催化蒸馏合成乙二醇乙醚的过程模拟

修正了非平衡级速率模型,使之能适用于催化蒸馏过程的模拟.此催化蒸馏塔的精馏段和提馏段为一般的填料塔结构,而反应段为CR＆L公司提出的特定结构的催化剂填充层.采用专门测定此特殊结构的催化剂填充层的气膜和液膜传质系数关联式来计算反应段中的传质速率,用Onda的关联式计算精馏段和提馏段填充层中的传质速率.结合在NKC-01分子筛催化剂上环氧乙烷与乙醇反应的动力学方程式,采用Newton-Raphson技术完成了催化蒸馏合成乙二醇乙醚过程的模拟,结果是令人满意的.     

Improvement potential analysis for integrated fractionating and heat exchange processes in delayed coking units

A novel diagram-based representation approach is developed to analyze the thermodynamic efficiency and identify quickly the promising energy-use improvement for integrated fractionating and heat exchange processes in delayed coking units. For considering temperature dependence of heat capacity and integrating fractionating and heat exchange processes, an advanced energy level composite curve is constructed by using the simulation results and a stepwise procedure. More accurate results of exergy analysis are obtained and the interaction between different components of the integrated system can be properly revealed in an integrated figure. Then the exergy calculation is performed to validate the performance of processes and to define the targets for improvement. The avoidable exergy destruction is also analyzed by applying the concepts of avoidable and unavoidable exergy destructions for the integrated system. In a case study for a Chinese refinery, the results reveal that the heat exchange between gas oil and deethanization gasoline is the most inefficient process with the highest retrofitting potential, and the lowest exergy efficiency of component in the integration system is only 29.4%. The improvement potential and exergy efficiency for the fractionator are 38.1% and 97.3%, respectively. It is obvious that the fractionator is not the most promising component for improvement.     

催化裂化装置主分馏塔模拟方法研究

催化裂化装置主分馏塔的准确模拟对于进行全塔分析及装置操作、优化和节能研究具有重要意义。针对目前催化裂化装置模拟存在主分馏塔脱过热段模拟不准确、关键数据无法获得等问题,根据脱过热段特点提出了4类模拟方法,并进行了对比分析,同时结合实际案例进行了研究。通过对比研究得到,对于催化裂化装置主分馏塔的模拟采用脱过热段与分馏塔分开处理、脱过热段利用2个闪蒸罐和1个混合器的模拟方式,能够有效提高主分馏塔的模拟准确度,从而为催化裂化装置生产操作提供有效指导。     

内部热耦合反应精馏塔塔构型的研究

以乙酸甲酯水解为例,利用模拟软件Aspen Plus建立了内部热耦合反应精馏塔模型,研究了内部热耦合反应精馏塔各种可能塔构型的节能效果,并且在相同的产品要求和最小传热温差下对内部热耦合反应精馏塔各构型的能耗进行了对比。结果表明,塔构型对乙酸甲酯水解的内部热耦合反应精馏流程的操作性能有重要的影响,并且存在最佳构型。其最佳构型的特征为,反应段全部在内部热耦合反应精馏塔的精馏塔内且精馏塔与提馏塔中理论板均参与传热的塔构型。     

Experimental Simulation of the Reactor Section of Fluid Cokers: Comparison of FCC and Fluid Coke Particles

The hydrodynamics of fluid cokers were studied in a pressurized fully cylindrical cold model of diameter 483 mm, geometrically and dynamically scaled down by a factor of ～20 from commercial units. Differential pressure fluctuations, voidage distributions, solids momentum flux distributions and steady state gas mixing behaviour in the reactor section are compared for the same operating conditions with two kinds of particles, FCC and fluid coke. The voidage distributions and core‐annular flow structures in the reactor section were similar enough that either FCC or fluid coke particles can be used for cold modelling of fluid cokers.     

Features of the De Smet Deodorizing Systems

Deodorization as applied to edible oils, is a refining step meant to eliminate odoriferous matters by distillation. There are a multitude of components imparting disagreable taste and flavour to crude oils; most of these have been identified by capillary gas chromatography of the head space. These products are partially removed in refining stages prior to deodorizing. Certain odoriferous substances in infinitesimal proportions are tenacious and most intimately linked to the glyceride. These are the ones that give to each oil its characteristic flavour. The consumer is generally most demanding and will not tolerate any flavour and still less any aftertaste in the refined oil. This is why deodorization of edible oils in a refining line is of the utmost importance and should be carried out under optimum conditions and with an adequate equipment. The discerning use of the live steam which is the stripping media during deodorization-distillation, acceptable heat recovery, minimum level of pollutants in the effluent streams and the flexibility and reliability of operation should be the main features of a modern deodorizer. In this paper the main principles of deodorization are mentioned and the currently available De Smet Deodorizers and vapors scrubbing units emphasizing their major features are described.     

