The 24-ton heat exchanger core flew more than 20 meters away
Thread Content
On the evening of November 29th, at the request and with the approval of the workshop, the relevant personnel from the construction team prepared the necessary permits, including work permits, permits for working at heights, and permits for hot work. The team leader led the workers in removing the bolts from the heat exchanger’s head; work was stopped when only 7 bolts remained. 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 in order to extract the heat exchanger core. The following morning, as requested by the workshop, blind flanges were installed first – 4 blind flanges of type PN4.0 DN200. The specifications and quantity of these blind flanges were determined based on the instructions provided by the workshop. Once all the permits were in place, the construction team began work. During this time, the team leader checked all the permits repeatedly, while the technicians and personnel from the gas protection station inspected the operation sheets. After all the blind flanges had been installed, the bolts connecting the heat exchanger cover were removed following instructions from the workshop. At that site, there were 10 members of the construction team, as well as 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; as a result, the core of the heat exchanger was ejected more than 20 meters forward, the cover was thrown more than 20 meters away, and the shell side of the heat exchanger moved several meters backward due to the reaction force. Causing casualties
The blind flange had been installed before the incident, and the local workshop confirmed that the pressure had been released. What could be the cause of this situation? ? ?
The pressure was not fully relieved, and the blind flange was not installed. It’s too dangerous.
Could these two situations have such a great impact? It is said that there are also cases of filler leakage; in any case, many reports have come in so far, but the exact details are unknown
Or safety is treated as a mere formality~~~
Alas, the casualties are too severe; it’s tragic.
Is it still that incident with the heat exchanger tube bundle flying off in Urumqi? The root cause is that the shell side of that slurry steam generator wasn’t properly depressurized; there was still a pressure of 2.2 Mpa. How on earth did the workshop managers and safety officers conduct inspections and issue work permits for maintenance?