CO气相偶联制草酸二乙酯工艺流程模拟

采用流程模拟软件PRO/II,对一氧化碳与亚硝酸乙酯合成草酸二乙酯工艺过程进行模拟。建立了工业过程设计详细流程,提供了模拟使用的主要物性参数、动力学模型及流程数据及其来源。流程模拟计算结果与实际生产数据吻合证明了模拟的可靠性。模拟考察了一氧化氮再生反应设计转化率对主要过程参数,如循环比、放空气中一氧化氮含量及乙醇补充量的影响。结果表明提高再生过程一氧化氮设计转化率,可以降低循环比,提高偶联过程CO的转化率,但亚硝酸乙酯利用率下降,乙醇补充量需相应提高。再生反应器较为适宜设计条件为:一氧化氮再生转化率为(92±2)%,压力为101.3～150kPa及温度为(308±2)K。     

反应精馏法提纯乙酸乙酯的研究

研究了通过化学反应精馏和加盐脱水联合分离乙酸乙酯-乙醇-水混合物的过程,探讨了该条件下反应精馏的流程、操作条件和加盐脱水的效果.流程中包括了控制可逆反应单向进行的反应条件,共沸蒸馏的操作参数,以及液-液分相去除水分的效果.文中最后给出了实验数据对理论分析的验证.     

离子液体催化反应精馏合成乙酸乙酯工艺模拟

为研究离子液体在反应精馏中的作用,采用离子液体1-丁基-3-甲基咪唑硫酸氢盐（[BMIM]HSO₄）作为催化剂,对乙酸和乙醇合成乙酸乙酯的反应精馏流程进行了计算模拟。在确定了参数的酯化反应动力学的基础上,用Aspen Plus软件建立了反应精馏流程,研究了催化剂用量、精馏段理论板数、反应段理论板数、乙醇进料位置、进料摩尔比、持液量及回流比等参数对反应精馏过程的影响。研究结果表明,塔顶乙酸乙酯的质量分数随催化剂用量、精馏段理论板数、反应段理论板数和持液量增大而增大,工艺流程存在最佳回流比以及最佳进料酸醇摩尔比。得到的优化条件如下：离子液体与乙酸摩尔比为1：2.5,进料酸醇摩尔比为4：1,理论塔板数为21块,乙酸和催化剂在第7块理论塔板进料,乙醇在第19块理论塔板进料,塔板持液量0.1L,回流比为4,塔顶乙酸乙酯的质量分数可以达到98.73%。     

离子液体反应萃取精馏合成乙酸乙酯

采用离子液体1-磺酸丁基-3-甲基咪唑硫酸氢盐([HSO₃bmim][HSO₄])和1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐([BMIM][Tf₂N])分别作为催化剂和萃取剂,对乙酸甲酯与乙醇合成乙酸乙酯和甲醇的反应萃取精馏(RED)过程进行了模拟计算。在反应动力学和汽液相平衡分析基础上建立了反应萃取精馏流程,研究了理论板数、回流比、持液量、进料位置、溶剂比(萃取剂进料与原料进料摩尔流量的比值)、催化剂进料流量等参数对反应萃取精馏过程的影响。在优化的操作条件下,甲醇纯度为0.9922,乙酸乙酯纯度为0.9905,乙酸甲酯转化率为0.9922。     

二甲苯-乙醇-乙酸乙酯的萃取精馏过程的模拟计算

应用Aspen Plus模拟软件对某化工废液二甲苯、乙醇和乙酸乙酯进行了连续精馏过程的模拟计算。先用普通精馏在塔底得到二甲苯产品的质量分数为99.9%,二甲苯的回收率为99.9%,塔顶可得到乙酸乙酯-乙醇的混合物。以乙二醇为萃取剂分离乙酸乙酯-乙醇,在回流比为5.5,溶剂比S为2.8时,可得到浓度为90%(质量分数)乙酸乙酯,回收率为90%;乙醇的浓度为90%(质量分数),回收率为90%,实现了废液的利用。     

Aspen Plus软件在延迟焦化主分馏塔上的应用

利用Aspen Plus化工流程模拟软件对国内某炼厂的延迟焦化主分馏塔进行模拟计算,探讨了焦化分馏塔的模拟策略以及在模拟过程中反应油气的组成估算、热力学方法的选择、理论塔板数的选取等。对比发现,Aspen Plus的模拟结果与标定数据基本上一致,说明模拟结果切实可靠,模拟结果基本上反应了主分馏塔的运行情况。     

