Founded in May 1958, Juhua Group Corporation (formerly known as Quzhou Chemical Corporation) is one of the largest producers of fluorochemicals in China. In June 1998, Juhua established Zhejiang Juhua Co., Ltd., a group company with more than a dozen subsidiaries that manufacture a total of 83 products in five categories for export to more than 30 countries and regions. One of these subsidiaries, Zhejiang Quhua Fluorine Chemical Co., Ltd., is a leading manufacturer of methane chloride and fluorine refrigerant. To optimize production management at this company’s methane chloride plant, Yokogawa provided a range of advanced solutions.
The Challenges and the Solutions
Yokogawa’s CENTUM CS DCS was already installed at this methane chloride plant, and the human interface stations for this system all ran on the UNIX OS. To achieve the desired results with today’s advanced solutions, Yokogawa first upgraded this plant’s DCS to CENTUM CS 3000, a more modern version of the Yokogawa DCS that uses the latest Windows software. The subsequent implementation of an advanced process control (APC) solution was a first both for Yokogawa (first-ever installation of an APC solution at a methane chloride plant) and the Juhua Group (first-ever use of APC at a Juhua Group company). To help users gain a deeper understanding of this complete management and optimization solution, Yokogawa used process data analysis in the early stages of this project to demonstrate in detail the benefits that can be obtained with the implementation of this solution.
The production management and optimization solutions provided by Yokogawa in this project included the Exaquantum plant information management system (PIMS), APC software, Exapilot operation efficiency improvement software, and PID tuning software. The Exaquantum PIMS provides access to both history data and real-time data on plant operations that is needed to monitor, analyze, and manage quality, operations, production, and safety. The APC solution enables the implementation of an advanced control strategy for multivariable estimation, overcomes the effects of interference and multivariable coupling, and stabilizes the operation of equipment throughout the plant. On this basis, through boundary control, economic benefits can be obtained by increasing the conversion rate of the hydrogen chlorination reaction, increasing the yield of high value-added products from the chlorination reaction, and reducing energy consumption. The Exapilot software improves efficiency by fully automating the monitoring and performance of plant operating procedures. The scope of implementation includes automatic device start-up/shut-down automatic switching of production load, and intelligent shielding from invalid alarms. This both improves efficiency and ensures safety. PID control plays a vital role in process control. Proper setting and tuning are a necessary condition for achieving stable plant operations and a prerequisite for advanced process control. The total number of loops set for this plant is 177. Yokogawa provides a standardized method for performing regulatory control stability by adopting fixed procedures and methods to ensure optimization and safe plant control.
The entire management and optimization solution took a year and a half to implement smoothly, and is currently operating well. The project has achieved its goals for improving economic benefits, enhancing plant safety, improving product quality, reducing power consumption and emissions, and reducing operator workload.
- Improved economic benefits
Steam consumption has been reduced, the conversion rate for the methanol reactor has improved, and CCl4 has been reduced.
- Enhanced plant safety
The number of process alarms has been reduced. The reduction of manual operations improves plant safety by reducing the incidence of operator errors.
- Improved product quality
Through the implementation of APC, the process automation rate has been improved. In terms of quality control, online real-time predictive analysis of product quality has been realized.
- Energy savings and emissions reduction
The plant’s annual steam consumption has been reduced by 6,370 tons, resulting in a 764 ton reduction in the amount of coal used by the Juhua Group.
・CO2 emissions reduction: 2,293 tons/year
・SO2 emissions reduction: 18.35 tons/year
・NOx emissions reduction: 5.3 tons/year
Yokogawa's production management and optimization solutions have been successfully applied at this methane chloride plant, thereby realizing the digitalization and automation of production management, improving production stability, and enhancing the safety and reliability of production operations. The customer is very satisfied with the implementation of Yokogawa's production management and optimization solutions.
Fang Min, assistant general manager of the Zhejiang Quhua Fluorine Chemical Company, commented as follows about Yokogawa's advanced control system:
"The successful implementation of the advanced control systems has brought multiple benefits to our enterprise. Through the improvement of product yield, the reduction of energy consumption, and the improvement of product quality, very considerable economic benefits have been achieved. At the same time, thanks to its automation of control and stabilization of operations, the advanced process control technology has greatly reduced operator workload, reduced process alarms, and enhanced safety. Based on the success of this pilot study at the Zhejiang Quhua Fluorine Chemical Company, the Juhua Group has been promoting the use of this solution since 2015.“ (This comment is translated from Chinese which is original.)
The customer has decided to introduce the same solution at a dozen other plants.
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