Application of Maintenance (RCM) Technology in Petrochemical Enterprises

With the continuous increase of international competition , the requirements for long-period operation of petrochemical plants in China are becoming more and more urgent. Long-term operation of the device on the enterprise equipment management level set higher requirements.

The traditional maintenance and repair strategies have undergone different stages of development, such as passive maintenance, regular maintenance, preventive maintenance and proactive maintenance. Great progress has been made in reducing equipment failures and reducing maintenance costs. However, the traditional inspection and maintenance procedures are based on past experience and conservative safety considerations, and lack of organic consideration of economy, safety and possible failure risks. The frequency and effectiveness of inspection and maintenance are not commensurate with the risks of the equipment being maintained , Limited inspection and maintenance resources are not used properly, and there are problems of over-inspection and over-inspection and maintenance. There is some blindness and experience in maintenance. Even active maintenance still has over-or under-maintenance, high cost, and maintenance strategies rely mainly on subjective and experience shortcomings.

Reliability-centric maintenance (RCM) technology adoption will further improve the overall level of enterprise equipment management.

RCM theory originated in the United States in the 1960s Boeing. To study the reliability of equipment based on the law, the development of the 20th century, 90 years tend to mature. Reliability-centered maintenance (RCM) is based on the characteristics of the petrochemical industry, research, update and development of applications, is based on the risk and reliability methods and the application of systematic methods and principles, systems To analyze and evaluate the failure modes and consequences of the equipment in the installation so as to quantitatively determine the risk of each failure mode of the equipment and the root cause of the failure and the root cause of the failure and identify the inherent or potential danger in the installation and its consequences Degree, draw up the proper risk reduction maintenance strategy for the reason of the failure.

This method has been successfully applied in large foreign oil companies such as ExxonMobil and ConocoPhilips, and has been introduced in the European Union's RIMAP Standards of Work Manual.

First, the application of RCM in domestic enterprises

In China, the RCM method has been applied to the ethylene cracking unit of China Petrochemical Corporation Maoming Petrochemical Industry Co., Ltd. The project was jointly implemented by Hefei General Machinery Research Institute (GMRI) and Det Norske Veritas (DNV).

The method includes all process systems including ethylene cracker, including 5 compressors, 73 pumps, 11 electromechanical turbines, 18 towers, 7 reaction equipment, 246 heat exchange equipment and containers, and Equipment itself from the stop electrical, safety chain alarm device 123 units. According to the failure history, degradation mechanism, dangerous medium and basic design data of the device provided by Maoming Petrochemical Co., Ltd., the risks of "high" or "low" were evaluated respectively for the failure probability and failure effect of all the equipments in the plant , Screening out low-risk equipment. Screening process shown in Figure 1.

1

The analysis results showed that the high-risk equipment accounted for 7.6%, accounting for 22 equipment, of which 48.6% were risk equipment, 141 were equipment, 43.8% were low-risk equipment and 127 were equipment. The analysis results are shown in FIG. 2.

2

In the medium-high risk of equipment in the following two situations: â‘  equipment failure probability, fault history. â‘¡ The consequences of equipment failure have greater impact on safety, environmental and production disruptions, and some of their higher maintenance costs.

The selected high-risk equipment further failure / failure mode, impact analysis, in order to clearly grasp the failure modes and high risk of failure, so as to formulate the appropriate maintenance strategy optimization.

The RCM begins with defining the function of a device or asset, analyzing the failure modes and effects / effects of the failure of the device, determining the failure of the function and, on that basis, determining the risk for each functional failure mode of the device. The main consideration in the analysis of the following four aspects: â‘  Failure probability of failure mode. â‘¡ functional failure mode of safety, environmental failure consequences. â‘¢ functional failure mode of production interruption failure consequences. â‘£ functional failure mode of maintenance costs.

In the RCM project, the RCM team determined the risk acceptance criteria and the acceptable criteria were translated into a risk matrix format that is more suitable for different types of risk. Risk is defined as a function of probability of failure and consequences, and the RCM team recommends 5 levels in the matrix. The X-axis of the risk matrix shows the consequences of failure and the Y-axis shows the failure frequency and probability. For all medium and high risk equipment, a total of 1 765 failure modes were analyzed, of which 1099 failure modes were non-functional failure modes and 666 were functional failure modes. Among the functional failure modes, 14 were high-risk, 321 items are medium risk and 331 items are low risk, with the total risk distribution as shown in Figure 3.

After completing the failure mode and failure consequence / impact analysis, the next step in a detailed analysis is to develop a risk-based strategy. Maintain the maintenance strategy is to consider the impact of risk, some based on safety considerations, some based on economic impact, and some based on the reliability of equipment to enhance.

Use RCM task strategy decision logic to determine tasks to reduce the cause of failure and the root cause of failure so that the risk is at an acceptable level. In the project, detailed maintenance, repair strategy and maintenance, maintenance tasks a total of 44 kinds, divided into the following categories: ① state-based maintenance. ② time-based maintenance. ③ functional test. ④ corrective maintenance. ⑤ front-line maintenance "operator inspection mission." ⑥ design and operation changes.

Second, the conclusion

Overall, this RCM analysis completely and systematically assesses the risks of ethylene cracker, systematically formulates plant maintenance strategies, effectively identifies high-risk projects, and establishes targeted maintenance strategies to reduce risk effectively , Thereby improving the safety and reliability of the equipment used and providing a basis for long-term operation; over-maintaining can be avoided through the RCM analysis - 80% of low-risk items can be identified and a decision-making basis can be provided for maintenance and maintenance budget; This RCM analysis not only strengthens personnel systematization and resource sharing in the operation and maintenance of equipment - it can be tracked, updated and inheritable, which improves equipment management as a whole.

("General Machinery" 2005 the twelfth period)

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