反应隔壁精馏塔合成乙酸丁酯模拟研究

提出用反应隔壁精馏塔合成乙酸丁酯的工艺流程,以反应隔壁精馏塔代替常规乙酸正丁酯反应精馏塔和乙酸正丁酯产品精制塔,将反应隔壁精馏过程和常规反应精馏生产过程模拟比较,在相同生产能力和产品纯度要求下,反应隔壁精馏塔可降低能耗30%以上,同时可减少设备投资。最后,对提出的反应隔壁生产乙酸丁酯的生产流程进行优化,考察进料位置、采出进料比、副塔液相分配比等因素对乙酸丁酯生产过程能耗和乙酸丁酯产品纯度的影响,并得到适宜的生产操作条件。     

隔壁塔反应精馏合成异丙醇模拟及节能效益研究

采用反应精馏隔壁塔技术,以甲醇钠为催化剂,通过乙酸异丙酯与甲醇酯交换反应合成异丙醇。利用Aspen Plus模拟软件对常规反应精馏工艺和反应精馏隔壁塔工艺分别进行模拟分析。结果表明:与常规反应精馏工艺相比,反应精馏隔壁塔不但可以得到纯度99.8%以上的异丙醇产品,而且异丙醇收率98.54%,节能20.4%。     

烯丙醇脱水共沸精馏过程的节能工艺研究

针对烯丙醇脱水共沸精馏过程能耗高的特点,本文使用专业模拟软件Aspen Plus对烯丙醇脱水工艺建立了共沸精馏稳态模型并将热泵精馏、隔壁塔分别应用到共沸精馏工艺,以能耗和年总费用为评价指标,对其进行节能优化。与常规共沸精馏对比结果为：回收期较短时（〈10年）采用共沸隔壁塔方案节能效果更明显。当回收期较长时（〉9年）热泵精馏方案经济效益更加突出。     

用分隔壁精馏塔分离松节油中蒎烯的模拟

提出采用分隔壁精馏塔代替常规精馏塔序列分离松节油以得到α-蒎烯和β-蒎烯的新工艺。为了选择适合松节油体系的分隔壁塔结构,采用Aspen软件分别模拟计算了DWC、DWC-SS和DWC-SR三种塔型,结果表明,与常规工艺相比DWC塔可节能26%,DWC-SS塔可节能16.6%,DWC-SR塔可节能12.5%。在此基础上考察了DWC塔进料位置、回流比、隔板位置、气液相分配比和中间产品出料位置对分离效果和热负荷的影响,得出气液相分配比是影响分隔壁塔操作稳定性的主要因素。     

甲醇精馏系统模拟与优化

本文应用过程模拟软件Aspen Plus,采用Wilson和PSRK相结合的物性方法,实现了对某厂甲醇四塔双效精馏系统的模拟.为降低生产成本,本文通过对系统模拟与分析,对生产的工艺流程进行进一步改进,并提出3个优化方案:(1)增加加压精馏塔侧线采出送常压精馏塔作为进料;(2)对常压精馏塔塔底和回收塔塔底部分废水进行循环;(3)采用加压精馏塔与预精馏塔双效精馏.经过模拟计算,改进后的新工艺流程在保证甲醇产品的产量与质量的前提下,共能节省公用工程热量21173 kW,节省公用工程冷量16268 kW,节省工业用水10375 kg/hr,污水处理量减少10 375 kg/hr.本文所选用的单元操作模型及物性方法对于模拟甲醇精馏系统是准确可靠的,因此本文所提出的优化方案能为甲醇工业生产节能、节水以及减少废水排放的改造和新工艺流程的开发提供理论依据.     

