1 The basic idea is: to analyze the function and failure of the equipment, to clarify the consequences of equipment failure; to determine the preventive maintenance countermeasures of each fault by using standardized logical decision methods; through on-site fault data statistics, expert evaluation, quantitative modeling, etc. Under the premise of ensuring the safety and integrity of the equipment, the maintenance strategy of the equipment is optimized with the principle of keeping the inherent reliability and safety of the equipment with minimum resource consumption.
For the built reciprocating compressor unit, the main reasons for equipment unreliability can be traced to poor design, inadequate maintenance, and improper operation.
Equipment failure (including defects) is one of the main causes of chemical disasters and safety accidents. Accident statistical analysis shows that more than 40% of accidents in the chemical and petrochemical industries are caused by equipment problems, so it is very important to ensure the integrity of equipment. Failure during equipment operation is usually caused by insufficient maintenance or unpredictable failure. Effective preventive maintenance can enable enterprises to achieve more than 80% active maintenance and less than 20% passive maintenance. The effectiveness of equipment maintenance is related to the maintenance mode. Optimizing the maintenance management mode is of great significance for improving equipment reliability and safety.
2 Reliability-centered maintenance analysis of reciprocating compressors
The main purpose of the reliability-centered maintenance analysis of reciprocating compressors is to determine the high and medium risk parts of the reciprocating compressor and to establish preventive and predictive maintenance tasks for maintaining safety and reliability in the operating environment of the reciprocating compressor. Arrange maintenance resources and avoid reciprocating compressors! Insufficient maintenance or over-maintenance? . Reliability-centered maintenance analysis of reciprocating compressors mainly includes boundary division of reciprocating compressor units, equipment function and failure mode and impact analysis (FM EA), maintenance and repair strategy formulation, optimized maintenance tasks and maintenance outline formulation.
2 1 boundary division of reciprocating compressor unit
The boundaries of the reciprocating compressor unit are defined to clarify the range of reliability and maintenance data acquisition, define equipment component functions, perform failure modes, and affect analysis. The reciprocating compressor unit system is mainly composed of a drive machine, a transmission system, a compressor unit, a cooling system, a lubrication system, a control and monitoring system, and a starting system.
2 2 Reciprocating compressor reliability and maintenance data collection
Reciprocating compressor equipment reliability data mainly includes fault date, fault mode, fault impact, fault severity, fault cause, fault subunit, fault component, fault description and fault observation method; maintenance data mainly includes maintenance record and fault location , fault record, repair date, type of repair, maintenance activities, maintenance resource consumption, maintenance start time, maintenance end time, failure start time, and failure end time. Maintenance data and reliability data are collected and stored in accordance with GB/T20172-2006 (Collection and Exchange of Equipment Reliability and Maintenance Data for Oil and Gas Industry) and ensure that the reliability and maintenance data used for analysis are of sufficient quality. The data collected by the specification is mainly used for safety, availability and reliability analysis of compressor systems; life cycle cost analysis; maintenance planning, optimization and implementation.
2 3 Reciprocating Compressor Function Failure Mode and Impact Analysis
2 4 risk assessment
The importance of key components of equipment is mainly considered from three aspects: safety risk, environmental risk and economic loss risk. The fault mode risk level is related to the fault rate of the fault mode, the impact mode of the fault mode, and the risk criterion and risk matrix. The safety risk (R s) of the equipment failure mode is related to the failure rate (PoF s) and safety consequences (CoF s) of the equipment failure mode. The safety risk can be expressed by the following formula: R s = PoF s CoF s
The environmental risk (RE) of the equipment failure mode is related to the failure frequency (PoF E) and environmental consequences (CoF E) of the equipment failure mode. The environmental risk can be expressed by the following formula:
RE = PoF E CoF E
The economic loss risk (RC) of the equipment failure mode is related to the failure rate (PoF C) of the equipment failure mode and the economic loss consequence (CoF C). The economic loss risk can be expressed by the following formula:
RC = PoF C CoF C
Among them, the consequences of economic loss include two parts: production loss caused by production interruption time and equipment maintenance cost loss. The production loss consequences and the production interruption time T i are related to the equipment failure repair time ti.