应用ChemCAD软件模拟反应精馏过程

应用ChemCAD软件中的SCDS精馏模型，对乙酸和乙醇反应生成乙酸乙酯的反应精馏过程进行了模拟，对过程参数对反应的影响进行了计算，选择了合适的反应条件。     

萃取精馏分离乙酸乙酯、乙酸丙酯、乙醇和水体系工艺研究

乙酸乙酯、乙酸丙酯、乙醇和水体系彼此间都存在共沸,且存在三元共沸,很难通过普通精馏进行分离。利用Aspen Plus对萃取精馏法分离乙酸乙酯、乙酸丙酯、乙醇和水体系的工艺进行模拟,热力学模型为UNIFAC,并对该体系进行萃取精馏实验研究,利用萃取精馏实验数据对热力学模型进行修正,使模拟数据与实验数据吻合,相对误差小于7.5%。通过乙酸乙酯、乙酸丙酯、乙醇和水体系萃取精馏实验,详细研究了理论板数、溶剂比、回流比等因素对分离效果的影响,结合流程模拟数据,得出了该工艺的适宜条件:理论板数68~75,溶剂比5.8~6.5,回流为3.0~3.5。在适宜的工艺条件下,乙酸乙酯和乙酸丙酯的收率达到95%以上。     

乙酸乙酯生产工艺的改进与优化

通过分析国内乙酸乙酯生产工艺的现状,提出了针对传统乙酸乙酯生产工艺的 3种可行改造方案;并采用美国SIMSIC公司的流程模拟软件PRO/Ⅱ对现有的年产 1 .5万t乙酸乙酯生产工艺进行了模拟计算,并以此为基础对比了不同投资规模的 3种改造方案,计算结果表明,经过改造后,分别比原有工艺节能 12%、13%和 21%。     

辅助化学反应强化反应精馏生产乙酸乙酯的模拟与优化

本文采用了辅助化学反应强化反应精馏生产乙酸乙酯,通过乙烯与水的反应将体系中的水除去,同时生成主反应的反应物乙醇,使得产品的纯度大大提高,原料消耗量降低。由于乙烯水合反应放出大量的热从而减小了能耗。采用Aspen plus软件模拟了辅助化学反应强化反应精馏生产乙酸乙酯的过程并对相应的操作参数加以优化,得到了质量分数为98.9%的乙酸乙酯,生产过程的能耗为384kw。     

合成气经草酸酯法制取乙二醇的技术进展

分析了当前国内乙二醇的供需状况和发展煤制乙二醇的优势;论述了草酸酯法制取乙二醇的工艺原理、工艺流程和技术进展;指出加强草酸酯加氢催化剂的研究并建立一定规模的工业化示范装置是合成气经草酸酯法制乙二醇工艺技术进入大规模工业化生产的当务之急。     

Hydroliquefaction of Wyodak coal using bottoms recycle

Wyodak coal has been liquefied using recycle solvents consisting of blends of Wyodak coal-derived distillates and SRC or SRC oils, asphaltenes and oils plus asphaltenes. Whilst the quality of the distillate portion of the bottoms recycle is maintained by hydrogenation and distillation in the Exxon Donor Solvent (EDS) process, no reported efforts have been made to hydrogenate the nondistillable portion of the EDS bottoms recycle solvent nor the bottoms recycle solvent in the SRC-II process. As hydrogenation of the distillate portion of the recycle solvent in the EDS process increased Wyodak coal distillate yields, this study was initiated to determine whether hydrogenation of the nondistillable portions of Wyodak coal-derived bottoms recycle solvent would show similar beneficial effects. Results suggest that distillable liquid yields in the range of 55–60 wt% of dry Wyodak coal can be obtained using mildly hydrogenated SRC or SRC oils plus asphaltenes as a bottoms recycle solvent component. This result can be compared to distillable liquid yields of 40 wt% of dry, Wyodak coal obtained from the EDS process using bottoms recycle. Further, the unhydrogenated, SRC-derived oil and asphaltene portions of the recycle solvent also appear to be effective solvent components. However, the most effective solvents were obtained using hydrogenated SRC or SRC-derived oils plus asphaltenes.     

Application of pressure-cycle purge (PCP) in dry-down of ultra-high-purity gas distribution systems

The existence of trace amounts of moisture in process gases could adversely affect the fabrication of semiconductor devices. One important and practical challenge in transporting ultra-high-purity (UHP) gases from the point-of-storage (POS) to the point-of-use (POU) is the susceptibility of the gas distribution systems to molecular contaminants, especially moisture. In modern micro/nanoelectronic manufacturing plants, the moisture content at the POU has to satisfy very stringent specifications. Once a distribution system is contaminated, a significant amount of purge time is required to recover the system background due to the strong interactions between moisture molecules and the inner surfaces of the components in a gas distribution system. Because of the very high cost of UHP gases and factory downtime, it is critical for high-volume semiconductor manufacturers to reduce purge gas usage as well as purge time during the dry-down process. In the present work, a combination of experimental investigation and process simulations is used to compare the traditional steady-state purge (SSP), which typically is operated at constant pressure and flow rate, with the pressure-cycle purge (PCP) process in which the pressure and flow rate are cycled at a controlled frequency and interval. The results show that under certain conditions the new PCP process has significant advantages over the SSP process; for example, it reduces the purge time and gas usage when the gas purity at POU is the principal concern. This conclusion was confirmed by the experimental investigation on lab-scale gas distribution test beds as well as by the simulation of industrial scale systems. The process model developed and used in this work couples gas phase transport processes with surface adsorption/desorption and the purge schedule introduced by pressure variation in the system. This model is then validated using experimental results under various operating conditions. The process simulator is a useful tool for industrial applications in parametric studies and purge process optimization. The effect of key operational parameters, such as start time of PCP process as well as choice of PCP patterns in the PCP process, are presented.     

