PPT on the application of advanced control
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This post was last edited by dxsy on 2010-5-2 02:04. Applications of advanced control: Advanced control technologies are used to address the issues where conventional PID control yields poor results, or even fails to manage complex industrial processes. By implementing advanced control, it is possible to enhance the operational stability and safety of the equipment, improve product quality and yield, increase the processing capacity of the facility, reduce operating costs, and achieve significant economic benefits. Successful control techniques include robust PID control and multi-variable prediction. • The use of advanced control in the production units of petrochemical enterprises can enhance the stability and safety of operations, improve the quality and yield of products, increase the processing capacity of these units, reduce operating costs, and bring significant economic benefits. Advanced Control • Some advanced control techniques are now quite mature, among which robust PID control and multivariable predictive control have been applied with success. • For advanced control software products in multivariable predictive control, abroad there are RMPCT from Honeywell in the United States and DMC Plus from Aspen Tech in the United States, etc.; domestically, there are various software solutions such as APC-HIECON (Zhejiang University Control Systems) and SMART (Tsinghua University). To date, dozens of units in petrochemical enterprises have adopted advanced control, achieving significant economic benefits. Main characteristics of advanced control: (1) It is a model-based control strategy. Such as: model predictive control and inference control, etc. Currently, knowledge-based control methods such as intelligent control and fuzzy control are becoming an important direction for the development of advanced control. (2) Advanced control is typically used to address complex multivariable process control problems. Such as large time delays, multi-variable coupling, and various constraints existing between the controlled variable and the control variable. Advanced control is a dynamically coordinated constraint control built upon conventional single-loop control, enabling the control system to adapt to the dynamic characteristics and operational requirements of actual industrial production processes. (3) The implementation of advanced control requires sufficient computing power as a support platform, and it can be implemented in a higher-level computer or a DCS/FCS. Companies in the field of advanced control: Abroad, the main ones include Honeywell’s PROFIT controller, AspenTech’s DMC-PLUS controller, ABB’s STAR controller, Foxboro’s CONNOISSUR controller, and Yokogawa’s SMOC controller. • In China, development has been primarily carried out by institutions such as Zhejiang University Zhongkong and Tsinghua University, with success achieved. • Examples of advanced control • Sinopec’s system, in collaboration with the American company Honeywell, successfully implemented advanced control for catalytic cracking units. • To date, the two major state-owned oil companies, Sinopec and CNPC, have had dozens of units operate with advanced control systems in place; these applications are mainly found in units for atmospheric and vacuum distillation, catalytic cracking, diesel hydrogenation, delayed coking, ethylene cracking, polypropylene production, and polyethylene production, and they have yielded significant economic benefits. Industrial control software is evolving toward advanced control. Industrial control software mainly includes human-machine interface software (HMI), PC-based control software, and production management software. • At present, China has developed a range of application software with independent intellectual property rights, including real-time monitoring software platforms, advanced control software, and process optimization control software. Significant progress has been made in terms of engineering implementation and product development, breaking the monopoly held by foreign counterparts in this field. • Through its application in hundreds of enterprises (units) in industries such as chemicals, petrochemicals, and papermaking, it has promoted technological upgrades in these enterprises, improved the level of control over production processes and product quality, and generated significant economic benefits for them. Advanced Process Control APC • Industrial control software will evolve from human-machine interfaces and basic strategy configuration toward advanced control. • There is currently no strict and unified definition. Control algorithms that are based on mathematical models and must be implemented using computers are generally referred to as advanced process control strategies. For example: adaptive control ； Predictive control ； Robust control ； Intelligent control (expert systems, fuzzy control, neural networks), etc. The value of advanced control software has doubled • Since advanced control and optimization software can generate significant economic benefits, their value has also doubled. • Internationally, dozens of companies have launched hundreds of advanced control and optimization software products, giving rise to a robust industry of process industry application software worldwide. • Therefore, it is of great significance to develop advanced control and optimization software with independent intellectual property rights in our country, to break the monopoly of foreign products, and to replace imports. Application of advanced control software 1• The main production units at Sinopec enterprises have been put into use. • Introduction of Honeywell’s RMPCT advanced control software for successful use in atmospheric and vacuum distillation units: Sinopec Qilu Petrochemical Company’s refinery, Daqing Petrochemical Complex, and Yanshan Petrochemical Company ； Lanlian has adopted the multivariable predictive control technology (IDCOM-M) from the American company Setpoint, and it has been successfully applied in catalytic cracking units. – Enterprises such as the Refinery of Qilu Petrochemical Company, Daqing Petrochemical Complex, Lanzhou Petrochemical Complex, Qiange Oil Refinery, Refinery No. 1 of Fushun Petrochemical Company, Yanshan Petrochemical Company, Urumqi Petrochemical Complex, and Jingmen Petrochemical Complex have all achieved good economic results. Application of advanced control software 2• The continuous reforming unit at Guangzhou Petrochemical Complex uses the multivariable prediction software SMCA from the American company Setpoint ； The continuous reforming and extraction units at the refinery of Jinling Petrochemical Company use Honeywell’s robust multivariable predictive controller, RMPCT ； The continuous reforming unit at the refinery of Zhenhai Refining & Chemical Co., Ltd. utilizes the advanced DMCplus control software developed by the American company Aspen. Companies such as Yangzi Petrochemical, Shanghai Petrochemical, Qilu Petrochemical, and Yanshan Petrochemical have achieved significant economic benefits by implementing advanced control technologies in their polypropylene plants. Applications of advanced control software 3• The advanced control systems for catalytic cracking units developed in China have been used at the Fujian Refinery, Luoyang Petrochemical Complex, and Maoming Petrochemical Company’s refinery ； The domestically developed multivariable constrained control software package MCC is an optimal controller for handling constraints in multivariable, multi-objective, multi-control mode, and model prediction applications. It has been successfully implemented in the catalytic cracking unit of Shijiazhuang Refining & Chemical Company, yielding significant economic benefits
There is a major problem with the advanced control systems used in domestic industries: they are unable to adapt to changes in the raw materials used in processing! ! ! The biggest difference between Chinese refineries and foreign oil refineries is the lack of a petroleum supply whose composition remains essentially stable over time; instead, many refineries use crude oils with varying compositions, and these proportions often change, which leads to changes in the processing conditions. Advanced control models are not yet capable of adapting to such changes. The phenomenon of premature control failure is that as the properties of crude oil change, the premature control system stops working! ! ! Suggestion: Further enrich the model with prior control, especially in response to changes in crude oil ； Even if it is not yet possible to have the system automatically adjust the model in response to changes in processing conditions, it is still necessary to be able to modify the model manually; after all, companies like PetroChina Yingke do not have technicians stationed on site on a long-term or regular basis!
I think what was said upstairs makes a lot of sense – we need to pursue an oil refining path with Chinese characteristics.
Advanced control should be implemented jointly by the project executor and the plant operator; in other words, the plant should have specialized instrumentation and process engineers involved in the project. This way, during implementation, the instrumentation engineers can assist in resolving issues related to the configuration of basic control loops using DCS systems, while the process engineers can gather users’ requirements and suggestions to improve the advanced control system； If there is any minor maintenance work required after the project is completed, the instrument and process personnel involved in the project can try to handle it; if they are unable to resolve it, they should notify the project owner to carry out on-site maintenance.
Why isn’t domestic technology as advanced as that of other countries? It isn’t widely adopted, and its market share is low. It’s a pity
Under stable operation, prior control is quite effective: it reduces the workload on operators and also helps to improve the quality of the products produced by the device. However, its effectiveness is very limited when there are large fluctuations in the device’s operation~~~