METHOD OF CONCENTRATING SULPHURIC ACID Russian patent published in 2020 - IPC C01B17/88 

FIELD: chemistry.

SUBSTANCE: invention relates to concentration of inorganic acids and can be used in chemical industry for concentration of weak or diluted sulphuric acid. Method for concentrating sulphuric acid in several steps, involving direct contact of acid with heat carrier gas in counter-current mode with separate supply of heat carrier gas to each stage, characterized by that in order to prevent formation of sulphuric fog in waste gases, concentration of sulphuric acid is carried out in three steps at acid temperature in steps within the following ranges: T stage 1 - 218–227 °C, T stage 2 - 193–207 °C, T stage 3 - 168–180 °C, wherein growth of maximum temperature of 2^nd stage is directly proportional to growth temperature of 3^rd stage and coefficient of proportionality k = 1.25, and heat carrier gas is supplied from one or more heat sources.

EFFECT: proposed method is efficient, reduces the number of acid vapours to values comparable to yield after electrostatic precipitator, and provides almost complete absence of sulphuric acid fog in waste gases.

1 cl, 4 dwg, 10 ex