PROCESS AND APPARATUS FOR CONCENTRATING A LIQUID WHICH CONTAINS SULFURIC ACID AND WATER

摘要

Two heated processing stages and a flashing stage for obtaining the final concentration are used to concentrate a salt-containing dilute sulfuric acid. The first processing stage consists of evaporating means which comprise a circuit for cirulating a liquid, an indirect heat exchanger and an evaporating vessel. The second processing stage consists of one or two of such evaporating means. The liquid to be processed is first fed to the first heated processing stage, in which the highest temperatures are between 50 and 70 .degree.C. The highest temperatures in the second processing stage are between 130 to 160 .degree.C. The second processing steam is heated with live steam and the first processing stage with vapors from the second stage. The liquid which is withdrawn from the flashing zone has an H2SO4 concentration from 60 to 80 % by weight, calculated without solids.