高真空扩散泵油275~#生产工艺改进

简述了高真空扩散泵油275#的生产工艺,分析了水解釜材质和精馏系统存在的问题,提出了改造意见,并比较了改造效果。结果表明,将水解釜材质由搪瓷更换成不锈钢后,既节约原材料消耗,又减少水洗过程中的物料损失和排污量,从而大幅度降低了产品的生产成本;精馏系统装置经过改造后,产品中的三甲基五苯基三硅氧烷含量比改造前生产的产品高出15个百分点,提高到84%以上;且产能翻一番。     

粗酚精制工艺的改进

上海焦化厂酚精馏改造工程设计采用三釜二塔间歇式减压蒸馏新工艺,以取代(冫日)有四釜三塔间歇式减压蒸馏工艺。并且在国内首家采用十字架型浮阀(轻阀)精馏塔。新工艺简化了生产流程,减少了一组精馏釜、塔及冷凝器等设备,节约了建设投资。多年运行结果表明,新工艺具有技术新,产品质量高和生产能耗低等优点。     

氯乙酸甲酯间歇精馏工艺改造

针对目前氯乙酸甲酯间歇精馏工艺存在产品损失量大、能耗高、精馏周期长等问题,采用带有液-液分离装置的全回流间歇精馏技术,通过将馏出物前馏分收集至储液罐中,经储液罐下部相连的液-液分离装置进行油水相分离后,油相氯乙酸甲酯直接回流至精馏釜中的方法,对原生产工艺进行改造,大幅降低了氯乙酸甲酯损耗,降低蒸汽消耗,缩短了精馏周期,取得了显著的经济和环境效益。     

多晶硅生产SiHCl_3精馏工艺改造

针对多晶硅生产中SiHCl_3精馏工艺存在的问题,对其进行改造。改造后,工艺流程简化,设备配套使用量大幅度减少;生产系统的安全性和稳定性有所改善,月均产量增加约11.1%;副产物SiH_2Cl_2得到有效利用,尾气的排放量得到控制,月均减少NaOH和CaO使用量约0.8t;精馏塔塔顶、塔釜可分别节能约25%、28.7%;精制SiHCl_3产品和多晶硅产品的总合格率分别提高5.3%和5.9%。     

先进控制在乙烯和丙烯精馏塔中的应用

介绍了先进控制技术在乙烯和丙烯精馏系统的应用情况。先进控制系统的投用,显著提高了精馏系统的运行稳定性,乙烯产品摩尔分数从99.96%降低为99.95%,塔釜损失的乙烯摩尔分数从0.077%下降为0.042%;丙烯产品摩尔分数从99.58%降低为99.51%,塔釜损失的丙烯摩尔分数从8.1%降低为4.3%。实现了乙烯、丙烯产品的"卡边"控制和塔釜物料组成有效控制,减少了乙烯、丙烯损失,提高了产品回收率、降低了装置能耗。     

三釜凝聚工艺在顺丁橡胶生产中的应用

介绍了顺丁橡胶生产装置中两釜凝聚和三釜凝聚工艺的特点以及后者所具有的优势,比较了中国石化北京燕山分公司橡胶一厂顺丁橡胶装置凝聚系统改造前后蒸汽消耗和橡胶中溶剂残留量的变化,结果表明三釜凝聚系统相对于两釜凝聚可节省蒸汽25%以上,同时至少能降低橡胶中50%的溶剂残留量。对三釜凝聚工艺进行优化的结果表明其最佳操作参数为1 号釜釜底温度85 ℃,釜顶压力48 kPa; 2 号釜釜底温度102 ℃,釜顶压力90 kPa; 3 号釜釜顶压力10 kPa。此外,指出了此次改造过程中的不足之处,并对今后的同类工作提出了建议。     