脱氢法生产乙酸乙酯的流程模拟与优化

运用化工流程模拟软件Aspen Plus,对乙醇脱氢生产乙酸乙酯的工艺流程进行模拟计算分析,建立了10 wt/a乙酸乙酯生产工业过程的详细流程,最终乙酸乙酯产品纯度达99.98%,收率可达98.26%。对精馏工段关键的乙醇塔和粗塔组成的差压精馏体系进行了灵敏度分析,重点考察了进料板位置、回流比、塔顶采出量等工艺参数对精馏塔分离效果和操作能耗的影响,得到优化的参数,即乙醇塔新鲜进料板位置为第12块,循环物料进料位置为第9块,回流比2.10,塔顶采出量为33500 kg/hr:粗塔进料板位置为第9块,回流比为1.43,塔顶采出量为21000 kg/h。本文研究结果为工业上选择合适的设备参数和操作参数提供有力的数据支持。随后对原换热网络进行了进一步优化设计,节省能耗24.56%。     

部分热集成变压精馏分离酚焦油裂解产物过程模拟与优化

由于酚焦油裂解产物中,苯酚-苯乙酮体系的共沸组成对压力变化敏感,提出了变压精馏分离苯酚-苯乙酮共沸体系的新工艺,选择UNIQUAC物性方法,根据变压精馏原理确定了高、低压塔间循环物流的流量,用Aspen Plus软件对该工艺流程进行了模拟,提出了ASPEN Plus中精馏塔参数优化的通用方法,从而获得了各塔的最优参数。通过对模拟结果的分析,提出以高压塔的塔顶蒸汽为低压塔的塔釜热源的热集成新工艺,并将该工艺所需能耗和年度总费用与常规的变压精馏工艺相对比,结果表明高压塔冷凝水用量节省近2万吨/年,低压塔年度投入总费用降低约30%。     

变压精馏分离乙酸乙酯与甲醇的工艺模拟及优化

基于乙酸乙酯与甲醇的共沸组成随压力的变化较为敏感的特性,提出采用变压精馏分离乙酸乙酯与甲醇的工艺。以NRTL方程为热力学模型,利用ASPEN PLUS模拟软件对此分离过程进行模拟计算,并由汽液相平衡数据对NRTL方程中二元交互作用参数进行回归。考察了高压塔与常压塔的理论塔板数、进料位置及回流比对分离效果的影响。结果表明,变压精馏可用于乙酸乙酯与甲醇的分离,最佳的工艺条件为:高压塔操作压力0.7 MPa,理论板数46,第35块塔板进料,回流比2,塔釜得到摩尔分数大于99.14%以上的乙酸乙酯;常压塔操作压力0.1 MPa,理论板数50,第10块塔板进料,回流比3,塔釜可得到摩尔分数大于99.98%以上的甲醇。     

高纯度酒精蒸馏中常见挥发性杂质的分离过程模拟

酒精工业在国民经济中具有重要的地位,酒精产品广泛地应用于重要的工业部门,其中高纯度酒精具有严格的杂质含量控制,其产品主要用于涉及人体健康的食品、制约行业.本文以酒精5塔蒸馏工艺流程为基础,利用稳态流程模拟软件Aspen Plus模拟高纯度洒精蒸馏过程,模拟结果与实际情况相当吻合,可为工艺流程的生产实践与诊断优化提供数据支持.通过流程中挥发性杂质的分布及运动情况阐述其传质过程,水洗塔利用酯、醛等轻物质在稀酒精中的强挥发性对其予以分离,精馏塔利用杂醇油物质的积聚性,通过塔中侧线抽取分离,甲醇塔利用浓酒精中甲醇与乙醇明显的挥发能力差异实现分离.由模拟可知,通过5塔蒸馏工艺可得到符合国家标准规定的高纯度酒精产品,但工艺并不能分离酒精发酵醪液中所有非目标组分.随着酒精产品贸易对象的拓宽,传统的5塔工艺需要进一步改进以适应新的要求.     

基于正交数值试验的精馏过程参数的优化

精馏是1种重要的高成本的工业单元操作,其操作费用及设备投资费用主要和进料位置、回流比及塔板数有关.然而,过程参数对精馏操作费用和设备投资费用的影响是复杂的,且参数之间有着强耦合关系.因此本文结合丙二醇脱水塔过程参数的优化实例,引入正交试验设计思想,基于Aspen Plus的模拟结果,确定精馏过程的年度化总费用,通过正交数值试验,实现参数优化,并验证了以上方法的可行性和有效性.结果表明,依据基于正交数值试验得到的精馏过程最优参数进行设计,即第6块板进料,回流比为1,塔板数为9,可使丙二醇脱水塔年度化总费用比现行工程实际年度化总费用降低0.35%,从而弥补了依次进行单参数优化方法中的缺陷,达到了节能降耗的目的.     

