Yuan Weijun, Xu Donghai
(Tangshan Keyuan Environmental Protection Technology Equipment Co., Ltd 063020)
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Abstract: A gas station failure characteristics, citing the use of fault tree analysis Gas Station failed steps and illustrate the use of fault tree analysis method of the gas station failure, pointing out that the use of fault tree analysis Gas Station failure intuitive, clear, analytical thinking clear, logical, systematic, comprehensive and so on. Also proposed the use of fault tree analysis method, Gas Station various failures that may occur to establish fault libraries and expert information database, combining fuzzy theory and other technical means, finally established gas station expert diagnostic system envisaged.
Keywords: gas furnace; Gas Station; fault; fault tree; expert diagnostic system,gasifiers, gasification, coal gasifiers, coal gas producer,coal gas generators
1 Introduction
China is the world's coal resources are more abundant one of the countries of coal in China's energy structure occupies a pivotal position, vigorously develop clean coal technology applications in line with our energy security strategy, and with the increasingly tense situation in the international energy, oil and gas, etc. energy prices soaring coal as raw materials of artificial gas, started to become the fuel of choice for many Chinese enterprises, of which generator gas is most widely used.
Currently, as in gas station operator and cultural level management personnel, knowledge structure is different, resulting in gas station operations management varies greatly, production accidents uncommon view of this, it is in terms of gas station, always observe the recording system operating data, operational data and analyzed by the scientific method to find out the crux of irregularities, the imminent accident nipped in the bud, the security on the Gas Station normal production is essential.
Two gas station failure characteristics
2.1 gas station system components
Gas station gas purification according to the degree distinction is generally divided into hot and cold gas station Gas Station; according furnace distinction is generally divided into a gas station, gas station, and two dry distillation gas station. Gas station usually consists of coal pretreatment, coal transportation, preparation gasification agent delivery, softened Preparation transportation, coal gasification, gas purification, gas pressure, gas desulfurization and sewage treatment system.
2.2 Fault gas station Features
(1) determine the source of information is more complex fault
System failure is often through some test data or abnormal phenomenon discovered for the gas station, the sources of information to determine fault more complex, gas pressure, temperature and gas composition is achieved by instrumentation or direct detection out of the laboratory equipment , with considerable accuracy; through fire detection occurs furnace operating conditions can get information, has a certain intuitive, but influenced by human factors; gas pipeline (device) or blockage of water inside the case, you can only indirect detection of gas pressure and other relevant information. Determine the gas station failure requires utilization of all aspects of information systems analysis to determine the cause.
(2) gas station system failures associated with the various branches of higher
Gas station as a system composed of many sub-systems are often reflected in a branch system failure is caused by another sub-systems, the need analysis to find out the source of the fault system, which effectively troubleshooting. For example, furnace exit gas temperature is too high, the direct cause of the oxide layer is generally due furnace slag or caused to move, but the subsequent purification equipment or gas pipeline blockage is often the source of failure is caused by factors, therefore, only when the plug parts of the dredge to adjust the furnace conditions normal, otherwise fruitless.
3 Gas Station using the fault tree analysis fault
3.1 Gas Station using the fault tree analysis procedure failure
Fault tree analysis technique is a major safety system engineering analysis methods, is widely used in building construction safety, mine safety, gas application security assessment and other aspects of accident analysis [1-2], the analytical techniques used in producer gas station failure analysis, logical reasoning system aims to identify the cause and to be excluded, so that the gas station to restore normal production safety.
(A) to gas station for the system, based on the phenomenon of the accident to determine fault tree top event, ie fault events to be analyzed.
(2) analysis to determine the cause of the top event for all events.
(3) Draw fault tree diagram, that in accordance with the interpretation of the analysis of the reasons for the event starting from the top, step by step analysis of each of the direct cause of the event, according to the logical relationship between each other using logic gates connected to upper and lower case, until the requested analysis depth, eventually forming an inverted logic tree.
(4) to determine the cause of the fault tree lowermost cause events one by one judge its existence, ultimately determine the cause of the fault and to be excluded. As a fault may cause two or more symptoms, so you can draw on all Symptom fault tree, its lowest level fault tree causes the intersection of events, it is likely that failure.
3.2 Fault tree analysis using the example of the gas station failure
(A) Failure Analysis Sample gas furnace
Because the system is less involved, gas furnace failure generally easier to judge, failure is generally divided into gas furnace components, gas pressure and gas temperature anomalies, usually associated with changes in levels of the furnace, the gasifying agent supply conditions, coaling and follow-up systems for gas consumption and system resistance.
Example 1, the furnace rising CO2 content of the gas, and its content is more than 6%, typically reducing incomplete combustion in the furnace or gas caused by, which can determine the cause of the cause of the failure, it should be restored layer is too thin or cause flaming furnace, thereby causing further determine the underlying causes of the failure to be corrected, the fault tree analysis process shown in Figure 1.
Figure 1 Gas CO2 content increased failure analysis
Figure 1 Gas CO2 content increased failure analysis
Example 2, a gas furnace pressure, usually by the furnace or gasifying agent supply amount due to changes in gas consumption, in addition to the resistance and subsequent purification equipment changes in resistance furnace, will also cause the gas pressure furnace furnace increases, the fault tree analysis process shown in Figure 2.
Figure 2 furnace gas pressure increases the failure analysis
Figure 2 furnace gas pressure increases the failure analysis
(2) gas station failure analysis sample
Gas station is composed of multiple subsystems of a complex system, it should be combined with fault diagnosis process and device configuration Gas Station specific circumstances, for example three, two environmentally friendly energy-saving furnace shown in Figure 3 Gas Station, Gas turbocharger outlet gas pressure fluctuations, mostly due to wind pipes or gas pipes (equipment) water surface fluctuations, causing the frequency of changes in the gas flow area, resulting in the system gas pressure fluctuations, changes or gas furnace gas consumption regularity booster air blower failure will cause the gas pressure fluctuations, which actually causes the gas turbocharger outlet gas pressure fluctuations in the system can be combined with various branches of the pressure fluctuations at the node analysis to determine which fault tree analysis shown in Figure 4 .
Figure 3 green energy for two-stage process flow diagram of gas station
Figure 3 green energy for two-stage process flow diagram of gas station
Figure 4 turbocharger outlet gas pressure fluctuations failure analysis
Figure 4 turbocharger outlet gas pressure fluctuations failure analysis
4 Conclusion
Gas Station using the fault tree analysis fault intuitive, clear, not only to analyze the direct cause of the accident, but also reveals the depth of the potential causes of failure, analytical thinking clear, logical, systematic, comprehensive and so on. Fault tree analysis method using the Gas Station various failures that may occur to establish fault libraries and expert information database, combining fuzzy theory and other technical means, finally established gas station expert diagnosis system [3-4], so as to effectively guide the Gas Station safe and normal operation.
References
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[3] Li; Zhang Fang; Yang Chang-chu, thermal power plant chemistry expert diagnosis system integrated development and design [J], Shanghai University of Electric Power, 2001,17 (1) :23-26
[4] LI Ping; Wang Zhiyun; Zhiqiang, IPC-based radar fault diagnosis expert system [J], wireless communication technology, 2001,27 (6) :63-64