2,3-丁二醇分离纯化中反应精馏的实验和模拟

对反应萃取-水解精馏法分离发酵液中2,3-丁二醇工艺中的水解精馏进行了实验和模拟研究。实验验证了4,5-二甲基-2-丙基-1,3-二氧戊环(DPD)水解精馏得到2,3-丁二醇的可行性。采用Aspen Plus建立反应精馏模型,以UNIFAC为热力学方程,RadFrac为反应精馏模块,对常压下DPD的水解精馏进行模拟,模拟结果与实验结果吻合较好。以2,3-丁二醇的收率为主要优化目标,考察最佳塔板数、进料位置、进料比、回流比和塔顶馏出比。模拟结果表明,在最佳操作条件下,塔釜2,3-丁二醇的收率为0.981,摩尔分率为0.150。     

精馏塔技必前后生产技术分析

对精馏四塔的改造，提高了其分离效率，馏出及釜液指标合格率明显提高，降低了VAc在系列的损耗，保证了后系统PVA质量的稳定。     

生物质基制乙二醇液相产物的反应精馏分离新工艺及装置

<正>天津大学开发出一种生物质基制乙二醇液相产物的分离工艺及其装置,它是通过三效蒸发脱水后,在2,3-丁二醇脱除塔塔釜产出的液相流股经过1,2-丙二醇分离塔塔顶获得丙二醇产品,1,2-丙二醇分离塔塔釜液相经过脱重塔脱除重组分后塔顶采出的乙二醇、1,2-丙二醇、1,2-丁二醇的混合二醇流股经缩醛/酮反应精馏、醛/酮产物分离后,再分别进行水解和精制获得相应的乙二醇、     

2,3-丁二醇分离纯化中反应精馏工艺

乙醛-环己烷反应萃取体系能够有效分离发酵液中的2,3-丁二醇。文章重点研究了2,3-丁二醇-乙醛反应萃取液的连续水解精馏工艺,为工业化生产提供理论基础。水解精馏使用阳离子交换树脂HZ732为水解催化剂,以2,4,5-三甲基-1,3-二氧戊环(2,3-丁二醇-乙醛缩醛)水解率为指标,考察了反应段温度、反应段级数、进料速度、进料油水比(2,4,5-三甲基-1,3-二氧戊环和水摩尔比)和回流比的影响。通过实验得到优化水解精馏工艺条件为:反应段平均温度90℃,反应段理论板数为20,进料油水比为0.6,进料速度0.2 h-1。在该条件下2,4,5-三甲基-1,3-二氧戊环水解率为73%,未水解2,4,5-三甲基-1,3-二氧戊环被回收。水解液经精馏得到2,3-丁二醇产品,纯度(质量分数)>96%,总收率≥93%。开发了连续水解精馏工艺,为整个工艺工业化实践提供了参考。     

A novel process for the synthesis of unsaturated polyester

Traditionally polyester production is done in a batch reactor equipped with a separation column for a batch distillation. A promising alternative for the intensification of this process is reactive distillation. The aim of this paper is to study the conceptual design of reactive distillation and to find out whether reactive distillation is potentially interesting compared to batch reactor process. Therefore, a reactive distillation model is developed and sensitivity analysis is used to obtain the design and operational parameters for the reactive distillation process. These parameters are the required number of stages, required residence time, feed ratio, reflux ratio and temperature of feed stream. The model predicts the polymer attribute, isomerization and saturation composition of the polymer in the range of industrial polyester production data. The simulation study shows that the total production time of polyester in a continuous reactive distillation system is reduced from 12 h to 1.5-2 h compared to the industrial batch reactor process. The equilibrium conversion is also raised by 7% compared to the conventional process. The model demonstrated that reactive distillation has the potential to intensify the process by factor of 6-8 in comparison to the batch reactor.     

A simple approach to improve the robustness of equation-oriented simulators: Multilinear look-up table interpolators

Equation-oriented simulators have some advantages over the modular sequential ones, but improvements are still necessary to deal with nonlinearities, while preserving the robustness of the solver. Linear approximations and/or surrogate models can be used in place of nonlinear models, but the loss of predictive accuracy may be a drawback. An alternative to circumvent this problem is the use of grid-based look-up tables for interpolating responses from rigorous models. This methodology was integrated in an equation-oriented simulator (EMSO). A case study involving the production of bioethanol from sugarcane is used to demonstrate the robustness of this approach. Look-up tables replaced the models of two distillation column trains and of the cellulose hydrolysis reactor. These models were included into the global process and an optimization problem aiming at the maximum production of ethanol was successfully solved by a PSO algorithm varying the solid mass fraction in the hydrolysis reactor.     

