Keywords : Chlor-alkali industry, heterogeneous system integration, MES, production scheduling, process management, equipment management 1. Introduction In recent years, driven by consumption, investment, and exports, China's economy has experienced sustained growth, with GDP growth rates far exceeding the world average. This rapid economic development has provided ample room for the domestic chlor-alkali industry, making it a hot investment sector. With the increasing openness of China's PVC market, especially with the entry of foreign and joint-venture enterprises, market competition will intensify further. Strengthening structural adjustment and achieving intensive management is a major trend in the development of PVC production. Through large-scale consolidation, older, smaller, and less established production enterprises will either be eliminated or merged and reorganized. The chlor-alkali industry faces pressure from resource and environmental constraints. To adapt to increasingly stringent environmental requirements, it must focus on technological advancements, information technology development, reducing production costs, increasing equipment utilization, improving product quality, optimizing product structure, reducing inventory, enhancing management, and increasing product added value. This requires developing a systematic business decision-making mechanism that can quickly optimize production plans and operating parameters in response to changes in domestic and international markets, thereby maximizing product value and increasing profits. Yibin Tianyuan Co., Ltd. (hereinafter referred to as "Yibin Tianyuan") is a conglomerate integrating chlor-alkali chemicals, fine chemicals, building materials, and papermaking. Founded in 1944, it is one of China's earliest chlor-alkali chemical enterprises, the largest chlor-alkali chemical enterprise in western China, and the largest manufacturer of polyvinyl chloride (PVC) using the calcium carbide method in China. As a leading enterprise in the chlor-alkali industry, Yibin Tianyuan has been committed to the application of computer information technology in production process control and management information. Its production lines have largely adopted intelligent instruments, DCS, PLC, and other control systems, achieving automated control of the production process. However, there are still some shortcomings in achieving comprehensive enterprise automation, mainly reflected in the lack of integration of heterogeneous systems, forming multiple "information silos"; incomplete network and poor information flow; data collection mainly relying on manual methods, resulting in many steps and low efficiency; and non-standardized business processes in various departments and positions, leading to poor effectiveness in handling business. Faced with ever-changing market competition, Yibin Tianyuan, in addition to making significant technological improvements in expanding production capacity and optimizing product structure, has also increased its investment in enterprise informatization. Starting in February 2007, Yibin Tianyuan closely cooperated with Zhejiang Zhongkong Software Technology Co., Ltd. (hereinafter referred to as "Zhongkong Software"), leveraging mature and advanced network technology, information technology, and management concepts. After more than six months of joint efforts, the two parties completed the design, development, and implementation of a factory-wide MES system for Yibin Tianyuan. Currently, the Yibin Tianyuan MES system is running stably and has achieved good application results. 2. System Construction The Yibin Tianyuan MES system adopts the MES-Suite solution for process industries. It establishes a system based on material flow, production scheduling management, process management, and equipment management, streamlining the business activities of the enterprise's production process. Based on full-process logistics tracking and full lifecycle equipment management, it provides Yibin Tianyuan with a standardized, efficient, and unified business information integration and application platform. The overall system architecture is shown in Figure 1. [align=center] Figure 1 Overall Architecture Diagram of Yibin Tianyuan MES System[/align] Following the principles of "efficiency-driven, overall planning, key breakthroughs, and phased implementation," the first phase of the Yibin Tianyuan MES system mainly includes four modules: a comprehensive data integration platform, production scheduling, process management, and equipment management. Comprehensive Data Integration Platform The comprehensive data integration platform establishes a unified core database based on the ISA-SP95 standard, mainly including a unified factory data model and a production management business model. The data integration platform supports the data integration of the main data sources of the MES system, including the Real-Time Database (RTDB) and the Laboratory Information Management System (LIMS), providing basic data support for business modules. Yibin Tianyuan has a total of 17 DCS/PLC systems of 7 brands (as shown in Table 1). The platform acquires real-time data from these control systems through the industry-standard OPC/DDE data acquisition interface (as shown in Figure 2) and stores it in the real-time database, providing unified data support for other functional modules of MES and even enterprise ERP systems. [align=center]Figure 2 Data Acquisition Architecture Diagram[/align] Table 1 Control System List[/table=556][tr][td=1,1,156][size=1][/size]Device Name[/td][td=1,1,73]System Name[/td][td=1,1,104]Version Number[/td][td=1,1,144]Operating System[/td][td=1,1,79]Interface Software[/td][/tr][tr][td=1,1,156]Power Plant Unit 2[/td][td=1,1,73]Holysys[/td][td=1,1,104]SmartPro 3.0.3[/td][td=1,1,144]Windows NT4.0 [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Power Plant No. 4 Boiler[/td][td=1,1,73]Xinhua[/td][td=1,1,104]XDPS-400[/td][td=1,1,144]Windows NT4.0[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Power Plant No. 5 Boiler[/td][td=1,1,73]Holysys[/td][td=1,1,104]SmartPro 3.1.3[/td][td=1,1,144]Windows 2000 SP4 [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Desulfurization in Thermal Power Plants[/td][td=1,1,73]Siemens[/td][td=1,1,104]WinCC 6.0[/td][td=1,1,144]Windows 2000 Pro[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Hydrochloric Acid (PVC Raw Material