基于分治策略的两段提升管催化裂解多目标优化运行方法

The possibility of feedstock diversification, high-yield of propylene and high-quality gasoline associated with the two-stage-riser catalytic pyrolysis enable a bright future of the corresponding industrial application. Facing the complicated and fluctuation market and industrial environment, how to achieve the optimal operation to maximize the economic benefits for accelerating the commercialization becomes a vital scientific issue. It should be pointed out that the complex nonlinear behavior forbids the optimal operation to some extent. The objective of this research hence is to propose a divide-and-conquer principle driven multi-objective optimization for promoting the optimal operation. In detail, (1) A new multi-objective optimization approach based on the division of decision variable space is going to be proposed to handle the obstacles associated with the solution to complex nonlinear constrained problems. (2) A new multi-criteria decision method is going to be established based on the classification of Pareto-optimal set using information from active constraints, to improve the efficiency and reliability of decision-making. (3) An advanced control system design method, which is integrated with the self-optimization control and model predictive control, is presented to ensure the optimal operation under various disturbances. Simulations, experimentations and field tests are used together to test and improve the proposed methods. It is expected that the achieved outcomes will be very helpful in not only guide the revealing of the potential rules with regard to the optimal operation of two-stage-riser catalytic pyrolysis, but also providing new ideas approaches to solve the optimal operation problem of other refining and chemical processes.

两段提升管催化裂解具有原料适应性强、丙烯和高品质汽油产率高等优点，工业应用前景十分广阔。在复杂多变的工业环境下，如何实现生产装置的优化运行以获得最大经济效益是该技术工业化过程中亟待解决的关键科学问题。针对裂解各产物收率之间互相关联且彼此制约的特点，本项目从多目标优化的角度，基于分治策略，研究面向产品分布协调的运行优化与控制方法。研究内容包括：1)提出一种基于决策变量解空间分区的优化方法，解决非线性约束多目标优化问题寻优困难的问题；2)提出一种基于积极约束分类的多目标决策方法，解决决策效率低、可靠性差的问题；3)提出一种融合自优化控制和模型预测控制的优化控制系统设计方法，解决运行优化与过程控制不协调的问题。通过仿真分析、实验验证和现场测试等途径对所研究方法进行改进和完善。项目成果将有助于揭示两段提升管催化裂解优化运行规律，为解决炼油化工其它过程的运行优化与控制问题提供新思路。

两段提升管重油催化裂解技术具有良好的原料适应性和较高的丙烯、高品质汽油产率，工业应用前景广阔。随着该技术的推广使用，迫切需要开展过程操作优化与控制方法的研究以保障生产过程在复杂多变的工业环境下仍能维持高效、优质运行。.本项目通过深入分析催化裂解反应机理和两段提升管工艺特点，针对催化裂解各产物间相互关联且彼此制约的复杂耦合关系，系统地研究了面向产品分布协调的过程多目标操作优化与控制方法：.(1) 根据两段提升管重油催化裂解过程工艺特点和经济运行要求，考虑多种操作约束条件，构造了同时最大化丙烯、汽油产量以及最小化干气产量的多目标操作优化问题，并采用标准化法向约束方法求解获得了完整、均匀分布的Pareto最优解，解决多目标优化问题寻优困难等问题；.(2) 针对催化裂解过程行为特性复杂、单个可操控性指标表征片面的问题，本研究将开环/闭环分岔图、敏感度分析和闭环动态仿真测试等方法有机融合，提出一种综合考虑稳定性和可控性的Pareto最优解集后验决策分析方法，解决了优化决策效率低、可靠性差等问题；.(3) 根据多目标优化结果所揭示的最优操作条件与积极约束之间的关系，提出了一种基于串级控制的自优化控制策略，研究结果表明，与传统的提升管出口温度设定值跟踪控制相比，本研究所提出的优化控制方能够及时调整操作条件以降低干扰对过程优化运行的不利影响，解决了离线多目标操作优化与在线过程控制不协调等问题。.项目研究成果有助于揭示两段提升管重油催化裂解装置优化运行规律，提升装置操控水平，为两段提升管重油催化裂解技术工业化提供必要理论依据和技术支持，并为解决炼油化工相关过程的操作优化与控制问题提供新思路。