Abstract: This paper focuses on the development of the structure, function, and interface of the catalytic cracking automatic monitoring system by applying an automatic monitoring system developed with embedded third-party software and its application in the catalytic cracking system. System simulation and actual operation demonstrate that the monitoring system is stable, easy to operate, and provides good monitoring results. Introduction: Catalytic cracking is the most important link in the secondary petroleum processing. Automatic monitoring and management of the entire process can greatly improve the automation level of enterprises, reduce production costs, and increase economic benefits. This catalytic cracking system utilizes the ForceControl configuration software from Beijing Sanwei ForceControl Technology Co., Ltd. for secondary development. The system's structural principle diagram is as follows: [align=center] Figure 1 System Structure Diagram[/align] 1. Monitoring Requirements and Flow Description The system monitors three main parts: reaction regeneration, fractionation, and absorption stabilization. The main task of the reaction regeneration system is to crack the feedstock oil and other heavy oils obtained by straight-run wax oil and other processing methods into lighter products through a series of chemical reactions at a certain temperature using a catalyst. The fractionation system uses the different volatility of each component to separate the mixed oil and gas from the settler into crude gasoline, diesel, rich gas, and other products. The absorption stabilization system further separates crude gasoline and compressed rich gas into dry gas, liquefied petroleum gas (LPG), and stabilized gasoline. Monitoring meets the following requirements: 1) Signal acquisition and data preprocessing: Acquires standard signals; converts, preprocesses, and calculates non-standard signal data from the industrial site using configuration software. 2) Dynamic display: Realistically reflects the process flow on a dynamic 3D flow chart using configuration software, displaying the parameter change trends at each measurement point and providing a real-time, dynamic effect. 3) Monitoring operation: Completes parameter settings for each station and automatically monitors temperature, liquid level, flow rate, and pressure, achieving automatic opening and closing of some valves and flow control. 4) Operation screen: Allows querying real-time and historical data such as temperature, liquid level, and flow rate at each station on the operation screen, and allows setting and printing real-time and historical reports as required. 5) System expansion and integration with third-party software: Integrates with expert system development tools CLIPS and MATLAB to achieve advanced controls that are difficult to implement with conventional control methods. 2. System Hardware Configuration The system consists of an Ethernet LAN composed of one or more industrial control computers, equipped with a 21-inch monitor, report and event printers, and other devices. To improve system redundancy, two I/O servers are configured to communicate with the lower-level computers: one as the primary server and the other as a hot standby server. The network server runs Windows NT Server 2000 and performs management-level functions, such as LAN management, generating records and reports of data required by the management department, and statistical reports. The system connects to the enterprise Intranet and the Internet through this server to achieve information exchange with other systems. 3. System Software Configuration This part completes the interactive interface between the monitoring system and operators, and is the core and key to realizing the monitoring, control, scheduling, and management of the entire system. The human-machine interface is divided into two parts: a main interface for daily monitoring and system parameter settings, and a sub-interface for non-daily monitoring information, various reports, trend charts, help information, or completing various process operations. Process parameters and equipment operating parameters are summarized in a table format. The process of system configuration is essentially establishing corresponding connections between the buttons, alarms, and production trend graphs on the configuration display interface and the field execution equipment or instruments. This allows operators at the workstation to control the corresponding objects on the system configuration screen to operate and monitor the field execution equipment and instruments. 3.1 Recycled System Configuration First, the system process flow is completed. In addition to dynamically displaying the working status of some key stations, such as valve opening, other important process parameters, such as feed rate, are also displayed. Its main screen is as follows: [align=center] Figure 2 Recycled System Main Screen[/align] The recycled system involves three major balances: material balance, heat balance, and pressure balance. These three balances are the foundation for the normal production of the entire unit. Therefore, each key station needs its own control and monitoring interface to monitor its temperature, flow rate, and pressure. Among them, reaction temperature is an important parameter for controlling the reaction depth, product distribution, and product properties. The temperature is mainly maintained by adjusting the catalyst flow rate, i.e., adjusting the opening of the regeneration single-acting slide valve. The opening of the single-acting slide valve can be adjusted manually or automatically. The reaction pressure is controlled by controlling the output pressure of the gas compressor. 