Question

How do I convert volume % to volumetric flow rate? This is occurring in a disitillation column. I have the volume amount poured into the tank, 10L that is 7% methanol. I have a power input of 1.5 kW. I understand the mass balance of a distillation column. What I am confused about is after I found in the distillate, the 1 microliter sample is 5% methanol and 95% water at 5 minutes, how do I conver this to volumetric flow rate. So to find the volumetric flow of methanol in the distilate, do I convert volume percent by dividing my 100 to remove the percent then multipling by one microliter to establish volume then divide by time? Is that correct or do I mulitply by the total volume (10L). Can you show me how to do this or if I need to have another variable to solve this, can you include that and explain why I need it?

Answer 1

here all given percentage is by volume.

Distillate composition given : Volume of distillate Vd = 1 microLiter

5% methanol + 95% water

Question asks methanol  volumetric flow rate then your procedure is right .

Methanol volume =( 5/100 )*1microL = 0.05microL

At t = 5 min , methanol volumetric flow rate,

Q = 0.05microL/5min = 0.05/5*60 = 1.67*10^-4 microL/s = 1.67*10^-10 L/s

Methanol volumetric flow rate = 1.67*10^-10 L/s

1 micro = 10^-6

Addition variable,

If asks distillate volumetric flow rate then = 1microL/5min = 3.33*10^-3 microL/s= 3.33*10^-9 L/s

Distillate volumetric flow rate is used for material balance and help to find other variables.

Don't need to multiply by total volume because when question asks about tank volumetric flow rate then we have to do this. And also given initially tank composition 7% methanol.