PRIME G+技术工艺参数的选择

探讨反应温度、压力、停留时间、氢烃比等工艺操作参数对Prime G+工艺选择性加氢和加氢脱硫的影响.在压力一定条件下,该工艺应尽可能在低温下操作.选择性加氢部分可提高氢烃比,满足适宜二烯烃加氢限制烯烃加氢并保持催化剂的稳定性.加氢脱硫部分提高氢/烃比增加了加氢脱硫的活性和选择性.在加氢脱硫的过程中要注意循环气中硫化氢的...     

焦炉气锅炉掺烧弛放气探讨

甲醇厂弛放气直接排入大气,既对环境产生污染,又无法实现经济价值。通过将弛放气减压掺入焦炉煤气中供锅炉燃烧使用的方法,可以解决弛放气的去向问题。     

镍-铝-钼合金展开过程钼流失抑制及催化性能

为了提高钼改性雷尼镍催化剂的性能,就镍-铝-钼三元合金展开过程钼的流失情况,以及在展开过程的初始氢氧化钠溶液中添加钼酸钠的抑制钼流失效果进行考察研究,并对采用抑制钼流失工艺所制备钼改性雷尼镍催化剂在葡萄糖加氢中的活性、循环使用寿命及抗毒性进行了对比考察。结果表明,添加钼酸盐对合金在展开过程中钼的溶出流失有明显的抑制作用,所制备的催化剂中Mo/Ni质量比提高,并伴随着催化剂在葡萄糖的加氢中催化初活性,临界用量的循环套用次数、抗糖化酶及亚硫酸氢钠毒性能力等性能有大幅度提高。     

半再生催化重整装置贫料和富料工艺流程的选择

以2套100 kt/a半再生催化重整装置为例,从预分馏、氢气流程以及重整产氢提纯方案工艺流程进行讨论分析,发现对贫料装置宜采用预加氢氢气循环和重整产氢再接触流程,对富料宜采用先分馏后加氢和重整产氢一次通过式流程.     

Combination of Reaction and Separation in Heterogeneous Catalytic Hydrogenation of Ethylformate

Continuous hydrogenation reaction of ethyl benzoylformate was studied over a (–)‐cinchonidine (CD)‐modified Pt/Al₂O₃ catalyst. The catalyst showed a good stability, and high enantioselectivity was achieved in the fixed‐bed reactor. Chromatographic separation of (R)‐ and (S)‐ethyl mandelate originating from a post‐continuous hydrogenation reaction of ethyl benzoylformate over the (–)‐CD‐modified Pt/Al₂O₃ catalyst was investigated in the same reaction mixture. A commercial column filled with a chiral selector resin was chosen as a perspective preparative‐scale adsorbent. Since adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post‐reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug‐flow model with linear driving force approximation.     

A New Numerical Approach for a Detailed Multicomponent Gas Separation Membrane Model and AspenPlus Simulation

A new numerical solution approach for a widely accepted model developed earlier by Pan [1] for multicomponent gas separation by high‐flux asymmetric membranes is presented. The advantage of the new technique is that it can easily be incorporated into commercial process simulators such as AspenPlus^TM [2] as a user‐model for an overall membrane process study and for the design and simulation of hybrid processes (i.e., membrane plus chemical absorption or membrane plus physical absorption). The proposed technique does not require initial estimates of the pressure, flow and concentration profiles inside the fiber as does in Pan's original approach, thus allowing faster execution of the model equations. The numerical solution was formulated as an initial value problem (IVP). Either Adams‐Moulton's or Gear's backward differentiation formulas (BDF) method was used for solving the non‐linear differential equations, and a modified Powell hybrid algorithm with a finite‐difference approximation of the Jacobian was used to solve the non‐linear algebraic equations. The model predictions were validated with experimental data reported in the literature for different types of membrane gas separation systems with or without purge streams. The robustness of the new numerical technique was also tested by simulating the stiff type of problems such as air dehydration. This demonstrates the potential of the new solution technique to handle different membrane systems conveniently. As an illustration, a multi‐stage membrane plant with recycle and purge streams has been designed and simulated for CO₂ capture from a 500 MW power plant flue gas as a first step to build hybrid processes and also to make an economic comparison among different existing separation technologies available for CO₂ separation from flue gas.