反应精馏合成乙酸乙酯的实验研究与模拟

本文以Amberlyst-36Wet离子交换树脂为催化剂,采用间歇搅拌釜式反应器,在消除内外扩散影响的条件下,测得不同温度下反应速率常数.研究自制反应精馏塔中(直径25 mm,高2.2 m)乙酸乙酯的合成工艺,得到反应精馏的工艺参数.在实验基础上,建立改进工艺的Aspen Plus模拟流程图.实验结果与模拟计算值吻合良好,表明所建立的Aspen Plus模型能够很好地描述反应精馏合成乙酸乙酯过程.以乙醇转化率、产品乙酸乙酯的收率和塔顶油相乙酸乙酯的质量分率为考察目标,通过流程模拟和灵敏度分析,确定该工艺的最佳工艺参数:精馏段、反应段和提馏段的理论板数分别为9、7和7;醋酸和乙醇的最佳进料位置在第9块和第16块塔板上;回流比R为1.6.在此工艺条件下,产品乙酸乙酯的含量是95.2%(wt),乙醇转化率为96.1%.     

Operation of divided wall column with vapor sidedraw using profile position control

Divided wall column is a promising energy-alternative for separation process which is capable of achieving typically 30% energy and capital cost savings compared with a conventional distillation system. Despite such advantages, divided wall column (DWC) is not widely used from the fear to run into controllability problems due to the DWC complexity. A profile position control scheme was proposed to overcome the control problems. Relative gain array analysis and singular value decomposition were used to determine optimal control configuration. Dynamic simulation showed that the profile position–product composition cascade control can keep the product purities at the desired values in the face of feed and internal disturbances.     

Plant-wide design and control of acetic acid dehydration system via heterogeneous azeotropic distillation and divided wall distillation

Energy-saving plant-wide design and plant-wide control of an acetic acid dehydration system with the feed containing methyl acetate and p-xylene are investigated in the study. A heterogeneous azeotropic distillation using isobutyl acetate as an entrainer is designed to obtain high-purity acetic acid at the column bottom and to keep a small acetic acid loss through the top aqueous draw. The accumulation of p-xylene in the column is avoided by adding a side product stream. The mixture in the aqueous phase of decanter, containing mostly water, methyl acetate, and isobutyl acetate is separated using a divided wall distillation column. The whole acetic acid dehydration system includes a heterogeneous azeotropic distillation column and a divided wall distillation column.The control strategies using temperature loops are proposed for this acetic acid dehydration system. For the heterogeneous azeotropic distillation column, the requirements for acetic acid compositions in both the aqueous phase of the decanter and the column bottom can be satisfied by designing entrainer inventory temperature control and cascade temperature control simultaneously. The stages of controlled temperatures are chosen by singular value decomposition and closed-loop analysis methods based on the criteria of minimum entrainer makeup. For the divided wall distillation column, steady-state analysis methods are used for the selection of proper controlled and manipulated variables and the determination of their pairings. Dynamic simulation results demonstrate that the proposed plant-wide control strategy can maintain product purities and reject external disturbances in feed flow and composition changes as well as internal disturbances such as changes in liquid and vapor splits.     

牛顿插值算法在精馏塔理论塔板数计算中的应用研究(英文)

图解法计算精馏塔理论塔板数是精馏塔设计中常用的一种理论塔板数的计算方法,该方法简单、直观,但计算精度相对较差,本文采用牛顿插值计算方法结合图解法计算精馏塔的理论塔板数,既保留图解法的直观效果,又可以直接进行计算.采用面向对象的设计方法.在VC++环境中开发了相应的软件,并对乙醛-苯、苯-甲苯、水-乙酸等二元体系进行验证.     

