反应精馏合成甲基丙烯酸甲酯工艺优化及节能

以等摩尔下甲基丙烯酸和甲醇反应精馏合成甲基丙烯酸甲酯过程为研究对象，探究了塔内耦合反应精馏工艺(RD)和带侧反应器的反应精馏工艺(SRC)。在MAA处理量为10kmol/h、MAA的转化率为98.6%条件下，以最小年总费用(TAC)为目标函数，采用序贯优化迭代法，经Aspen Plus对RD工艺和SRC工艺进行模拟计算与优化研究，得到优化后的RD工艺和SRC工艺参数；以TAC和CO₂排放量为考察指标，对比了RD工艺和SRC工艺。研究结果表明：相比于RD工艺，SRC工艺具有显著优势，TAC降低8.5%,CO₂排放量降低16.3%，此时SRC工艺参数为：N_T=26,N_R=3,3台侧反应器(R1/R2/R3)的进料位置NF分别为第6、第11和第14块塔板，SRC塔侧线采出进侧反应器(R2/R3)的进料位置为第23和第24块塔板，进3台侧反应器(R1/R2/R3)的MeOH的分配比为0.58∶0.22∶0.2,TAC为115.23×104 CNY/a。     

多效反应精馏过程生产氯化苄的能量集成

以甲苯氯化生产氯化苄为研究对象,对带侧反应器的反应精馏与精制塔串联工艺(CSRRT)进行研究及能量分析,建立了分段反应精馏与精制塔串联生产氯化苄的新工艺。利用精制塔塔顶蒸汽潜热加热第一段反应精馏塔的塔釜,建立了多效反应精馏(MERD);进一步利用侧反应器的甲苯氯化反应热加热第一段反应精馏塔的塔板物料,建立了多效透热反应精馏(MEDRD)。在相同生产要求下,对3种工艺的能耗进行比较。结果表明,MERD和MEDRD过程实现了能量的优化利用,与CSRRT过程相比,塔釜总再沸器热负荷分别降低16.8%和33.7%。     

苯氯化三相催化精馏工艺技术研究

针对苯氯化生产氯化苯气液连串反应体系 ,提出采用三相催化精馏技术 ,通过分别改变苯的回流量和氯气通入量 ,考察了这些因素对催化精馏过程的影响。实验结果表明 :采用催化精馏技术是完全可行的。在适宜的操作条件下 ,到达反应终点 (间歇操作 )时塔釜氯化产物中苯的含量可低于 1% (质量 ) ,同时氯化苯的含量可达到 96 % (质量 )     

甲苯氯化物系列产品市场开发应用

邻氯甲苯是邻氯甲醛、邻氯苯甲酸的重要原料。 　　工业上生产邻氯甲苯以甲苯为原料,催化氯化(或选择性氯化)后经过精馏而得,该工艺的关键技术是精馏。国内最大的氯甲苯生产厂为株洲化工厂,产能2 500 t/a。国内1997年1～7月份氯甲苯的进口量为519.9 t。……     

带多台侧反应器的间歇反应精馏生产氯化苄非稳态模拟与过程设计

建立了带多台侧反应器的间歇反应精馏过程,采用Aspen Plus模拟软件构建该过程的非稳态模拟方法。以甲苯氯化生产氯化苄为对象,研究了侧反应器台数、侧线采出率和采出位置、氯气分配、反应精馏时间及再沸器蒸发量等设计参数对间歇反应精馏过程的影响规律。模拟结果表明反应能力和分离达到最佳匹配的最优设计参数为:精馏塔塔板数8块、侧反应器2台、氯气分配7:3、从第3块塔板侧线采出、采出率85%、再沸器蒸发量25 kmol?h?1。在此结构参数和操作条件下完成50 kmol甲苯氯化所需时间为9 h,甲苯的转化率和氯化苄的选择性均可达到98.0%以上。     

