Study on kinetics of propylene polymerizationat different temperatures via Monte Carlo simulation

在不考虑其他杂质参与聚合反应的情况下,并基于已有对丙烯聚合反应过程的普适化认识,提出了一个普适的丙烯聚合反应机理(基元反应).在已有的丙烯聚合反应机理基础上,为了证实该聚合反应过程总活性基是否满足“稳态假定”以及考察聚合反应温度对聚合过程的影响,采用蒙特卡罗模拟方法研究了传统Ziegler-Natta催化剂催化下的丙烯聚合动力学.模拟得到的总活性基数目在丙烯聚合初期快速增加到峰值,然后随聚合反应的进行保持恒定,证实了丙烯聚合过程中总活性基符合稳态假定.同时,模拟得到了聚合温度对丙烯聚合过程的转化率、分子量的影响.模拟结果表明:在聚合过程中,丙烯单体的消耗速率随聚合温度升高而增加;不同聚合温度下的数均聚合度峰值相同,但随温度增加,数均聚合度峰值来得早;随聚合温度增加,数均分子量减少,分子量分布变宽.The elementary reactions of propylene polymerization catalyzed by conventional Ziegler-Natta catalysts was proposed according to the comprehensive view and without considering the effect of any impurity in the material on propylene polymerization.The Monte Carlo simulation technique was employed to investigate the kinetics of propylene polymerization in order to determine the validity of the stationary state assumption and the effects of the polymerization temperature on the polymerization.The simulated total amount of active species,which only increases quickly at the beginning of the polymerization,indicates that the stationary state assumption in the studied system is valid.Moreover,significant effects of polymerization temperature on the polymerization conversion,and the molecular weight and its distribution were also analyzed.The simulated results show that the consumption rate of propylene increases with the increase of polymerization temperature;the maximum values of the number-average degree of polymerization are constant at different polymerization temperatures,however,the peak appears earlier with the higher temperature;as the polymerization temperature increases,the average molecular weight decreases and the molecular weight distribution changes greatly.The National Natural Science Foundation of China(No.20406016);; the Project of Fujian Petrochemical Company of SIN-OPEC (No.MS/FJ-08-JS-15-2005-01)

Studies on Model of Fccu Reactor

根据提升管反应器的动态机理,考虑反应对压力的影响,结合物料平衡、能量平衡方程,建立了馏分油5集总催化裂化反应动力学模型。使用Nelder-Mead最优化法进行了参数的拟合,并用MATLAB对模型进行了仿真。通过对工业装置数据的计算比较表明,该模型能较好的预测催化裂化产品产率,可用于实际催化裂化过程。Baseing on the equations of mass,energy,composition balance,the five lumping dynamic mechanism models of the Fluidized Catalytic Cracking Unit(FCCU) reactor were developed.Nelder-Mead minimization algorithm was adopted to model parameters and used MATLAB to describe model.The results of the simulation showed that this simple model was capable of sensible predictions of the dynamic responses of each lupmings

On-line calculation and analysis of heat efficiency of circulating fluidized bed boiler unit

提出一种基于正平衡方法的热效率在线计算方法:通过在线采集锅炉运行中主蒸汽、给水、一二次风等锅炉运行参数,计算锅炉有效利用能量和输入能量,实现热效率的在线计算;采用福建某135 t/h工业CFB锅炉发电机组现场数据进行仿真计算,仿真结果验证了算法的有效性。在此基础上采用正交试验设计方法分析影响CFB锅炉热效率的影响因素;由于工业现场采样的操作数据难以得到各个因素不同水平下的热效率的对应值,故首先采用工业数据和热效率计算数据建立基于LM-BP算法的人工神经网络热效率预测模型。根据模型预测数据设计正交试验,结果表明对于该锅炉风煤比、主汽压力和炉床温度对该锅炉热效率的影响最大。最后进行工业调优试验,试验结果验证了分析结果并初步实现了锅炉热效率的在线优化。A new method of on-line calculation of heat efficiency of circulating fluidized bed boiler(CFB Boiler) was proposed.Based on some measurable operation parameters,including pressure,temperature and the flow rates of main steam,water and primary and secondary air,which were collected online,input energy and the utilization of energy in effect could be deduced respectively,and then heat efficiency could be calculated.Using the plant-site data from a 135 t/h CFB boiler unit in Fujian,the online calculation of heat efficiency was simulated and the result of industrial simulation indicated that this method was accurate and effective.Furthermore,orthogonal experiment was performed to analyze seven factors which contributed to heat efficiency of CFB boiler.Because it is hard to get corresponding data on the orthogonal layout,a Levenberg-Marquardt(LM)_back propagation(BP) algorithm-based predictive model was established by using the data collected from plant-site and on-line calculation model.The result of orthogonal experiment indicated that air/coal ratio,main steam pressure and boiler firebox temperature were key factors.The result was validated by the industrial optimization experiment.This method will help on-line optimal operation of the CFB boiler.福建省科技计划重点项目(2005H044