从甲醇合成油中提取高附加值重芳烃的工艺

针对褐煤气化、合成等工序得到的甲醇合成油芳烃含量高的特殊情况,提出采用分馏-脱轻-脱重工艺路线来富集高浓度均四甲苯的分离方案。通过流程模拟计算发现,分馏塔在常压条件下,当塔顶温度为129.7℃、塔底温度为211.5℃时,分馏得到的均四甲苯富集液质量分数为71.72%;在真空操作下,通过脱轻塔和脱重塔脱除轻组分和重组分后,可得到质量分数高达91.3%的均四甲苯溶液。精馏实验证明,上述工艺路线是可行的。     

外部热耦合复合精馏塔的经济性与可控性评价

外部热耦合复合精馏塔系统是一种新型的精馏塔系统,通过操作在不同压力下的两个精馏塔的精馏段和提馏段之间的热传递来提高热力学效率。根据精馏段和提馏段热耦合的相对位置不同,外部热耦合复合精馏塔系统可分为对称型和非对称型两种结构。为便于设计和实现,可用外部换热器替代外部热耦合得到简化的结构。本文以乙烯乙烷物系分离过程为对象,通过对外部热耦合复合精馏塔系统建立了静动态模型,采用四点控制的方法,对三种结构的外部热耦合复合精馏塔的经济性和可控性两方面做了分析,证明了非对称型优于对称型外部热耦合复合精馏塔。同时,对使用外部换热器简化外部热耦合结构的方法提供了理论依据和参考。     

前脱丙烷预切割分离MTO粗产品工艺的模拟与优化

选择"前脱丙烷"流程对甲醇制烯烃粗产物进行分离。先利用高低塔脱丙烷工艺, 然后经过脱甲烷塔、脱乙烷塔、乙烯精馏塔、丙烯精馏塔, 最终得到聚合级的烯烃产品, 其中脱甲烷工段采用"预切割-油吸收"脱甲烷工艺, 使用耗能较小的中冷分离, 吸收剂选择产自工艺自身的丙烷产品。丙烯精馏工段采用双塔预分流程, 降低塔高。采用Aspen Plus流程模拟软件对脱甲烷工段进行模拟和优化, 选用Radfrac精馏模型和RKS-BM热力学模型进行计算, 对脱甲烷工艺段进料位置、塔板数、回流比进行灵敏度分析, 并确定出丙烷吸收剂的用量和温度, 最终得到纯度为99.98%的乙烯和99.90%的丙烯。     

基于流程模拟器和列队竞争算法的精馏操作优化

精馏是高耗能的操作单元,对其进行操作优化是企业实现节能降耗、提高经济效益的有效手段。本文提出列队竞争算法与流程模拟软件相结合的精馏操作优化方法,通过MATLAB-Aspen Plus的接口工具调用Aspen Plus模拟精馏操作过程,得到目标函数值,使用列队竞争算法对其进行操作条件的优化。将所提出的方法应用于某石化企业催化裂化主分馏塔的操作优化,其中目标函数值同时考虑了热能利用与产品分布,优化求解得到了总体效益最大的优化操作方案。     

A novel model for multi-plant mixed heavy crude oils refinery planning

In this paper, multi-refinery using the same heavy crude oils as raw materials is studied, while a new nonlinear model for mixed heavy crude distillation is proposed. In practical crude distillation operation, the distillate yield and product distribution of distillation units are different due to their various equipment and operating parameters, even the same ratio of raw materials is provided, so different process models for multi-refinery planning is therefore required. For process modeling, the relationships between total yields and mixing ratio of different refineries were determined, which is combined with process simulation using production data. Then, the yields and properties of crude distillation unit (CDU) fractions were calculated with the use of true boiling point (TBP) curves and property curves respectively when the initial cutting temperatures were given. Finally, in order to maximize the economic benefit of distillation, the optimal product distribution and the best mixing ratio of crude oil were calculated under the constraints of different properties of fractions. Comparing to previous models, the proposed model takes the influence of different refinery parameters on production process into account, while avoiding the complex process for determining the cutting points, which is considered more effi-cient and more accurate with respect to heavy crude refinery. Model was successfully verified by a case study, allowing a significant improvement of the refinery profit to be achieved.     

隔壁精馏塔应用于空气分离的研究

以空气分离为例,考察了将隔壁精馏塔应用于空气分离的建模与基于年总成本的优化过程。首先对于空分上塔的氩浓度剖面进行了分析,提出了两种应用隔壁精馏塔的可能性,最终选择了带侧线精馏段的隔壁塔。然后考察了空分隔壁精馏塔上塔的各个结构参数与操作参数对其年总成本的影响,在保证产品质量的基础上得到优化的结构参数与操作参数。研究表明,与传统流程相比,将隔壁精馏塔应用于空气分离过程可使年总成本减少7.69%。     

