Effective ways to improve safety instruments in petrochemical industry

1. Effective improvement of petrochemical safety instruments

In order to ensure the integrity of instrument system performance of equipment in petrochemical production, a comprehensive analysis is carried out on it. Through the analysis results, it is known that there are problems in safety instrument system that are not conducive to system integrity. The problems and optimization measures are analyzed in detail as follows:

1.1 Scientific design of sensor redundancy

As far as redundant configuration is concerned, it plays an important role in instrument systems and is also the main content of system design. However, not all sensors are suitable for the design of redundant configuration [1]. SIL is regarded as the main probability requirement of sensor failure, if the sensor in the safety instrument system meets this requirement, it is necessary for relevant personnel to select the integrated sensor, so as to make the safety instrument system meet the design requirements. When the sensor does not meet the requirements of SIL, the use of redundant sensors should be strengthened. However, in the application of redundant sensors, designers need to fully consider the safety of the system, while strengthening the interlocking action and frequency as the basis for rational use of the logical structure, not only to comprehensively consider the applicability of the system, but also to ensure that the instrument system has reliable security, so in practice, A two-out-of-three structure in a logical structure should be used appropriately.

1.2 Carry out a comprehensive design of the safety instrument system

SIL is the main requirement for the safety and integrity of the function of the instrument system. However, the function of the safety instrument system is not determined by one device, but by several devices during operation, which mainly include: sensors, actuators and logic controllers. At the same time, there is a corresponding relationship between each instrument, the SIL between the three and the SIL of the logical sensing has an important relationship, at this time, the relevant staff should pay more attention to, especially the failure rate of the relevant instrument, which has a certain corresponding relationship with the level of SIL. For example, in the analysis of the relevant logical control, if the control unit has a SIL level of 3, the real efficiency of the controller will be less than 0.1%, and in the case of the sensor, when its SIL level is 2, the failure rate will be less than 1%. At the same time, the corresponding execution system is analyzed, and the structure is a level 1 SIL, and the failure rate of the execution structure will be less than 10% [2]. However, in practical applications, the reliability of safety instrument system operation will be directly affected by the logic controller. In addition, according to the investigation in the production process of petrochemical enterprises, many staff are too dependent on the reliability of the logic controller, which is also the main problem in the actual production process. Due to the greater emphasis on it, they ignore the importance of the actuator. If they do not pay more attention to the failure rate level of the actuator, it will lead to problems in the function of the entire safety instrument system. It can even make the safety of the instrument lose its function. Therefore, in the design of safety instrument system, relevant designers need to analyze from an objective point of view, pay attention to the comprehensive design of the system, ensure that various instruments can meet the standard of failure rate level in the design process, provide guarantee for the improvement of the safety level of the system, and make its safety performance meet the safety level standard.

1.3 Performing Integration Configurations

In the actual design process, there will be more failure rate problems, so relevant personnel need to fully study the failure rate level of each instrument in the process of system design, and analyze the failure rate level of the whole system through the parallel relationship. For example, when the failure rate of the logic controller is level 3, which meets the specific requirements of the system, in the actual design process, the designer also controls the actual failure rate at level 3, while the failure rate of the sensor and the actuator are respectively controlled at level 2, then the failure rate of the whole system is also level 2 through calculation and analysis. In this case, according to the specific requirements of the safety instrument system, if the failure rate of the whole system is level 2, the standard of the system cannot be met. If this happens, the relevant designer should take appropriate measures to deal with it, usually using redundant configuration to improve the sensor. For example, in the application of redundant configuration, according to the characteristics of the sensor failure rate to choose the appropriate way to configure, through the analysis of the above content, the use of two-to-one redundancy method, can make the safety level of the system to be improved. At the same time, in the process of redundant configuration, the designer can also configure the actuator and solenoid valve at the same time, which should be scientifically and reasonably configured according to the characteristics of the two, so that the safety level of the entire system has been effectively improved, so that it reaches the standard of SIL3, in order to promote the safety of the system to meet the specific requirements of the staff in the production operation. Because different situations in the instrument system have different requirements for the actuator, and there are certain differences in the type and function of the actuator, different actuators have different redundant configuration methods, requirements and standards in the actual design process. For example, in the process of system design, the main performance of the actuator is to cut the interlock, and at this time, the two actuators in the system are connected in series and applied, which can effectively improve the SIL. Therefore, in the design process, the designer should make a detailed analysis according to the actual situation of the system, based on this, the selection of the actuator, and according to the functional characteristics of the actuator reasonable redundancy configuration, only in this way, can promote the improvement of the SIL level.