Effects of the operating parameters on the reverse osmosis-electrodeionization performance in the production of high purity water

An RO-CEDI (Reverse osmosis-continuous electrodeionization) hybrid process was investigated to produce high purity water. The RO system, with an effective membrane area of 1.1 m², was operated using tap water with conductivity of 64 μs·cm⁻¹, and the CEDI system experiments were carried out in a cell-pair stack consisting of 3 compartments. During the parametric study of the RO-CEDI hybrid system, the optimal operating conditions were determined based on the water purity. The electrical resistivity and water dissociation of the ion exchange resins and ion exchange membrane were verified as the key mechanisms of the CEDI system in the water purification. The produced water met the quality requirements as a make-up water in a nuclear power plant with a resistivity of 10–16.7 MΩ·cm.     

Ozone in the Laundry Industry—Practical Experiences in the United Kingdom

Since the early 1990s, the use of ozone in many commercial and industrial laundering applications has been evolving rapidly. Ozone allows washing to be conducted using cold water, thereby saving considerable heat energy and water consumption. Additionally, ozone enhances the wash process, resulting in a significant reduction in detergent dosage and number of rinses, thus saving water. Ozone/cold water cycles are gentler to fabrics, thus extending linen life. Finally, ozone/cold water laundering is beneficial for effluents, resulting in reductions in COD (chemical oxygen demand). Microorganisms are destroyed effectively in ozone-wash waters, and washing and drying cycles are shorter, thus saving labor. In this paper, the authors describe some specific case studies at commercial laundering installations in the UK, whereby the users of ozone have reaped major benefits, including enhanced microorganism kills/inactivation and significant cost savings.     

Preparation and characterization of UV‐grafted ion‐exchange textiles in continuous electrodeionization

Ion‐exchange textiles (IETs) suitable for use in continuous electrodeionization (CEDI) stacks were prepared using the ultraviolet (UV)‐induced grafting of acrylic acid and sodium styrene sulfonate for cation‐exchange textiles, or 2‐hydroxyethyl methacrylate and vinylbenzyl trimethyl ammonium chloride for anion‐exchange textiles, onto nonwoven polypropylene fabric using benzophenone as photoinitiator. Although the ion‐exchange capacity (2.2 meq g^?1) of the prepared strong acid cation‐exchange textile was lower than that of IRN77 strong acid cation‐exchange resin (4.2 meq g^?1), the overall rate constant of IET was very high due to its low crosslinking and high specific surface area. There was no significant difference between the two different media in terms of the Co(II) removal rate. Furthermore, the current efficiency for IETs was higher than that of IRN77 cation‐exchange resin during a CEDI operation, with efficiencies of 60% and 20%, respectively. The IET also showed the faster exchange kinetics. Therefore, IETs prepared in this study proved to have desirable ion‐conducting characteristics within the CEDI systems. Also this study revealed that the primary removal mechanism in CEDI is the transport of ions through a medium and not the ionic capacity of a medium. Copyright © 2004 Society of Chemical Industry     

Preparation and characterization of immobilized ion exchange polyurethanes (IEPU) and their applications for continuous electrodeionization (CEDI)

Immobilized ion-exchange polyurethanes (IEPU) were prepared as ion conducting spacers in continuous electrodeionization (CEDI) for the treatment of a synthetic primary coolant. Ion exchange resins were immobilized by using allophanate/biuret cross-linking in preparation of polyurethane. Synthesized IEPU was characterized in terms of mechanical strength, ion exchange capacity (TEC), electrical conductivity and the porous plug model, which schematically represents the transport pattern through the IEPU. CEDI was carried out in a laboratory scale with an effective area of 20 cm². The CEDI operation with a layered bed configuration showed the main removal mechanism of cobalt ion was dependent on the active surface area between ion conducting materials. The performance of the CEDI operation showed over 98% removal of cobalt ions, suggesting the feasibility of IEPU as ion conducting spacers in a CEDI system.     

