尿素水解器建模与仿真

利用尿素水解器处理回收尿素解吸废水有利于环境保护和企业经济效益的提高。目前国内对尿素水解的研究工作仅进行了工艺技术研究和稳态模拟计算,尚未进行动态模拟及仿真工作。利用水解工艺理论研究成果,分析了尿素水解器的反应动力学、物料衡算和能量衡算,对尿素水解器进行了动态建模,并组态为仿真软件进行测试,并对误差产生原因进行了分析。结果表明:模型运行至稳态时各项主要参数指标和生产装置设计数据的相对误差控制在3%以内,达到了仿真应用要求。     

TE过程闪蒸罐双时间尺度建模与动态特性分析

闪蒸罐是工业常用的化工单元设备, 在对其进行动态机理建模时, 气相物质的动态特性方程被拟稳态处理转化为稳态代数方程, 而液相仍为微分方程。由此一来, 与气相相关的压力的真实动态信息无法得到, 而是完全依赖于液相相态的变化。基于闪蒸罐的化工动态学机理和“拟稳态”的系统特点, 通过增加快变量的动态物料守恒关系式, 还原系统的气相快暂态过程, 建立了TE过程闪蒸罐的双时间尺度全阶模型。利用奇异摄动方法将全阶模型精确求解后, 与拟稳态模型进行了仿真对比;最后, 设计了全阶模型的压力控制回路, 得到很好的控制效果, 验证了建模方法的合理性和工业应用价值。     

高速铣削加工切削参数的优化选择

基于数控机床动力学测试分析和仿真系统,利用X-cut软件获取加工时的切削稳定域,确定加工参数的范围,再依据弯曲应力和挠度变形理论筛选切削参数,进一步缩小实验参数范围。最终经实验得到合适的切削参数,切削后经三坐标测量,零件满足设计尺寸要求和表面粗糙度要求,从而验证了软件优化参数的合理性和有效性。     

显著误差等效集及其求解方法研究

在过程工业中,显著误差检测与估计是成功实现过程数据校正的基础。无论是稳态过程还是动态过程显著误差检测,目前都没有找到高可靠性的方法,由此引发了对显著误差可识别问题的讨论。在分析显著误差可识别结果和等效集理论的基础上,对显著误差可识别问题进行了研究,提出了一种基于整数规划的显著误差最小势等效集的求解策略。理论和仿真说明了所讨论问题的存在性和所提方法的有效性。     

振荡热管模型中液膜的分析与假定

在经典Nusselt膜理论的假定基础上,结合毛细管内液膜的特点,考虑了液膜附加压力、界面热阻、液膜过热度,分别对平衡液膜区、过渡液膜区和宏观液膜区进行了详细分析,建立了相应的控制方程,研究了毛细管内液膜稳态蒸发过程中液膜厚度、传热系数等参数的变化特性;根据毛细管内稳态蒸发液膜的轮廓和特性,对振荡热管内的动态液膜作出了相应的假定,并提出了如何确定动态液膜的厚度、长度以及相变传热系数。     

深冷空分精馏系统动态过程研究

通过深冷空分精馏系统动态建模对象,建立了动态机理模型;重点研究空分精馏塔建模与其他模块机理建模的动态研究过程,以实例进行精馏塔动态仿真分析;分析结果显示约简模型不仅能准确地描述装置稳态运行,还能刻画装置的动态行为及动态特性,提高精馏装置实用性,避免了氮塞故障出现,实现了预期效果,可为相关研究提供参考。     

塔式太阳能电站接收器的建模及动态仿真

太阳能接收器是塔式太阳能电站的重要组成部分,是光热转换的重要部件,因此接收器的建模和仿真对实现电站的平稳运行具有重要意义。根据能量守恒、质量守恒定律,对以美国Solar Two电站接收器为原型的高温熔盐接收器吸热管进行空间离散化,建立了接收器分段集总参数模型。模型稳态仿真结果与Solar Two电站接收器测试结果的对比验证了模型的正确性。通过接收器动态仿真,分析了输入变化和接收器接收能量不均匀时的传热特性,可为定日镜场聚焦策略以及电站安全运行的研究提供依据。     

基于漂移流理论的蒸汽发生器动态特性

以大亚湾核电站U型管自然循环蒸汽发生器为研究对象,根据蒸汽发生器上升通道沸腾段特点,建立了适合工程应用的漂移流模型动态方程。在验证稳态工作特性及与漂移流理论所涉及的关键参数准确性的基础上,进行了蒸汽发生器动态特性仿真与分析。结果表明,所建立的漂移流模型能够较准确地反映蒸汽发生器两相流的流动与换热特性。随着扰动的添加蒸汽发生器各参数都表现出合理的变化趋势,并准确地模拟出“虚假水位”现象,且负荷越高水位对扰动的响应速度与程度越大。     

