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水级联法确定间歇用水过程的夹点及废水最小化 总被引:1,自引:1,他引:0
利用水级联分析法对间歇过程用水网络进行研究,确定过程的用水夹点及最小新鲜水用量和最小废水排放量,提出了间歇用水过程的全局夹点的概念,考虑了用水过程的流率限制,在水级联表格中用流率替代了传统水级联分析法中的传质量,识别过程中每个时间段的局部夹点及公用工程目标,通过全局夹点和局部夹点的比较,指出过程的用水瓶颈,设置储罐打破瓶颈,使用水网络公用工程目标最小化。通过实例对水级联分析法进行了详细的阐述,计算结果与文献一致,表明该方法是一种易于理解、直观且简便有效的确定间歇过程用水网络的夹点及最小公用工程的方法。 相似文献
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针对大型复杂过程系统用能的诊断与调优,发展了夹点分析(夹点技术)方法。提出采用虚拟温度法,确定各流股匹配换热的传热温差;将过程的夹点分析区分为操作型夹点计算与设计型夹点计算两个层次:操作型夹点计算用于过程用能的诊断;设计型夹点计算指导过程用能的调优。基于以上改进,开发了大型复杂过程系统用能诊断与调优策略,并应用于国内某厂乙烯装置的节能改造,可使该装置吨乙烯能耗降低4.187GJ。应用表明本文提出的方法是指导大型复杂过程系统用能诊断与调优的有利工具。 相似文献
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首先阐述了夹点技术的基本原理,利用夹点技术对原油常减压蒸馏装置的换热网络进行设计,运用问题表法求取夹点温度、最小公用工程。 相似文献
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《高校化学工程学报》2021,35(5)
针对单/双压蒸发有机朗肯循环(ORC)系统的工质和结构选择问题,结合Aspen Plus模拟和夹点理论分析,以120~200℃的低温热源为例,对单\双压蒸发ORC系统在不同工质条件下的热力学性能和换热过程进行了研究。结果表明:热源和工质换热形成的夹点类型是单/双压蒸发ORC系统结构选择的关键。对于单压蒸发ORC,随着工质临界温度的降低,工质在最优条件下与热源形成的夹点类型由泡点夹点(VPP)逐渐变为泡点和进口双夹点(VPPPPP),并最终形成单独的进口夹点(PPP);在形成VPPPPP双夹点时,单压蒸发系统效率达到最大;研究还指出VPPPPP双夹点是单/双蒸发结构选择的临界点,并据此获得了单/双压蒸发系统结构选择的定量关联式,为ORC系统工质和结构的选择提供了定量分析基础。 相似文献
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受网络夹点控制的装置的改造分析 总被引:4,自引:0,他引:4
本文分析了过程夹点和网络夹点的不同,指出了在改造过程中存在网络夹点,并且节能潜力受网络夹点的控制,同时提出了克服网络夹点的途径,即分流和调整换热网络结构。通过对某炼油厂润滑油加氢补充精制装置的分析。提出了不分流时克服网络夹点的方法,即同一温闰的冷流体按热溶流率CP值减小依次被加热;同一温位的热流体按CP值减小依次被冷却。最后,文章对该装置提出了采用“一改动方案”的改造方案,节能效果和经济效益显著。 相似文献
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夹点技术是目前化工过程设计中一种全新的,强有力的方法,现已有许多领域得到广泛应用。本文概述了夹点技术的基本原理,介绍了国内外夹点技术在化工过程中设计中的应用现状,并对其应用前景作了展望。 相似文献
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The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion. 相似文献
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Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement 总被引:1,自引:0,他引:1
In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably. 相似文献
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组合凹模的应力分析是一个非常复杂的问题,对其进行精确分析是解决模具寿命的关键。本文采用有限元分析软件Ansys对转子的组合凹模进行了分析,为转子组合凹模的优化设计提供了依据。 相似文献