Summary of the technology
A comprehensive method to assess the technical condition of the pressure equipment of installation operated in the chemical and petrochemical industry, with the use of acoustic emission signal analysis, structure stress field and the degradation st
The algorithm for the assessment of the technical condition of pressure equipment of chemical and petrochemical installations, subjected to the long-term operation, allows to determine the damage degree of the material and allows to predict the further development of degradation processes in a function of time.
The proposed approach to the problem of safe operation of devices is fundamentally different from the solutions which are currently used in industrial practice. Currently, the supervision of these objects is based mainly on standard non-destructive testing methods. The main limitation of used methods is the lack of the possibility of both examining the object in its entire volume and testing the device in working conditions.
Developed algorithm allows to effectively solve current problems in the diagnosis of chemical installations related to the assessment of their technical condition and determination of the conditions for further operation in real time. The algorithm is particularly recommended for monitoring devices in which adverse damages occur due to the long-term operation.
Description of the technology
Pressure equipment in the chemical and petrochemical industry very often work under extreme conditions. It is associated with the simultaneous influence of aggressive media, such as: variable pressure and load as well as high/low temperatures.
Long-term operation under extreme conditions causes defect initiation and growth in the microstructure of the equipment materials. These defects, which grow due to workloads, may damage the entire structure and may lead to the failure of the entire industrial unit. A threat to the natural environment is also possible. In exceptional cases, there is a potential threat to human health and life. Currently, the monitoring of such objects is based mainly on standard non-destructive testing methods (NDT), such as visual testing (VT), ultrasonic testing (UT) or radiographic testing (RT). All of the listed research methods are included in local research. One of the modern methods which treats the object in a global way and allows to examine it in its entirety is the acoustic emission method (AE – acoustic emission testing (AT). It is a high-sensitive, passive research method that allows detecting discontinuities developing, e.g. in the walls, joints, and elements of the coats of devices working under load.
The main advantages of this method include:
• the possibility of global inspection of large elements and structures,
• the ability to research and monitor the entire facility, also in working conditions,
• possibility of locating the source of AE signals generated by defects/damages,
• possibility of conducting continuous tests - long-term tests,
• the ability to determine the dynamics (kinetics) of damage development.
The nature of the generated AE signal during damage development varies at every stage of its propagation and also depends on the type of material. Thus, the analysis of AE signal parameters allows specifying the stages in which the destruction processes take place in real time of their appearance such as: nucleation, constant propagation or critical state (uncontrolled cracking).
This method also allows for the change evaluation of material state based on emission characteristics and appropriate criteria evaluation. This method is currently considered as the most suitable method in the word among other non-destructive methods for periodic testing of large-size devices. Therefore, the AE method is the foundation of the developed algorithm for a comprehensive assessment of the technical condition of equipment operating under pressure in the chemical and petrochemical industry.
The developed diagnostic methodology is a combination of numerical simulations of the stress field construction in the real-time operation, material condition evaluation and in-depth analysis of acoustic emission parameters which are generated as a result of degradation processes.
The optimal combination of these analyzes and defined mutual correlations allow to effectively solve current diagnosis problems of chemical and petrochemical installations related to the assessment of their technical condition and determination of conditions for their further operation. This solution is especially dedicated to devices in which adverse damage occurs due to the long-term operation.
Cracow University of Technology
Technology Transfer Office