4 replies to this topic

[diego]

Dear all,

this is my first topic on the forum so please be nice !

I've found very interesting many discussion and I have to submit a "funny" matter.....

I'm trying to simulate a compressor start up on closed loop with hysys dynamic and I am not able to smooth the Surge controller action when controller starts its function when compressor reach the 60% of max rpm.

What I'm doing is keeping the bypass valve open till the compressor reach the 60% of its max rpms and then switch on the surge controller: at this point the controller turns the set point from complete valve open to fully closed moving the operative point from choke flow to surge conditions and then starts the real surge control.

Any idea on how to ramp the surge valve closure?

No ramp is available on surge controller of hysys....

If you need it I can post the simulation basis.

Thank you in advance for any kind of help

Bye from the incredible hot italy.

Diego

[diego]

For the Admins:

probably should I post this in the other foum on simulation?

Thank you

Diego

[rxnarang]

Diego,

I am tuning the anti-surge for shutdown in HYSYS dynamics, so maybe I can work with you. Could you post the basis to rxnarang@gmail.com?

Please do remember to send the tuning parameters for the antisurge valve. The opening rate needs to be 100% in 1 second or 1.5 secs?


Regards
Rajiv

[Girish Galipelli]

Initially, when you start the compressor at low speeds, ramp it to around 95% of the speed with the help of helper motor. Say, you have 3600 as normal operating speed, then ramp your speed till 3420rpm.

At this point, if you follow the start-up typical procedures, then they say to close the bypass valves and then put the ASC in to auto mode.

Instead, you try the ASC switch to auto mode after ramping to 3420 rpm. Then, you increase the motor speed from 3420 rpm to 3600 rpm and only then close the bypass valve of the compressor.

Remember, that the ASC output has a closure time of 1 second and if the compressor has enough flow in it then the output may or may not be zero but of course it will be in control.

I think this should certainly avoid the surge of the operating point. It may well move towards the surge region but will not enter it. Also, please make sure you have good parameters for the surge control line.

Hope that helps. If you need anything else on this, please let me know. MAil: girish.galipelli@yahoo.co.in

Thank You.
Girish L Galipelli

[d.durante4486]

Dear Diego,
i'm facing your same problem. I'm trying to simulate in Hysys Dynamics the start up of a centrifugal compressor. Could you please send me some info about the procedure you used to start it up and, if possible, your Hysys simulation?

thanks in advance..
davide