Internal column reflux ratio calculation

[uu78hswang]

Dear Sir

I would like to bother you a Reboiler Internal Reflux question
There is DEA Columns and packed with two beds of high efficiency wire gauze packing specified for low delta P.
And, the Column is provided with a horizontal top mounted condenser and bottom with a film type reboiler. The Internal column reflux ratio is about 0.7 for DEA column(L/D pls ref the attached drawing)

But, I don't know which stream means L and D
So I assume L is count as the outflow from the DEA column (1)+(2)
and D is mean return flow to the column (3)
And I got the L/D=0.07 insteand of 0.7
Is anything wrong with my calcuation? Could you lease kindly help me out ?
And the other issue is how to control this internal reflux ratio through temperature and pressure control?

Thank you very much

 

[Latexman]

D is the "Distillate", which is the DEA product flow rate (1.5 kg/s). L is the internal liquid flow down the column.(1.5 x 0.7 = 1.05 kg/s).

I believe the refux from most internal condensers is controlled by restricting the flow of the distillate and this causes the reflux to overflow a collection area back into the column.

Good luck,
Latexman