Optimal Control of Periodic Adsorption Processes

周期性吸附过程的优化控制

• 批准号: 25616871
• 负责人: Professor Dr. Hans Georg Bock
• 金额: --
• 依托单位: Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/25616871?language=en
• 关键词: Optimal; Control; Periodic; Adsorption; Processes

Periodic adsorption processes are widely established in process engineering for the production of gases, fine chemicals or Pharmaceuticals, and novel uses involve the combination of adsorption and reaction processes. Characteristic for all these processes are traveling concentration fronts of different species in a solid fixed bed, and periodic switching between different types of operation. The dynamics of each phase can be modelled by instationary partial differential algebraic equations (PDAE) in one or two spatial dimensions, so that the overall system is described by periodically switched PDAE. Following start-up, a periodic attractor, or Cyclic Steady State (CSS), is finally reached and used for production. This CSS should ideally be optimal with respect to operational costs and product specifications, and recent years have seen the development of a variety of novel process operation variants to improve efficiency. Two of these are the processes to be investigated in Dortmund: the simulated moving bed (SMB) with variable inlet concentrations (ModiCon-SMB) studied in the group of Prof. Engell and the entirely novel fixed bed catalytic reactor with desorptive cooling (in the following called Desorptive cooling (DC)-Process ) in the group of Prof. Agar.Due to the large scale of the process models and due to their periodic nature, only few model based optimisation approaches exist and their use for large scale applications is limited by prohibitive computation times. Aim of the project is to develop efficient numerical methods for optimisation of periodic adsorption processes described by periodically switched large scale instationary PDAE. These methods shall combine novel reduced Newton type optimisation methods with a type of Picard iteration to cope efficiently with the periodicity constraints. The following features shall characterise our new methods:¿ a simultaneous optimisation framework is chosen in which the discretised model equations enter the optimisation problem as nonlinear constraints¿ only one cycle is simulated and optimised, and periodicity is imposed in form of additional constraints¿ a time-domain decomposition is used to handle the intermediate switching and the enormous amount of data¿ a novel reduced SQP framework being able to cope with inexact Jacobians is used to solve the nonlinear programming problem resulting after discretisation of model equations and controls¿ a mixed Newton-Picard scheme is used to treat the periodicity constraints efficientlyThe method development is driven by the requirements of the two processes in Dortmund. Final application aim of the project is the optimisation and experimental validation of the operating regime of the novel desorptive cooling (DC) process.

周期性吸附过程在气体、精细化学品或药物生产的过程工程中广泛建立，并且新的用途涉及吸附和反应过程的组合。所有这些过程的特征是固体固定床中不同物种的浓度前沿，以及不同类型操作之间的周期性切换。每个阶段的动态可以在一个或两个空间维度的非定常偏微分代数方程（PDAE）建模，使整个系统描述周期性切换PDAE。在启动之后，最终达到周期性吸引子或循环稳态（CSS）并用于生产。理想情况下，这种CSS应该在操作成本和产品规格方面是最佳的，近年来已经开发了各种新的工艺操作变体以提高效率。其中两个是在多特蒙德进行研究的过程：变入口浓度模拟移动床Engell教授的小组研究的ModiCon-SMB和具有解吸冷却的全新固定床催化反应器（在下文中称为解吸冷却（DC）-过程）。由于过程模型的大规模和由于其周期性，基于模型的优化方法很少，并且它们在大规模应用中的使用受到计算时间限制。该项目的目的是开发有效的数值方法，用于优化周期性切换的大规模非定常PDAE描述的周期性吸附过程。这些方法应结合联合收割机新颖的减少牛顿型优化方法与皮卡德迭代的类型，以有效地科普周期性约束。新方法的特点如下：选择一个同步优化框架，其中离散化的模型方程作为非线性约束进入优化问题;只模拟和优化一个周期，并以附加约束的形式施加周期性;使用时域分解来处理中间切换和大量数据;一种新的简化的SQP框架能够科普不精确的雅可比矩阵，用于解决模型方程和控制离散化后产生的非线性规划问题;一种混合的Newton-Picard格式用于有效地处理周期性约束。该项目的最终应用目标是优化和实验验证的新型解吸冷却（DC）过程的操作制度。