Calculation of high-pressure to low-pressure safety valves in hydrogenation units
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Question 1: When calculating the discharge capacity of the safety valve on the roof of the lower-level tank, how is it determined by combining the values from the higher-level tank and the lower-level tank? Question 2: The emergency pressure relief system of hydrogenation units typically releases pressure at a rate of 0.7 MPa/min. How is the release rate calculated in the case of reducing pressure from 12 MPa to 2 MPa? Thank you all.
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Question 1: Based on the requirement of a pressure release rate of 0.7 MPa/min, it is possible to calculate the volume flow rate that needs to be released per minute. There is an issue related to changing pressures here; simplifying things, one can assume a pressure of 12 MPa for the calculations, which will provide some margin of safety for the safety valve. Question 2: Calculate the volumetric flow rate when the pressure changes from high to low, using the temperatures, pressures, and media associated with the two different operating conditions of 12 MPa and 2 MPa. Once the calculated volumetric flow rate is known, a suitable safety valve can be selected.
This post was last edited by Little Wood Bug 11 on 2017-7-17 at 18:52. Thank you very much, moderator; could you please provide more details? Thank you
Well, thank you very much. I roughly understand Question 1. Question 2 refers to the pressure and temperature of the high-pressure gas before the valve when it reaches the low-pressure side; is the difference in their volumes the volumetric flow rate that passes through? Looking forward to your reply. Thank you very much.