Simplified Dynamic Model of Evaporation Zone in Circulating Fluidized Bed Boiler

气包压力与气包水位是确定锅炉是否安全稳定运行的重要参数,其中气包水位又是锅炉主要控制参量之一,要实现给水的自动调节,就必须掌握其动态特性。建立循环流化床(CFB)锅炉蒸发区动态模型,对研究锅炉的动态特性和确定控制策略具有重要意义。本文在分析前人工作的基础上,建立了新的简化的锅炉蒸发区的动态数学模型.利用所建模型对气包的动态特性进行了仿真研究,结果证实了模型的有效性。Drum pressure and water-level are the critical issues for normal operating condition of drum boiler,and the level is one of the main controlled variables of the boiler.In order to control it,its dynamic characteristics must be obtained.CFBB dynamic model of evaporation zone was developed to research boiler behavior and design control system.Based on the previous results in open literature,a new and simplified model of evaporation zone was developed.Finally,the model was used to do simulation,the results showed the model was valid.福建省自然科学基金计划资助,项目批准号:E071002

Modeling of the combustion process of circulating fluldized bed boiler

针对具有多维非线性和纯滞后特性的循环流化床锅炉燃烧过程,采用基于PLS学习算法和OLS学习算法的径向基函数(RBF)神经网络进行建模研究。首先通过循环流化床锅炉仿真平台产生用于建模实验的网络训练数据和泛化数据,然后分别采用OLS算法和PLS算法进行网络训练和泛化研究,最后讨论了影响建模结果的算法参数及其选取方法,重点讨论了PLS算法的4个网络参数的影响和选取。与基于小波网络的建模实验比较,对具有复杂特性的循环流化床锅炉燃烧过程,采用RBF网络建模在保证建模精度的同时,算法参数的选取也较为方便易行。To get a online dynamic model of the combustion process of Circulating Fluidized Bed(CFB)Boiler which was difficult to be modeling because of its complex characteristics such as non-linear,time-delay,time-variation and multidimensional,the RBF net- work based on the PLS arithmetic and the OLS arithmetic was adopted.The data used as the network training samples and the data used in the generalization test of the network was produced by a CFB Boiler simulation system.The network training and generalization study was done by means of PLS arithmetic and OLS arithmetic individually.The arithmetic parameters,especially the parameters of PLS a- rithmetic were discussed to study their influence and selected methods.Contrasting to the online dynamic model of this process which was credited by the wavelet network,the model put forward in this paper keep the same precision and is more easily to select the pa- rameters in the modeling.福建省科技计划重点项目(2005H044

烧结板布风的甲烷化流化床反应器建模与分析

采用双流体模型对烧结板型气体分布器的甲烷化流化床反应器进行数值模拟,在ANSYS-FLUENT平台中利用用户自定义函数建立了烧结板型气体分布器的数学模型;并对过程反应动力学模型进行改进,在宏观上实现了反应速率与催化剂浓度的正相关;通过模型的计算结果与实验数据对比验证了模型的有效性.在模拟结果的基础上对烧结板型气体分布器的甲烷化流化床反应器的参数分布进行了分析,结果表明:烧结板模型的引入增强了反应器进口边界描述的精确性,对反应动力学模型的合理改进更好地反映了甲烷化反应过程,并更符合实验结果,从而提高了模拟计算的精确性.国家自然科学基金(21576228

