压力变化对乙苯/苯乙烯塔分离效率的影响

通过模拟计算,分析乙苯/苯乙烯塔压力变化对乙苯/苯乙烯、间二甲苯/苯乙烯、对二甲苯/苯乙烯相对挥发度的影响;压力变化对塔釜乙苯含量、间二甲苯含量、对二甲苯含量及塔顶乙苯中苯乙烯浓度的影响.得出降低操作压力,有利于提高粗苯乙烯塔分离效率的结论.     

沸石膜反应器苯脱氢反应性能

采用管式沸石膜反应器,研究了乙苯脱氢反应生成苯乙烯的性能。考察了不同渗透分离性能的沸石膜对乙苯脱氢反应的影响和不同沸石膜反应器上乙苯脱氢反应的规律。结果表明,与固定床操作条件下相比,沸石膜反应器乙苯转化率可提高近10％－16％,苯乙烯选择性可提高3％－5％。渗透分离性能是决定沸石膜提高脱氢反应性能的最重要因素,H2渗透量越大、H2／C3H8分离系数越高,对反应越有利。渗透分离性能相近但类型不同的沸石膜对乙苯脱氢反应性能有差异,其中Fe-ZSM-5沸石膜反应性能较好,这是杂原子Fe进入沸石骨架后引起的。反应后膜的渗透分离性能略有变化。     

导向筛板研究

详细介绍了导向筛板的结构和性能,用水和空气作了流体力学和传质效率的测定并与浮阀塔板作了比较;以乙苯-苯乙烯为介质作了分离试验;介绍了乙苯-苯乙烯分离的应用计算。     

离子交换树脂球体悬浮聚合技术探讨

对苯乙烯－二乙苯悬浮共聚制离子交换树脂珠体进行研究，搪塞了各种因素对珠体粒径的影响。     

乙苯/苯乙烯分离塔塔釜聚堵的原因分析及对策

对乙苯/苯乙烯分离塔塔釜聚堵的原因进行分析,提出相应的改进措施,通过技术改造及有效合理地利用阻聚剂解决了乙苯/苯乙烯分离塔塔釜聚堵的难题,稳定了苯乙烯精馏系统的生产。     

乙苯苯乙烯分离工艺技术经济分析

石油化工生产中,苯乙烯的制取生产主要是运用乙苯脱氢工艺在高真空条件下,反应锅低温二次加热而成,生产实践表明该工艺优点明显,反应物分离过程中,苯乙烯的损耗较低。比起同等的生产规模和生产能力的进口的反应锅高温真空条件下的乙苯/苯乙烯实施分离的化工工艺,效能高,损耗少,产量大,折合成本影响因素,运用该工艺投入苯乙烯制取生产,经济效益明显。本文通过对乙苯苯乙烯的特点及其分离技术和化工工艺的分析探讨,提出了现有条件下,生产苯乙烯的化工合成技术,应该优选真空条件下反应锅二次低温加热的乙苯脱氢实施分离的化工生产工艺。     

石油化工技术的新进展

对催化裂解制乙烯、丙烯、烯烃歧化、对二甲苯的分离技术、二甲苯异构化催化剂、乙苯／苯乙烯生产技术、环氧丙烷、1，4－丁二醇的生产技术、α－烯烃的制备技术及合成纤维及其原料中间体的研究进展进行了评述。     

用斜孔板与导向筛板单塔分离乙苯-苯乙烯的分析

国内已经成功地应用了斜孔板和导向筛板进行乙苯-苯乙烯的单塔分离技术。由于单塔板数多,又在减压下操作,所以,板压降和板效率是选择其板型的两个重要因素。本文试图通过两种板型在乙苯-苯乙烯分离的实验装置中测定的数据和工业装置中使用情况的分析,来比较两种板型的板压降和板效率。     

