Process for purification of an organic acid including an electrodialysis treatment step
It is an object of the invention to provide a process for producing an organic acid, comprising: providing an incoming stream containing an organic acid and impurities; subjecting said incoming stream to a step of chromatographic separation, using a solution of mineral acid as an eluent, so as to collect an extract and a raffinate, the organic acid being recovered in the extract; and subjecting the raffinate to an electrodialysis step, so as to collect a diluate and a concentrate, the mineral acid being concentrated in the concentrate. The invention also provides an installation for implementing this process.
1. A process for producing an organic acid, comprising:
providing an incoming stream containing an organic acid and impurities;
subjecting said incoming stream to a step of chromatographic separation, using a solution of mineral acid as an eluent, the eluent containing less than 20 g/L mineral acid, so as to collect an extract and a raffinate, the organic acid being recovered in the extract; and
subjecting the raffinate to an electrodialysis step, so as to collect a diluate and a concentrate, the mineral acid being concentrated in the concentrate.
2. The process of claim 1 , wherein the solution of mineral acid is selected from a solution of sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid and combinations thereof.
3. The process of claim 1 , wherein the organic acid comprises citric acid.
4. The process of claim 1 , wherein the eluent contains less than 10 g/L mineral acid.
5. The process of claim 1 , wherein the diluate is subjected to a concentration step so as to collect a diluted fraction on the one hand and a concentrated fraction on the other hand.
6. The process of claim 1 , wherein at least part of the concentrate is recycled with the incoming stream.
7. The process of claim 1 , wherein at least part of the concentrate is recycled with the eluent in the step of chromatographic separation.
8. The process of claim 1 , wherein providing the incoming stream comprises at least one of the following steps:
an upstream fermentation step;
an upstream filtration step;
an upstream ion exchange step; and
an upstream evaporation step.
9. The process of claim 1 , wherein the extract is subjected to at least one of the following steps:
a downstream adsorption step, or a downstream ion exchange step, or a downstream treatment step on activated carbon;
a downstream evaporation step; and
a downstream crystallization step.
10. The process of claim 5 , wherein at least part of the diluted fraction is recycled with the incoming stream.
11. The process of claim 5 , wherein at least part of the diluted fraction is recycled with the eluent in the step of chromatographic separation.