Urgent! Those working on atmospheric and vacuum distillation, please come in—is it necessary to keep the large valve at the bottom of the tower?
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A new atmospheric and vacuum distillation unit with a capacity of around 1.5 million tons has been installed. The design includes three bottom valves in total, one for each of the flash tower, the atmospheric pressure tower, and the vacuum tower; all of these valves are made of 316L material with a diameter of DN300. The investment in just these three valves exceeds 100,000 yuan. The technical staff are divided; some argue that it should be eliminated and connected solely using flanges. Some people suggest keeping it as is and respecting the design. Please discuss, and it would be good to specify which factories should be kept or not. I need to go persuade the manager. Here’s my opinion: These three valves are cut-off valves, but they are only used in emergency situations; therefore, as long as the valves are reliable, they will not be closed throughout their lifetime. (Here, we don’t use the bottom vent of the tower during purging – instead, we use the vent provided by the bottom pump.) ). Therefore, it is recommended not to keep it. Another consideration is that, given the generally small size of these devices, the stubs built into equipment such as towers are connected to pipelines through valves. Including the vacuum furnace outlet and the atmospheric tower inlet. However, with the adoption of low-speed oil transfer line technology, the outlet pipelines of the vacuum furnace have become increasingly thick, making it increasingly impossible to install valves; therefore, flange connections are used. The same is true for the inlet of the atmospheric tower; in a vacuum distillation unit designed with a capacity of 200,000 tons per year, the inlet of the atmospheric tower is only DN150. However, in a unit with a capacity of 1.5 million tons per year, the inlet of the atmospheric tower is DN600. Therefore, flange connections are also used in the design, with no valves employed. Therefore, I recommend removing both the outlet valves and the bottom valve of the atmospheric pressure furnace; it is likely that such design elements exist only out of inertia.
I really don’t see any use for these valves; personally, I think it’s better not to use them. But the flanges cannot be removed.
The bottom pump has failed, there is a leak and a fire – where should the shutdown be performed? It has to be until the oil at the bottom of the tower is completely burned out for it to be over. Safety comes first; although it’s just in case, anything can happen... 100,000 yuan is utterly insignificant compared to the costs of accidents and lost lives.
My personal suggestion is to keep it in place, for use during shutdowns. The key is to cut off its operation in emergency accident situations. If, for various reasons, a fire breaks out in front of the bottom pump and it’s impossible to get close to it, even turning off the power won’t help – the fire will still continue. In such cases, the only option is to shut off the bottom discharge valve. Without this valve, if oil keeps flowing out of the tank and burning, the losses incurred will not be just a matter of the cost of a valve; it will come down to whether the entire facility can still be saved. Can you take responsibility for that? ? Be careful; everything that exists has a reason for being. Safety involves preventing mistakes in the details, which is why this valve is really necessary!
I also suggest keeping it; even if the chance of an emergency is one in ten thousand, it still needs to be taken into consideration! ! :handshake
Is the 150 capacity atmospheric and vacuum distillation unit still under construction? ? ? ? How was the approval granted, hehehe
Here’s my opinion: These three valves are cut-off valves, but since they are intended to be used in emergency situations or when the pump in question does not close properly, I recommend keeping them. However, is the material chosen too high-grade? For reference only.
It is recommended to keep it; I agree with the view above. Also, why is a 1.5 million tons per year atmospheric and vacuum distillation unit still being built now? Local small refineries?