Interesting. A batch process with mineral salts AND organo-tins, etc, to be extracted, presumably from a fine powder. i guess your process is frequent enough to require recovery of methanol and not just evaporation or evaporation and flaring. one would also presume that the contaminant production can't be eliminated in the first place. i wonder what your industry is? what are you producing?
If you tell us more, we'd be better equipped to converse.
Depending upon concentrations, the NaCl would reduce organic salt contaminants' solubility in water (salting out). Perhaps introducing the water in stages, first stage to get rid of inorganic salt, and you may be able to get away with cold water for this, then decanting to remove all water, and then doing a second (or more) stage(s) with hot water (assuming no retrograde solubility) to remove the organic salts with NaCl-free water? You may be able to use less hot water and even less water overall? Just a thought. You are likely doing this already?
Info on contaminant solubilities in hot and cold water and in hot and cold salt water, and hot and cold methanol, would help. Is salting out an issue? Is leaching time required due to solid particle porosity and diffusion? Have you considered purifying the solvent for recycle with reverse osmosis to remove NaCl and activated carbon to remove organo-tins? Oops, the carbon would also remove solvent. Maybe there is a second membrane that would pass solvent but not the contaminant, enabling high % solvent recycle?
Methanol distillation is well established technology, of course .. but it sounds like you may just need to flash or evaporate it and condense it to recycle essentially all of the solvent? Why would you need to separate the water from the methanol? Can you demonstrate that the organic contaminants won't decompose and distill or just distill over with the methanol? Your batch frequency would enable sizing of equipment and operatingn costs.
Nuff said from a non-specialist in this area!? Hopefully we'll hear more. Good luck.