2,4-二氯甲苯生产工艺的改进

针对目前国内2,4 二氯甲苯生产工艺存在的主要问题,通过改进氯化合成工艺,采用先进碱洗精馏技术,提高了氯化反应收率和碱洗精馏效果,其中氯化反应收率达到了75%以上,氯气利用率>92%,产品质量在99.5%以上,从而有效地降低了生产成本,减少了环境污染,经济效益和社会效益显著,具有很好的推广应用前景。     

不同温度反应与精馏集成生产醋酸叔丁酯的过程模拟

针对醋酸与异丁烯加成酯化可逆反应温度低、精馏分离温度高的特点,采用带侧反应器的反应精馏集成过程(SRC)建立了低温反应与高温精馏集成的醋酸叔丁酯生产新工艺。固定塔釜上升汽化量100 kmol·h^-1,规定新鲜醋酸进料的转化率达到99.9%、醋酸叔丁酯选择性达到97.0%,采用过程模拟考察了进入侧反应器的精馏塔采出量、精馏段塔板数、侧反应器进出口间隔塔板数和侧反应器台数等参数对合成醋酸叔丁酯的SRC过程的影响。模拟结果表明,醋酸与异丁烯加成酯化生产醋酸叔丁酯的SRC过程中只有反应能力与分离能力达到最佳匹配才能使单位产品的生产成本最小。研究结果为醋酸叔丁酯生产新工艺的放大设计与优化奠定了基础。     

乙酸光氯化制备氯乙酸的反应动力学

在环流反应器中实测了在光照下、不同氯化温度时乙酸、氯乙酸和二氯乙酸的浓度随反应时间的变化关系。建立了乙酸光氯化连串反应动力学模型 (Ⅰ )和平行 连串反应动力学模型 (Ⅱ ) ,得到了模型的解析解。通过参数估值 ,求得了表观反应速率常数。经模型检验 ,发现模型 (Ⅱ )与实验数据的吻合程度较好。计算了实验温度下的氯气在乙酸 氯乙酸混合液中的溶解度数据 ,结合表观反应速率常数 ,计算得到了本征反应速率常数     

对氟苯甲醛的合成研究

以对氟甲苯为起始原料,经光氯化、精馏分离、水解合成对氟苯甲醛,总收率为93.2%(以对氟甲苯计)。重点讨论了光氯化条件。     

醋酸甲酯侧反应精馏过程的多变量动态控制

侧反应器与精馏塔的耦合结构与物料交换方式的灵活性,造成系统的自由度高、设计变量多,增加了该过程的稳态优化模拟和动态控制的难度。针对侧反应精馏过程(SRC)的平滑操作和自动控制问题,以醋酸甲酯工业生产过程为例,采用基于独立反应量的稳态设计方法获取最佳的反应精馏集成结构和操作参数,在此基础上设计了以产品成分调节变比值控制为主的多变量控制方案,并通过在Aspen流程模拟软件建立醋酸甲酯侧反应精馏动态流程模拟系统,验证控制方案的有效性。     

A novel process integrating vacuum distillation with atmospheric chlorination reaction for flexible production of tetrachloroethane and pentachloroethane

In this paper,we developed a novel process integrating vacuum distillation with atmospheric chlorination reaction (VD-ACR) to realize the flexible production of tetrachloroethane (TeCA) and pentachloroethane (PCA)from 1,2-dichloroethane (DCA).During the simulation,the distillation column and reactors were operated for separation and chlorination respectively under variable pressures and temperatures.It is interesting to note that VD-ACR processes producing pure TeCA or PCA can exhibit the similar configuration parameters after optimization,which enables the flexible production of TeCA and PCA with different molar ratios via changing operating parameters.The molar ratio of TeCA/PCA can be fine-tuned within the range of 0.9∶0.1-0.1∶0.9 through adjusting the amount of chlorine pumped into side reactors,giving rise to the increase of the heat duty of reboiler by five times.A pilot-scale experiment was then operated based-upon this VD-ACR process and the result matched well with the simulation.Therefore,the VD-ACR model presented in this study will be beneficial for the industrial-scale flexible production of TeCA and PCA from DCA.     

