Bala0610
Chemical
- Nov 13, 2001
- 19
We have 2 separators operating in parallel - with symmetrical piping etc. However, we experience a 1 : 2 liquid flow distribution at approximately same gas rates, despite the u/s symmetrical piping arrangement.
The control system aims to control the vapour outlet flow from the vessel seeing the higher liquid rate, so that the gas can be made to preferentially flow into the other separator. Though this helps to improve (not correct !) the situation with respect to liquid flow, it causes much different gas rates.
I think the low operating flow rates could be an issue with the vertical inlet leg experiencing inadequate velocity and hence, not being able to "wash" the liquid into the separator efficiently. This can be seen when the horizontal pipe shows flow regime change from annular to stratified at about 75% of design flow rate...so if the line goes on to become vertical, would it not result in slugging ?
I have seen designs where the separator inlet is split into two vertical legs of half cross sectional areas, with isolation valve on one, to be shut down in times of low flow. Basically the intention is to keep the inlet velocity high enough at low flow conditions (start up, high turn down). Is there a technical basis in published literature or common engineering practise that I can use to implement such an arrangement ?
I'd appreciate if anyone whos experienced this problem of flow disturbance or engineered these systems successfully could share your experience.
Thanks
Bala
The control system aims to control the vapour outlet flow from the vessel seeing the higher liquid rate, so that the gas can be made to preferentially flow into the other separator. Though this helps to improve (not correct !) the situation with respect to liquid flow, it causes much different gas rates.
I think the low operating flow rates could be an issue with the vertical inlet leg experiencing inadequate velocity and hence, not being able to "wash" the liquid into the separator efficiently. This can be seen when the horizontal pipe shows flow regime change from annular to stratified at about 75% of design flow rate...so if the line goes on to become vertical, would it not result in slugging ?
I have seen designs where the separator inlet is split into two vertical legs of half cross sectional areas, with isolation valve on one, to be shut down in times of low flow. Basically the intention is to keep the inlet velocity high enough at low flow conditions (start up, high turn down). Is there a technical basis in published literature or common engineering practise that I can use to implement such an arrangement ?
I'd appreciate if anyone whos experienced this problem of flow disturbance or engineered these systems successfully could share your experience.
Thanks
Bala