Solvent Distilling/Recovery 1

[rhodie]

I have a solvent distiller that is running on a continuous duty basis, 24/7/365. Aside from a poor engineering decision to purchase an undersized unit for the purpose at hand (which I had no hand in), I have been left trying to maximize uptime on a unit that breaks down frequently. The unit mostly processes alkyd paint products.

With that in mind, I am curious to find out your method for recovering solvents. Is distilling the only option for seperation, or is there a precipitating (flocc?) technology that I am just not familiar with? Aliphatics, keytones, acetones, napthas, xylenes, are all solvents that we are currently recovering for reuse. With the price of oil above US$60/gal, any thrift that we demonstrate in this area can make a significant difference.

Thanks in advance!

 

[UmeshMathur]

Before selecting an alternative unit operation, the key questions that must first be answered are:
(1) What are the amounts of solvents you are recovering
(2) Is your current distiller batch or continuous
(3) What is the mixture composition, and is it fully defined and measured
(4) What are the key separations
(5) What does the distiller design look like
(6) Why do you have frequent breakdowns

None of the compounds you have listed should form a solid precipitate unless thay have extremely large molecular weights.

 

[Montemayor]

rhodie:

UmeshMathur has covered the exact items I was going to note and I won't risk up-staging his great reply but only add the following:

(7) Does your raw feed stream contain solids or fines?
(8) Do you have waste L.P. steam or back pressure steam available? - and at what pressure(s).

 

[ibmem]

Rhodie,

The "Solvent Recovery Handbook" from Smallwood (McGraw-Hill) should become your bible: it describes the separation methods (distillations but also adsorption, membrane separation, extraction, coalescing, fractional freezing,..) and also the data part is very usefull.

regards,
PS

http://www.ibmem.com