Specification and Design
Pressure Vessels – Pressure Relief Devices, Corrosion Protection
Pressure Relief Devices
All pressure vessels should be equipped with one or more pressure safety valves (PSVs) to prevent overpressure. This is a requirement of both the ASME Code and API RP 14C (refer to Chapter 14). The PSV should be located upstream of the mist extractor. If the PSV is located downstream of the mist [...]
Pressure Vessels – Vessel Supports, Ladder and Platform
Vessel Supports
Small vertical vessels may be supported by angle support legs, as shown in Figure 12-11. Larger vertical vessels are generally supported by a skirt support, as shown in Figure 12-12. At least two (2) vent holes, 180° apart, should be provided at the uppermost location in the skirt to prevent the accumulation of gas, [...]
Pressure Vessels – Vortex Breaker, Manways
Vortex Breaker
As liquid flows out of the exit nozzle, it will swirl and create a vortex. Vortexing would carry the gas out with the liquid. Therefore, all liquid outlet nozzles should be equipped with a vortex breaker. Figure 12-9 shows several vortex breaker designs. Additional designs can be found in the Pressure Vessel Handbook. Most [...]
Pressure Vessels – Nozzles
Nozzles should be sized according to pipe sizing criteria, such as those provided in API RP 14E. The outlet nozzle is generally the same size as the inlet nozzle. To prevent baffle destruction due to impingement, the entering fluid velocity is to be limited as:
If an interior centrifugal (cyclone) separator is used, the inlet nozzle [...]
24Sep2009 | admin | Comments Off | ContinuedPressure Vessels – Shop Drawings
Before the vessel fabrication can proceed, the fabricator will develop complete drawings and have these drawings approved by the representative of the engineering firm and/or the operating company. These drawings are called shop drawings. They will show detailed vessel design and fabrication/welding, nozzle schedules and locations, details of vessel internals, and other accessories. Examples are [...]
24Sep2009 | admin | Comments Off | ContinuedPressure Vessels – Specifications
Most companies have a detailed general specification for the construction of pressure vessels, which defines the overall quality of fabrication required and addresses specific items such as:
• Code compliance
• Design conditions and materials
• Design details
• Vessel design and tolerances
• Vessel connections (nozzle schedules)
• Vessel internals
• Ladders, cages, platforms, and stairs
• Vessel supports and lifting lugs
• [...]