Design and control of an ethyl acetate process: coupled reactor/column configuration

In this paper, design and control of a realistic coupled reactor/column process to produce ethyl acetate is studied. The process design is more complicated because the ethyl acetate product is neither the lightest nor the heaviest component in the system. A search procedure is proposed to obtain the optimum process design and operating condition of this process. The optimum process design is the one that minimize the Total Annual Cost (TAC) of this process while satisfying the stringent product impurity specifications. The optimum overall process design includes a continuous-stirred tank reactor (CSTR) coupled with a rectifier, a decanter, another stripper, and a recycle stream. After the process design is established, the next step is to use dynamic simulation to test the appropriate control strategy for this process. Sensitivity analysis is performed to obtain the suitable temperature control points for the columns. The proposed control strategy is very simple containing only one temperature control loop in each column. This recommended simpler control strategy uses the ratio of acetic acid feed rate to ethanol feed rate to control the 5th stage temperature of the rectifier and uses the stripper reboiler duty to control the 5th stage temperature of the stripper. The proposed control strategy does not need any on-line composition measurements and can properly hold product purity in spite of feed flow rate and feed composition disturbances. For small deviations of the product impurity compositions during disturbances, a slow cascade outer composition loop structure can be implemented using off-line composition measurements from the quality lab.     

复合萃取精馏分离乙酸乙酯-乙醇-水的研究

介绍了乙酸乙酯在工业生产中的应用；在前人的研究基础上，采用合适的萃取剂，在萃取塔上考察了不同溶剂比、回流比等因素对产品纯度的影响，并摸索复合萃取分离乙酸乙酯－乙醇－水三元体系的适宜操作条件，在溶剂比为1：1：1，R=4时，能一次得到高浓度（99．5％）的乙酸乙酯，同时得到95％的乙醇溶液，得率高、能耗低，为工业试验提供了基础数据。     

The effect of the microfluidic diodicity on the efficiency of valve-less rectification micropumps using Lattice Boltzmann Method

The efficiency of the valve-less rectification micropump depends primarily on the microfluidic diodicity (the ratio of the backward pressure drop to the forward pressure drop). In this study, different rectifying structures, including the conventional structures (nozzle/diffuser and Tesla structures), were investigated at very low Reynolds numbers (between 0.2 and 60). The rectifying structures were characterized with respect to their design, and a numerical approach was illustrated to calculate the diodicity for the rectifying structures. In this study, the microfluidic diodicity was evaluated numerically for different rectifying structures including half circle, semicircle, heart, triangle, bifurcation, nozzle/diffuser, and Tesla structures. The Lattice Boltzmann Method (LBM) was utilized as a numerical method to simulate the fluid flow in the microscale. The results suggest that at very low Reynolds number flow, rectification and multifunction micropumping may be achievable by using a number of the presented structures. The results for the conventional structures agree with the reported results.     

Computational simulation of flow over stepped spillways

Numerical simulations of water flow over stepped spillways with different step configurations are presented. The finite element computational fluid dynamics module of the ADINA software was used to predict the main characteristics of the flow. This included the determination of the water surface, the development of skimming flow over corner vortices, and the determination of energy dissipation. Since the actual flow is turbulent, the k-ε flow model was used. A two-phase solution process was adopted in order to optimize the overall simulation efficiency. In the first phase, a simple yet reasonable water surface consisting of three straight lines was used as an initial guess and was treated as a fixed wall. In the second phase, the results from the first phase were used as initial conditions and the water surface was treated as a free surface that evolved to attain a steady state configuration. For all the cases considered, the predicted water surface profile over the entire length of the spillway was in close agreement with the experimentally measured water surface profile. The predicted energy dissipation was also comparable to the experimentally attained values.     

分隔精馏塔分离烷烃混合物的模拟

提出采用分隔精馏塔替代常规精馏塔分离烷烃混合物的新工艺。通过Aspen模拟和灵敏度分析,着重探讨分隔精馏塔中进料位置、回流比、连接流的位置、回流气液分配比等工艺参数对分离效果和热负荷的影响,并确定分隔精馏塔的最佳操作条件是。结果表明,分隔精馏塔单塔就能达到常规的烷烃分离要求,但是对精馏塔的控制要求更高。能耗分析表明分隔精壁塔工艺比传统的分离过程节能45%。