The use of electrodialysis to desalinate waste water in low-waste viscose manufacturing technology

Conclusions The advisability of using electrodialysis to desalinate and concentrate waste water from viscose manufacturing has been shown.The attainable degree of desalination makes it possible to carry out secondary use of the purified waste water for industrial means and also the degree of concentration permits return of the brine to the precipitation bath loop with the objective of repeated use of the acid and zinc sulfate and preparation of commercial sodium sulfate (in regeneration of the precipitation bath by crystallization).The fundamental technological scheme has been developed and parameters and energy indices of the process for desalinating acid waste waters have been developed for the Sokal'skii man-made fibre plant.It is advisable to carry out further studies on selecting ion exchange membranes with improved characteristics, on increasing the degree of concentration, on preparation of acid and alkali from the brines, and on improving the process of preliminary clean-up of waste waters from organic contaminants.Translated from Khimicheskie Volokna, No. 1, pp. 44–46, January–February, 1990.     

From laboratory experiments to simulation studies of methanol dehydration to produce dimethyl ether—Part I: Reaction kinetic study

Most of the reaction rate equations for methanol dehydration are derived from the experiments conducted for crude methanol as feed and laboratory prepared catalysts, which are not exactly the same as industrial reactors conditions. In the present contribution, it is attempted to find suitable rate of reactions for pure methanol with no water as feed and commercial catalysts of HZSM-5 and γ-alumina at industrial conditions in methanol dehydration process. In addition, a comparison between the performances of the catalysts is performed. It is found that HZSM-5 has superior performances compared to the γ-alumina in terms of conversion. Modeling results are also indicated that the proposed rate of reaction predicts the behavior of the process, properly.     

Relation between the cleanability of bare or polysiloxane-coated stainless steels and their water contact angle hysteresis

Cleaning of bare or coated stainless steel surfaces is investigated using some specific techniques for both particulate soil and oil removal. Particulate soil is removed from the surface by a water drop sliding, whereas oil is eliminated by shear flow of a commercial detergent. The cleanability performance is found to depend both on surface energy and topography. In general, the water contact angle hysteresis, which itself is related to the advancing contact angle and the surface roughness, is found to be an appropriate criterion for characterizing the cleaning performance. This finding is discussed in terms of retention and removal forces during the cleaning process and could provide in the future a criterion for material selection for industrial use of stainless steel surfaces.     

A review of nanoparticle-enhanced membrane distillation membranes: membrane synthesis and applications in water treatment

Membrane distillation (MD) is a thermally driven process that uses low-grade energy to operate and has been extensively explored as an alternative cost-effective and efficient water treatment process compared to conventional membrane processes. MD membranes are synthesized from hydrophobic polymers, e.g. polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) or polypropylene (PP), using various methods including phase inversion and electrospinning techniques. Recent literature on MD membranes clearly shows their important role in surface water/wastewater treatment and seawater desalination. Modification of MD membranes with nanoscale materials significantly improves their performance, preventing wetting and fouling. This review presents a critical assessment of the progress on the use of nanomaterials for the modification of MD membranes. The techniques commonly used to synthesize MD membranes, the modifications that have been adopted for the incorporation of nanomaterials onto membranes, and the unique properties these nanomaterials impart on the membranes are discussed. The use of modified membranes in different MD configurations and their application in groundwater, surface water, wastewater, brackish water and seawater treatment is reviewed. Finally, cost implications, commercial viability, environmental sustainability, and future prospects of MD are also discussed to elucidate promising approaches for a future and successful implementation of MD at an industrial scale. © 2019 Society of Chemical Industry     

选煤尾矿制备水煤浆的研究

介绍了利用选煤尾矿（滤饼）制成具有一定的流变结构特性和热物理特性的水煤浆燃料的可能性,并研制出复合增塑添加剂成分,可以大大降低选煤尾矿制成的水煤浆的粘度;确定了水煤浆的主要结构-流变性和燃料的热物理特性,最后进行了尾矿制备水煤浆的工业性试验,结果表明,该种燃料可用于工业供热系统。得出的结果用于实施建立电能1.2MW的自动化动力能源综合体计划框架的选煤尾矿制水煤浆及其燃烧综合装置工艺流程的计算。     

高压静电技术在固液相分离中的应用

论述了静电分离技术在固液相分离等中的发展和应用。     

对羟基苯甲醚合成工艺改进

研究了对羟基苯基甲醚新的合成工艺:以加氢取代原工艺中硫化碱还原,避免了含硫废水的产生;以水汽蒸馏法快速移走生成的对羟基苯甲醚,提高了收率,并避免使用低沸点易燃易爆的溶剂乙醚。改进后的工艺解决了环保问题,降低了生产成本,使其更适合工业化生产。     