乙苯-苯乙烯单塔分离的部分工艺操作条件

苯乙烯单体是一种重要的化工原料。主要的生产方法是苯与乙烯烃化制乙苯,乙苯再脱氢制苯乙烯。在苯乙烯生产的精制过程中,乙苯和苯乙烯的分离是最关键的步骤。由于乙苯和苯乙烯在常压下的沸点分别为136.1℃和145.1℃[1],二者只相差9℃,     

乙苯/苯乙烯的节能分离方法

<正>公开(公告)号:CN101602640公开(公告)日:2009.12.16本发明涉及一种乙苯/苯乙烯的节能分离工艺,主要解决现有技术中乙苯/苯乙烯分离工业装置减少苯乙烯聚合损     

ADV微分浮阀在甲醇精馏系统改造中的应用

本文简要介绍了ＡＤＶ 微分浮阀塔的性能、特点,指出ＡＤＶ微分浮阀在老厂精馏或吸收系统改造中具有扩产降耗的作用,应用前景广阔。     

塔设备改造选型的分析

就当前扩产增容中塔设备设计和改造时板式塔和填料塔的选型问题加以分析。在评述目前国内常用的几种塔板和新型填料之后，着重介绍一种新型塔板（导向梯形浮阀塔板）和一种新型填料（波环填料——乾隆帕克）。     

甲苯二异氰酸酯精制塔的扩产优化改造

为对原年产20ktTDI的流程进行扩产改造,使其能满足年产75ktTDI的能力,对重溶剂法生产工艺中TDI精制塔进行了模拟分析,认为原塔板数太少,造成需要很大的回流量来保证塔的分离要求,另外,此塔上下负荷相差较大,可以将原来塔分成为两段操作。在此基础上,提出了双塔流程的改造方案,并对双塔流程进行了模拟优化,找到了最优的设备参数和操作参数,即新增一塔径3m、理论板数25块的塔与原有旧塔组成双塔流程,即可满足年产75ktTDI的能力。两塔循环量为14000kg/h时,既可保证系统耗能不太高,又能够利用原有设备,达到了优化流程、节省投资的目的。     

SBS胶粒干燥特性及后处理装置扩量改造

针对SBS现有生产工艺和设备中存在的问题 ,在单层圆筒形流化床干燥试验装置上 ,采用减重法对SBS生产装置中膨胀干燥机出口处的SBS胶粒进行了干燥动力学的研究。测定了风温、风速、筛板开孔率与干燥速率的关系 ;并从微观结构上分析了不同牌号SBS的干燥特性。得到了适合生产装置操作条件的干燥曲线 ,为优化生产装置 ,提高产量提供了理论依据 ,并提出了可行的改进措施     

高效导向筛板及填料在醋酸乙烯精馏塔中的应用

对醋酸乙烯 -醋酸甲酯精馏塔进行了技术改造。采用计算机模拟精馏塔的回流比、塔板数、能耗、冷却负荷等 ,优选出最佳方案 ,即采用回流比 15、塔板数 70 ,并应用高效导向筛板塔及填料代替原浮阀塔 ,改造后生产能力、产品质量均得到提高     

Overall efficiency evaluation of commercial distillation columns with valve and dualflow trays

The main objective of this work is to establish appropriated ways for estimating the overall efficiencies of industrial distillation columns with valve trays with downcomer and dualflow trays. The knowledge of efficiencies has fundamental importance in the design and performance evaluation of distillation columns. Searching in the literature, a tree of alternatives was identified to compose the tray efficiency model, depending on the mass transfer models, the liquid distribution and vapor flow models on the tray, the liquid entrainment model, the multicomponent mixture equilibrium model, the physical properties models, the height of froth on the tray model and the efficiency definition. In this work, different methods to predict the overall efficiency of distillation columns with valve and dualflow trays were composed and compared with data from three commercial distillation columns under different operating conditions. The models were inserted in the Aspen Plus 12.1 simulator, in Fortran language, together with tray geometrical data, fluid properties and operating data of the distillation columns. For each column, the best thermodynamic package was chosen by checking the temperature profile and overhead and bottom compositions obtained via simulation against the corresponding actual data of industrial columns. A modification in the fraction of holes evaluation that is jetting parameter of the Garcia's hydraulic model of dispersion above the tray was proposed. This modification produced better results than the original model to predict the fraction of holes that are jetting and in the efficiency of dualflow trays and similar results to Garcia model in the efficiency evaluation of valve trays. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

