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Thanks nondim and Little. nondim, for compressible flow, my understanding is that friction losses depend on Reynolds number and wall roughness. Little, indeed I was looking at 100% methane. The problem involved cutting the gas supply by half. I started with Weymouth formula (due to pipe size...

Wondering what formula(s) are more suitable to calculate additional pressure required to drive increased gas flow rate in both incompressible and compressible cases. Thanks!

Thanks George, now I see what you meant.

Ok I'm now confused but thanks, Little, for pointing out to the post of George made on Feb 2. I totally missed that. George, you mentioned two points: 1. Tank is adiabatic isentropic: since there is no corresponding kinetic energy gain for the VdP work done (there is no KE gain, gas velocity...

Thanks again George and Little. My conclusion for the original problem why nitrogen vent line is getting frozen: The pressurized N is expanding to atmosphere above a critical velocity. The work done by the system is reducing pipe wall temperature, which is freezing the surrounding moisture...

Thanks guys. I ended up using ms word and using own custom made shapes for instrumentation.

The internal N pressure is 140 psi for this tank and doing no harm to shell. Neither the frozen vent is of any concern. However, I was just looking for a calculation lately how to determine the vent valve opening rate so Joule Thomson effect is subdued. Thanks for all the good information. I...

What are the some best free online process piping and instrumentation (P&ID) drawing tools out there? Never tried any so wondering if there is simplified drag and drop kind of tools. Thanks.

Thanks for the explanation on why tank is not icing, LittleInch. Is there any equation to calculate flowrate to avoid icing or Joule-Thomson effect?

Thank you guys for your very precise answers. It's a shame that there is no reply option to each answer post. We are not preventing the icing. I speculate the tank wall is double layered as there is no icing on the tank exterior. Thanks LittleInch for pointing out the Joule-Thompson effect.

We have a tank filled with nitrogen gas at 140 PSI. The tank undergoes depressurization time to time round the clock from 140 to atmospheric through a vent line. This vent line is 24/7 ice-covered. To explain the icing, I conclude that from 140 to atmospheric, the temperature plunges below...

I read somewhere an aircraft weighs more at banking due to the centrifugal force. I was trying to do a free body diagram but couldn’t see how centrifugal force adding additional weight. Any thought pls? Thanks.

From this Link I get, 1. Pumps in series: Head is added, not the flow rate 2. Pumps in parallel: Flow rate is added, not the head However, for parallel case, not sure what I'm missing but find it not so intuitive to visualise why heads are not added. How the energy is dissipated in this case...

We have two inlet sources for two pumps system (one being the spare pump) isolated by two ball valves. Both pumps performs perfectly separately when the respective isolated valve is 100% closed. However if the isolation valve is not closed 100%, both pumps exhibit vibration. What's the...

Thanks to all for feedback. Once the spool is connected back, I'd ask to check the shaft alignment test, if it passes, I'd give it a go, else perform alignment.

Is it necessary at all to perform the shaft alignment if only I remove the spool either from the suction or the discharge or both? I need to disconnect the pumps from the piping by removing the discharge spools and jacking up the suction line without actually touching/moving the volute or...

In relation to #2 above, to gain more pump heads (assuming the impeller size has already maxed out) instead of adding a VFD, can a higher constant speed motor be used? thanks for your answers.

1. How do the pump manufacturers determine the pump speed or RPM? 2. A motor with a constant speed rotates the impeller at the same speed. Hence higher the motor speed, the larger the impeller RPM. 3. Higher the motor hp, larger the motor speed. So one way to increase the pump RPM is to upgrade...

Thanks jte.

Does anybody know the derivation of (B31.3, paragraph 304.5.3) the minimum required thickness for the following blank equation: t = d * ((3*P /16*SEW) + c)^0.5, which can be further simplified to (assuming E = 1, W = 1, and no corrosion allowance) t = d(3P/16S)^0.5. So far I managed to get t =...