煤基合成气一步制备高纯度二甲醚的全流程建模与模拟

As a result of shortage supply of oil resources, the process for the alternative coal-based fuel, dimethyl ether (DME), has emerged as an important process in chemical engineering field. With the laboratory experiment data about DME synthesis and separation, the production process for DME with high purity is proposed when one-step synthesis of DME in slurry bed reactor from syngas is adopted. On the basis of experimental research and process analysis, the proper unit modules and thermophysical calculation methods for the simulation process are selected. Incorporated the experimentally determined parameters of reaction dynamic model for DME synthesis, regression constants of parameters in non-random two-liquid equation (NRTL) model for binary component in DME separation system with built-in properties model, the process flowsheet is developed and simulated on the Aspen Plus platform. The simulation results coincide well with data obtained in laboratory experiment. Accordingly, the accurate simulation results offer useful references to similar equipment design and process operation optimization.     

浅谈《化学反应过程与设备》的多媒体教学

化学反应过程与设备是化工类专业的主要课程,针对该学科的特点及学生的学习状态阐述了在教学中引入多媒体技术具有化抽象为直观、理论与实践紧密结合的优点,能够适应对化工类人才培养模式对新型化工人才的要求,多媒体技术在本课程教学中具有广阔的应用前景。     

Experimental Investigation and Simulation of Organophilic Pervaporation in Laboratory and Pilot Scale

Pervaporation is a well‐established separation technology for the production of anhydrous solvents, but its distribution in the chemical industry is still limited to a few individual applications. Besides the need of high‐selective membranes, the development of membrane modules adapted to the specific requirements of this process needs more research effort. Furthermore, only few modeling tools for the pervaporation process are available. In this work, a three‐step modeling approach ranging from a shortcut to a rigorous model is developed. A hydrophobic membrane is characterized in a laboratory test cell for the separation of 2‐butanol from water in a wide temperature and concentration range. The identified performance data are used to simulate the same separation task with an industrial‐scale membrane module. The results are validated by experiments conducted with a novel membrane module in pilot scale.     

Guidance on Safety/Health for Process Intensification Including MS Design. Part III: Risk Analysis

The new technology of process intensification by multiscale equipment can significantly contribute to achieve a safer design by going from batch/semi‐batch to continuous operation combined with a reduction of inventory of hazardous substances in critical stages. On the other hand, the shift to higher space‐time‐yields comprises new risks such as runaway reactions with hot spot formation, described in Part I, and handling an explosive atmosphere in the presence of potential permanent ignition sources, described in Part II. A tool was developed for preliminary risk assessments, called HAZOP‐LIKE study, to cover the characteristic features of micro‐designed equipment that are relatively unimportant when handling conventional equipment. Two generic cases concerning liquid/liquid and gas/gas reactions were studied to demonstrate the method.     

Characterization of a New Flat Sheet Membrane Module Type for Gas Permeation

Modern high‐performance flat sheet gas separation membranes exhibit high permeances as well as high selectivities, e.g., for CO₂ separation. Novel membrane modules are desirable to transfer the intrinsic membrane performance to the process. The introduced module implements countercurrent flow, which allows for the best utilization of the required driving force, provided concentration polarization and pressure drops can be kept at bay. As such, it is different from established flat sheet modules for gas separation. The design features allow for straightforward scaling and easy adjustment to other operating conditions. During module development equation‐oriented modeling, computer‐aided engineering design and application of computational fluid dynamics for flow optimization were integrated. The prototype was investigated in a pilot plant. The experimental results reflected the simulation predictions and proved the validity of the module concept.     

分步反应的气相催化氧化法生产蒽醌

介绍了分步反应的气相催化氧化法生产蒽醌的新工艺及主要设备，阐述了工艺的重要特点。     

Designing and Testing a Chemical Demulsifier Dosage Controller in a Crude Oil Desalting Plant: An Artificial Intelligence‐Based Network Approach

The aim of this paper is to present an artificial neural network (ANN) controller trained on a historical data set that covers a wide operating range of the fundamental parameters that affect the demulsifier dosage in a crude oil desalting process. The designed controller was tested and implemented on‐line in a gas‐oil separation plant. The results indicate that the current control strategy overinjects chemical demulsifier into the desalting process whereas the proposed ANN controller predicts a lower demulsifier dosage while keeping the salt content within its specification targets. Since an on‐line salt analyzer is not available in the desalting plant, an ANN based on historical measurements of the salt content in the desalting process was also developed. The results show that the predictions made by this ANN controller can be used as an on‐line strategy to predict and control the salt concentration in the treated oil.     

