氨肟化装置膜分离系统的应用和优化

分析了环己酮肟生产中氨肟化装置膜分离系统运行不稳定的原因;提出了技术改造和工艺优化措施。结果表明:膜分离系统膜管表面污染导致其运行不稳定,原因是生产中弱碱性条件下破碎的催化剂颗粒附着在膜表面形成沉积层。通过提高错流速率,稳定反冲压力,改变反冲方式和反冲介质等优化措施,可实现膜分离系统的稳定运行。     

无机陶瓷膜在环己酮氨肟化工艺中的应用

通过对陶瓷膜工作机理分析,结合环己酮氨肟化工艺的实际情况,确定了用于氨肟化工艺中无机陶瓷膜的选择要求,讨论了无机陶瓷膜在70 kt/a己内酰胺氨肟化工艺装置中的应用效果。结果表明:采用孔径为120 nm、厚度为20μm、孔隙率为30%的非对称无机陶瓷膜,可有效实现平均粒径为200 nm的钛硅分子筛催化剂与反应清液的分离,完全满足氨肟化工艺过滤系统的要求;在工业装置中,控制陶瓷膜的临界压力0. 2 MPa、装置操作压力0. 08～0. 12 MPa、反应错流速度3～4 m/s、减少膜污染,可有效提高膜通量;通过优化运行工艺和操作条件,可有效防止陶瓷膜膜管的泄露、断裂及膜管通道堵塞,成功实现了无机陶瓷膜在环己酮氨肟化工艺中的工业应用,且使用寿命达3年以上。     

无机陶瓷膜分离技术在大型化工装置的应用

主要从无机膜分离原理、性能特点、表征方法结构特点等几个方面介绍了在化纤16万t扩容改造氨肟化装置应用的无机膜分离技术,并对同类装置无机膜系统出现的异常现象进行了分析,介绍了10万t氨肟化装置针对这些情况所采取的改进措施.     

氨肟化装置叔丁醇回收系统双效精馏的节能改造

氨肟化反应以叔丁醇为溶剂,溶解反应系统中的环己酮肟、氨、水等反应混合物,叔丁醇回收系统是氨肟化装置耗能最大的工序.双效精馏是精馏操作中一种较为高效的节能方式.本文简要介绍了氨肟化装置叔丁醇回收系统的双效精馏工艺改造情况,对改造前后的实际能源消耗做了详细的对比和评价分析.工艺改造中采用了双效精馏中的逆流流程,有效防止环己...     

应用旋液分离净化技术 提高己内酰胺产品质量

分析了影响环己酮氨肟化装置蒸馏系统稳定运行和中间产品环己酮肟质量的主要原因,结合装置现有的工艺、设备情况,经过进行甲苯-肟混合物旋液分离侧线试验,实施了采用旋液分离净化技术的改造方案,提高了己内酰胺产品质量。     

环己酮氨肟化反应控制条件的优化研究

环己酮的氨肟化反应是己内酰胺生产中核心工序,但是氨肟化反应催化剂价格昂贵,传统的氨肟化反应控制条件不能最大化发挥催化剂的催化作用,使肟的生产成本较高,本文对氨肟化反应主要的影响因素进行了探索研究,并于实际生产中进行验证,通过改变反应温度、双氧水与环己酮比例、叔丁醇与环己酮比例等几个主要影响因素,最大化的发挥了催化剂的作用,大大降低了生产成本。     

HTS-1钛硅分子筛催化环己酮氨肟化工业试验

通过工业试验,考察了钛硅分子筛HTS-1新剂和再生剂在环己酮氨肟化制备环己酮肟工艺中的工业试验性能,工业运行结果显示:环己酮转化率99.6%,环己酮肟选择性99.5%,催化剂单程寿命大于600h。同时介绍了亚微米级HTS-1催化过程中的分离和粘壁问题及其工程解决措施,应用陶瓷膜微滤技术解决了催化剂和反应液的分离和循环使用问题,应用波纹管技术克服了催化剂粘壁现象,达到正常换热的效果,并通过优化使系统满足生产要求。     

氨肟化法己内酰胺生产废水处理技术研究及应用现状

氨肟化法己内酰胺生产废水成分复杂,处理难度较大,已成为我国己内酰胺生产领域的研究热点。综述了氨肟化法己内酰胺生产废水的预处理技术、生化处理技术和深度处理技术,以及各类组合处理技术的研究和应用现状,指出己内酰胺生产废水处理工程化技术的开发,不仅要考虑到工艺技术的有效性,也要考虑到运行成本等因素,设计出抗冲击能力强、运行效率高、处理成本低、自动化程度高的己内酰胺生产废水处理系统是今后的发展方向。     