Gas)[/td][td=1,1,73]Zhejiang University Control System[/td][td=1,1,104]ECS-100[/td][td=1,1,144]Windows 2000 SP2 [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Cement Plant Line I[/td][td=1,1,73]Siemens[/td][td=1,1,104]WinCC 6.0[/td][td=1,1,144]Windows 2000 Pro[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Cement Plant Line II[/td][td=1,1,73]Schneider[/td][td=1,1,104]IFIX 3.5[/td][td=1,1,144]Windows 2000 Server [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Chronic-Alkali Plant Solid Soda Section[/td][td=1,1,73]Siemens[/td][td=1,1,104]WinCC 6.0[/td][td=1,1,144]Windows 2000[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Ion Membrane Section I/II Group[/td][td=1,1,73]Yokogawa, Japan[/td][td=1,1,104]CS-3000[/td][td=1,1,144]Windows XP [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Ion membrane section III group[/td][td=1,1,73]Yokogawa, Japan[/td][td=1,1,104]CS-3000[/td][td=1,1,144]Windows XP Pro[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Organic plant ketone azide[/td][td=1,1,73]Xinhua[/td][td=1,1,104]XDPS-400[/td][td=1,1,144]Windows 2000 Pro [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Alkali Plant Soda Steaming Section[/td][td=1,1,73]Siemens[/td][td=1,1,104]WinCC 4.0[/td][td=1,1,144]Windows NT4.0[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]PVC Polymerization Section[/td][td=1,1,73]Rosemount[/td][td=1,1,104]DELTAV V7.3[/td][td=1,1,144]Windows 2003 Server [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]PVCⅡ Synthesis[/td][td=1,1,73]Rosemount[/td][td=1,1,104]DELTAV[/td][td=1,1,144]WindowsXP Pro[/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]PVCI Synthesis[/td][td=1,1,73]Holysys[/td][td=1,1,104]SmartPro 3.1.3[/td][td=1,1,144]Windows 2000 SP4 [td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]Old Production Line of Chemical Plant No. 2[/td][td=1,1,73]Zhejiang University Control System[/td][td=1,1,104]ECS-100 [/td][td=1,1,144]Windows 2000 [/td][td=1,1,79]OPC[/td][/tr][tr][td=1,1,156]New Production Line of Chemical Plant No. 2[/td][td=1,1,73]Zhejiang University Control System[/td][td=1,1,104]ECS-100 [/td][td=1,1,144]Windows 2000 [td=1,1,79]OPC[/td][/tr][/table] Production Scheduling The main contents of the production scheduling subsystem include: production plan tracking management, contingency plan management, real-time monitoring, output statistics, operation records, and shift records. Its main features are reflected in the following aspects: 1) Production plan tracking: The management layer issues production plans, calculates material and energy balance based on production processes and flow requirements, and combines this with equipment status collected by the control system to form scheduling orders, which are then issued to the production site. After confirmation, the system controls and monitors the production operation in real time through a flowchart, thereby optimizing production management, improving production efficiency, and increasing output. The system's production process visualization front end is used to monitor, manage, track, and improve the production operation process, enabling dynamic control and real-time monitoring of key process control points (process, safety, environmental protection, quality) indicators at the site and management levels (even remotely). It also allows for alarm management of corresponding indicators. This replaces the outdated management method of reporting on-site production by telephone and provides real-time basic information for production scheduling. 2) Contingency Plan Management: Chemical production processes are inherently risky. Effective production scheduling is crucial for mitigating losses from malfunctions or accidents, making contingency plan management a vital tool for company prevention and mitigation. Contingency plan management involves providing real-time production adjustment plans and related information to production schedulers at the moment of an accident or potential hazard, offering data and emergency plan support for effective scheduling. [align=center] [/align] Process Management The process management subsystem primarily includes: process card library, process ledger, trend analysis, operational indicator management, and 6σ management. Its main features are reflected in the following aspects: 1) Process Operation Quality Management: Based on the process indicator operation data provided by the integrated data platform, the system evaluates the operational quality of key process control indicators, promoting various process management tasks. This mainly includes the following management contents:  Process control indicator optimization;  Process operation method revision;  Process optimization;  Process indicator assessment (KPI). 2) 6σ Management of Process Control Indicator Stability: To effectively assess the operational stability and controllability of process indicators in production units, the company uses 6σ (Six Sigma) statistical analysis tools to analyze and evaluate process indicators. The statistical results are incorporated into performance evaluation management as key performance indicators (KPIs) for production unit operation. Equipment Management The equipment management subsystem mainly includes: fixed asset management, equipment file management, equipment standardization management, equipment maintenance management, equipment status monitoring management, equipment status assessment management, equipment repair and maintenance work order management, and spare parts management. Equipment management is a comprehensive equipment management system based on equipment operating status management and equipment technical and economic management. Its main characteristics are reflected in the following aspects: 1) Real-time monitoring of equipment status: Through multi-disciplinary monitoring and data collection of the operating status of equipment and related process control indicators, integrated and visualized management of equipment status information is achieved; timely analysis and evaluation of equipment status information enables "preventive" management of equipment status and provides professional data support for the technical and economic evaluation of individual sets of equipment. 