Steam flow rate
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Dear experts, I have a question: Given that the pressure in the main steam pipe is 3 MPa and the temperature is 300℃； It is reduced to 0.5 MPa at 160°C through a pressure relief valve, and a safety valve is installed afterward to maintain a pressure of 0.5 MPa. All the pipes are DN50; how is the discharge capacity of the safety valve calculated? Is the flow rate estimated based on flow velocity inaccurate, and therefore not suitable for use in determining the discharge volume of a safety valve?
The steam discharge velocity and discharge volume can be calculated using Bernoulli’s equation
The Bernoulli equation can’t be used for calculation, right? The flow velocities at the inlet and outlet are unknown, as is the friction loss; there are three unknown parameters
Many conditions are unknown; for example, the pressure relief size of the safety valve, the pressure at the rear end where the safety valve is connected, as well as the size and length of the pipe used for discharge are all unknown.
I just want to calculate the discharge volume of the safety valve, so that I can determine the pressure relief dimensions you mentioned. The main issue is that I don’t know how to calculate the discharge volume of the safety valve
The pressure difference before and after the safety valve = 0.5 MPa; by determining the diameter of the safety valve’s throat and calculating the flow area, the flow rate can be obtained. It must be said that setting the safety valve pressure at the same level as the operating pressure of the low-pressure steam pipeline is not very reasonable ； If the pressure is to be adjusted to 0.5 MPa, the safety valve will trip frequently; to prevent this from happening, the operating pressure must be reduced.
Based on the information available so far, I need to know the discharge volume before determining whether the throat diameter of the safety valve is appropriate. How to determine the leakage rate? The discharge pressure of the safety valve is actually 0.55 MPa; it shouldn’t trip frequently, right?
My knowledge is too limited; I can’t answer this question. It’s embarrassing