Blunders at work
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This post was last edited by chensf123 on 2016-8-30 at 15:51. One day, thunder caused the gas escaping from the venting pipeline at the site (a small amount of gas was escaping) to catch fire. When the process engineers opened the ITCC alarm panel, they found that the 3500 system alarms on the HMI of all four units were displayed in red. They contacted the personnel in the automation department for inspection. Since it was a weekend at that time, the instrument technicians on duty at our facility were not familiar with the ITCC system, and they informed the process engineers that those were alarms from the BENTLY3500 system. It is necessary to contact the person in charge of the system to handle this. As soon as the system maintenance personnel arrived at the company, they conducted a thorough inspection of all components of the BENTLY3500 system – including the status of indicator lights, vibration levels, displacement data, phase detection components, transient data cards, relay cards, communication cards, and so on – as well as the software. Attempting various operational procedures and resets failed to eliminate this alarm. . . . . . Finally, it is suspected that the previous thunderstorms caused high voltage from lightning to be introduced through the electrical grounding, leading to the aforementioned malfunction ； I contacted Bentley’s manufacturer and sent over the 3500 data for analysis, but to no avail; they all believed it was a fault in the transient data card. Two days later, upon checking the SOE and DI curve records of the ITCC, it was found that the 3500 alarm output relay had not flipped at any point ； By reviewing the manual for the 3500 and considering our wiring and configuration for it, we realized that the configuration and jumpers related to this alarm output relay were also set to remain powered. The mistake occurred because the color of this setting was reversed during HMI configuration. The subsequent series of revisions and adjustments will not be discussed in detail...
This device of yours must have been running for quite some time already; how come I didn’t notice it before?
The last edit to this post was made by chensf123 on 2016-8-30 at 20:12. To be honest, the alarm panels for these units are located on the last page of the process diagram; usually, the process engineers don’t look at them. In our company, as far as the automation field is concerned, only I and one chief engineer are responsible for unit control, and we also didn’t notice this issue.
“One day, thunder ignited the gases being released from the venting pipeline at the site (a slight amount of venting, but in small quantities). This indicates that your company is releasing combustible gases directly into the atmosphere, which is a serious violation of environmental protection laws. Thunder can ignite it, posing a significant safety hazard. It is recommended to make adjustments so that this exhaust air is discharged into the flare system.
Look carefully from upstairs; the operating conditions were abnormal at that time, and under normal circumstances a flare would have been used. Our self-control only focuses on the processes of the processing system; there are no issues related to safety or environmental protection
The 3500 relay module comes in two connection types: NC and NO. In similar interlocking systems, people in China tend to use NO, as it won’t operate even if the wire is broken, while foreigners prefer to use NC
It seems that all the alarm settings for the instruments are set to NO alarm! Let there be no borders!
The wire is broken! It must be in the open circuit state, so an alarm will definitely be triggered.
In the event of an accident, it should also be discharged through the flare system, rather than being released directly into the atmosphere. How did your environmental impact assessment get approved?
It was directed to the system from the very beginning, went around in a circle and returned to the HMI; the system should be trusted, and system issues should be investigated later.
This post was last edited by chensf123 on 2016-9-1 22:11. I’m sorry; I wasn’t clear enough – it was ignited by lightning after the safety valve. This pipeline is connected to the vent leading to the flare.