Verfahren zur Gewinnung von Chlor und Wasserstoff

摘要

Chlorine and hydrogen are recovered from HCl by absorbing the HCl in an aqueous medium, neutralizing it with caustic alkali, e.g. NaOH, electrolyzing the resulting alkali metal chloride brine, e.g. NaCl in an electrolysis cell to obtain Cl2 and H2, the caustic alkali formed in the catholyte being used to neutralize further HCl. Preferably, the HCl is absorbed in the anolyte (Fig. 2), but it may be absorbed by water, e.g. separated from brine during concentrating or by brine circulating in an auxiliary cycle. The above brine electrolysis may be carried out in conjunction with a Cl2-yielding main alkali metal chloride electrolysis process associated with a chlorination process, e.g. in plastics manufacture, in which HCl is supplied as a by-product, the caustic alkali content in the catholyte preferably not exceeding 6% and being separated from the diluted brine to feed a common caustic alkali supply (Fig. 4).ALSO: Chlorine and hydrogen are recovered from HCl by absorbing the HCl in an aqueous medium, neutralizing it with caustic alkali, e.g. NaOH, electrolysing the resulting alkali metal chloride brine, e.g. NaCl, in an electrolysis cell to obtain Cl2 and H2, the caustic alkali formed in the catholyte being used to neutralize further HCl. Preferably the HCl is absorbed in the anolyte (Fig. 2), but it may be absorbed by water, e.g. separated from brine during concentrating or by brine circulating in an auxiliary cycle. The above brine electrolysis may be carried out in conjunction with a Cl2-yielding main alkali metal chloride electrolysis process associated with a chlorination process, e.g. in plastics manufacture, in which HCl is supplied as a by-product, the caustic alkali content in the catholyte preferably not exceeding 6% and being separated from the diluted brine to feed a common caustic alkali supply (Fig. 4).