Re: Pressure-Compensating TCs at Regulatory Level ?

Posted by Don Snowden on June 10, 1999 at 00:12:13:

In Reply to: Re: Pressure-Compensating TCs at Regulatory Level ? posted by Dan O'Connor on June 09, 1999 at 11:03:06:

:Dan
I guess I can apprecitate your previous comment on how one must observe the relative volatilities of the the components. If you move the pressure and the TC feedback initially goes up (verses staying the same or even falling) then I can really see how a PCT would really help. In my demeth and deeth case, the PCT (more of a multi-component distillation,verses near binary distillation) calc actually dropped much quicker than what the actual temperature could rise.

etc.., etc..
Thanks
Don
: Don,

: It was a tray temperature in the bottom section of the tower, maybe 5-10 trays from the bottom. Reflux in auto, and Pressure in auto (3 mvs in the tower, no side draw)

:
: : Dan
: : In your DIB application of PCT at regulatory level, what was it adjusting (i.e. where you controlling top temp or bottoms temp). I can see, as in Jim Gunderman's depropanizer example, that a PCT would work good for holding upper tray temp via reflux. Reflux rate movement does little to the vapor loading on the condenser, thus little impact on overhead PIC.
: : Thanks in advance
: : Don

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• Re: Pressure-Compensating TCs at Regulatory Level ? Doug B Robertson 17:08:41 6/17/99 (0)

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: 
: :Dan
: I guess I can apprecitate your previous comment on how one must observe the relative volatilities of the the components.  If you move the pressure and the TC feedback initially goes up (verses staying the same or even falling) then I can really see how a PCT would really help.  In my demeth and deeth case, the PCT (more of a multi-component distillation,verses near binary distillation) calc actually dropped much quicker than what the actual temperature could rise.

: etc.., etc..
: Thanks
: Don 
: : Don, 

: : It was a tray temperature in the bottom section of the tower, maybe 5-10 trays from the bottom.  Reflux in auto, and Pressure in auto (3 mvs in the tower, no side draw)

: : 
: : : Dan
: : : In your DIB application of PCT at regulatory level, what was it adjusting (i.e. where you controlling top temp or bottoms temp).  I can see, as in Jim Gunderman's depropanizer example, that a PCT would work good for holding upper tray temp via reflux.  Reflux rate movement does little to the vapor loading on the condenser, thus little impact on overhead PIC.
: : : Thanks in advance
: : : Don


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