Recovering heat in sulfuric acid production process for warming water for contact with oxidation gas, which is then contacted with concentrated acid

摘要

A low temperature heat source (3) is used to pre-heat water (1) which is sprayed into the oxidation gas (6) and this humid gas (7) is then contacted with concentrated sulfuric acid (9), diluting the acid (10) and both drying and heating the gas (11). A method for recovering waste heat in a sulfuric acid production plant is used where the production process comprises the oxidation of sulfur to sulfur trioxide with a dry, oxygen-containing gas, and the absorption of sulfur trioxide in concentrated sulfuric acid. Water is heated using the waste heat from one or more low temperature heat sources and then used to humidify the oxidation gas in a moisturizing tower (5). The warm, humid gas is brought into contact with concentrated sulfuric acid so that any moisture in the gas condenses out in the acid, which becomes diluted. The oxidation gas becomes dried and heated. The heat of condensation is transferred to a fluid (13) to give a high temperature heat source (14).