Issues with air-open and air-close operation of valves at the intermediate heat exchange stage in atmospheric and vacuum distillation
Thread Content
As shown in the diagram, the crude oil from atmospheric and vacuum distillation comes in from outside the unit and is divided into two streams that enter the heat exchange process. There is a control valve on each of these streams; the symbol FO is displayed on these valves, indicating that the valves should be opened in case of an accident. Does the crude oil supply continue during an accident? I’m not sure what the considerations are in this regard; I hope someone experienced can give me some guidance
This is definitely for safety reasons, but should the feed be turned off in the event of an accident?
Determining the fault condition of a control valve primarily takes into account the need to ensure the safety of the equipment and meet the requirements of the process when the control valve fails.
I understand this. It’s specifically regarding atmospheric and vacuum distillation – why is this setting set to operate in emergency mode? Wouldn’t it be better to set it to shut down in an emergency?
It’s not possible to tell the sequence of steps just by looking at this part; could you take another screenshot with a broader view?
That’s right; if the accident shutdown mode is chosen, it could lead to interruptions in the production of the equipment, and it might also pose safety risks, as the supply from upstream is suddenly interrupted. This could result in issues such as pressure buildup. On the other hand, the accident startup mode ensures that production can continue, without any safety problems arising.
I consulted experts, and it is indeed an emergency shutdown here; in the atmospheric and vacuum distillation process, the crude oil is used as a cooling source to remove heat from the equipment. As for the shutdown controls in case of a fire, they are not located here.