METHOD FOR RECOVERY OF WORKED OUT SULFURIC ACID IN TROTYL PRODUCTION Russian patent published in 1997 - IPC

FIELD: chemical engineering. SUBSTANCE: into initial 65-68% worked out sulfuric acid combined with mononitrotoluene at ratio 3:1 entering dilution apparatus, worked out saline containing 0.22-0.26 wt % of dissolved and 1.4-1.5 wt % of suspended nitro- bodies is introduced at acid to saline ratio 15:1. In apparatus, extraction of nitro-compounds with mononitrotoluene occurs followed by return of nitro-compounds back into the basic production. Acid with reduced nitro-body content is directed into recovery process. Acid is concentrated in concentration apparatus with furnace gases. Preliminarily, worked out sulfuric acid is freed from nitrogen oxides upon heating with steam in denitration column. Withdrawn furnace gases contain, along with steam, acid components (sulfuric acid, nitric acid, sulfur dioxide, and nitrogen oxides), which are trapped by ammonium hydroxide in ejection absorber. Salt solution produced in the last stage and containing 20-40% ammonium salts is fed into dilution apparatus. EFFECT: improved operational safety and eliminated sulfuric acid waste. 1 dwg, 1 tbl