4 replies to this topic

[curious_cat]

Does anyone know the typical salt specs for the Chlor Alkali process that uses the modern membrane cell route? Either at the final cell stage or at the feed stage (before the purification section)

 

I see specs on Mg, Ca, and other inorganics at several sources but what I'm missing is a spec on organic contamination. Is there a typical TOC / COD or Total Organics limit on the feed salt?

 

 

[schecterman]

One thing I'm currently looking at where I work is using ceramic membranes instead of polymer membranes. We were worried our COD in our salt stream would be too high and foul polymer membranes too quickly. The rep I talked with that sells ceramic membranes acted like that is no problem at all for them. 

[curious_cat]

schecterman, on 21 Apr 2015 - 8:27 PM, said:

One thing I'm currently looking at where I work is using ceramic membranes instead of polymer membranes. We were worried our COD in our salt stream would be too high and foul polymer membranes too quickly. The rep I talked with that sells ceramic membranes acted like that is no problem at all for them. 

 

Very interesting. May I ask what your plant manufactures? Is it a conventional Chlor Alkali unit? Or an add on to a Glycerol to Epichlorohydrin process?  I've a feeling we might be working on similar problems. 

 

What are the figures for COD you have for your polymer membranes? 

Edited by curious_cat, 21 April 2015 - 03:23 PM.

[schecterman]

curious_cat, on 21 Apr 2015 - 8:31 PM, said:

 

schecterman, on 21 Apr 2015 - 8:27 PM, said:

One thing I'm currently looking at where I work is using ceramic membranes instead of polymer membranes. We were worried our COD in our salt stream would be too high and foul polymer membranes too quickly. The rep I talked with that sells ceramic membranes acted like that is no problem at all for them. 

 

Very interesting. May I ask what your plant manufactures? Is it a conventional Chlor Alkali unit? Or an add on to a Glycerol to Epichlorohydrin process?  I've a feeling we might be working on similar problems. 

 

What are the figures for COD you have for your polymer membranes? 

 

 

One of our processes generates a saturated sodium chloride solution with some residual organics in it (various amines, mostly), and currently we pay to have that stream shipped off and treated/disposed of elsewhere. We were looking at putting in a ceramic membrane system to convert the sodium chloride into sodium hydroxide and hydrochloric acid and recycling those in our processes to eliminate the cost of shipping the salt waste stream. 

 

 

EDIT: We haven't implemented the ceramic membrane yet, but it's a project I started working on recently. Just to see if it truly is more economical to do this. 

Edited by schecterman, 21 April 2015 - 03:34 PM.

[curious_cat]

I've a very very similar problem. I've a stream with about 25,000 ppm COD that has a high NaCl conc. Approx. 20%. So not exactly saturated but close. With pre-treatment we've developed a process to get COD down to 500 ppm. 

 

In  our case, the process needs NaOH(30%), HCl(30%) as well as Hydrogen. So the attractiveness of Chlor Alkali is multifold. 

 

What scale of electrolysis plant are you looking at?

 

I've collected a bunch of patents etc. If you want we could discuss off list & I can share my material. 

Edited by curious_cat, 21 April 2015 - 11:38 PM.