醋酸甲酯水解反应及产物分离工艺的改进研究

针对现有的醋酸甲酯水解反应及产物分离工艺提出一种反应与精馏结合的改造方案。使用工厂提供的进口阳离子交换树脂作为催化剂在间歇反应器中对醋酸甲酯水解反应动力学进行了研究,结果表明,反应平衡常数随着温度的升高而增大,温度对反应速率的影响符合Arrhenius公式,反应速率与催化剂用量呈线性关系。在消除外扩散的影响下得到了醋酸甲酯非均相水解的反应速率方程为:dcMeAc-r=-1dt=k(cMeAccH2O-cMeOHcHAc/K)Mk=4.95954×105exp(-69682.7/RT)m6·kmol-1·min-1·kg-1K=exp(1.44707-1114.9/T)在此基础上通过模拟计算对改进工艺进行研究并确定,理论塔板数为20块的精馏塔和第二水解塔结合后进料位置为第10块塔板,侧线采出位置为第2～9块塔板,适宜回流比为1 2603。经比较表明,新工艺比原工艺节约能耗8 33%。     

火电厂脱硝用尿素水解中试试验

为降低火电厂NO_x排放造成的环境污染,采用尿素水解法制备烟气脱硝还原剂,在自主研发尿素水解反应器和尿素水解制氨工艺的基础上,搭建产氨量10kg/h规模的尿素水解中试试验台。结果表明,尿素水解反应速率是由温度控制的单调递增函数,蒸汽耗量随反应压力的增加而增加,当反应压力大于0.6MPa时加剧,装置经济性降低。提高进料浓度可减少过量水吸热造成的能量损失,有益于降低装置运行成本。多批次测试期间,进料浓度为40%~60%,操作压力与温度为0.6MPa、160℃,装置最大产氨量为16kg/h,水解率均大于98%,产品气氨气质量分率22.6%~34%(体积分率28.5%~48%),装置性能良好。     

直馏汽油碳四非临氢改质装置改造运行分析

直馏汽油和碳四馏分非临氢改质技术是近年来增产汽油、提高产品辛烷值的新工艺。但是由于碳四馏分中含有较多烯烃,其聚合反应较多,反应放热剧烈,反应器温升无法控制,为解决反应放热问题,扬州石油化工有限责任公司（以下简称扬州石化）对碳四线进行了改造。本文阐述了扬州石化直馏汽油和碳四馏分改质装置改造前后装置运行情况。     

乙酸甲酯水解工艺设计

在分析目前国内乙酸甲酯水解工艺的基础上,提出采用福州大学催化精馏水解技术代替传统的固定床水解反应器进行水解的新工艺。着重从工程设计方面对其工艺过程进行探讨。     

Production of structured TAG rich in 1,3-capryloyl-2-arachidonoyl glycerol from <Emphasis Type="Italic">Mortierella</Emphasis> single-cell oil

Two oils containing a large amount of 2-arachidonoyl-TAG were selected to produce structured TAG rich in 1,3-capryloyl-2-arachidonoyl glycerol (CAC). An oil (TGA58F oil) was prepared by fermentation of Mortierella alpina, in which the 2-arachidonyoyl-TAG content was 67 mol%. Another oil (TGA55E oil) was prepared by selective hydrolysis of a commercially available oil (TGA40 oil) with Candida rugosa lipase. The 2-arachidonoyl-TAG content in the latter was 68 mol%. Acidolysis of the two oils with caprylic acid (CA) using immobilized Rhizopus oryzae lipase showed that TGA55E oil was more suitable than TGA58F oil for the production of structured TAG containing a higher concentration of CAC. Hence, a continuous-flow acidolysis of TGA55E oil was performed using a column (18×125 mm) packed with 10 g immobilized R. oryzae lipase. When a mixture of TGA55E oil/CA (1∶2, w/w) was fed at 35°C into the fixed-bed reactor at a flow rate of 4.0 mL (3.6 g)/h, the degree of acidolysis initially reached 53%, and still achieved 48% even after continuous operation for 90 d. The reaction mixture that flowed from the reactor contained small amounts of partial acylglycerols and tricaprylin in addition to FFA. Molecular distillation was used for purification of the structured TAG, and removed not only FFA but also part of the partial acylglycerols and tricaprylin, resulting in an increase in the CAC content in acylglycerols from 44.0 to 45.8 mol%. These results showed that a process composed of selective hydrolysis, acidolysis, and molecular distillation is effective for the production of CAC-rich structured TAG.     

