Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
Chapter 9
9-1.
a. Unlocked valve cannot exist between rupture disc and spring relief. It is possible to
b. Similar to part a. Valve will prevent rupture disc operation when closed. Rupture
c. Relief device should be mounted on the top of the vessel with a dedicated nozzle. In
d. A couple of issues here. First, if the relief device is protecting both vessels from
overpressure, then the valve cannot be present on the connecting piping. If present, it
the top of the vessel using a dedicated nozzle.
i. This configuration was used at an actual plant site. The goose neck at the top above
the roof was used to prevent rain water from getting into the relief header.
9-2.
a. The equipment that must be protected by relief devices are:
PD pumps 2x on the discharge side
Cooling water lines on heat exchangers, 2x
All vessels, including distillation column, drum and revoiler.
Cooling water lines on heat exchangers, 2x:
If cooling water lines are shut in due to closed valves and the cooling coils are
c. The type of relief required for each location is:
PD pumps 2x:
Liquid service spring relief
9-3. a. The equipment that must be protected by relief devices are:
The 2 vessels on the left side.
4
b. The relief scenarios for each relief device are:
The 2 vessels on the left side:
All pressure vessels are required by code to have relief protection. There are
c. The type of relief required for each location is:
The 2 vessels on the left side:
Rupture disc followed by a spring relief. Use balanced bellows spring relief if
9-4.
9-5. a.
b.
6
c.
d.
9-6. The relief device must be operational all the time and cannot be disabled, even
momentarily. Thus, a manual valve placed before the relief device cannot be used. A
7
9-7.
Examples of process conditions creating a vacuum in a storage vessel:
a. Open valves V-1 and V-2.
b. Connect steam line to V-2 and steam out volatiles.
9-8. a. For toxic fluids can use a spring relief or a spring relief in combination with a rupture
disk. A pilot operated valve is also possible. A rupture disk or buckling pin relief is not
suitable since once open they do not close.
b. A pilot-operated relief would be suitable here – they can operate up to 98% of the set
pressure.