内部热耦合精馏塔的操作性能与模拟

对同轴式内部热耦合精馏塔的操作性能和节能效果进行了研究,考察了全回流操作条件下,压缩比对回流量、冷凝器负荷和再沸器负荷的影响。结果表明,随着压缩比的增大,回流量、冷凝器负荷和再沸器负荷均降低。通过实验数据计算得到了该塔的理论板数和两塔间的传热量,精馏段为9块理论板,提馏段为4块理论板,当压缩比为2.2:1时,两塔间传热量为9.98kW。连续操作条件下,对内部热耦合精馏塔的节能效果进行了分析,通过与常规精馏塔的比较,内部热耦合精馏塔可节约52.3%的冷量,输入的再沸器和压缩机总负荷可节约20.34%。另外,基于实验数据,对该内部热耦合精馏塔进行了动态模拟,经连续操作下的实验验证,该内部热耦合精馏塔可在2h后达到稳定操作。     

Hydrodynamics of the Stripper Section of Fluid Cokers

The hydrodynamics of fluid bed cokers were studied by analyzing pressure fluctuations and particle motion in a half‐column cold model, geometrically and dynamically similar (with key dimensionless groups matched) to the stripper section of two commercial fluid cokers. Superficial gas velocity and solids circulation strongly affected the hydrodynamics. The pressure drop over the top section of the stripper decreased at high solids circulation fluxes and high gas velocities due to flooding. Flooding occurred prematurely when fouling was simulated. Steam redistribution did not improve stripper performance for the conditions investigated. However, steep sheds on the top row, aeration behind the solids exit and standpipe aeration all improved solids circulation, leading to reduced fouling in two commercial fluid cokers.     

2-Methylpropylacetate synthesis via catalytic distillation

The paper deals with a 2-methylpropylacetate synthesis process development. The process is based on esterification of acetic acid with 2-methylpropanol by the reactive distillation method. A column in which separation of the reaction products takes place together with esterification in catalytic active separation packing is utilized in this process. Computer simulation of catalytic distillation has been performed to study the process and to evaluate the pilot plant experimental data. KATAPAK^® S structural packing was used in the reaction zone, while stripping and rectifying sections of the column were packed by CY^® packing. A good agreement between the simulation results and pilot plant data has been achieved.     

带有侧线采出回流的部分透热精馏的节能优化

以正丙醇-异丙醇体系为例，研究了带有侧线采出回流的部分透热精馏操作。在该操作中，精馏段侧线采出气相，经塔外冷凝后回流至塔内采出板上方；提馏段某塔板被同轴的夹套式中间再沸器环绕，侧线采出该板处的气相回流至塔内采出板上方。通过单因素分析和响应面法对精馏段和提馏段操作的相关工艺参数分别进行了模拟优化，并对相应操作的热力学性能和分离性能的变化进行了分析。最终优化结果表明：达到规定的分离效果，带有侧线采出回流的部分透热精馏相较于绝热精馏有效能损失降低了26.5%。带有侧线采出回流的部分透热精馏操作通过合理分配能量、降低对热剂和冷剂的品位要求和提高能量利用率，最终达到节能目的。     

连续复合精馏提取裂解C_9芳烃中三甲苯

对乙烯生产过程中的主要副产物裂解C9芳烃的用途简要概括;提出采用连续复合精馏法提取裂解C9芳烃中的三甲苯馏分,为生产二甲苯歧化反应提供原料,建立连续复合精馏装置,精馏段采用θ环填料结构,提馏段采用泡罩板式结构,研究进料体积流量、塔板数、出料体积流量及回流体积比对分离过程的影响,并采用气质联用色谱分析实验结果。在优化条件下,可以将三甲苯的质量分数由原料中的8.28%提高至22.33%,收率94.37%。同时采用ASPEN PLUS软件对实验进行模拟,实验值与模拟值最大相对平均误差为-0.46%。为进一步放大实验及萃取精馏提取高纯度三甲苯馏分提供依据。     

先进控制技术在延迟焦化装置的应用

以某厂延迟焦化装置为工业应用背景,在焦化反应机理模型的基础上,对控制目标、主要变量选择、约束条件、控制器结构等方面进行详细的分析,设计了延迟焦化装置的先进过程控制系统。工业实际应用表明：先进控制系统投运后,整个生产过程的平稳性和控制精度得到了明显的改善。     

一种外部热耦合反应蒸馏系统的模拟研究

根据常规反应蒸馏塔的热力学特性提出并研究了一种外部热耦合反应蒸馏系统（EHIRDS）。EHIRDS由一个高压的反应塔和一个低压的分离塔组成,且前者的精馏段与后者的提馏段进行热交换。引入四元理想放热反应体系A + B ? C + D,并以年总费用（TAC）最小为目标函数,对EHIRDS进行了研究,发现EHIRDS能够降低操作费用。采用三个换热器简化EHIRDS的设计（即S-EHIRDS）还可以进一步降低设备投资和操作费用。这些仿真结果初步确认了EHIRDS相比于常规设计具有更高的优越性。