PROCESS AND APPARATUS FOR REGENERATING SULPHURIC ACID

摘要

The invention provides a process for regenerating contaminated sulphuric acid using indirect heating in apparatus of, or at least coated with, enamel, characterized in that the acid is first concentrated to an output concentration of from 60 to 80% by weight of H2SO4 in an indirectly heated, single-stage or, optionally, even multistage preconcentration unit; the acid is subsequently introduced into a high concentration unit where it is concentrated to a level of from 90% by weight to 98.3% by weight of H2SO4 at temperatures of from about 160.degree.C to 250.degree.C and under a pressure of from about 30 Torr to 100 Torr; the acid is then delivered to a purification stage in which a temperature of from 220.degree.C to 350.degree.C is maintained; and the acid is purified under atmospheric pressure or reduced pressure; and an apparatus for carrying out the process described above.