2) Equipment Status Management: The company's "operation, mechanical, electrical, and instrumentation integrated" equipment operation, inspection, and maintenance system, as well as its "management, use, and repair integrated" equipment management system, utilizes the integrated and visualized equipment status information provided by the management platform for professional assessment, effectively leveraging the role of professional technicians and effectively promoting various management tasks. 3) Comprehensive Equipment Management System:  Equipment maintenance management;  Equipment status monitoring/hazard management;  Equipment status assessment;  Equipment maintenance plan/work order management;  Spare parts management;  Equipment technical and economic evaluation; 3. System Features The Yibin Tianyuan MES architecture design follows the SP95 standard, uses SOA technology, and implements component-based development on the .NET platform. It possesses strong adaptability, interoperability, scalability, and reusability, emphasizing the implementation of component-based technology and architectural technology. It has significant advantages in terms of controlling system software complexity and rapid adaptation to changes. Unified Data Services Based on a unified MES data platform, it provides MES system data access services, mainly including ERP system data support and unified data access based on WEB services. The highly scalable design of the MES platform provides complete support for object encapsulation of various system metadata, giving it excellent configurability. Only minor modifications to the configuration files are needed to adapt to future changes in most equipment and processes. High Integration : From a technological development perspective and user needs, the software architecture itself should be able to integrate with other application systems, achieving information and resource sharing. This has been fully considered in the MES structural design, not only improving the system lifecycle of the enterprise's MES and reducing investment in information systems, but also providing greater flexibility for enterprises to choose suitable software in the future. Strong Openness: The MES has built-in data interfaces supporting various mainstream real-time databases (ESP-iSYS, PI, Uniformance, InfoPlus) and achieves data integration with ERP and other MIS systems through standard relational database interfaces (ODBC, OLE DB). The platform's openness allows for the tailoring of different functions from different data modules of the MES system to meet the needs of specific tasks, achieving interoperability. 4. The implementation of the MES system has brought many beneficial changes to the production and management of Yibin Tianyuan, greatly improving work efficiency, standardizing management processes, and effectively promoting various production plans, management, and scheduling tasks. It has also enhanced the company's informatization level, which is particularly evident in the following aspects: Unified Data Integration Platform and Plant-wide Dedicated Production Network A unified data model and data communication protocol were established. A unified data integration platform was used to collect, store, and publish real-time data from DCS/PLC control systems of different manufacturers, ensuring a high degree of data integration. In addition, a dedicated production management network was established, covering all relevant departments and workshops throughout the Yibin Tianyuan plant. This enabled online information sharing, changing the traditional manual paper-based data transmission method, shortening data collection and analysis time, strengthening information communication and work arrangements between departments within the company, and improving office efficiency. Real-time Monitoring and Alarm Management of the Production System The Yibin Tianyuan plant area is large, with numerous and dispersed equipment and highly complex processes. Due to the inability to promptly understand the situation on the production site, system management of the coordinated operation of various facilities has always been difficult. The establishment of the MES system provides remote real-time production process information to management departments at all levels, effectively helping dispatchers to adjust logistics directions in a timely manner, reducing unplanned shutdowns, and maintaining stable production operation. By comparing current data with historical trend data, and especially by combining experience in safe operation of the equipment, trend charts and data analysis can be used to report potential accidents early. Furthermore, by analyzing historical data recorded in real time before and after an accident, the cause of the accident can be identified, providing early warnings for the operation and management of critical equipment throughout the plant. Real-time tracking and stability analysis of process indicators improve product quality management . The system provides real-time tracking of process card operation. Through stability analysis of indicator operation, process management is optimized, providing data support for judging whether product quality is qualified. It automatically calculates the Six Sigma value of process indicators, and its data can be highly integrated with data from other application systems such as ERP, MIS, and OA, further improving product quality management. Establishing monitoring and management of the entire equipment lifecycle improves equipment utilization and ensures stable production operation. The system provides real-time monitoring of equipment operating status and comprehensive data analysis of relevant process indicators. By improving the management of the entire equipment lifecycle from both dynamic and static equipment perspectives, downtime during the equipment lifecycle is shortened, equipment utilization is increased, and long-term stable production operation is guaranteed. Providing a Basis for Production and Operation Decision-Making The system's information is based on data from two databases, establishing a unified interface and various display formats, such as tables, trends, and bar charts. Users can monitor the production site via the web, bringing the "office closer to the production site," and even from other locations, they can access and browse information anytime via the Internet to obtain timely, comprehensive, and accurate information about the company's production, operation, and management, providing a basis for leaders to make scientific and timely decisions.