3的性能进行了比较研究．结果表明,周期性浓缩的全循环是一种快速、方便、可靠的阻垢剂评价技术,     

Silicon nanoelectronic devices with delta-doped layers

Electronic devices grown by molecular beam epitaxy on a nanometer scale are presented. The use of a vertical device design in combination with delta-doping layers increases the performance of these devices. The vertical design offers the possibility of three dimensional device integration and allows the scaling of MOS field effect transistors down to its physical limits. The excellent crystal quality and doping profile is demonstrated by the very good performance of the grown devices.     

反渗透系统的结垢污染与清洗维护

系统阐述了反渗透膜组件发生结垢和膜污染的成因及其特征,对浓差极化,胶体污染,微生物污染等膜结垢污染形式,以及减轻污染的手段作了说明,并提出相应的解决方法,对膜组件清洗维护的频度,药剂,时间等参数,以及对其它反渗透预处理系统的设备的清洗维护,也提出较详细的建议。     

Monitoring of scaling in dilute phase pneumatic conveying systems using non-intrusive acoustic sensors – A feasibility study

Scale formation in pneumatic conveying systems is a major industrial challenge. The underlying scale formation mechanisms can be intricate as they often involve a combination of several mutually enhancing binding forces and can be affected by a number of different factors. A non-intrusive monitoring technique capable of measuring scale growth would be a valuable tool to investigate different scaling mechanisms. In this study, the feasibility of an active acoustic sensor technique for monitoring of scale growth in a pneumatic conveying system is evaluated. Tests are performed in a pilot scale pneumatic conveying system transporting sand in dilute phase. The acoustic sensors conducts measurements on test pipes which are coated with a primer/powder mixture, one layer after the other, to simulate scale progression. Reference measurements of the coating layer thickness in the test pipes are obtained by a laser imaging technique for each added coating layer. A multivariate method is used to calibrate prediction models of the scale thickness using acoustic measurements as independent variables and the reference measurements as the dependent variable. Results show that the active monitoring method is capable of monitoring scale growth in pneumatic conveying systems and that dilute phase conveying of sand does not affect the precision of predictions made by the method.     

On the scaling of impact loaded composite beams

Approaches to the scaling of impact experiments on laminated composite beams are presented and problems associated with incomplete similitude are discussed. In the case of beams scaled on a sublaminate basis, a correction factor is presented to scale the dynamic response of beams subjected to drop-weight impacts. The scaling procedure is evaluated in a series of scaled experiments on graphite-epoxy composite beams. It is shown that the correction factor provides a valid scaling procedure for the dynamic response but a significant scale effect on damage development and strength is observed.     

Energy efficiency of RO and FO–RO system for high-salinity seawater treatment

Forward osmosis (FO) has been proposed as an alternative method for seawater desalination, wherein reverse osmosis (RO) membrane technology is used for regeneration of the draw solution. Previous studies have indicated that a standalone RO unit is more energy efficient than an FO–RO system, and as such it was recommended that an FO–RO system is best employed only for the desalination of high-salinity seawaters. This study examined FO–RO applicability in more detail by examining the impact of seawater salinity, impact of an energy recovery device (ERD), and the effect of membrane fouling. For comparison purposes, the performance of the FO process was improved to minimize the impact of concentration polarization and optimize the concentration of draw solution. Model calculations revealed that FO–RO is more energy efficient than RO when no ERD was employed. However, results showed that there was no significant difference in the power consumption between the FO–RO system and the RO unit at high seawater salinities particularly when a high-efficiency ERD was installed. Moreover, the FO–RO system required more membrane area than a conventional RO unit which may further compromise the FO–RO desalination cost.     

火电厂中水回用RO膜污染特征研究

城市污水深度回用为火力发电厂锅炉补给水已成为世界各国解决缺水问题的主要方案之一,中水水质对深度回用工艺中反渗透膜的影响不容忽视.将电厂中水回用工程中污染的反渗透膜组件进行解剖分析,通过加压染料试验、表观观察、烧失量分析、SEM-EDX、GC-MS等方法对膜面污染物及其在膜面的分布特征进行研究.结果表明,膜面主要为有机污染,主要污染物为烃类、脂肪酸类物质;少量无机污染主要是SiO2;污染物总量沿从膜卷进口端到出口端的方向逐渐增多,无机污染的变化与之相同,而有机污染的变化与之相反.表明阻垢和杀菌预处理系统及维护管理工作完善.     

反渗透膜法处理多糖发酵废水的过程模拟

在一自制的高压反渗透评价池内,对反渗透法处理微生物多糖发酵废水的过程进行了研究,建立了描述这一过程的数字模型,该模型的模拟结果能与实验结果较好的吻合。在此基础之上。进一步分析了操作压力,发酵废水的初浓度对处理过程的影响,这些结果可供反渗透膜法处理微生物多糖发酵废水的工业开发参考。