Discussion on the technical upgrade and renovation of a 17 kt/a alkylation waste acid cracking and regeneration acid production plant
The technical upgrade and renovation of the 17 kt/a alkylation waste acid cracking and regeneration acid production plant is introduced.The waste acid cracking furnace adopts a hot wall design,adds external insulation,and controls the outer wall temperature of the waste acid cracking furnace to be no less than 250℃higher than the dew point temperature of the cracking process gas,and lower than the allowable using temperature of the metal material on the outer wall of the cracking furnace shell.Adjust the heat exchange process in the cracking section to avoid dew point corrosion of the cold air preheater,extend the service life of the cold air preheater.Adding quick opening for ash cleaning to the hot air preheater and cold air preheater enables online operation for ash cleaning,avoiding the need for regular shutdown to clean the heat exchanger and achieving long-term operation of the device.Single effect evaporation is used to concentrate the dilute sulphuric acid produced in the purification section to over w(H2SO4)50%,and the concentrated dilute sulphuric acid is returned to the cracking furnace for regeneration.