12
Nov
Api 521 Thermal Relief. The flare headers are sized using the maximum combined relieving rates of all devices that may reasonably be expected to discharge simultaneously in a single overpressure event. For general applicaiton we select NPS34 X NPS1 relief valve size. Compliance with API 526. This is coinciding with the designset pressure and therefore somewhat lower than what is predicted by the API 521 relief sizing which has assumed that relieving conditions are at 121 of the designset pressure.
Identical internal parts for SGL for. A complex dynamic analysis of the system may be required. In accordance with API RP 521 the rated capacity of the PSV is used for sizing individual discharge lines. Minimum slope of the flare header shall be 1 450 per API 521. As shown in Figure 1 the relief devices maximum allowable set pressure is equal to the vessels MAWP. Calculation matrix with steady-state API 521 relief valve sizing.
As shown in Figure 1 the relief devices maximum allowable set pressure is equal to the vessels MAWP.
A DN 20 DN 25 NPS ¾ NPS 1 relief valve is commonly used. The calculated relief temperature is the temperature when the relief valve starts to lift. Discussions at the API Subcommittee for Pressure Relieving Systems many years ago indicated that the correlation published in API Standard 521 was specifically for a vertical cylindrical vessel anchored to a foundation. When vessels are exposed to heat hydraulic expansion or thermal expansion is expected to occur wherein there is an increase in liquid volumes due to increase in temperature. This is coinciding with the designset pressure and therefore somewhat lower than what is predicted by the API 521 relief sizing which has assumed that relieving conditions are at 121 of the designset pressure. Calculation matrix with steady-state API 521 relief valve sizing.