大功率PEMFC空气供给系统建模与实验验证

近年来,质子交换膜燃料电池(PEMFC)作为车载燃料电池的主要动力源受到广泛关注。空气压缩机为电堆提供系统所需的氧气和阴极压力,是质子交换膜燃料电池系统中必不可少的一部分,其工作性能对燃料电池稳态和动态工作性能有很大的影响。基于实验室已有150 kW质子交换膜燃料电池系统,对离心式空压机的工作特性进行了研究,建立了包含离心式空气压缩机的空气供给系统应用模型。通过实验验证,仿真模型能够准确地反映离心式空压机与空气系统的特性,同时能真实反映包含离心式空压机的大功率质子交换膜燃料电池空气系统的稳态控制效果,以及不同控制策略下的动态响应效果。该模型对研究大功率质子交换膜燃料电池空气供给系统以及相应的控制策略提供理论支持,仿真模型与实验结果为下一步控制策略优化提供基础与参考。     

大功率PEMFC空气供给系统建模与实验验证

近年来,质子交换膜燃料电池(PEMFC)作为车载燃料电池的主要动力源受到广泛关注。空气压缩机为电堆提供系统所需的氧气和阴极压力,是质子交换膜燃料电池系统中必不可少的一部分,其工作性能对燃料电池稳态和动态工作性能有很大的影响。基于实验室已有150 k W质子交换膜燃料电池系统,对离心式空压机的工作特性进行了研究,建立了包含离心式空气压缩机的空气供给系统应用模型。通过实验验证,仿真模型能够准确地反映离心式空压机与空气系统的特性,同时能真实反映包含离心式空压机的大功率质子交换膜燃料电池空气系统的稳态控制效果,以及不同控制策略下的动态响应效果。该模型对研究大功率质子交换膜燃料电池空气供给系统以及相应的控制策略提供理论支持,仿真模型与实验结果为下一步控制策略优化提供基础与参考。     

苯氯化反应与精馏过程的模拟与实时监控系统

以反应与精馏集成生产氯化苯过程为研究对象,依据化工机制模型和动态特性,采用化工流程模拟HYSYS软件建立苯氯化反应与精馏集成过程流程模拟系统。采用Visual Basic语言编写通讯模块,实现WINCC集成监控系统和模拟系统数据之间的实时通信。构建了苯氯化反应与精馏集成过程的实时监控平台。实现了模拟过程动态显示、PID控制器参数整定、历史数据查询、报表显示与打印、实时报警等多项集成功能。     

Dynamic simulation of liquid—liquid operations using simple non-linear models

In this paper a new method for the dynamic simulation of multistage, multifeed liquid-liquid extraction operations is described. This is achieved by the use of simplified non-linear local models for the equilibrium representation of partially-miscible three-component systems.The probable transient response of the system to perturbations in the input parameters is illustrated. Whilst this has yet to be confirmed experimentally, several examples have been successfully solved and the steady-state results agree with those reported by previous authors.The method, using a simulation language (GEMS), is stable and shows computer requirements well within the range of the steady-state algorithms commonly used for simulation of extraction units.     

基于IGA和Hammerstein模型的非线性系统广义预测控制

针对非线性程度较高的系统,设计了一种广义预测控制器。该设计基于Hammerstein模型的动静态可分离特性,首先利用具有全局搜索能力的免疫遗传算法（IGA,Immune Genetic Algorithm）在线辨识模型的一些关键参数,然后运用广义预测控制策略实现对该系统的预测控制。仿真试验结果表明,该设计能够准确预测,而且稳定性好、稳态误差小。     

变增益的非线性预测控制算法

采用变增益策略,用输入与稳态输出的映射表示系统的静态非线性,用一个增益为1的ARX模型表示系统的动态模型,代替多数文献中常用的分段线性多模型方法进行非线性系统的预测控制.文中通过对连续搅拌釜反应器(CSTR)的仿真,验证了本算法的有效性.     

INTEGRATING THE EFFECTS OF PROCESS CONTROLLERS WITH STEADY-STATE, EQUATION-BASED SIMULATION

Process controllers have a significant influence on the steady-state, as well as the dynamic, behavior of chemical processes. Thus, the steady-state simulation of processes should include the effects of control. A new method for including controllers in steady-state simulation is presented in this paper. The method provides equations that represent the steady-state control algorithm and can be solved simultaneously with the process model to yield the steady-slate behaviour of the closed-loop system. Most importantly, the controller models include saturation effects and can be formulated and solved within an open-form model. The method is general and can be applied to single-loop controllers, to complex control designs including split range and signal select, and to several single-loop controllers in a multiloop controller design.     

