Research on the Failure Patterns and Prevention of Chemical Engineering Equipment

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Abstract: This paper analyzes the necessity of understanding the patterns of failure in chemical processing equipment. It examines the inherent quality and installation quality of such equipment during its initial operation, as well as the process layout. Additionally, it investigates the factors that lead to failures during the normal operating period of the equipment, as well as the common types of failures and their patterns that occur later in its operational life. It elaborates on the reliability analysis methods for fault diagnosis of chemical engineering equipment and proposes fault prevention and maintenance control measures. Keywords: Chemical equipment failure ； pattern ； Preventive Measures 1 Overview: The production capacity of chemical enterprises is formed by various equipment, which constitutes the important technical foundation for their production. To create a safe and stable production environment for enterprises and ultimately maximize their profitability, it is necessary to modernize equipment management within these enterprises. Equipment management is a science; throughout the life cycle of a piece of equipment, it can be generally divided into three stages: the initial stage of operation, the intermediate stage of normal operation once it is in use, and the later stage of continuous operation. After each major or medium-scale repair, the equipment goes through these same three stages. Through years of practical experience and management knowledge, there are patterns and characteristics associated with the occurrence and prevention of failures at each stage. 2 Analysis of the patterns of failures in chemical processing equipment 2.1 Occurrence of failures in the initial stage of operation After installation and initial commissioning, although the equipment has undergone technical evaluations and inspections, failures still occur to varying degrees. This can take anywhere from a month to several months, or even a year. Such failures can be attributed to issues related to the internal quality of the equipment, such as its design and performance, defects in the manufacturing of components and the choice of materials, the level of understanding that operators have regarding the equipment’s structure, performance, and characteristics, as well as errors made by operators during operation that lead to equipment failures. In terms of installation quality: the quality of equipment installation is a reflection of various factors within a company, such as technical management, the competence of staff, overall efficiency, and measurement and testing methods. Attention should be paid to the qualifications and practical experience of equipment installers, as this is an important factor in preventing early equipment failures. Defects in the process layout: Due to an unreasonable layout, it may accelerate the physical wear of the equipment, leading to equipment failures ； Sometimes, process-related issues can cause changes in the equipment’s performance and operating conditions, which may also lead to severe damage to the equipment; such incidents have occurred on many occasions. Inadequate skill levels of the staff: The workers do not possess the basic knowledge and skills required for operating the equipment on site; they even fail to follow the established procedures, which is also one of the reasons why failures occur frequently in the early stages of equipment operation. The cause of such failures is often due to improper operations or violations of regulations. 2.2 Fault factors during the intermediate stage of normal equipment operation: During the operation of equipment, after a period of running-in, initial faults are generally eliminated. The skills of on-site operators also improve over time, and they come to understand the characteristics, principles, and performance of each piece of equipment, which leads to a significant reduction in failure rates. Nevertheless, new problems can still arise during equipment operation. For example, faults tend to occur in wear-prone components or those that should have been replaced but weren’t in time. Since all static and dynamic components of each piece of equipment, as well as sealing elements and bearings, have a certain service life and lifespan, equipment in the intermediate stage of operation is gradually approaching this limit. After replacing components due to shutdown for maintenance, issues such as mismatched parts, poor fit, components still in the running-in phase, or assembly errors can also lead to equipment failures, or even operation under faulty conditions; such failures occur frequently. Inadequate routine maintenance or poor work quality, or even the accidental entry of foreign objects into the equipment, can lead to sudden accidents and shorten the equipment’s maintenance cycle. An excessive focus on high yields, along with prolonged operation under conditions of overload, excessive temperature, and high pressure, is also one of the reasons for equipment failures; sometimes this even leads to equipment accidents. Equipment defects that are not easily apparent at the beginning of operation may emerge over time, during the middle phase of use, such as fatigue of non-fragile components, wear due to combined stresses, material degradation, and failures caused by inherent defects. Among the above fault phenomena, it is worth noting that apart from inherent causes, human factors play a significant role in the occurrence of these faults. Establish the necessary operation records and maintenance logs to address various causes of failures at an early stage, ensuring a safe and stable operating system over extended periods of time. 2.3 Failures often occur in the later stages of equipment operation. Chemical production equipment enters a period with frequent failures in its later operational phase; on one hand, after years of use and numerous major, medium, and minor repairs, many spare parts need to be replaced. If the level of maintenance is insufficient or appropriate testing methods are lacking, coupled with the periodic wear and tear from operation, the equipment can no longer achieve its designed performance levels. On the other hand, in equipment that remains in operation for extended periods, gaps and wear occur in various components, and even those parts that are not repaired frequently see their operational efficiency decline due to aging and fatigue. During this period, the decline in overall efficiency is attributed not only to wear and aging but also to various unexpected malfunctions of the machine. The frequency of repairs and the costs associated with consumables keep increasing, to the point where major repairs, upgrades, or even disposal of the machine become necessary. 