3.2 Fractionation System Configuration The primary principle of the fractionation system is to control the reflux and temperature of each section, stabilize the liquid level at each point, and reasonably adjust the thermal balance to achieve stable operation. Therefore, during configuration, it is important to monitor the reflux temperature and flow rate of each section. The main configuration screen is shown in the figure below: [align=center] Figure 3 Fractionation Main Screen[/align] The bottom liquid level of the fractionation tower, the flow rate of the circulating oil slurry at the bottom of the tower, and the liquid level of Capacity 201 (oil-gas separator) are controlled in cascade. The top temperature of the fractionation tower is controlled by fuzzy control to ensure the quality of the crude gasoline dry point. When a fault occurs during operation, the system automatically alarms and records the time, type, alarm level, and other parameters of the fault, as shown in Figure 4: [align=center] Figure 4 Alarm Record[/align] 3.3 Absorption Stabilization System Configuration This part completes the absorption stabilization overview diagram, alarm diagram, and data table. The data table consists of temperature, pressure, flow rate, liquid level, and gas pressure status. Like other systems, daily operational data is automatically summarized and generated into a report, as shown in the figure below: [align=center] Figure 5 Report[/align] 3.4 Control Strategy 3.4.1 Conventional Control Conventional control in the system is implemented using the control algorithm function block in the force control strategy generator of the configuration software, such as the PID function block, as shown in the figure: [align=center] Figure 6 PID Controller[/align] The controller completes the PID (Proportional-Integral-Derivative) algorithm based on the deviation between the setpoint (SV) and the process measurement value (PV), where OP is the PID output. The control loop can use three control methods: manual (MAN), automatic (AUT), and cascade (CAS). When the loop is in MAN state, SV has the function of automatically tracking PV to ensure a smooth transition when switching from MAN to AUT state. In the cascade control loop, when the next level loop is in AUT state, the previous level control loop has the function of automatically tracking the SV of the next level control loop to ensure a smooth transition when the next level control loop switches from AUT to CAS. The setting and tuning of PID parameters are implemented in the property box. 3.4.2 Fuzzy Control Fuzzy control is employed to address situations where conventional control methods yield unsatisfactory results. Advanced control and optimized control are connected to a real-time database via a control programming interface, enabling the integration of third-party software with the configuration software. The fuzzification module calculates the membership degree of a precise input variable to various fuzzy sets using a membership function defined on its universe of discourse, and transforms it into a fuzzy variable. [align=center]Figure 7 Controller Attributes[/align] Taking deviation as an example, seven fuzzy subsets f(Zi) are defined on its universe of discourse: {negative large, negative medium, negative small, zero, positive small, positive medium, positive large}. The membership function uses a trigonometric function. The knowledge base contains knowledge from specific application domains and the required control objectives, consisting of a database and a fuzzy control rule base. Fuzzy rule inference consists of a series of "IF …THEN…" type fuzzy conditional statements. 3.4.3 The catalytic cracking equipment is a core profit-generating unit in refineries, with complex processes and numerous operating conditions. Statistics show that unplanned downtime caused by various faults accounts for over 70% of the lost profits. Therefore, researching how to prevent and reduce unplanned downtime caused by equipment and process operation faults is of significant practical importance. Using the DBCOM interface of this configuration force control software, the fault diagnosis expert system developed by CLIPS software is also embedded as third-party software into the configuration software. Based on field monitoring data, the expert system analyzes and infers from the rules, procedures, and models in the knowledge base to find and judge these fault trends, quickly diagnose problems, provide information prompts, hazard predictions, or alarms, and take correct measures in advance to prevent faults from occurring, thereby reducing economic losses. Our automated monitoring system, which incorporates third-party software methods for secondary development of the configuration software system, has been tested in actual production. Currently, in catalytic cracking production, the monitoring system primarily diagnoses faults by monitoring the operating conditions of key equipment such as the compressor, main unit, and heat exchanger, as well as other systems. This has yielded good experimental results. 3.5 Team Accounting and Network Communication The widespread application of computer control systems has made integrated management and control possible. Production data obtained from the data acquisition system is directly used for accounting, eliminating tedious manual calculations and reducing workload, improving management efficiency, and enabling remote monitoring and management. Currently, the most common economic management method in China is team accounting. It extracts relevant parameters from actual production and calculates them according to the company's established accounting formulas, thereby obtaining the team's economic benefits and expenses for each position within a certain period. Users can print team accounting sheets periodically as needed and save relevant parameters in a database or upload them via a web server. The application of network technology and information management technology can, on the one hand, improve production efficiency and management level in the production process, optimize material balance, and reduce inventory and intermediate storage; on the other hand, it can realize a real-time, accurate, comprehensive, and systematic information system for the entire plant, providing support for senior management decision-making. 4. Conclusion The configuration software automatic control system we developed, which incorporates third-party software technology, has demonstrated through debugging and testing that: the overall system is easy to operate, has a user-friendly interface, runs stably, is highly intelligent, has comprehensive monitoring program functions, strong integration, outstanding early warning functions, good monitoring effect, and strong remote monitoring capabilities. It is an ideal automatic monitoring system that ensures the safety of the equipment, the stability of production, and the long-term operation of the system.