化工过程机械学科“一体两翼”建设模式及特色

为培养适应当前社会所需的过程工业专门人才,本文对华南理工大学化工过程机械学科"一体两翼"建设模式进行介绍和探讨,从专业设置、师资队伍两方面介绍了我校化机学科建设基本情况,以过程装备主体为核心、过程控制与安全系统设计为外层要素建立化机学科发展战略洋葱模型;基于空客模型提出以化机学科为主体、过程安全和油气储运为两翼的"一体两翼"建设和发展模式,并对"一体两翼"模式内涵、特色及实施成效进行阐述。     

Dynamic modelling and predictive control for the sequential collaborative reactors of cobalt removal process under time‐varying conditions

The accuracy of the process model directly affects the performance of the model‐based controller. In zinc hydrometallurgy, the overall dynamics of the cobalt removal process can hardly be described by a fixed model since there are a series of interconnected reactors working together under time‐varying inlet and reaction conditions. In this study, an interacting continuously stirred tank reactors (ICSTR) model is developed to describe the cooperative relationship of these cascaded reactors. Considering the time‐varying inlet and reaction conditions, the reaction surface conversion coefficient is defined and incorporated into the ICSTR model, and the kernel partial least squares (KPLS) is employed to update the dynamic model online. The effectiveness of the time‐varying ICSTR model is validated using industrial data. Based on the proposed time‐varying ICSTR model, a predictive controller is designed to realize the optimal operation of the cobalt removal process. Simulation results indicate that compared with conventional predictive control and manual manipulation, the time‐varying ICSTR model‐based predictive control method can not only maintain the outlet cobalt ion concentration but also reduce the zinc dust dosage.     

A Recursive Nonlinear PLS Algorithm for Adaptive Nonlinear Process Modeling

Partial least squares (PLS) regression has been shown to be a powerful multivariate linear regression method for problems where the data are noisy and highly correlated. However, in many practical situations, the processes being modeled exhibit nonlinear behavior, which cannot be reliably modeled by linear regression methods. Furthermore, the processes often experience time‐varying changes. In this paper, a recursive nonlinear PLS (RNPLS) algorithm is proposed to deal with this problem. First, a nonlinear PLS (NLPLS) model is built by performing PLS regression on the extended input matrix and the output matrix, where the extension of the input matrix includes the outputs of the hidden nodes of an RBF network and a constant column with all elements being one. When new data cannot be described by the old model in the sense that the model performance on a moving window of data is not satisfactory, the recursive algorithm is then used to modify the structure and parameters of the model to adapt process changes. Applications of this RNPLS algorithm to a simulated pH neutralization process and an industrial propylene polymerization process are presented and the results demonstrate that this algorithm adapts the process changes effectively and gives satisfactory prediction results.     

Net Present Value Analysis of Modular Chemical Production Plants

Modular plants consist of modules that autonomously operate parts of the plant. These modules are technically and organizationally limited areas of the plant that fulfill defined tasks. Starting with these modules, companies can create capacity either by equaling up modules from general structures or by numbering up equipment. Here, the economics of a modular chemical plant are compared with those of a traditional large‐scale plant by investigating the net present value. The modular plant presents a more efficient concept for fast growing products or products with volatile demands. This is because the market impact during operation is more important than the preceding influence of the investment. In those cases, the effects of flexibility surpass the effects of scale.     

Revamping Dimethyl Ether Separation to a Single‐Step Process

Process intensification techniques were recently proposed to improve the eco‐efficiency of the conventional dimethyl ether (DME) purification and methanol recovery distillation sequence, but they all require new specific equipment and hence rather high investment costs leading to several years of payback time. However, the alternative of reusing the existing equipment to revamp the two distillation columns of the downstream processing section into a single‐step separation was so far overlooked in the open literature. To solve the problem of costly DME separation, a novel single‐step DME separation taking place in a dividing‐wall column (DWC) is proposed that effectively integrates in one shell the tasks of DME purification and methanol recovery. The new process is optimized in terms of minimal energy requirements, taking into account the restrictions caused by reusing one distillation column like, such as limited diameter or reboiler/condenser heat duty. The results demonstrate that the DWC alternative is feasible and has better performances as compared to the classic sequence, i.e., 28 % lower operating costs and 20 % less capital investment.     

A Novel Technology for Natural Gas Conversion by Means of Integrated Oxidative Coupling and Dry Reforming of Methane

A novel process concept for the oxidative coupling of methane followed by the oligomerization to liquids has been developed within the frame of the EU integrated project OCMOL. This technology is based on process intensification principles via cutting‐edge structured microreactor technology. It is also a fully integrated industrial process through the re‐use and the recycling of by‐products, in particular CO₂, at every process stage. The focus of this contribution is on the reaction engineering aspects of the core steps, i.e., catalysts, kinetics and reactor design for the methane coupling and reforming.     

CHALLENGES AND INNOVATIONS IN REACTION ENGINEERING

The importance of reaction engineering in generating a myriad of products on which developed societies depend is outlined. The challenges of a political, economic, and technical nature that need to be addressed in rendering conversion of raw materials into desired products that are more environmentally friendly and sustainable are briefly discussed. It is shown that multiphase reactors are prevalent in all applications, and improvements in the reactor material and energy efficiencies lead to more environmentally benign processes. This requires, in addition to the selection of green process chemistry, systematic implementation of the multi-scale reaction engineering methodology to accomplish proper reactor type selection and scaleup for commercial applications. It is also illustrated that recent innovations in multiphase reaction engineering basically utilize two key concepts: process intensification (e.g., enhancement in mass and heat transfer rates) and simultaneous reaction and separation. Examples of these are discussed, such as micro-reactors, reactive distillation, etc. It is also shown that commercialization of bench-scale discoveries requires either scaleup in parallel or vertical scaleup. New tools for visualization of opaque multiphase flows and development of appropriate rational phenomenological multiphase reactor models for scaleup and design are also briefly discussed.     

