Process for the purification of an aqueous stream coming from the fischer-tropsch reaction

摘要

Process for the purification of an aqueous stream coming from the Fischer-Tropsch reaction which comprises: —feeding said aqueous stream containing the organic by-products of the reaction to a distillation column, obtaining two output streams: —an aqueous stream (i) exiting from the column head, enriched with alcohols having from 1 to 20 carbon atoms, preferably from 1 to 9 carbon atoms, and other optional volatile compounds; an aqueous stream (ii) exiting from the column bottom, enriched with organic acids having from 1 to 10 carbon atoms, preferably from 2 to 6 carbon atoms; —subjecting said aqueous stream (ii) to an anaerobic biological treatment obtaining a purified aqueous stream (iii); wherein said anaerobic biological treatment is carried out with a hydraulic retention time lower than 15 hours, preferably ranging from 4 hours to 10 hours, more preferably ranging from 5 hours to 8 hours.

主权项

1. A process for purifying an aqueous stream coming from the Fischer-Tropsch reaction, the process comprising:
feeding said aqueous stream comprising organic by-products of the Fischer-Tropsch reaction to a distillation column, obtaining two output streams: an aqueous stream (i) exiting from the column head, enriched with alcohols having 1 to 20 carbon atoms, and other optional volatile compounds; and an aqueous stream (ii) exiting from the column bottom, enriched with organic acids having from 1 to 10 carbon atoms; and subjecting said aqueous stream (ii) to an anaerobic biological treatment to obtain a purified aqueous stream (iii), wherein the anaerobic biological treatment is carried out with a hydraulic retention time lower than or equal to 15 hours and with an organic substrate load higher than or equal to 17 kgCOD/m3/day to yield a purified aqueous stream, and wherein the purified aqueous stream (iii) has a COD lower than or equal to 50 mg/l; a pH of lower than or equal to 9; a quantity of suspended solids (SS) lower than or equal to 250 mg/l; and a total quantity of dissolved solid lower than or equal to 600 mg/l.