Design of entrainer-enhanced reactive distillation for the synthesis of butyl cellosolve acetate

An innovative entrainer-enhanced reactive distillation (RD) process is presented, which aims to the production of high-purity butyl cellosolve acetate from butyl cellosolve and acetic acid via an esterification reaction. This entrainer-enhanced RD process can procure technical advantages from both heterogeneous azeotropic distillation and RD. Solvents such as cyclohexane, ethylene dichloride, toluene, and octane are considered as candidates in this esterification RD process. The function of entrainers is to simplify the separation between water and acetic acid. For this purpose, the proper entrainer to use is thus evaluated based on its mutual solubility with water in two liquid phases. Simulation results reveal that total annual cost can be substantially reduced when cyclohexane, toluene, and octane are used as entrainers in the RD column. The octane-enhanced RD provides the most economical design in this studied case.     

A novel multistage vapor recompression reactive distillation system with intermediate reboilers

Most of the published studies have focused on the thermal integration of nonreactive distillation columns. The key limitation of reactive distillation (RD) technology is that the necessary conditions (such as pressure and temperature) for the reaction must match those of distillation. Owing to this constraint, the reaction conversion may be adversely affected at the elevated pressure in the reactive section of an internally heat integrated distillation column (HIDiC). This fact forces us to adopt an external heat integration approach for an industrial heterogeneously catalyzed ethyl tert‐butyl ether (ETBE) RD column. The direct vapor recompression column (VRC) is an external heat integration scheme that is successfully used as an energy efficient scheme for separating a close‐boiling mixture. Interestingly, there exists a large temperature difference between the two ends of the representative ETBE column, and it makes the external heat integration more challenging. Aiming to improve the thermal efficiency of the ETBE column under the VRC framework, various heat pump arrangements with intermediate reboiler(s) (IR(s)) are explored and analyzed with performing a comparative study in terms of energy consumption and economics. To improve further the thermal efficiency, in this contribution, a novel multistage vapor recompression RD column with IRs is introduced addressing a number of practical concerns. An algorithm for the proposed column is formulated showing the sequential steps involved in heat integration. It is inspected that the proposed multistage vapor recompression RD system appears overwhelmingly superior to the classical vapor recompression RD and its conventional stand alone column providing a significant savings in energy as well as cost. © 2012 American Institute of Chemical Engineers AIChE J, 59: 761–771, 2013     

Separation of ternary system (1,2-ethanediol + 1,3-butanediol +1,3-propanediol) by distillation

A study on separation of system (1,2-ethanediol (1,2-EG) + 1,3-butanediol (1,3-BD) + 1,3-propanediol (1,3-PG)) was conducted in the article. Vapor–liquid equilibria (VLE) behaviors of systems (1,2-EG + 1,3-BD), (1,2-EG +1,3-PG), (1,2-EG + 1,3-BD + 1,3-PG) were studied at 101.3 kPa . A two-column (column C1 and column C2) sequence distillation process at normal pressure was designed and optimized to separate the ternary mixture. The results have shown Wilson model is the most appropriate one to describe the ternary system; product amounts of 1,2-EG, 1,3-BD, and 1,3-PG can be up to 0.970, 0.945, and 0.980, respectively, under optimized conditions.     

