Stripping time
Stripping time
(OP)
I would like to know how to calculate time required to strip acetone from acetone-water solution by direct steam injection in an agitated vessel.
I have a vessel filled with 300 gallons of water and polymer solution (polymer +solvent) is pumped at 10 gpm. Steam is injected directly to strip acetone out to 1000 ppm. This is not diffusion limited (thermodynamics limited). Please help me how to calculate residence time requirements to strip solvent out.(stripped solvent and water mixture will then go to distillation for solvent recovery).
Thank You





RE: Stripping time
RE: Stripping time
What are the conditions of your steam (temperature or pressure)?
RE: Stripping time
What is sounds like you really want is to calculate the steam rate required to strip the acetone.
If you are simply sparging your steam into a vessel, then you need the equilibrium vapor pressure of acetone above the 1000ppm liquid. Using this equilibrium value and the amount of incoming acetone, you can calulate the total vapor flow that needs to be coming off the vessel. The steam rate will be the steam component of that flow plus extra steam required to heat the feed to the boiling point, so please include your feed stream temperature if you supply the feed acetone concentration data ajs1972 asks for.
If it were done countercurrent, then you would use less steam vs having the loaded acetone feed stream mixing with the stripped (1000 ppm) product.
best wishes,
sshep
RE: Stripping time
Once you get the bulk liquid heated to the boiling point of water, if your acetone concentrations are only modestly greater than your target concentration at the outset, you could use Henry's Law and an estimate (guess) of the approach to an equilibrium stage that your sparger-in-a-mixed-tank represents. You could then set up a finite difference or differntial equation to estimate the concentration of acetone remaining versus the volume of steam leaving the vessel. Note that Henry's Law constants are somewhat unreliable for water-miscible species like acetone.
If your concentrations are 1% or greater at the outset, Henry's is probably no longer valid. You can use a better thermo model than Henry's if you have access to a good simulation package- and someone who knows which thermo model gives the most accurate VLE data for the acetone/water system.
RE: Stripping time
25 gpm of water
Initial amount of water in tank is 300 gallons
Steam will be supplied at 360 deg F
Outlet: Acetone content should be 1000 ppm(w).
I would like to residence time requirements please.
Thank You
RE: Stripping time
You will never get an answer without understandable data. Consider a sketch or something.
RE: Stripping time
RE: Stripping time