METHOD FOR ABSORBING SULFURIC ANHYDRIDE Russian patent published in 2003 - IPC

FIELD: inorganic chemistry, chemical technology. SUBSTANCE: invention relates to the large-scale production of sulfuric acid. Method of absorption of sulfuric anhydride from gaseous mixture comprising 7-20 vol. % of SO₃ with temperature 150-260 C involves contacting with sulfuric acid with concentration of H₂SO₄ 98-101% and temperature 120-240 C for two stages in direct-flow interaction of gas with acid and without elimination of heat. At the first stage 25-90% of the parent SO₃ is absorbed, acid concentration is elevated by 0.3-1.83% of H₂SO₄ and its temperature is increased by 11-46 C. After the first stage gas-liquid mixture is fed to the second stage where remained part of SO₃ is absorbed and process is carried out by direct-flow contacting into working tubes and with simultaneous elimination of heat through walls using coolant and total temperature of gas-liquid mixture is reduced by 0-65 C. Invention provides the development of economical method for absorbing SO₃ where utilization of heat from technological processes for preparing steam of low and middle pressure is possible. EFFECT: improved absorbing method. 2 cl, 4 dwg, 5 tbl