环丁砜萃取精馏过程模拟分析及工艺参数优化

以环丁砜-烃类相平衡数据和NRTL-RK热力学方法为基础，对环丁砜萃取精馏过程进行了全流程模拟和工艺操作参数优化。综合考虑各个操作变量及其关联，提出了基于局部耦合参数迭代优化的整体协同优化的策略。通过文献数据回归和Aspen Plus物性估算系统相结合，补充修正了缺失的模型参数，并以此模拟分析了各关键操作参数对环丁砜萃取精馏过程能耗和分离效果的影响。结果表明：当萃取精馏塔操作压力为0.17 MPa，溶剂回收塔操作压力为0.05 MPa时，贫溶剂最佳温度为100℃，原料饱和气相进料的最佳进料位置为第50块塔板；溶剂回收塔最佳回流比为0.33；最佳进料位置为第6块塔板，汽提水量为2853 kg·h^-1。优化后，装置最小热公用工程由1.158 GJ·t^-1下降至0.802 GJ·t^-1，节能效果显著。     

带侧反应器反应精馏塔的苯氯化与氯苯精馏过程模拟研究

引入独立反应量概念建立了多侧线进料的带侧反应器的反应精馏塔平衡级模型,并运用Newton-Raphson法解该模型的MESH方程. 将该方法应用于苯氯化反应精馏过程模拟,模型具有很好的收敛效果. 在给定的模拟条件下,Cl2进料量为8 kmol/h时,产品氯化苯纯度达96.8%,最佳苯进料量为7.77 kmol/h. 模拟结果可用于指导苯氯化生产.     

Process intensification and energy saving of reactive distillation for production of ester compounds

Reactive distillation(RD) process is an innovative hybrid process combining reaction with distillation, which has recently come into sharp focus as a successful case of process intensification. Considered as the most representative case of process intensification, it has been applied for many productions, especially for production of ester compounds. However, such problems existing in the RD system for ester productions are still hard to solve,as the removal of the water which comes from the esterification, and the separation of the azeotropes of ester–alcohol(–water). Many methods have been studying on the process to solve the problems resulting in further intensification and energy saving. In this paper, azeotropic–reactive distillation or entrainer enhanced reactive distillation(ERD) process, reactive extractive distillation(RED) process, the method of co-production in RD process, pressure-swing reactive distillation(PSRD) process, reactive distillation–pervaporation coupled process(RD–PV), are introduced to solve the problems above, so the product(s) can be separated efficiently and the chemical equilibrium can be shifted. Dividing-wall column(DWC) structure and novel methods of loading catalyst are also introduced as the measures to intensify the process and save energy.     

Inter-integration reactive distillation with vapor permeation for ethyl levulinate production: Equipment development and experimental validating

Ethyl levulinate, one of the main derivatives of levulinic acid (LA), is of significant potential as platform chemicals for bio-based materials. The esterification of LA was generally carried out in a conventional batch reactor or in a conventional reactive distillation column. However, traditional methods are hard to deal with equilibrium limited reactions and azeotropic issues. Therefore, the inter-integration reactive distillation with vapor permeation (R-VP-D) process, which integrated reaction, vapor permeation, and distillation into one single unit, is proposed in this paper and validated in the pilot-scale experiments. A comparative study is made between a pilot-scale RD column with and without VP module. Owing to the water-selective VP membrane and the ingenious design of related apparatuses, the R-VP-D process reveal a superiority in LA conversion of 21.9% maximum higher than RD without VP process and removing of product water about 53.6% from VP module, which indicates its promising industrial application in process intensification field.     

萃取精馏分离碳酸二甲酯-乙醇二元共沸物

测定了101.3 kPa下乙醇-碳酸二甲酯（DMC）和DMC-糠醛二元体系的汽液平衡数据,以及乙醇-DMC-糠醛体系在溶剂比为1∶1时的三元汽液平衡数据。结果表明,糠醛的加入可以改变乙醇和DMC的相对挥发度,并且当糠醛的摩尔分数大于0.25时,乙醇-DMC二元物系的共沸点消失。因此,可以采用萃取精馏的方法以糠醛为溶剂分离乙醇和DMC的混合物。采用Aspen Plus软件对连续萃取精馏分离乙醇-DMC共沸物的过程进行了模拟。结果表明,单塔带侧线采出的操作方式比双塔操作方式更有优势。