pressure dropping in process gas recirculation loop
pressure dropping in process gas recirculation loop
(OP)
Greetings,
Apologize in advance as my question may seem very basic, still I would like to have a clearer picture of what I am dealing with for an ongoing project.
The set up includes one centrifugal compressor of barrel type which is recirculating a mixture of process gas in a closed loop.
The loop is actually a big process loop which comprises pipes, components, process coolers, drums, vessels, etc.
Upstream of the compressor there is a process gas cooler so that the inlet temperature to compressor is always constant =35 degC.
At the initial phase of recirculation operation, the gas is 99% Air + some Argon content and the temperature of the loop is around ambiant 35 deg C. Next phase of operation, the gas in the loops is heated up to 150 deg C maximum.
Last phase of operation, the gas in the loop stays heated up at 150 deg C whereby a small amount of helium is added in the loop so the gas molecular weight drops.
During all these phases our process engineer says that standard volume flow (std m3/h) circulated in the loop needs to stay constant. (I hope Process is not confusing with keeping actual m3/hour constant to have gas velocity kept constant somewhere in critical equipment area - but that is another story)
What I am trying to figure out is the impact on the total pressure dropping in the loop corresponding to each phase.
I think that if the initial phase has a certain pressure drop, say Dp, when the temperature increases in the loop, the pressure dropping increases further in this case significantly (say by Dp2) so total dropping becomes (Dp + Dp1). At final phase, the molecular weight decreases a bit (by 1 or 2 points) thereby the pressure dropping decreases so we are slightly below (Dp + Dp1). Again this is keeping the standard volume flow constant throuout the loop in all three cases.
Is the reasoning correct ? Is there a rule of thumb or a book reference to use so I can confirm all this ?
Process has to do all the math here and evaluate pressure losses for each case. This is however not available at the moment.
thanks
Apologize in advance as my question may seem very basic, still I would like to have a clearer picture of what I am dealing with for an ongoing project.
The set up includes one centrifugal compressor of barrel type which is recirculating a mixture of process gas in a closed loop.
The loop is actually a big process loop which comprises pipes, components, process coolers, drums, vessels, etc.
Upstream of the compressor there is a process gas cooler so that the inlet temperature to compressor is always constant =35 degC.
At the initial phase of recirculation operation, the gas is 99% Air + some Argon content and the temperature of the loop is around ambiant 35 deg C. Next phase of operation, the gas in the loops is heated up to 150 deg C maximum.
Last phase of operation, the gas in the loop stays heated up at 150 deg C whereby a small amount of helium is added in the loop so the gas molecular weight drops.
During all these phases our process engineer says that standard volume flow (std m3/h) circulated in the loop needs to stay constant. (I hope Process is not confusing with keeping actual m3/hour constant to have gas velocity kept constant somewhere in critical equipment area - but that is another story)
What I am trying to figure out is the impact on the total pressure dropping in the loop corresponding to each phase.
I think that if the initial phase has a certain pressure drop, say Dp, when the temperature increases in the loop, the pressure dropping increases further in this case significantly (say by Dp2) so total dropping becomes (Dp + Dp1). At final phase, the molecular weight decreases a bit (by 1 or 2 points) thereby the pressure dropping decreases so we are slightly below (Dp + Dp1). Again this is keeping the standard volume flow constant throuout the loop in all three cases.
Is the reasoning correct ? Is there a rule of thumb or a book reference to use so I can confirm all this ?
Process has to do all the math here and evaluate pressure losses for each case. This is however not available at the moment.
thanks
"If you want to acquire a knowledge or skill, read a book and practice the skill".





RE: pressure dropping in process gas recirculation loop
There is only Dp1, sorry for the typo. this should read:
"If you want to acquire a knowledge or skill, read a book and practice the skill".