新世纪的化工机械技术展望

就进入21世纪之后化工机械技术所面临的新的挑战，全面介绍与化工机械工业相关的高新技术进展，提出面向先进制造技术、面向新材料技术、面向再制造工程和面向高技术工艺过程4个战略方针，以适应新世纪科学技术发展的潮流，为化工机械技术的未来展示广阔的前景与机遇。     

Optimal conditions of isobutane dehydrogenation in radial flow moving bed hydrogen-permselective membrane reactors to enhance isobutene and hydrogen production

In the isobutane dehydrogenation process, coupling reaction and separation and optimization of the intensified process can improve the isobutane conversion and selectivity, reduce operational costs and lets to produce pure hydrogen. In this research, the radial flow moving bed reactors in the Olefex technology have been supported by Pd–Ag membrane plate to remove hydrogen from the reaction zone. The reactions occur in the tube side and the hydrogen is permeated from the reaction zone to the sweep gas stream. The proposed configuration has been modeled heterogeneously based on the mass and energy conservation laws considering reaction networks. To prove the accuracy of the considered model, the simulation results of the conventional process have been compared against available plant data. The Genetic algorithm as an effective method in the global optimization has been considered to optimize the operating condition of membrane reactors to enhance isobutene productivity. In this optimal configuration, the isobutene production has been enhanced about 3.7%.     

A generalized method for the synthesis and design of reactive distillation columns

Owing to the combination between the reaction operation and the separation operation involved, it is extremely difficult to determine in advance the optimum configuration of a reactive distillation column and this makes process synthesis and design a great challenging task. Currently, no easy-to-use and yet effective methods are available to guide process synthesis and design, restricting considerably the applications and therefore the impacts of reactive distillation columns to the chemical process industry. In this paper, a generalized method is proposed for the synthesis and design of reactive distillation columns in terms of the insights from process intensification. The method is initiated from a simple process design with all feeds of reactants at the middle of the process and all stages as reactive ones. In terms of an economical objective function, it can be evolved into the optimum process design via sequential structure adjustments, including reactive section arrangement, feed stage relocation, feed splitting, and catalyst redistribution. The generalized method proposed is characterized by great simplicity in principle, the capability to tap the full potentials of process intensification, and the high robustness to the initial guess of process configuration as well as the thermodynamic properties of the reacting mixtures separated. Four example systems are employed to evaluate the generalized method proposed and the obtained outcomes demonstrate its effectiveness and applicability to the synthesis and design of various reactive distillation columns.     

Predictions for Start‐Up Processes of Reactive Distillation Column via Artificial Neural Network

The time consumed in starting up the unit with appropriate holdups can form an important part of the total distillation time, particularly for reactive distillation systems with large holdups. Also, the products formed during the start‐up time are off specification, and are not easily recycled as for traditional distillation, but must be carefully disposed of, which can be very costly. A back‐propagation algorithm artificial neural network model is presented as a tool to assess the start‐up process for a given reactive distillation system. All the data required for training and testing the artificial neural network have been generated using the CHEMCAD simulator, version 5.2–0. The values for the learning rate, momentum term, and gain term of the artificial neural network have been taken as 0.01, 0.6, and 1.0, respectively. From the case studied in this work, it can be seen that a good start‐up policy can reduce both the energy and time requirements in the start‐up phase of reactive distillation processes. Results from predictions show the time consumed in the start‐up period has an average error of 2.833 %, and a maximum error of 7.600 %, for the case studied here. The accuracy of the model will depend upon the data available and the type of model being approximated.     

蒸馏技术现状与发展方向

分析了精馏传质过程与分离工程的特点 ,介绍了精馏过程的基础理论和过程强化的研究现状。从学科研究的角度 ,提出进行精馏过程非线性、非平衡传质行为和特征的研究 ,是解决设备放大效应的理论基础。而发展精馏技术的科学的工程设计方法 ,需要将过程传递行为与设备结构相结合。并提出了相应的促进措施和研究方法。     

Prototyp eines wissensbasierten Programmsystems für die Systemsimulation

Prototype of a Knowledge-Based Program System for System Simulation. The present article describes a new approach for merging numeric simulation techniques and knowledge-based methods for process simulation. In a first step the potential of such a combined technology is outlined, concerning both knowledge-based user support in handling and application of simulation codes as well as the support of the engineering task for chemical process development. An analysis of implementation techniques outlines, how an adequate integration of numeric and knowledge-based software modules can be achieved by adoption of the object oriented programming paradigm. The resulting requirements for the modelling of knowledge and the corresponding inference mechanisms are explained and a software prototype is presented by which this knowledge-based simulation technology is currently being evaluated and refined using a case study from aerospace domain.