高级氧化法处理废水研究进展

近年来,水环境污染问题引起人们越来越多的重视。发展新型水处理技术,实现废水达标排放对国家的可持续发展具有重要作用。高级氧化法因其具有氧化彻底、速度快、效率高、无公害等特点而被关注。文章综述了Fenton试剂氧化法、臭氧氧化法、湿法空气氧化法、催化湿法氧化法、光化学氧化法等处理废水的原理和进展。高级氧化技术在废水处理领域具有广阔的应用前景,但要真正实现其工业化应用,在降低成本的同时,还需加强其机理研究。     

The british coal spouted fluidised bed gasification process

British Coal Corporation has been developing an air-blown spouted fluidised bed gasification process for the production of low calorific value fuel gas. Development of the gasifier at atmospheric pressure for the industrial market has established the commercial basis for a flexible gasification process, which can achieve coal conversion efficiencies of up to 95%. For larger-scale use, a pressurised gasifier is under development as part of an integrated partial gasification combined cycle, coal-fired, electricity generating system. Known as the British Coal Topping Cycle, the system offers significant advantages in terms of improved thermal efficiency, reduced generating costs and low environmental impact. The paper outlines the gasifier development programme for both applications.     

Electrocoagulation as a revived wastewater treatment method-practical approaches: a review

This review paper aims to demonstrate electrocoagulation (EC) as a revived technology and introduce recent steps of advanced configurations, along with hybrid approaches for the efficient electrochemical treatment of multi-sourced wastewaters. A brief theoretical background is also provided. Moreover, the practical applications of the process are presented, while no previous research has ever attempted to do so. Through online-based data research, it was found that there are 75 manufacturers of EC systems internationally. Industrial case studies reveal actual process conditions and economical data. America holds 33% of global EC systems' manufacturing share and it is considered the leader in EC innovative designs with a percentage of almost 59%. In America and Europe, composite schemes are nearly equivalent to EC autonomous systems, with respective percentages of 41% and 47%. The performance of a two-stage process combining electro-coagulation (EC) and electro-oxidation (EO) has been proven to be the most successful combination in industrial wastewater treatment, representing 54% of hybrid systems available globally. Most of the commercialized EC systems are of small-medium sizes, accounting for 88% of all systems available worldwide. The latest trends on new reactor and electrode configurations are also presented. EC has great potential for further improvement as there is strong academic background to support water treatment companies for industrial scale ups. Cylindrical type reactors tend to dominate due to the ease of their use and maintenance; meanwhile, hybrid systems of EC with EO, membranes and/or adsorption will continue to expand on the market due to the mature level of these technologies and their ease of adaptation. © 2021 Society of Chemical Industry (SCI).     

Ozone in the United States of America -- State-Of-The-Art

Applications for ozone in the United States have evolved through a lengthy maturation process, which began with drinking water treatment (taste/odor/color removal) in the early 1900s, and grew slowly until acceleration began in the mid-1980s. Although deodorization became a stable market in the 1960s-1970s, these applications were small, for the most part. One of the largest uses for ozone is oxidation of process chemicals in the chemical industry, which began in the USA about the 1940s, and subsequently has spread worldwide. Today, thanks primarily to environmental regulatory pressures which began to impact ozone in the mid-1980s, ozone now is used increasingly in the USA for drinking water treatment and for some municipal and industrial wastewater applications. The U.S. Environmental Protection Agency (EPA) has recognized the growing importance of ozone (> 200 drinking water plants use ozone today), and has appointed IOA representatives to two of its regulatory development committees as stakeholders. Several U.S. cities have installed or are installing wastewater treatment processes for potable reuse purposes, which include the use of ozone. Three full-scale U.S. pulp bleaching plants use tons/day quantities of ozone. Smaller applications for ozone include water treatment for cooling tower waters (biofouling control), swimming pools and spas, marine aquaria, bottled water disinfection and maintenance of high purity waters in the pharmaceuticals and electronics industries. A new application for ozone is in commercial laundries to reduce energy costs and replace chemicals. In mid-1997, a public declaration was made by an expert panel that ozone is Generally Recognized As Safe (GRAS) for contact with foods. This declaration opens the door for ozone to be used in U.S. food processing industries. U.S. research scientists and engineers are at the forefront in studies which define the technical aspects of ozone technologies in a variety of applications employing advanced oxidation, including the treatment of hazardous wastes, groundwater remediation, and process water recovery and reuse in the semi-conductor industry.     

