hi all,
i am junior engineer, i need to know how to calculate the relieving condition of PRV. i need to sizing the PRV in the natural gas plant, to separate natural gas from water. i have tried to understand
from this forum, but i need your correction. i have several questions that i hope you can help me to find out
a. Set Pressure of PSV is 110/90 x Design Pressure of vessel (for blocked discharge) and 121/90 x design pressure vessel (for Fire case). is that true ?
b. because the liquid that i want to separate from the natural gas is only water (almost no condensate), how do i calculate the heat of vaporization of this ? because it will be used to calculate the mass flow rate in fire case PSV sizing. as far i know , the heat of vaporization it depends on the temperature and pressure. can i simulate this in HYSYS or is it ok to take the most conservative constant value of latent heat ?
c. how do i calculate the relieving temperature in fire case in wetted vessel (separator gas - water) ? i have no idea for this, but i think if i simulate this in HYSYS, i will put Q (Q= C F A ^ 0,82) to the separator and evaluate the outlet of vapour temperature.
d. relieving temperature for blocked discharge is calculated by adiabatic compression equation :
Tr = To*(Pr/Po)^(1-1/k) with,
o: operating conditions
r: relieving conditions
k: ratio of specific heats (or adiabatic exponent, isentropic exponent, k-value)
can i simulate the relieving temperature of blocked discharge in HYSYS ? or is it enough by the equation above ?
thanks in advance