The risk level of a critical component is determined by the highest risk level of all failure modes of the component, that is: if the risk level of a certain failure mode of the component is high (H), the risk level of the component is high risk (H); If all fault mode risk levels of a component are low risk (L), then the risk level of the equipment is low risk (L); the rest is defined as medium risk (M). Assume that the i-th failure mode risk level is R i and the component's risk level is R, then
R i = M ax(RS i, RE i, RC i)( 4)R= M ax(R i)
Where i= 1, 2, 3, , n.
2 5 maintenance maintenance strategy and optimized maintenance task formulation
A petrochemical branch of PetroChina and Beijing University of Chemical Technology collaborated on the risk assessment of the 4D12A-62/20 CO2 reciprocating compressor to improve the reliability, availability and safety of the equipment. Through the RCM evaluation analysis, the reciprocating compressor failure mode risk level distribution.
The reliability-centered maintenance strategy of reciprocating compressors is mainly divided into preventive maintenance strategy, predictive maintenance strategy and default strategy: one-time design change, corrective maintenance and so on. For the low-risk failure mode, the operation to the bad maintenance strategy is generally adopted; for the medium-risk equipment with the high failure rate, the one-time change task such as the redesign and redesign is generally considered; for the high-risk failure mode and part of the risk failure mode Predictive maintenance tasks are monitored online or offline; for hidden faults, periodic testing is typically used to find faults.
Establishment of a reliability-centered maintenance management model for 2 6 reciprocating compressors
Reliability-centered maintenance of reciprocating compressors is a management system whose primary function is to ensure safe and efficient operation of the equipment throughout its life cycle by controlling the operational risk of the equipment. Reliability-centered maintenance (RCM) allows for the classification of risk levels for equipment and the development of inspection/maintenance strategies to reduce equipment risk based on equipment risk levels.
Reliability-centered maintenance management is a systematic engineering method. The Safety Research Center of the Ministry of Education of Beijing University of Chemical Technology has established a reliability-centered intelligent maintenance decision-making information platform based on the current situation of enterprise equipment management and equipment management development. . As shown, the model uses reliability-centered maintenance (RCM) as an assessment tool for the identification and classification of critical equipment, rational allocation of maintenance resources based on equipment risk and failure effects, and targeted risk reduction measures; Adopting optimized preventive maintenance and predictive maintenance strategies, through online and offline detection of equipment operation status, automatic or manual prediction of equipment early failure or mastering the development trend of faults to strengthen the abnormal management of equipment to prevent disasters; Maintenance task specialist adjustment, strengthen equipment inspection and maintenance operation process management and quality control; strengthen the performance management of equipment by evaluating inspection and maintenance operations effectiveness.
The reliability-centered intelligent maintenance decision-making model information input content is the file management block content: inspection/maintenance history database, file management data database, reliability standard database, etc., which is the basic data needed for RCM evaluation analysis. At the same time, file management is also the most basic work of enterprise equipment management. Through the human-machine dialogue interface, the administrator formulates RCM risk acceptance criteria, risk discriminant matrix and fault frequency statistical analysis according to factory policies and objectives for FMEA analysis, and performs risk distribution correction based on FMEA results.
For high-risk equipment failures, it is recommended to perform root cause analysis (RCA), find out the root cause of the fault and formulate fault eradication measures, and optimize the inspection/task work package.
The reliability-centered intelligent maintenance decision model information output content is an inspection/maintenance task package related to the equipment risk level, which includes maintenance tasks such as predictive, preventive, and fault finding.
The maintenance decision output is a work plan to reduce equipment risk, improve equipment reliability, availability, and safety, and is the starting point for RCM to evaluate plant policies and objectives. Equipment operation management and fault management execution (Do) RCM optimized inspection/maintenance tasks, equipment operation data, fault data and maintainability data are stored in the file management module in accordance with the reliability standard data format as inspection/maintenance history data. The equipment performance management indicator is a check that evaluates the effectiveness of the inspection/maintenance task. It passes RAM (reliability, availability, and serviceability), fault frequency (PoF.), failure consequence (CoF.), and mean time between failures. (MTBF), Mean Time to Repair (MTTR) and other indicators quantify equipment performance. The statistical analysis results of the quantitative data are stored in the inspection/maintenance history database in accordance with the reliability annotation data format. Managers adjust RCM plant policies and objectives by assessing the effectiveness of inspection/maintenance tasks. Reliability-centered maintenance decisions go through the PDCA cycle to complete the spiraling process of equipment risk management.