氨肟化反应釜内挡板安装角度的模拟及应用

运用CFD软件模拟氨肟化反应釜内挡板安装角度不同时的搅拌效果,通过流场分析,找出挡板安装角度对氨肟化反应的影响,并应用于实际生产。结果表明:在氨肟化反应釜内,挡板安装角度为+30°时比安装角度为-30°时具有更快、更均匀的混合效果,更有利于改善反应效果;对氨肟化反应釜进行改造,采用ZCX型搅拌浆叶,浆叶直径1 700 mm,挡板安装角度为+30°,搅拌电机功率为22 k W,改造后氨肟化反应的转化率和选择性有所提高,有效提高了环己酮肟质量,降低了装置消耗。     

新型催化剂在氨肟化装置的应用

从催化剂的定向氧化性、可再生性、可分离性、催化作用的连续性等几个方面,对石家庄炼化16万t扩容改造核心装置——环己酮氨肟化装置所采用的新型催化剂进行了较为详细的论述,并从不同角度说明催化剂性能对环己酮氨肟化装置的稳定运行起着重要作用。     

Effect of intermittent back ozonation for membrane fouling reduction in microfiltration using a metal membrane

In a microfiltration system using a metal membrane for municipal raw sewage reclamation, the following research points were mainly investigated: 1) Effect of intermittent back ozonation for membrane fouling reduction, 2) effect of operational parameters for permeation flux, and 3) the estimation of optimal operational conditions using an empirical model in the case of back ozonation. Intermittent back ozonation dramatically improved the membrane fouling. The permeation flux was recovered up to 90% of initial flux with dosage of 0.27 (mgO₃/cm³/cycle). Among operational parameters, we found that ozone concentration was the most influential parameter for membrane fouling reduction. In the case of back ozonation, the optimal values of each operational parameter with respect to ozone concentration, ozone gas flow rate and injection time to satisfy 90% recovery of initial flux were 20.2 (mgO₃/L), 3.1 (L/min) and 2.1 (min), respectively. Intermittent back ozonation is believed to be an innovative and feasible technology for fouling reduction and high permeation flux in case inorganic membrane material is being used.     

Effect of fouling reduction by ozone backwashing in a microfiltration system with advanced new membrane material

The effect of ozone back washing for membrane fouling reduction was experimentally investigated in a submerged metal membrane microfiltration system. A cleaning by intermittent ozone gas backwashing was effective in recovering the permeation flux. Intermittent ozone backwashing was highly effective than the air or permeates backwashing for flux recovery. Regarding the operational parameters, the increase of ozone gas flow rate was more effective than the increase of injection time under the conditions of same ozone dose. However, the backwashing cycle was longer, the effect of flux recovery by ozone backwashing decreased. Therefore, it is favorable to operate membrane cleaning before the foulant was consolidated on membrane surface.     

The Role of Synthetic Membrane Pre-Treatment in Influencing Filtration Performance over Multiple Operational Cycles

Manufacturers of polymeric membrane filters used for treating food streams routinely recommend that they are chemically cleaned prior to first use. In this paper, two pre-treatment methods are compared for the filtration of a spent sulphite liquor [SSL] (17.8 wt.% dry solids) using a 20 kg mol^?1 molar mass cut off (MMCO) fluoropolymer membrane. In an extension of previous work that considered the effect of the application of a pre-treatment protocol over a single operational cycle, this paper reports the effect of pre-treatment protocols over four complete fouling and cleaning cycles. The pre-treatment methods evaluated were the conditioning with water at 60°C only [Protocol 1], and the conditioning with water at 60°C followed by cleaning with 0.5 wt.% NaOH [Protocol 2]. Results are presented that demonstrate that for the system examined, the positive effect of the NaOH pre-treatment protocol diminished after three complete operational cycles, and disappeared after four cycles.     

PBI‐Based Polymer Membranes for High Temperature Fuel Cells – Preparation,Characterization and Fuel Cell Demonstration

Proton exchange membrane fuel cell (PEMFC) technology based on perfluorosulfonic acid (PFSA) polymer membranes is briefly reviewed. The newest development in alternative polymer electrolytes for operation above 100 °C is summarized and discussed. As one of the successful approaches to high operational temperatures, the development and evaluation of acid doped polybenzimidazole (PBI) membranes are reviewed, covering polymer synthesis, membrane casting, acid doping, physicochemical characterization and fuel cell testing. A high temperature PEMFC system, operational at up to 200 °C based on phosphoric acid‐doped PBI membranes, is demonstrated. It requires little or no gas humidification and has a CO tolerance of up to several percent. The direct use of reformed hydrogen from a simple methanol reformer, without the need for any further CO removal, has been demonstrated. A lifetime of continuous operation, for over 5000 h at 150 °C, and shutdown‐restart thermal cycle testing for 47 cycles has been achieved. Other issues such as cooling, heat recovery, possible integration with fuel processing units, associated problems and further development are discussed.     

