Problems with the reboiler safety valve?
Thread Content
I have seen some processes in which safety valves are installed on both the medium outlet pipeline and the hot water outlet pipeline of the reboiler, and the reboilers are also operated in a tandem configuration. So what is the purpose of installing safety valves on the medium outlet pipeline? Why is a safety valve still needed on the hot water outlet pipeline? If, according to the specifications, a safety valve is required when the pressure difference between the high-pressure side and the low-pressure side exceeds 2/3, then the safety valve should be designed to handle the situation of rupture of the heat exchange tubes; therefore, it should be of a large size. In reality, however, it is chosen to be quite small, with a diameter of only 1 inch. What on earth is going on here?
Because if the fluid on the shell side is high-pressure and flammable or toxic, you certainly don’t want it to be released into the atmosphere through the safety valve on that side of the pipe in case of a leak. Although steam flows on the pipe side, the setting pressure of its safety valve is usually around 10% higher than the operating pressure on the shell side; this way, even if a leak occurs, the valve may not open. After all, you don’t want to release this high-pressure, flammable or toxic fluid from the shell side into the environment. Due to the high pressure, the area of the orifice is small – in my experience, it’s usually in the 1D2 range... Of course, since it’s high-temperature steam on the pipe side, it’s better for the safety valve to be equipped with a pull rod... However, you can request that the design pressure for the pipe side be the same as that on the shell side, in which case there’s no need to consider tube rupture