The second law optimal state of a diabatic binary tray distillation column

A new numerical procedure to minimize the entropy production in diabatic tray distillation columns has been developed. The method was based on a least square regression of the entropy production at each tray. A diabatic column is a column with heat exchangers on all trays. The method was demonstrated on a distillation column separating propylene from propane. The entropy production included contributions from the heat transfer in the heat exchangers and the mass and heat transfer between liquid and vapor inside the distillation column. It was minimized for a number of binary tray distillation columns with fixed heat transfer area, number of trays, and feed stream temperature and composition. For the first time, the areas of heat exchange were used as variables in the optimization. An analytical result is that the entropy production due to heat transfer is proportional to the area of each heat exchanger in the optimal state. For many distillation columns, this is equivalent to a constant driving force for heat transfer. The entropy production was reduced with up to 30% in the cases with large heat transfer area and many trays. In large process facilities, this reduction would ideally lead to 1-2 GWh of saved exergy per year. The most important variable in obtaining these reductions is the total heat transfer area. The investigation was done with a perspective to later include the column as a part in an optimization of a larger process. We found that the entropy production of the column behaved almost as a quadratic function when the composition of the feed stream changed. This means that the feed composition is a natural, easy variable for a second law optimization when the distillation column is a part of a process. The entropy production was insensitive to variations in the feed temperature.     

Hydrodynamic model for controlled cycling in tray columns

The paper describes a model for controlled cycling in tray columns. Gas phase dynamics and hydrodynamic relations are included in the proposed model. The model has been simulated on a digital computer.Gas phase dynamics is found to play an important role for cyclic operation of distillation columns, while as the effect of gas phase dynamics can be ignored for absorption columns.In a 5-tray distillation column reasonable separation between liquid and vapour flow periods can be achieved, but with increasing number of trays the switch-over from one period to another becomes less ideal. For a ten tray column the flow situation is unacceptable.The simulations also show that the plug flow condition in the liquid flow period is most difficult to satisfy in the top and bottom of the column. The risk of flooding on some trays and other trays running dry increases when the numbers of trays increases.Finally it is shown that the hydrodynamic behaviour may be improved by changing the geometry of some of the trays.     

计算传质法预测精馏塔效率(英文)

A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for de-sorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the ex-perimental measurement. The validation of the proposed model was further tested by comparing the simulated re-sult with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the strip-ping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray effi-ciencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column re-ported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.     

Theoretical and experimental investigation on the characteristics of fly‐ash scrubbing in a fixed valve tray column

The goal of this study is to evaluate the performance of a fixed valve tray column designed to remove fly‐ash particles. A series of experiments were carried out at room temperature to demonstrate the collection efficiency of a fixed valve tray column at different gas and liquid superficial velocities. The fly‐ash particles removal characteristics of the fixed valve tray column were evaluated by measuring variations of concentration and size distribution of particles in the outlet. The mechanism of particle removal in this turbulent dispersion system was theoretically analyzed on the basis of diffusion, interception, sedimentation and impaction, and a model was proposed to predict the collection efficiency. The results show that the simulation results agree well with the experimental data. In contrast to most of the conventional models, the present model is capable of evaluating the effects of bubble hydrodynamics, system property, and operation conditions on the collection efficiency. The model is expected to guide effectively the design and operation of valve tray washing columns, which is widely applied nowadays. © 2012 American Institute of Chemical Engineers AIChE J, 59: 2168–2178, 2013