卷式反渗透海水淡化系统膜清洗与更换策略优化

膜污染是导致反渗透海水淡化(seawater reverse osmosis,SWRO)系统操作成本增加和产水性能下降的重要因素。为了降低系统运行操作成本,本文针对卷式SWRO系统提出了一种新的膜清洗与更换策略优化方法。首先,根据反渗透和膜污染过程机理建立了膜污染情况下的SWRO系统性能模型;然后将生产过程中的总操作费用与膜清洗和更换规划联系起来,建立了以系统日均操作费用最低为目标、以膜清洗次数、膜清洗和更换时间等为寻优变量、以开放式方程模型为约束的优化命题,并通过联立求解等技术使得原本复杂的优化命题可快速方便地求解;在此基础上对SWRO系统进行了实例研究和分析。优化求解结果表明:(1)本优化策略可以大幅降低系统操作费用,并同时获得最佳膜清洗和更换时间以及膜清洗次数;(2)进料海水温度对最优膜清洗和更换策略影响很大,固定周期的膜更换策略并不合适。另外本优化方法还可得到不同条件下最优操作费用组成、以及最优目标下最优操作压力和操作流量曲线等信息,对优化SWRO系统运行和深入分析系统内部状态变化具有重要意义。     

Investigation of different operational strategies for the variable operation of a simple reverse osmosis unit

Recent studies and projects showed that a combination of a reverse osmosis desalination plant with a wind power supply is technologically feasible if the reverse osmosis plant is operated with fluctuating and intermittent loads and thus follow the energy supply characteristic of the wind turbine. On this background the goal of this paper is to simulate the system behaviour of a simple reverse osmosis plant under changing process parameters (e.g. feed pressure, recovery or feed flow). These variations are systematized within so-called operational strategies. Therefore, four different operational strategies are analysed in detail with regard to given restrictions e.g. by the membrane system. For each of these strategies the specific energy consumption over the total usable load range is computed with the simulated hydraulic characteristics of each operational strategy. The analysis of the gathered data shows that a membrane system should be operated with constant permeate recovery under fluctuating wind power. This operational strategy provides low specific energy consumption over a broad load range.     

膜法碳捕集技术——研究现状及展望

碳捕集是实现CO₂减排的重要技术手段之一。在众多碳捕集技术中,膜分离技术具有操作简单、能耗低、环境污染小等优势,吸引了广泛关注。完整的膜法捕集CO₂技术研究链条包括膜材料开发、分离膜规模化制备、膜组件研制和膜分离工艺及装置的设计建造。本文针对膜法碳捕集技术链的四个环节,总结对比了国内外技术水平和研究进展,分析了碳捕集膜从实验室研究到工业放大的瓶颈问题,并对本文作者课题组在各个技术环节所积累的研究成果进行了综述。在此基础上,对进一步提高膜法碳捕集技术水平的研究方向进行了展望。     

Treatment performance of metal membrane microfiltration and electrodialysis integrated system for wastewater reclamation

The integrated system with microfiltration/electrodialysis was proposed for wastewater reclamation. The filterability of metal membrane, membrane fouling reduction by ozonated water and the effect of operational parameters were experimentally investigated. Backwashing by ozonated water showed stable and effective membrane fouling reduction. The removal ratio of nutrients such as NH₄⁺-N and PO₄³⁻-P concentration was about 96 and 94%, respectively, within 30 min of operation in the system. Proposed system showed good rejections on bacteria, suspended solids as well as ionic nutrients. Suggested wastewater reclamation system showed stable water quality during operational period over 6 months. Therefore, it is expected to be an effective and useful system for the reclamation of wastewater.     

PTA精制废水处理工艺的优化

阐述了PTA精制废水处理工艺即萃取-超滤-反渗透系统的原理以及该系统的运行情况及出现的问题;分析了反渗透膜受损机理,并通过实验提出了解决方案;通过吸附操作来处理废水中少量的PX,以达到保护膜的作用,从而优化了废水处理工艺;通过实验论证了方案的可行性。     

Modeling and simulation of motor/turbine processes in utility plant

To achieve safe operation and to improve economics it is imperative to monitor and analyze demand and supply of utilities and to meet utility needs in time. The main objective of motor/turbine processes is to manipulate optimal balances on steam and electricity in utility plants. The optimal operation of motor/turbine processes is by far the most important to improve economics in the utility plant. In order to analyze motor/turbine processes, steady state models for steam generation equipment and steam distribution devices as well as turbine generators are developed and analyzed in this work. In addition, heuristics concerning various operational situations are incorporated in the models. The motor/turbine optimal operation system is based on utility models and operational knowledgebase, and provides optimal operating conditions when the amount of steam demand from various steam headers is changed frequently. The optimal operation system also produces optimal selection of driving devices for utility pumps to reduce operating cost.