Hey there all,

I'm hoping to get some help on how to calculate the gain of a level control loop at the bottom of a distillation tower. The tower is actually a condensate stabilizer, and this is what I have: Easy things first - The valve is capable of 0 - 500m3/day of liquid flow, the transmitter output is 0-100%, and the level transmitter is

0-100%. Because it's going in and out of the DCS, the signals are 4-20 mA. So for a valve gain I have 5m3/day/%(valve opening) The volume of the well is 13.1 m3 with a 0-100% Level Transmitter. This means that I have 0.131m3/%Level. I know that it is difficult (or impossible??) to calculate the gain of an integrating process, as this is. I have no trouble calculating the time constant, so I know how fast the process will act (slope of line assuming constant inlet flow) with a valve position change. Even though I don't want tight level control, I'm just kind of playing around, figuring out how everything interacts, and responds. If I did want tight level control, how would I get process parameters to tune it? Any thoughts/comments?Thanks.