第一讲 概 论 本课程内容： （一）术语和概念目的：了解工业过程的动力学知识和控制技术内容：过程的动态与稳态；质量、能量平衡；过程控制系统的概念；开环与闭环；工程控制系统的构造 （二） 知识驱动的动态数学模型(机理模型)及其应用目的：掌握建立过程机理模型的一般方法内容：以传热（简单过程）和反应（复杂过程）为例，介绍动态建模的思想和步骤；微分方程的数值求解法Runge-Kutta；参数优化的Simplex；基于机理模型的前馈-反馈控制,（三） 数据驱动的过程动态数学模型目的：了解数据驱动建模方法的实质内容：将工程问题表述为ANN问题的技巧；动态数据库的建立和更新；应用举例(复杂生物制药过程的状态软预报) （四） 先进过程控制目的：掌握先进过程控制的核心方法内容：重点介绍模型预测控制MPC和动态矩阵控制DMC （五） 统计过程控制SPC目的：掌握过程宏观监控和故障诊断的方法内容：SPC-Statistical Process Control,成功的过程控制工程师：, 熟知控制对象的工艺流程 能够从工艺问题中抽提出控制问题 综合应用工程知识 通过实施控制工程项目使生产企业得到经济效益的提升 成为不可或缺的角色,System or Process,Objective of control：Safety, quality and productivity, or profit optimization more generally,Importance of Process Control, PC directly affects the safety and reliability of a process. PC determines the quality of the products produced by a process. PC can affect how efficient a process is operated. Bottom Line: PC has a major impact on the profitability of a company.,Safety and Reliability, The control system must provide safe operation Alarms, safety constraint control, start-up and shutdown. A control system must be able to “absorb” a variety of disturbances feed composition upsets, temporary loss of utilities (e.g., steam supply), day to night variation in the ambient conditions and keep the process in a good operating region,Benefits of Improved Control,原来的控制系统,新的控制系统,新的控制系统抗干扰能力更强、超调量更小，故Impurity浓度设定值得以抬高 结果是：确保产品合格但又降低了成本,Better Control Means Products with Reduced Variability,For many cases, reduced variability products are in high demand and have high value added (e.g., feedstocks for polymers). Product certification procedures (e.g., ISO9000) are used to guarantee product quality and place a large emphasis on process control. SA8000 2001 (Social Accountability),Maximizing the Profit of a Plant,PC involves controlling against constraints. The closer that you are able to operate to these constraints, the more profit you can make.,CH4 + H2O CO + 3H2,CO + H2O CO2 + H2,3H2 + N2 2NH3 +92.4(kJ),Ammonia synthesis（30MPa, 500oC, Fe）, Consider a reactor temperature control example, at excessively high temperatures the reactor will experience a temperature runaway and explode. But the higher the temperature the greater the product yield. Therefore, better reactor temperature control allows safe operation at a higher reactor temperature and thus more profit.,Constraint Control Example,Types of Control, Feedback Feedforward Cascade Ratio Statistical Process Control (not really control) Others,Feedback Control Terminology, Setpoint Controlled variable Manipulated variable Sensor Actuator Controller Disturbance,The key feature of all feedback control loops is that the measured value of the controlled variable is compared with the setpoint and this difference is used to determine the control action taken.,Process Control and Optimization,Control and optimization are terms that are many times erroneously interchanged. Control has to do with adjusting flow rates to maintain the controlled variables of the process at specified setpoints. Optimization chooses the values for key setpoints such that the process operates at the “best” economic conditions.,Optimization and Control of a CSTR,Introduction to distillation,Distillation: a process in which a liquid or vapour mixture of two or more substances is separated into its component fractions of desired purity, by the application and removal of heat., distillation is the most common separation technique it consumes enormous amounts of energy, both in terms of cooling and heating requirements it can contribute to more than 50% of plant operating costs,Distillation is the most common form of separation technology used in petroleum refineries, petrochemical and chemical plants and natural gas processing plants. In most cases, the distillation is operated at a continuous steady state. New feed is always being added to the distillation column and products are always being removed. Unless the process is disturbed due to changes in feed, heat, ambient temperature, or condensing, the amount of feed being added and the amount of product being removed are normally equal. This is known as continuous, steady-state fractional distillation.,Industrial distillation is typically performed in large, vertical cylindrical columns known as “distillation or fractionation towers“ or “distillation columns“ with diameters ranging from about 65 centimetres to 6 metres and heights ranging from about 6 metres to 60 metres or more. The distillation towers have liquid outlets at intervals up the column which allow for the withdrawal of different fractions or products having different boiling points or boiling ranges. By increasing the temperature of the product inside the columns, the different hydrocarbons are separated. The “lightest“ products (those with the lowest boiling point) exit from the top of the columns and the “heaviest“ products (those with the highest boiling point) exit from the bottom of the column.,