PTA装置中溶剂脱水系统工艺流程浅析

阐述了溶剂脱水系统的工作原理,介绍了溶剂脱水系统的3种典型工艺流程——以三井工艺为代表的两釜流程、以杜邦公司为代表的三釜流程和以DOW化学公司的四釜流程,同时也指出了3种流程的各自特点。     

PTA装置溶剂脱水塔模拟及塔板效率分析

精对苯二甲酸装置溶剂脱水塔在去除氧化反应生成水,保持整个氧化单元水含量稳定,减少醋酸消耗中起到核心作用。基于ASPEN PLUS流程模拟软件,以模型计算偏差最小为目标,通过调整板效率,实现溶剂脱水塔的模拟,为溶剂脱水塔的优化调整提供了基础。同时,分析主要参数之间的相关性,以及对各塔板成分板效率的影响,结果表明:塔负荷与塔压降之间存在线性相关;塔压降对夹带剂醋酸正丙酯的板效率影响较大,对水、对二甲苯、醋酸和醋酸甲酯的影响很小。     

乙酸仲丁酯为溶剂的乙酸脱水过程模拟及优化

乙酸脱水是精对苯二甲酸生产过程中实现乙酸回收的一个重要的生产环节。文中从节能降耗角度出发,提出采用乙酸仲丁酯(SBA)作为乙酸脱水过程的萃取剂和共沸剂,替代传统工艺中使用乙酸异丁酯(IBA)溶剂。采用Aspen Plus软件对江苏某石化企业的乙酸脱水单元进行模拟,分析采用SBA溶剂替代IBA的可行性,并对工艺过程进行系统的优化研究。稳态模拟分析结果表明:采用SBA作为乙酸脱水过程的萃取剂和共沸剂,在原有工艺参数基本不变的条件下,将乙酸脱水塔油相回流比从0.83调整至0.84,水相回流比从0.22调整至0.234,就可达到乙酸脱水系统的设计要求,同时节省蒸汽消耗2.71×10~(4 ) t/a,减少共沸剂损失578 t/a。     

工业醋酸脱水过程五元体系非均相共沸精馏的流程模拟

针对以醋酸正丙酯为共沸剂的醋酸脱水过程,考虑醋酸溶剂中未反应的前体对二甲苯以及反应的副产物醋酸甲酯的影响及回收利用,分别选用HOC和UNIQUAC模型来修正体系中五元混合物系的汽液非理想性,通过拟合醋酸甲酯-对二甲苯和醋酸正丙酯-对二甲苯两体系的二元汽液平衡实验数据获得了该两组体系UNIQUAC模型的二元交互作用参数,借助模拟软件Aspen Plus,结合软件内置其他二元体系参数,对工业醋酸脱水塔系包括溶剂脱水塔、PX回收塔、共沸剂回收塔在内的三塔体系进行系统的分析模拟,得到了与工艺数据误差小于±6%的能正确描述工业醋酸脱水塔系操作特性的工艺机理稳态模型,为工业醋酸脱水过程工艺的进一步研究提供理论基础和依据。     

PTA装置溶剂脱水塔浅析

扬子石化公司化工厂精对苯二甲酸（ＰＴＡ）装置溶剂脱水塔（ＨＴ ７０１）在氧化单元高负荷运行时存在工艺指标不合格的问题，严重影响了粗对苯二甲酸（ＴＡ）的产量和质量。从氧化单元正常运行和母液回收系统故障两种工况出发，结合氧化降温改造设计和生产实际运行状况，对溶剂脱水塔进出料情况进行分析，并用美国精馏协会提供的筛板塔计算软件（ＦＲＩＶｅｒ５．０）核算，找出了该塔工艺指标严重超标的原因，１９９６年大修后生产运行结果表明，改进的脱水塔完全达标，经济效果十分显著     

