Long-term operation record of the device! Jinling Petrochemical’s p-xylene unit has operated continuously and stably for 2,295 days

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On April 15, Jinling Petrochemical shut down its xylene plant for maintenance, marking a milestone as the plant achieved its longest period of continuous, stable, and safe operation to date – 2,295 days – thereby reaching the best level of operational longevity since its commissioning. Since the unit entered its third production cycle on January 3, 2020, Jinling Petrochemical has significantly improved its operational efficiency by implementing dynamic optimization of production plans, addressing operational bottlenecks, and accelerating talent development, thereby providing a solid foundation for breaking new records for long-term operation of the unit. 　　Focus on maintaining stable production and make every effort to increase output and efficiency. “The company has set requirements to optimize the adsorption and separation processes in order to boost the production of aromatic products.” Everyone must stabilize the operation period before equipment maintenance, address production fluctuations promptly, and secure a steady return on profits. ”On April 10, Feng Xiongwei, the director of the xylene unit at Jinling Petrochemical’s Chemical Production Department II, gave a reminder. 　　During the third phase of operation, the department adhered to the principle that \"greater stability translates into greater efficiency.\" It kept a close eye on market conditions, continuously carried out calculations and optimizations, adjusted the ratios of various feedstocks used in the process, and optimized the structure of product output. Focus was placed on refining process parameters, ensuring high levels of stability, and addressing potential risks. Sixteen optimization plans were developed; changes in market conditions were monitored in real time to adjust the ratios of feedstocks accordingly. Key parameters such as temperature differences and tower pressure were carefully controlled, allowing for a scientific and rational increase in the load associated with the disproportionation reaction, thereby maximizing the production of benzene-based products. 　　At the same time, they continue to strengthen process safety management by working together with teams from fields such as electrical and instrumentation, safety, process engineering, and equipment management; through holding on-site meetings and reviewing design documents, they develop customized solutions ； Carry out targeted efforts to address issues related to alarms, interlocks, and blind flanges; increase supervision of weak areas such as shift handovers, compliance with scheduling rules, and responses to abnormalities. Focus on critical, important, and frequently occurring alarms to conduct root-cause analysis and take corrective actions, thereby improving the timeliness of alarm handling. 　　Feng Xiongwei said, “Through a series of measures, the automatic control stability rate of the xylene production unit during this period increased to 99.5%. A total of over 5 million tons of benzene-based products were produced, and the yield of key products remained at an advanced level in the industry, resulting in significant increases in efficiency and revenue.” ” 　　Striving to overcome bottlenecks: A three-pronged approach yields tangible results. “At present, the heavy aromatic hydrocarbon tower is operating at a low load, which is like trying to fit big shoes into small feet; this makes it easy for the stable state within the tower to be disrupted. When disruptions occur, parameters tend to fluctuate, posing difficulties for operation.” Close attention should be paid to the trends in bottom pressure and the temperature of the bottom reboiler liquid returning to the tower; adjustments should be made promptly when these values deviate from the steady-state parameters. ”On April 12, during the department’s aromatic compounds optimization team’s monthly meeting, engineer Liu Xiaofeng said. 　　In response to issues such as gradual equipment aging, changes in raw material composition, and reduced catalyst activity in the units, this department focuses on overcoming operational bottlenecks through technical innovation, equipment maintenance, and process optimization. 　　The department organized technical teams to assess the conditions of the plant’s long-term operation. Focusing on the issues that hindered its efficient functioning, tasks such as optimizing the ratio of reactants and controlling bed temperature were undertaken. As a result, problems such as high overall energy consumption, unstable quality of o-xylene, and rapid degradation of the isomerization catalyst were successfully addressed. At the same time, adhering to the principle that \"equipment issues should not be left unresolved overnight,\" they formed a special task force to address these issues. They incorporated the monitoring of unit operation parameters and pump conditions into the monitoring and alarm systems, made full use of the equipment condition monitoring system to maintain records of dynamic data related to key units, and emphasized preventive maintenance. Strict procedures were implemented for confirming critical steps, conducting external inspections, and monitoring internal operations, all in order to minimize production fluctuations. They also carried out process optimization by transferring all the mixed aromatic components from one of the continuous reforming units to the disproportionation distillation unit of the p-xylene plant. This not only allowed the distillation unit of the continuous reforming unit to be shut down, but also enabled the disproportionation distillation unit in the p-xylene plant to operate at full capacity.