3 applications
A petrochemical branch of PetroChina and Beijing University of Chemical Technology collaborated on the risk assessment of the 4D12A-62/20 CO2 reciprocating compressor to improve the reliability, availability and safety of the equipment. According to the RCM analysis, the failure modes of medium-high (H) and medium-risk (M) accounted for 8 7% and 34 8% respectively. The root cause analysis (RCA) of high- and medium-risk failure modes is concluded as follows: Machine Synchronous Motor Stator Winding Coil Aging Insulation Fault The root cause of the fault is that the compressor installation plant only has roof to cover the rain. The unit is often in a humid and dusty environment, which causes the motor insulation performance to drop and affect the reliability. Through the plant renovation and periodic coil insulation test, regular Purging and other means to eliminate the root cause of the fault, reduce the equipment risk and improve the reliability of the equipment; vibration or abnormal noise or noise occurs with the key components bearing (main bearing, connecting rod large tile, connecting rod small tile), crosshead, even Related to the rod, piston body, cylinder and other components, using state monitoring technology to monitor the dynamic analysis data of vibration and temperature of key components can early diagnose or predict the wear of the piston guide sleeve of the reciprocating compressor, the wear of the packing support ring, the valve damage or air leakage, The sliding bearing is worn or poorly lubricated, the equipment is abnormally vibrated, etc., and the training is regulated by the operation and maintenance personnel. The training guarantees the quality of maintenance and operation, which also greatly reduces the risk of equipment.
Using the built-up periodic reminder function of the reliability-centered intelligent maintenance decision-making system platform, the safety valve periodic calibration, the lubricating oil periodic testing analysis, and the instrument electrical control loop periodic testing eliminate the hidden faults of the equipment and reduce the equipment risk. Increased device availability. At the same time, the reciprocating compressor intelligent maintenance decision-making system platform provides fault mode, fault cause, fault solution, inspection and maintenance specification standards, replacement parts, labor and equipment for maintenance, periodic prevention tasks, condition monitoring and forecasting tasks, optimized spare parts storage. A list of planning and maintenance intervals, etc., to normalize and institutionalize the reliability-centered maintenance strategy and task execution of reciprocating compressors.
4 Conclusion
The reliability-centered maintenance management model for reciprocating compressor unit management is an innovation that has met with enormous challenges. First, the enterprise equipment infrastructure management is weak, and the objective standardized reliability and maintenance data required for risk assessment are difficult to carry out quantitative evaluation. Second, equipment managers rely on empirical qualitative methods to determine the way of equipment inspection/maintenance content. Deep-rooted, the reliability-centered maintenance management model of reciprocating compressors involves a series of changes in management procedures such as equipment file management, operation management, failure or abnormal management. Third, reliability-centered maintenance management requires professionals to Experts and skills such as reliability, probability and statistical analysis, root cause analysis, condition monitoring and predictive maintenance, and evaluators need to have rich experience in safety, environmental protection, mechanical, electrical, instrumentation, maintenance, operation, etc. Fourth, Reliability-centered maintenance is a change in management system and management culture. Without the strong promotion and institutional guarantee of leaders, even the best equipment management methods are difficult to succeed.
The reliability-centered intelligent maintenance decision-making model of reciprocating compressors provides enterprises with an institutionalized equipment management model, which enables all levels of personnel to input the reliability and maintenance data required by the system on the one hand through the network platform; Enables managers to accurately grasp equipment risk status and optimized maintenance schedules to provide scientific support for equipment maintenance decisions. The practical results show that the established intelligent decision-making information system for equipment maintenance has a positive effect on improving equipment reliability, availability and safety. It reduces the frequency of equipment failure, reduces the consequences of failure, and makes reasonable use of maintenance resources.
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