PTA溶剂回收及脱水系统简析

简述ＰＴＡ溶剂回收和脱水系统的过程及原理，减小产品质量指标波动，增强单元优化，确保最小的消耗．     

叔丁醇脱水制异丁烯的共沸反应精馏过程研究

以环己烷为共沸剂,磺酸树脂为催化剂对叔丁醇常压脱水共沸反应精馏工艺进行了模拟和实验研究,实验验证了该工艺制备异丁烯的可行性。通过Fortran编写动力学子程序接口,以NRTL为热力学模型,采用Aspen Plus建立反应精馏模型对该过程进行模拟,模拟结果与实验结果吻合较好,证明模拟计算方法是可靠的。进一步通过模拟计算考察了塔顶冷凝温度、分相器温度、塔板数、上升蒸汽量、进料位置、叔丁醇水溶液质量分数对共沸反应精馏过程的影响,获得在进料流率0.25 g/min、催化剂填充量为10 g时的最佳工艺条件:塔顶冷凝温度和分相器分别为2℃和50℃,总塔板板数为6块,上升蒸汽量为3.0 g/min,叔丁醇进料位置为2—5块板。在此最佳条件下,当进料中叔丁醇质量分数在75%以上时,叔丁醇的转化率达到96.00%以上。     

溶剂共沸脱水法合成BP04粉体

以硼酸和质量分数为85％磷酸为反应原料,环己烷做带水剂,在不同的反应时间下,利用溶剂共沸脱水法制备磷酸硼粉体。产物的XRD、FT-IR分析表明,在磷酸硼中含有少量未反应的硼酸。产物分别在120、140℃下进行热处理,每2h取样进行FT-IR、XRD测试。测试结果表明,共沸2h制得磷酸硼在120℃下热处理6h,或140℃下热处理4h,可得到纯的磷酸硼粉体。共沸5h制得磷酸硼120℃下热处理4h,或140℃下热处理2h,可得到纯的磷酸硼粉体。     

PTA装置共沸精馏塔脱水系统

简述PTA装置溶剂脱水系统的原理和过程。通过共沸精馏减少产品质量指标波动,优化单元操作,确保更小消耗。     

PTA老装置溶剂脱水塔HT-701优化改造

对PTA二装置HT701塔的改造方案进行了分析和比较,提出了合适的改造方案,通过改造,HT701塔完全满足装置的需要,同时,为类似PTA装置溶剂脱水塔的改造提供了参考。     

Design and control of acetic acid dehydration system via heterogeneous azeotropic distillation

Acetic acid dehydration is an important operation in the production of aromatic acid, such as terephthalic acid or in the manufacture of cellulose acetate. Although acetic acid and water does not form azeotrope, but using simple distillation to separate these two components is not practical. The reason is because the system has tangent pinch on the pure water end, thus it is more customary in industry to use an entrainer via a heterogeneous azeotropic distillation column system for the separation. In this study, a suitable entrainer is selected from three candidate acetates through rigorous steady-state simulation of this system. Optimum process design and operating condition are determined to keep high-purity bottom acetic acid composition and also keep a small acetic acid loss through top aqueous draw. Furthermore, the overall control strategy of this column system is proposed to hold both bottom and top product specifications in spite of feed rate and feed composition load disturbances. The proposed overall control strategy is very simple requiring only one tray temperature control loop inside the heterogeneous azeotropic column.     

磺酰氯生产废液中醋酸的回收利用

磺酰氯是生产除草剂噻吩磺隆的中间体,其生产过程中要使用大量醋酸作为溶剂,醋酸如果不回收,将全部作为废液排放,造成严重的污染和浪费。由于废液成分复杂,醋酸的回收利用比较困难。通过比较各方法优劣,分别采用恒沸精馏和溶剂萃取的方法进行了醋酸回收实验,结果表明,恒沸精馏难以达到预期目的,而溶剂萃取则可以实现醋酸的分离和循环利用,回收的醋酸经厂家实验证明完全符合生产要求。     

先进控制技术在PTA溶剂脱水塔上的应用

阐述了应用APC-Hiecon先进控制软件建立溶剂脱水塔多变量预测控制系统,解决了PTA溶剂脱水塔控制中存在的主要问题,稳定了溶剂脱水塔的操作,降低了醋酸的消耗,取得了预期的目标。     