3 Analysis of Fault Prevention and Maintenance Control Measures 3.1 Technical Foundations for Fault Prevention and Maintenance The technical foundations for prevention and maintenance are equipment condition monitoring and fault diagnosis techniques. That is, to monitor the status of various components while the machine is in operation, understand its condition, and formulate maintenance plans based on production needs. It covers a wide range of topics; aspects such as the monitoring of mechanical state variables (force, displacement, vibration, noise, temperature, pressure, and flow rate, etc.), the identification of changes in state characteristic parameters, the analysis of the causes of vibration and mechanical damage in machines, the determination of the source of vibration, fault prevention and correction, as well as the reliability analysis of mechanical components during their use and the estimation of their remaining lifespan, all fall under the category of machine fault diagnosis. In recent years, with the continuous advancement and development of theories and methods in related fields, modern equipment technology diagnostics has gradually improved. In particular, the progress in sensor technology, signal processing technology, and computer technology has laid a solid foundation for the development of this field. Currently, equipment diagnosis technology is divided into many branches, such as vibration diagnosis technology, non-destructive testing technology, thermal diagnosis technology, ferrography diagnosis technology, estimation and prediction technology, comprehensive diagnosis technology, and diagnostic decision-making technology. Their implementation involves several key steps: monitoring of the status parameters of mechanical equipment ； Perform signal processing to extract fault characteristic information ； Determine the type and location of the fault ； Take preventive and control measures against identified faults. 3.2 It should be implemented in stages. To carry out fault prevention and maintenance, equipment managers first need to master as much as possible of the basic theories and practical techniques from related disciplines, thereby becoming advanced technical and managerial professionals proficient in modern detection and diagnosis techniques. This requires necessary theoretical and technical training, as well as the accumulation of practical experience; it is a long-term process. On the other hand, implementation methods and practical techniques vary among different enterprises, all of which require practice, summarization, exploration, and improvement. Therefore, it should be carried out in a step-by-step and selective manner at the initial stage, with gradual expansion only after sufficient experience has been gained. 3.3 Levels should be determined based on the function and impact of the installations and equipment, so as to develop an implementation plan. Appropriate monitoring methods, inspection points, and monitoring intervals for the equipment should be established by considering the enterprise’s production characteristics, the importance of the equipment, and the costs associated with monitoring. Implement preventive maintenance measures of different levels and contents for different equipment. Generally, the priority of each device is determined based on its impact on production volume, product quality, product cost, maintenance schedules, adjacent processes, safety and environmental protection, as well as maintenance costs. Further, different management levels are established based on key factors, with distinct standards set for each level. In addition to the aforementioned key principles, management approaches such as the profit principle and the exception principle are also applicable as tools in equipment management or maintenance management. Furthermore, various strict operational standards must be established for fault prevention and maintenance, including process sequences, testing and inspection standards, maintenance standards, replacement standards, and cost standards. 3.4 Implementation of fault prevention and maintenance techniques Control in terms of technical implementation involves a combination of various disciplines such as the principles, structures, operating conditions, and performance of different mechanical and electrical devices, various testing techniques, signal processing techniques, monitoring and diagnostic techniques, information organization and management techniques, as well as computer hardware and software technologies. Therefore, it is a complex dynamic system that requires decision-making based on various pieces of information in order to achieve overall balance, thus enabling full-process management from planning, implementation, monitoring, information feedback, analysis to summarization and archiving. The implementation of such a technology relies on comprehensive talent management as a foundation and is supported by a proper organizational structure; for a large enterprise, this enables scientific maintenance practices and cost-effective solutions when dealing with thousands of devices. At the same time, equipment diagnostic technology must play a role throughout the entire life cycle of the equipment. In other words, it is difficult to make an accurate diagnosis if one tries to do so only at a specific point in the entire device lifecycle, or by focusing on just a particular fault or anomaly; or else no substantial results can be achieved. Therefore, based on the comprehensive equipment management theory, the entire life cycle of the equipment should be considered as the scope of application for diagnostic techniques. Conclusion: The production capacity of chemical enterprises is formed by various equipment, which serves as an important technical foundation for enterprise production. Initial equipment failures such as issues related to the internal quality of the equipment, installation quality, defects in the layout of the manufacturing process, and insufficient technical skills on the part of the staff ； During normal operation, failures often occur in vulnerable components or those that need to be replaced but haven’t been replaced in time. After replacing such components, there may be issues with compatibility; inadequate routine maintenance or poor work quality can also lead to problems. Operating components for extended periods under conditions of overload, high temperature, or high pressure can cause fatigue in non-vulnerable components, as well as wear due to combined stresses and material degradation ； Faults that often occur in equipment during its later operation, such as a decrease in operational efficiency due to aging and fatigue, were analyzed. It explains the reliability analysis methods for fault diagnosis of chemical engineering equipment: fault tree construction, qualitative analysis of fault trees, and quantitative calculation of fault trees. Research was also conducted on the technical foundations of fault prevention and maintenance, on the step-by-step implementation of these measures, on applying them according to the function and impact of various devices and equipment, as well as on the control of fault prevention and maintenance techniques. References: Li Yugang. Reactive Scheduling of Intermittent Chemical Processes Based on Equipment Failures. 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