Investigation on and industrial application of degrading of methanol feed in methanol to propylene process

At present, methanol to propylene (MTP) technology developed by Lurgi Company is adopted for commercial plants and refined methanol with the purity ≥ 99.85 wt% is required as the feed of MTP unit in Lurgi's technology. Therefore, high energy cost for refined methanol production is one of the bottlenecks to improve the economy of MTP technology. Reducing the grade of feed refined methanol may be an effective method to save energy and reduce operation costs in MTP process. In this work, experiments and process simulation were carried out to investigate the influence and feasibility of degrading the methanol feed. Experiments were conducted to investigate the influence of crude methanol feed on conversion and selectivity of MTP reaction as well as the performance of ZSM-5 catalyst. The experimental results showed that degrading the methanol feed had no obvious influence on the conversion and selectivity of MTP reactions and the catalyst deactivation was caused by the carbon accumulation and metals deposition on the active sites. The process simulation results showed that the influence on the conversion and selectivity as well as the stream load of MTP process was negligible if 98mol% methanol was used as feed. Finally, industrial experiments were conducted by adjusting the operation parameters to degrade of feed methanol of the commercial 500 kt·a^-1 MTP unit of Ningmei Group in China. The results of industrial application illustrated that annually 180 kt fuel coal and 150 kt desalted water as well as1770 MW·h^-1 electricity would be saved when the water content increased from 0.01% to 0.4%. This work has identified the feasibility to improve MTP technology by degrading the methanol feed.     

中铬黄生产过程中硝酸钠的回收及水的循环使用

对铅铬颜料生产过程中产生的废水中的硝酸钠进行了专门研究,将生产过程中产生的母液水及梯度提浓含硝酸钠的水重复用于化学合成前的溶料和制作硝酸铅工序中,经多次循环使用,使硝酸钠浓度成倍提高,再对其进行浓缩结晶,经检测,副产品硝酸钠的品质可达工业级。     

聚酯（PET）反应过程研究：Ⅶ后缩聚反应过程研究和数学模拟

对聚酯的后缩聚反应过程进行了分析，把该过程分解为反应动力学和反应器内各种传质；对后缩聚反应进行了实验研究。建立了适用于工业装置的后缩聚反应过程的数学模型     

Fabrication and application of Diachem® electrodes

Conductive diamond coated electrodes have undergone intensive investigation over the past number of years. The unique electrochemical properties of diamond electrodes such as their extreme chemical resistance, even at high doping concentrations, and high overvoltage for water electrolysis opens the door to numerous applications. For the industrial use of extremely promising electrode material sufficient availability, also for large area electrodes is necessary. The development of large area DIACHEM^® electrodes therefore has been performed on a range of base materials of numerous material geometries. For the production of these electrodes a large area HFCVD process is used which allows for reproducible coatings of substrates up to 50×100 cm. A doping with boron allows the reproducible setting of the resistivity of the diamond coating in the range of 5 to 100 m Ω cm. The extent to which DIACHEM^® electrodes have been developed by now means that they can presently be applied in various industrial applications. The most important applications include: industrial waste water treatment, in particular the mineralization of toxic organic compounds; the disinfection of water; circulation systems with water which are only possible through use of an electrochemical recycling process; electrochemical synthesis, in particular from strong oxidising solutions and galvanic processes such as the recycling of chrome baths. Previous investigations have shown that the use of DIACHEM^® electrodes results in either a significant improvement in the effectiveness or that the process was only possible through use of this particular electrode material. The user gains a combination of the typical advantages of the electrochemical process with the high efficiency of the DIACHEM^® electrode which, in turn, has generated enormous interest in this particular material. In order to satisfy this interest, CONDIAS GmbH offers the DIACHEM^® electrode commercially.     

Computer Simulation of Industrial Dryers

The use of computers to perform simulation of chemical engineering processes has lead to the development of software tools that Perform most tedious computations in the field of process analysis and design. The most popular Structures regarding process simulation of conventional and specialized processes are analyzed properly by considering the basic parts of commercial programs. Computational procedures. graphical aspects. management of properties database are outlined. Modeling aspects of drying technology regarding simulation are summarized and classified. The need for specialized software and development efforts in the field of commercial dryers simulation are enlohasized and nppropriately addressed. Moderm aspects. such as obiectoriented programming in simulation of industrial dryers are suitably presented and various case studies are used to indicate the effectiveness of modern simulation methods in the field of dryers operation.