“背包式”反应精馏水解乙酸甲酯的工艺

采用“背包式”反应精馏深度水解乙酸甲酯,考察了工艺条件对水解率和酸水比的影响,并与传统的单塔催化精馏工艺进行了对比。结果表明：提高水酯比可以显著提高乙酸甲酯的水解率;回流进料比的增加有利于提高水解率但会增加能耗,较佳回流比为3.0左右;乙酸甲酯水解率随空速的增加而降低的速度较慢,可以适当提高空速以增加处理能力;增加固定床体积有利于酯的预水解,但是不一定有利于酯的总转化率。采用“背包式”催化精馏工艺可以实现乙酸甲酯的深度水解,且优于传统的单塔催化精馏工艺。     

A techno‐economic comparison of various process options for the production of 1,1‐diethoxy butane

BACKGROUND: Acetals can be considered important bio‐based diesel additives. The production of most of these compounds, from an alcohol and an aldehyde, suffers from low conversion due to thermodynamic limitations. These limitations can be overcome through the removal of the by‐product water. Previous studies showed that the in situ dehydration options of reactive distillation and pervaporation membrane reactor integration offer little advantage or at least not at reasonable unit dimensions. The aim of the present work is the development of a membrane based process and comparison with other alternatives (based on experimental data). RESULTS: Three different membrane processes were developed. The one in which the reaction mixture is recycled over a first dehydration membrane module and subsequently through a simple distillation column, was found to give the highest overall conversion (100%) at low recycle rates and reasonable membrane area. This process was techno‐economically compared with other possible alternatives: (1) a process based on a conventional tubular reactor and several distillation columns; and (2) a process based on reactive distillation. CONCLUSIONS: Efficient water removal by membranes avoids possible azeotropes in downstream distillation units making them much simpler, reducing considerably the unit sizes and the energy demand (40% lower). Copyright © 2012 Society of Chemical Industry     

Quantitative comparison of dynamic controllability between a reactive distillation column and a conventional multi-unit process

A comparison of the steady-state economic optimum designs of two alternative chemical processes was presented in a previous paper [Kaymak, D. B., & Luyben, W. L. (2004). A quantitative comparison of reactive distillation with conventional multi-unit reactor/column/recycle systems for different chemical equilibrium constants. Industrial & Engineering Chemistry Research, 43, 2493–2507]. A generic exothermic reversible reaction A + B ↔ C + D occurs in both flowsheets, which consist of a conventional multi-unit reactor/separator/recycle structure and a reactive distillation column. Results showed that the reactive distillation process is significantly less expensive than the conventional process for a wide range of the chemical equilibrium constant when there is no mismatch between the temperature favorable for reaction and the temperature favorable for vapor–liquid separation.

A reactive distillation column has fewer control degrees of freedom than a conventional multi-unit system. Therefore a reactive distillation column may have worse dynamic response than a conventional process. The purpose of this paper is to compare the dynamic controllability of these two alternative processes.

Three different chemical equilibrium constants are considered. Several control structures are developed for each flowsheet, and their effectiveness is evaluated. Disturbances in production rate and fresh feed compositions are considered.

The conventional multi-unit process provides significantly better control. The operability region is much larger, there is less variability in product quality and the dynamic responses are faster than those of the reactive column. Thus, these results demonstrate that there is a significant trade-off in this system between optimum economic steady-state design and dynamic controllability.