Calculating Flow Rate for CO2 Cylinders System

In summary: I am a Mechanical Engineer with a degree in Mechanical Engineering from a prestigious university. I am also certified in Fire Protection Engineering by the International Fire Protection Association. My professional education and certifications give me the qualification to design this fire extinguishing system. I am asking on an Internet forum how to design a system that has life-saving (or not) ramifications because the system is already designed.
  • #1
cerny77
3
0
Hello guys,
I need to calculate the flow rate for the following system. 2 lines of CO2 cyclinders at 60 bar. Each line (1/2'') goes to a 1/2'' PSV valve. Downstream the 2 PSV the line are collected together into 1'' pipe.
The two PSV are identical and as per datasheet they have the following characteristics:
- max volume flow (working condition): 24,669 m^3/h
- max volume flow (standard condition): 4265,116 m^3/h
- max mass flow: 8372,849 kg/hr
First question: Do you think it is possible to calculate the flow rate trhough the 1'' pipe with the datas above?
second question: don't you think that 8372,849 kh/hr are a huge quantity considering that all this mass with pass through 1/2'' hole?
Thank you very much!
 
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  • #2
Is this a sustained flow? Carbon dioxide has a huge Joule-Thomson coefficient, and it's no trick at all for a flow path to freeze closed at even small constrictions. You say PSV: this is to relieve a system to prevent overfilling of bottles?
 
  • #3
The flow will occur in case, during CO2 discharge for fire extinguish, pressure in the line will go for some reason above 170 Barg (PSV set point). Under this circumstances I will have flow through the system (CO2 nozzles) plus flow through the 2 PSV valves which will relieve the pressure. I need now to calculate the flow on the two (1/2'') lines downstream the PSV's having just data sheet of the valves and pressure upstream each valve (170 Barg).
 
  • #4
cerny77 said:
Hello guys,
I need to calculate the flow rate for the following system. 2 lines of CO2 cyclinders at 60 bar. Each line (1/2'') goes to a 1/2'' PSV valve. Downstream the 2 PSV the line are collected together into 1'' pipe.
The two PSV are identical and as per datasheet they have the following characteristics:
- max volume flow (working condition): 24,669 m^3/h
- max volume flow (standard condition): 4265,116 m^3/h
- max mass flow: 8372,849 kg/hr
First question: Do you think it is possible to calculate the flow rate trhough the 1'' pipe with the datas above?
second question: don't you think that 8372,849 kh/hr are a huge quantity considering that all this mass with pass through 1/2'' hole?
Thank you very much!

cerny77 said:
The flow will occur in case, during CO2 discharge for fire extinguish, pressure in the line will go for some reason above 170 Barg (PSV set point). Under this circumstances I will have flow through the system (CO2 nozzles) plus flow through the 2 PSV valves which will relieve the pressure. I need now to calculate the flow on the two (1/2'') lines downstream the PSV's having just data sheet of the valves and pressure upstream each valve (170 Barg).

What are your professional education and certifications for being given the job of designing this fire extinguishing system? Why are you asking on an Internet forum how to design a system that has life-saving (or not) ramifications?
 
  • #5
The system is already designed... i wanted just to double check backpressure downstream the PSV valves and i have just asked feedback on how to calculate flow rate of CO2 gas flow... not to design the system, but anyway... you're right...maybe i shouldn't ask such kind of info trhough a forum just thought it could be interesting also for others.
Thanks
 

Related to Calculating Flow Rate for CO2 Cylinders System

1. How do you calculate the flow rate for a CO2 cylinder system?

To calculate the flow rate for a CO2 cylinder system, you will need to know the pressure of the CO2 in the cylinder, the size of the cylinder, and the length and diameter of the tubing or piping through which the CO2 will flow. You can then use the ideal gas law (PV = nRT) to calculate the number of moles of CO2 in the cylinder, and from there determine the flow rate using the equation Q = n/t, where Q is the flow rate in moles per second, n is the number of moles of CO2, and t is the time in seconds.

2. What units are typically used to measure flow rate for CO2 cylinders system?

The flow rate for CO2 cylinders system is typically measured in moles per second (mol/s) or grams per second (g/s). Other common units include liters per minute (L/min) and cubic feet per minute (CFM).

3. How does temperature and pressure affect the flow rate of CO2 in a cylinder system?

Temperature and pressure have a direct effect on the flow rate of CO2 in a cylinder system. According to the ideal gas law, as temperature and pressure increase, the volume of the gas also increases. This results in a higher flow rate as more gas is able to pass through the system in a given amount of time.

4. Are there any safety considerations to keep in mind when calculating flow rate for CO2 cylinders system?

Yes, there are safety considerations to keep in mind when calculating flow rate for CO2 cylinders system. CO2 is a compressed gas and can be dangerous if not handled properly. It is important to follow safety protocols and guidelines, such as wearing proper protective gear and ensuring proper ventilation, when working with CO2 cylinders and calculating flow rates.

5. Can the flow rate for a CO2 cylinder system be adjusted?

Yes, the flow rate for a CO2 cylinder system can be adjusted by changing the pressure of the CO2 in the cylinder or by adjusting the size and length of the tubing or piping through which the CO2 flows. It is important to carefully monitor and adjust the flow rate as needed to ensure safe and efficient operation of the system.

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