What kind of situation could cause a 24-ton heat exchanger core to fly more than 20 meters in the air?
Thread Content
On the evening of November 29th, at the request and with the approval of the workshop, the relevant personnel from the construction unit prepared the necessary permits, including work permits, permits for working at heights, and permits for hot work. The team leader from the construction unit led the workers in removing the bolts from the heat exchanger’s head; work was stopped when only 7 bolts remained as anchors (given the overall plan and the fact that it was already dark, it was decided to use a crane to remove the cover the next day, after which the heat exchanger core could be taken out). The next morning, as required by the workshop, blind flanges were installed first – a total of 4 blind flanges of PN4.0 DN200; the specifications and quantity of these flanges were determined according to the instructions provided by the workshop. Once all the necessary permits were in place, our team began the construction work. During this time, the team leader conducted repeated checks on all the permits, while the technicians and personnel from the gas protection station inspected the work instructions. After all the blind flanges had been installed, we started to remove the bolts that connected the heat exchanger cover, following the instructions given by the workshop. At that time, there were 10 members of the construction team on site, along with other people such as the general manager of the general contracting company, the head of the technical department, the head of the safety and environmental protection department, the head of the gas protection station, the supervisor responsible for the project from the local workshop, and the workshop team leader. There were also 2 fire trucks equipped with firefighters. When only 4 or 5 bolts remained to be removed, the bolts connecting the heat exchanger cover suddenly failed and broke, causing the heat exchanger core to be ejected more than 20 meters forward, while the cover was thrown more than 20 meters away. The shell side of the heat exchanger moved several meters backward due to the reaction force, resulting in serious injuries to several people present at the scene. Several members of the construction team died, while another 16 people suffered injuries of varying degrees.
The construction workers were not engaged in any illegal operations; could such a significant disturbance be related to the process system? The 3 heat exchangers of this unit (including the one that was under maintenance at the time of the incident) are new, and the entire unit has just been renovated
How can such nonsense happen? Is it really enough to just fill out a form and sign it without going to the site to verify things? How are the blind flanges installed? How is the pressure in the shell side released? Didn’t there have to be a pressure gauge to show the pressure in the shell side during disassembly?
That’s why there is confusion: the equipment intended for construction and maintenance needs to have its pressure relieved. The pressure, as confirmed by the supervisors of both parties the night before the incident, was only 2 kilograms. Yet, after the incident, the investigation team found that there was still 22 kilograms of steam pressure inside the heat exchanger. Moreover, didn’t the operators in the control room check the instruments when renewing the tickets on the day of the incident? There were also shift leaders and other workers present in the workshop at the time of the incident. Could 22 kilograms of steam pressure really cause the 24-ton heat exchanger core and the approximately 3-ton cover to be ejected more than 20 meters away?
Isn’t wiping this different from what happened some time ago?
I don’t know if something weighing 22 kilograms can fly that far, but it’s certain that such an object would cause serious harm to those around it. Are the people on site idiots, daring to carry out such an action without first determining the pressure involved? As for whether a blind plate has really been installed, whether there are any leaks, and where this pressure comes from
Isn’t this just playing house? It’s like a game; then they just go and start working. Ah!
It seems to be something that many people and many departments are supposed to handle, but it’s likely that no one is actually taking responsibility for it; everyone is just going through the motions, signing documents, and acting as spectators. . .