Early in my career, my mentor would do an interesting thing with me. A lot of time when I would ask a similar, open ended question, he would turn it back to me and tell me, "come up with a proposal to do <blank> that you think will work, then propose that to me and we can talk about the strengths and weaknesses of your proposal." If no one else responds, I would suggest that you come up with an idea and propose it. State why you think it will work and state the reasons that you would be hesitant to try your proposal. I often find that I get better discussion when I propose something for critique than when I ask "open ended" questions.
Thanks for the advice MrShorty. I should explained what I have already accomplished. I started out from scratch again as I am doubtful about my current design. Please see the attached PFDs.
Here's what I had planned.
Given the composition if crude glycerol, the first process would be to remove ash from the feed. This is achieved using a 0.45 um micro-filter. This process is followed by recovering a fraction of the FAME using a liquid-liquid hydrocyclone. The FAME is fed back to the biodiesel production plant.
The remaining FAME is now converted into soap via the following saponification process:
R-COOCH3 + NaOH à R-COONa + CH3OH
Methyl Oleate + Sodium Hydroxide à Sodium Oleate + Methanol
The overhead product of from the reactor is largely methanol and water. This too is fed back to the biodiesel plant. The liquid product is then fed to a second reactor where the following reaction occurs:
R-COONa + HCl à R-COOH + NaCl
Sodium Oleate + Hydrochloric acid à Oleic acid + Sodium chloride
By the acidification process, soap is converted to the free fatty acid, oleic acid, and salt. Since glycerol (SG: 1.26) is more dense than oleic acid (SG: 0.89), the two phases are easily separated using a phase separator.
In order to remove salt which remains dissolved in the glycerol, glycerol is evaporated under vacuum conditions at 71.3 kPa and 230°C. The vapour product is fed to a distillation column, also operating under vacuum conditions to remove methanol and water.
The product of distillation is 99.9% glycerol with trace amounts of salt and water.