共查询到20条相似文献,搜索用时 93 毫秒
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在ROMeo中建立丙烯精馏塔的优化模型,利用ROMeo的数据校正功能使模型与装置相匹配,并计算得到精馏塔的默佛里板效率。在满足工艺约束的条件下,以工厂效益为目标函数,进行优化计算,获得新的操作目标。利用ROMeo的实时系统,可自动实现丙烯精馏塔的在线优化。 相似文献
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通过对小本体聚丙烯装置丙烯尾气回收系统不凝气排放所造成的丙烯损耗进行理论分析和计算,说明加强不凝气中丙烯回收,对降低聚丙烯生产成本的重要意义,并提出了回收不凝气中丙烯的工艺方法。 相似文献
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通过对气体分馏装置丙烯精馏塔的主要工艺参数进行调整,分析进料组成、回流比、塔压和温度的变化对丙烯精馏塔顶丙烯纯度的影响,优化丙烯精馏塔工艺操作,保障丙烯产品体积分数(?)≥99.50%,达到合格标准。 相似文献
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间歇式液相本体法聚丙烯(PP)生产管理优化系统是应用于PP生产中的管理软件.自动计算丙烯单耗是在此管理软件的基础上根据生产管理的实际需要开发的一项新功能.此功能的应用可优化PP的生产操作、降低丙烯单耗. 相似文献
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区间牛顿法具有较强的全局收敛性。在实际应用过程中,只要给出非线性方程组中所有自变量的变化范围,区间牛顿法就能在数学上保证找到非线性方程组的所有解。因此,广泛应用于化工过程计算与优化中。 相似文献
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针对Mo-Bi系催化剂作用下的丙烯氨氧化反应过程,采用氧浓度的强制周期振荡操作,根据理论推导和所定义的催化剂表面活性中心分率α,得到了丙烯转化率X及丙烯腈选择性SAN的动态动力学模型如下。进而结合在不同振荡操作周期,不同振幅条件下所采集到的实验数据,确定了模型参数,并进行优化计算得到最佳的振荡操作条件,丙烯腈周期平均收率达81.1%,比非振荡操作时提高了3.09个百分点。 相似文献
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<正> 本文采用计算机模拟计算的方法对丙烯氨氧化合成丙烯腈反应体系催化剂的稀释条件进行优化计算,得到在不增加管长,保持原转化率的前提下的优化装载条件。它对现有的生产改造有参考价值,且可用于其他反应。 相似文献
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Godambe's (1985) theorem on optimal estimating equations for stochastic processes is applied to non-linear time series estimation problems. Examples are considered from the usual classes of non-linear time series models. A recursive estimation procedure based on optimal estimating equations is provided. It is also shown that pre-filtered estimates can be used to obtain the optimal estimate from a non-linear state-space model. 相似文献
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NONLINEAR MODEL PREDICTIVE CONTROL 总被引:3,自引:0,他引:3
Ashutosh A. Patwardhan James B. Rawlings Thomas F. Edgar 《Chemical Engineering Communications》1990,87(1):123-141
Nonlinear Model Predictive Control (NMPC), a strategy for constrained, feedback control of nonlinear processes, has been developed. The algorithm uses a simultaneous solution and optimization approach to determine the open-loop optimal manipulated variable trajectory at each sampling instant. Feedback is incorporated via an estimator, which uses process measurements to infer unmeasured state and disturbance values. These are used by the controller to determine the future optimal control policy. This scheme can be used to control processes described by different kinds of models, such as nonlinear ordinary differential/algebraic equations, partial differential/algebraic equations, integra-differential equations and delay equations. The advantages of the proposed NMPC scheme are demonstrated with the start-up of a non-isothermal, non-adiabatic CSTR with an irreversible, first-order reaction. The set-point corresponds to an open-loop unstable steady state. Comparisons have been made with controllers designed using (1) nonlinear variable transformations, (2) a linear controller tuned using the internal model control approach, and (3) open-loop optimal control. NMPC was able to bring the controlled variable to its set-point quickly and smoothly from a wide variety of initial conditions. Unlike the other controllers, NMPC dealt with constraints in an explicit manner without any degradation in the quality of control. NMPC also demonstrated superior performance in the presence of a moderate amount of error in the model parameters, and the process was brought to its set-point without steady-state offset. 相似文献
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This study shows how the optimal control theory for distributed parameter systems can be implemented for a problem of tubular
reactor with axial dispersion described by partial differential equations. Two methods are implemented. One is based on differential
equation approach and the other is based on integral equation approach. It was found that the approach with partial differential
equations is preferable to the one with integral equations for the type of problems treated in this study. Computation algorithms
and programs for both cases are developed. 相似文献
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针对集成反应分离耦合控制中存在最佳耦合点难以确定的技术难点,自主提出了一种能将反应分离进行耦合控制的建模方法。其基于电化学还原反应与连续色谱分离原理,通过将电化学反应方程的浓度值输出作为连续色谱分离传质方程的初始边界条件,耦合两者的传质方程进行联立求解,能够揭示电化学反应时间控制与产物转化率以及分离效果等之间的作用关系。将该方法应用于甘露醇的制备过程,其实验与模拟结果对比表明,两者吻合较好。该建模方法具有较强的预测能力,不仅获得了集成反应分离制备甘露醇的最佳耦合控制点,而且方法具有一定的推广应用价值。 相似文献
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控制向量参数化方法是求解最优控制问题的一种常用数值方法。它通过离散化控制时域,将控制向量近似地表示成一组参数化的函数。离散化后的时间网格通常是固定的,其划分会影响到最优控制问题数值求解的精度和效率。为了同时优化控制参数和时间网格节点,提出了一种时间节点可变的控制向量参数化方法。推导出了最优控制性能指标对时间参数的导数与对时间分段长度导数之间的关系,得到了性能指标的梯度表达式。用两个经典最优控制实例对所提出的方法进行了测试,结果表明所提出方法能够更好地逼近最优控制轨迹。 相似文献
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Conventional design procedures use physical reasoning to construct equations describing the system. To find the optimal design for some specified performance criterion, it is desirable to change these equations into inequalities so that generalized polynominal programming, a highly nonlinear optimization technique, can be used. For illustration, a chemical reactor system optimal design problem with 11 variables and 8 constraints is formulated as an equality constrained optimization problem, then transformed into an inequality constrained generalized polynominal program and finally solved on the computer. 相似文献
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第二代PFBC-CC脱硫是在强还原气氛下进行的,本文利用热分析方法对该脱硫过程进行了静态试验研究,获得了硫化和氧化反应适合的反应条件以及相应的动力学方程 相似文献
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Although it is a simple matter to derive equations for the optimal multimodal control of a multivariable process, it is shown that no solutions to these equations exist unless the number of control variables is equal to the number of state variables or unless the number of control variables is equal to the number of state equations in which the control variables appear. 相似文献