The maintenance campaign has concluded, and the equipment is renewed and ready to set sail again.

With the conclusion of the company's annual major overhaul campaign, the yellow drug production unit presents a brand new appearance, marking a solid step forward for the company in improving production efficiency and stabilizing production operations. This overhaul is the largest and most efficient maintenance campaign since the establishment of the factory.

At noon on November 20, the company orderly suspended production as planned, marking the official start of the company's 2024 annual overhaul work. This overhaul, as an important annual strategic deployment of the company, aims to improve production quality and efficiency, and to sprint towards the goal of creating a national secondary safety production standardization enterprise.

1. Advance planning and strict control of maintenance quality

The company has given high attention to this overhaul from top to bottom. Even before the official start, Chairman Zhu Yuanbin led the relevant leadership team to conduct multiple rounds of in-depth discussions, carefully planning and laying out core issues such as time planning, cost budgeting, personnel allocation, and customer supply guarantees during the overhaul period. At the same time, he supervised the production, procurement, sales, and comprehensive departments to work together, completing thorough and detailed preliminary preparations, laying a solid foundation for the smooth progress of the overhaul.

2.Unity and cooperation, fighting hard for maintenance

(1) In terms of cooperation with external professional companies

The replacement of nine kneaders, careful maintenance of the refrigeration unit, cold preservation project of the brine pipeline, maintenance and transformation of the air source pipe and wiring pipe, explosion-proof transformation of the fire protection system, comprehensive cleaning of the brine system, replacement of evaporative condenser packing, and fine-tuning of the yellow drug control system, etc., these series of arduous and critical tasks are like peaks that require our joint efforts to climb. In this process, every link is closely connected, and every task is related to the overall success or failure. We know that this is not something that can be achieved by one person; only through unity and cooperation can we gather an invincible force. When we work hand in hand, mechanical engineers and electrical technicians cooperate with each other, technical backbones and frontline workers fight side by side, and different departments connect seamlessly, allowing information and resources to flow efficiently, we lay a solid foundation for success.

Figure 1: Kneader removal

Figure 2: Kneader replacement

(2) In terms of maintenance projects undertaken by internal personnel:

Maintenance personnel and production workers work together to orderly advance multiple tasks, accurately replace oil and gas separator filter elements to ensure oil and gas separation effects and equipment stability; meticulously clean the brine tank's insulation layer to restore its insulation performance, assisting in energy saving and efficiency improvement; deeply clean the cooling tower to significantly enhance heat dissipation efficiency, meeting equipment cooling needs.

Figure 3: Cooling tower cleaning

   The top priority of this internal maintenance project is the replacement of the 200KW motor of the refrigeration unit. As the core refrigeration equipment in the company's production process, the stable operation of its motor plays a decisive role in maintaining the production environment temperature and product quality. Facing this complex and challenging task, the company organized professional technical backbones to form a special team and developed a detailed and meticulous replacement plan. During the removal of the old motor, maintenance personnel strictly followed electrical and mechanical safety operating procedures, carefully disconnecting power connections, removing couplings, and loosening anchor bolts, then using professional lifting equipment to safely remove the old motor. In the new motor installation phase, technicians meticulously cleaned the motor base and checked its flatness to ensure the new motor's installation position is accurate. By carefully adjusting the concentricity of the motor shaft and the refrigeration unit shaft, firmly installing anchor bolts, accurately connecting couplings, and rigorously conducting electrical wiring and performance testing, the new motor was successfully installed and started on the first attempt. During the trial operation phase, maintenance personnel closely monitored key parameters such as current, temperature, and vibration of the motor to ensure smooth operation without abnormal noise, with all indicators meeting technical requirements. The successful replacement of the 200KW motor of the refrigeration unit marks a significant breakthrough for the company in the maintenance and upgrading of key equipment, providing strong technical support for the long-term stability of the company's production operations.

Figure 4: Maintenance of brine insulation facilities

   In the metering tank area, by optimizing the exhaust system and installing blind plates on the metering port and pipeline ends, the accuracy of measurement and the safety of material transportation have been effectively enhanced, preventing leakage and contamination, providing a solid guarantee for product quality stability. Strong guardrails and protective doors have been added at key locations such as the third floor of the granulation workshop, the initial drying machine platform, and the discharge port. This measure greatly reduces the risk of personnel operations, minimizes the possibility of accidents, and improves the overall working environment of the workshop, ensuring orderly production.

To enhance equipment operating stability and transmission efficiency, the chain drive of kneaders #11 to #14 has been successfully transformed into belt drive. After the transformation, the equipment's operating noise has significantly decreased, and vibration has been reduced, which not only extends the equipment's service life but also lowers maintenance costs and energy consumption.

The installation of mass flow meters for carbon disulfide and butanol has been completed, achieving precise measurement and real-time data monitoring of key materials, assisting in the refined management of production processes. The successful installation of the UPS power supply in the control room ensures the continuous operation of key equipment in the event of sudden power situations, effectively avoiding data loss and production interruptions. At the same time, the installation of gas alarm devices in flammable gas areas further strengthens the workshop's safety protection system, enabling timely detection of potential dangers and issuing alarms, safeguarding the safety of employees' lives and property as well as the company's production facilities.

Before the end of the maintenance, the company organized personnel to thoroughly clean the platforms of kneaders #1 to #10 in the yellow drug workshop of the synthesis building. As one of the core devices on the production line, the cleanliness of the kneader's operating platform directly relates to the working environment and efficiency of the operators. Maintenance personnel used brooms, mops, and cleaning agents to conduct a comprehensive and thorough cleaning of the platform, leaving no sanitary dead corners. The cleaned platform is tidy and clean, free of oil stains and debris, providing operators with a safe and comfortable working environment, helping to reduce potential safety hazards due to poor operating conditions.

3. Strict management and detailed inspection to build a solid safety barrier on site

   While actively carrying out equipment maintenance work, the company places great importance on safety management, emphasizing responsibility, strictly controlling project safety and construction progress, and strengthening on-site safety control from multiple aspects such as raising awareness, risk identification, supervision management, and operational process control, building a solid safety fortress for the maintenance site.

The Safety and Environmental Protection Department conducts safety education before operations, emphasizing safety precautions, protective measures, and safety briefing before work; during operations, safety personnel control work points by area to ensure that maintenance projects are strictly executed according to schedule, all safety measures are implemented, and they discuss pre-planning and in-process control plans with project leaders; after operations, the department reports any issues encountered during the maintenance process and corrects them in a timely manner.

Figure 5 Safety Training

   The company has implemented multiple measures to effectively enhance the safety management of maintenance personnel, ensuring that there is no relaxation in mindset, no loss of control in behavior, and no neglect of responsibility in management. It fully utilizes the role of all employees in safety supervision and inspection, establishing a collaborative safety work pattern to ensure that all maintenance operations are safely controlled.

The comprehensive upgrade and transformation of the Huangyao workshop fully demonstrates the company's firm commitment to safe production and efficient operation, laying a more solid foundation for the company's future stable development, helping it stand out in market competition, and achieving the long-term goal of sustainable development.

The successful conclusion of this maintenance campaign will further improve the company's production efficiency and quality, effectively promoting the creation process of national secondary safety production standardization enterprises, solidifying the foundation for the company's safe production and efficient operation, and effectively supporting the company's high-quality development while strengthening production guarantees.