ES448720A1 - Process for producing sulphuric acid - Google Patents

Abstract

Procedure for the preparation of sulfuric acid by catalytic transformation of SO2 into SO3, in gases with an SO2 content greater than 10% by volume, with refrigeration, purification and drying of the gases containing SO2 before use in the catalysis installation, heating of purified gases containing SO2 to the working temperature of the first catalysis bed, in heat exchange with hot gases containing SO3, between catalysis beds and simultaneous cooling of the gases containing SO3 at the working temperature of the next bed catalysis, intermediate absorption in sulfuric acid with elevated temperature of SO3 formed after several catalysis beds in a first stage of catalysis, two-stage cooling of gases containing SO3 leaving the first stage of catalysis before intermediate absorption, with new heating of the gases leaving the intermediate absorption at the working temperature of the next Entity catalysis bed, in the first stage of refrigeration, refrigeration of the fully catalyzed gases in the second stage of contact in a final heat exchanger, obtaining the heat not necessary in the catalysis system, and absorption of SO3 produced in the second stage of catalysis in a final absorber, characterized by the combination of the following stages: a) combination of obtaining sulfuric acid with an operation of concentration of dilute sulfuric acid; b) adding oxygen-containing gases to a partial stream of SO2-containing gases, in an amount that makes possible a reaction of the gas mixture in at least a first catalysis bed until equilibrium of the SO2 + 1/2 reaction O2 harr; SO3, without exceeding the maximum admissible temperature for the catalyst; c) heating the gas mixture to the working temperature of the first catalysis bed, in thermal exchange with the SO3-containing gases, between catalysis beds; d) mixing the SO3-containing gas, originating from at least the first catalysis bed, with the rest of the SO2-containing gas, in front of another catalysis bed from the first catalysis stage; e) adjusting the amount of the partial stream of SO2-containing gases conducted to the first catalysis bed, so that the amount of SO3 produced in step (b), after mixing according to step (d), provides a proportion of S02: SO3 that enables a reaction in the other catalysis beds until equilibrium, without exceeding the maximum admissible temperature for the catalyst; f) carrying out the intermediate absorption and final absorption of SO3 from the catalysis gases, as hot absorption at working temperatures of 100-200ºC, preferably 110-160ºC; g) carrying out the catalysis in the second catalysis stage in at least two catalysis beds, with cooling of the gases between the catalysis beds; h) expulsion of water from the diluted sulfuric acids, by direct catalysis with hot gases, consisting of the final gas of the catalysis after the final absorption and / or inert gases poor in water; i) heating the exhaust gases with at least part of the resulting heat in the final heat exchanger, after the second stage of catalysis; k) heating the exhaust gases with at least part of the heat produced in the cooling of the catalysis gases according to step (g) and / or with at least part of the heat resulting in the second cooling stage, after the first stage of catalysis and before intermediate absorption. (Machine-translation by Google Translate, not legally binding)