Sulphuric Acid Plant

Molten sulphur is burned to sulphur dioxide, converted to sulphur trioxide over a catalyst, and absorbed to make acid. The sulphur furnace delivers gas at high temperature; the waste heat boiler cools it to the converter inlet and raises high-pressure steam. Between catalyst beds, gas-gas heat exchangers move heat from converted gas to incoming gas so that each bed runs at its design temperature; economisers and superheaters take the remaining heat. Acid can also be made from metallurgical off-gas or by regenerating spent acid, with the same heat recovery logic.