SIMULATION FOR LIQUID PHASE BULK PROPYLENE POLYMERIZATION IN LOOP REACTOR AT STEADY OPERATION CONDITIONS

采用机理建模方法,研究了丙烯在环管反应器中的液相本体聚合过程。基于流体全混流流动模式并联用机理分析方法,建立了环管反应器中的丙烯液相本体聚合的微观数学模型,模拟了在稳态操作条件下环管反应器中丙烯液相本体聚合动力学。以采集到的工业数据对模型进行了考核。从反应器内反应物料密度和聚合物熔融指数来看,模拟结果与工业现场采集数据相吻合。采用模型考察了稳态下,主要工艺条件对丙烯聚合过程的影响。结果表明,丙烯转化率和聚合产物质均相对分子质量均随聚合温度升高而增加;随丙烯进料量的增加,转化率下降,聚合产物质均相对分子质量则先增加后减小;随催化剂量的增加,转化率与聚合产物质均相对分子质量均增加;而H2进料量对转化率没有影响,但增加H2进料量将导致聚合产物质均相对分子质量下降。The liquid phase bulk propylene polymerization in loop reactor was simulated based on the polymerization mechanism.According to the flow behavior in the loop reactor and the mechanism analysis of bulk polymerization of propylene,the micro-model for liquid phase bulk propylene polymerization in loop reactor at steady operation condition was proposed in order to determine the polymerization kinetics.Moreover,the proposed model was testified by using the spot data in industry.The comparison between simulated and industrial data of the materiel density and melt index showed that they were in good agreement with each other.The model was applied to investigate the effects of the main factors,including polymerization temperature,the mass flow rates of propylene,catalyst and hydrogen,on the polymerization process.The results indicated that the propylene conversion and the weighted average relative molecular mass of the product polymer increased with the rise of polymerization temperature.With the increase of the mass flow rate of propylene,the conversion decreased,and the weighted average relative molecular mass of the product polymer increased first and then decreased.The conversion and weighted average relative molecular mass increased with the increase of the mass flow rate of catalyst.However,the mass flow rate of hydrogen had no effect on the conversion,but the increase of hydrogen could cause the weighted average relative molecular mass of the product polymer to be decreased.国家自然科学基金(20406016);; 中国石油化工股份有限公司项目(X505029)资

The Design of an Intelligent and Full Automatic Perfumery Equipment

针对香精调配过程,阐述了一种全自动调香设备的基本设计思路、系统的结构组成和工作原理。该系统包括:PC机、机械模块、电源模块、控制模块和人机界面。其主要功能是根据调香师输入的配方自动实现各种液态香料的多线程进样,并结合现有调香理论对香精性质进行仿真。它不但能够达到调香过程自动化、精确化、信息化的目的,而且有助于调香师制定配方。尽管设计的原型机只能进行3种液态香料加注,但其实验与理论的一致性证明了其潜在应用价值。This article expounds the train of thought on a full automatic equipment for perfumery, also its system structure and operational principle are explained. This system integrates personal computer, mechanism module, power supply module, control module and human-computer interface. The main function of the proposed equipment is to automatically implement the multithreading sampling of each kind of liquid flavor according to perfumers′ prescription, and simulate the property of the fragrance based on the existing perfumery theories. It could not only realize the goal of automation, informatization and precision for the perfumery process, but also help the perfumers to frame the prescription. Although the designed equipment can only process 3 kinds of liquid flavor, the conformity of the design and the experimental results indicated its potential application value.2007年国家大学生创新性实验计划项目;; 2007年福建省大学生创新性实验计划项

烧结板布风的甲烷化流化床反应器建模与分析

以烧结板型气体分布器的甲烷化流化床反应器为研究对象,在ANSYS-FLUENT平台中利用用户自定义函数建立了烧结板型气体分布器的数学模型;并对过程反应动力学模型提出了合理的改进,在宏观上实现反应速率与催化剂浓度的正相关。通过模型的计算结果与实验数据对比验证了模型的有效性,在模拟结果的基础上对烧结板型气体分布器的甲烷化流化床反应器的参数分布进行了分析。结果表明:烧结板模型的引入可增强反应器入口边界描述的精确性,对反应动力学模型的合理改进可更好地反映甲烷化反应过程,提高了计算的精确性。国家自然科学基金(21576228

On Teaching Reform and Practice at Biochemical Engineering Experiments

本文从工科专业实验课教学的重要性入手,阐述了进行生物工程专业实验课教学改革的必要性和重要意义,介绍了生物工程实验教学改革的相关体会。This article,based on the importance of the engineering experiments teaching,expounds the necessity and importance of the reform in Biochemical Engineering Experiments Teaching,and also introduces the experience about Biochemical Engineering Experiments Teaching reform