Waste heat recovery in spent alkylation sulfuric acid treatment process

Exergy analysis of a furnace section of spent alkylation sulfuric acid facility. Internal and external exergy losses, exergy efficiency are calculated. The exergy efficiency of the furnace section was calculated to be 51.36 %. The highest exergy losses were observed in the gas duct for the high temperature oven gas. It was suggested to replace the gas duct with a boiler producing steam with P = 4 MPa and T=250 degreesC which can be used for technological purposes. The amount of steam produced was 1482.42 kg/h or 228.1 kg per 1 ton sulfuric acid. The replacement of the gas duct with boiler would increase the value of the exergy efficiency to 59.6 %.