基于CATIA二次开发的风力机叶片建模技术

针对风力机叶片三维模型,利用VB平台建立与EXCEL的接口,方便叶片模型参数从EXCEL读入.为精确建模,计算过渡翼型以及叶片空间离散数据点坐标,再基于VB平台建立CATIA应用软件的二次开发,输出CATIA几何图形集.此软件的开发意义在于能够快速、高效、精确、智能化建立风力机叶片三雏模型,从而可进行气动分析、结构有限元分析、动态仿真以及为制造叶片模具提供数控加工模型.     

乙烯装置裂解气压缩机开车过程动态模拟

裂解气压缩机作为乙烯装置的核心设备,其顺利启动对乙烯装置开车过程有着重要影响.传统的乙烯装置开车流程大多使用裂解气启动压缩机,近年来已经逐步被氮气、天然气和混合烃等开车工质取代.由于无法利用实际压缩机装置进行测试,因此化工模拟技术成为了解决上述问题的重要工具.本文根据"稳态-动态-开车"的研究方法,建立了某裂解气压缩机的稳态模拟模型,确定了氮气、混合烃和裂解气运行时的稳态运行参数.之后,将稳态模型转换为动态模型,通过动态模拟验证了各工况之间转换过程的安全性和可行性.     

微机用于抛物线齿同步带传动强度理论的研究

采用啮合原理与弹性力学复交函数相结合的方法，借助计算机对抛物线齿同步带传动强度理论进行了系统研究，并将整个计算过程编制成ＲＨＤＧＲＡＰＨ软件。利用该软件进行了带齿和轮齿及刀具齿形设计、啮合原理分析、应力和变形计算、刀具可加工最小齿数的确定及加工误差分布计算。     

Parallel dynamic simulation of industrial chemical processes on distributed-memory computers

We describe here a parallel-modular approach to solve plantwide, as well as multiple plant problems, by running simulations in parallel on a distributed network of computers. Two implementations of the parallel-modular approach are presented. In the first, SPEEDUP (Aspen Technology, Inc.) serves as the master process and converges the overall simulation using simultaneous calls to SPEEDUP slave simulations for function and/or derivative evaluations, for both steady-state and dynamic simulations. In the second implementation, MUSIC (MUlti-SImuIation Configuration) combines any number of independent dynamic simulations together with a graphical-user interface to create a single client-server environment for parallel dynamic simulation. In this paper, we use MUSIC to integrate SPEEDUP and OTISS dynamic simulations, running them in parallel in a networked computer environment (MUSIC and OTISS from Aspen Technology, Inc.).The parallel-modular approach is tested using large industrial simulation case studies. For the parallel SPEEDUP environment, we present results for the steady-state simulation of three integrated sections of a petrochemical facility (>175,000 equations). Good speedup factors are achieved by exploiting parallel execution and problem decomposition. One of the plant sections is also used for dynamic simulation by decomposing it into two subsections. Numerical results are presented showing a significant improvement by using two processors. Using the MUSIC environment, we demonstrate performance on the dynamic simulation of a gas injection and processing plant (>80,000 equations). Parallel execution on two processors provides real-time performance for this integrated OTISS and SPEEDUP dynamic simulation.     

Dynamic behaviour and simulation of a liquid-liquid extraction column

Dynamic behaviour of a stirred liquid-liquid extraction column was studied experimentally. Various input variables of the column were varied stepwise and the resulting variations in the system and output variables were measured. In addition to experimental work, a computer model was developed on the basis of the dispersion model to simulate the dynamic behaviour of the extractor. This model forms a component program of the dynamic process simulator DIVA, developed at the TU Stuttgart. The experiments showed that the hydrodynamic parameters exhibit no significant dynamic behaviour of their own. Therefore, changes occurring in these parameters closely follow variations in input and system variables. As a result, steady-state relationships for the calculation of flow parameters could be used in the simulation program. The simulator satisfactorily reproduced the experimental results for a number of disturbances. However, this was not always the case. As shown in the following, the model did not take into account the column level controller which, under certain conditions, exerts a very strong influence on the column's dynamic behaviour. As a result, larger differences occurred between experimental and simulated data. This influence on the extractor's dynamic behaviour can, however, be eliminated by a simple modification of the level controller arrangement.