共沸脱水法干燥灭多威肟新技术研究

介绍采用共沸脱水原理进行灭多威肟干燥的新方法。将30.0g湿品灭多威肟,100.0ml二氯乙烷加入到旋转蒸发器中,减压将溶剂蒸出,得到干燥的灭多威肟产品,水分<0.3%,干燥损失<0.3%。     

Investigating the need of a pre-concentrator column for acetic acid dehydration system via heterogeneous azeotropic distillation

In our previous study [Chien, I.L., Zeng, K.L., Chao, H.Y., Liu, J.H. (2004). Design and control of acetic acid dehydration system via heterogeneous azeotropic distillation. Chemical Engineering Science 59(21), 4547-4567.], an acetic acid dehydration system has been designed. The suitable entrainer selected for that system is iso-butyl acetate. Design and control of the system has been studied in detail to maintain high-purity bottom acetic acid concentration and also keep a small acetic acid loss through top aqueous draw. In that previous study, the feed composition is assumed to contain equal molar of acetic acid and water. However, in a typical waste acid recovery application, the above assumption may be too rich in acetic acid. In this paper, a feed stream containing 80 mol% water and 20 mol% of acetic acid is investigated. Several design alternatives can be deduced including one commonly used in industry by adding a pre-concentrator column in the upstream of a heterogeneous azeotropic distillation column. The necessity of this pre-concentrator column from design and control view points will be thoroughly investigated in this paper. The final recommended process design is a tradeoff between total annual cost (TAC) and operability of the system. The recommended design is a single heterogeneous azeotropic distillation column with aqueous reflux stream. Very wide feed composition and flow rate changes can be handled by this design with proper choice of the overall control strategy.     

Conceptual design of an extractive distillation process for the separation of azeotropic mixture of n-butanol-isobutanol-water

In many chemical processes, large amounts of wastewater containing butanol and isobutanol are produced. Given that n-butanol-isobutanol-water can form triple azeotrope, high-purity butanol cannot be recovered from the wastewater by ordinary distillation. To economically and effectively recover butanol from this kind of wastewater, 1,4-butanediol is selected as an extractant to break the formation of the azeotropes, and a doubleeffect extractive distillation process is proposed. The conceptual design of the proposed process is accomplished based on process simulation. With the proposed process, the purity of recovered butanol and water is greater than 99.99 wt%. In comparison with the conventional azeotropic distillation process, economic analysis shows that the operating cost of the proposed process is lower:when the capacity of wastewater treatment is 100 t·h^-1, the total operating cost decreases by 5.385×10⁶ USD per year, and the total annual cost of the new process decreases by 5.249×10⁶ USD per year. In addition, in the extractive distillation system, variable effects on separation purities and cost are more complex than those in the ordinary distillation system. The method and steps to optimize the key variables of the extractive distillation system are also discussed in this paper and can provide reference for similar studies.     

天然气脱水系统现状分析及优化

针对陕北某天然气净化厂脱水系统中原料气水含量偏高、产品气无法满足国标要求这一生产难题,本文利用ChemCAD对该脱水系统进行了全流程模拟,研究分析得到最佳的优化操作参数为：TEG循环量为6.16 m3/h,原料气进气温度为33 ℃。通过FRI、HTRI和Pipe Flow Expert等专业软件对系统改造后的关键设备及管线进行优化,核算结果表明,脱水塔的各个流体力学参数均可满足生产需要;套管换热器换热能力不足,通过对比分析可知选用高效板式换热器替代在役套管换热器是一种较为经济、合理的优化方案;通过提高原料气预冷器换热管束的表面翅化率可以有效改善它的换热效果,使其达到系统指定的换热要求。研究结果可为该脱水系统的升级改造提供可靠的理论依据,对同类型装置亦具有一定的借鉴作用。     

叔丁醇-水-环己烷体系恒沸精馏过程模拟研究

本文运用Aspen plus过程模拟软件模拟计算了叔丁醇-水-环己烷恒沸精馏过程,计算出了各塔板的温度和气液相流量及组成,同时考察了理论塔板数和最小共沸剂流量及全塔热负荷的关系;加料板位置的变化对恒沸精馏塔分离效果的影响;以及设备压强的变化对共沸精馏的影响。