Desulphurising hot combustion gas streams - by treatment in spray drier with aq. sodium hydroxide to produce dry sodium sulphite particles and oxidising in aq. soln. to sulphate

摘要

In desulphurisation of a hot combustion gas stream, the hot gas stream is contacted in a spray drier type unit with aq. NaOH soln. at at least 200 deg.C so that the SO2 in the gas is converted into spray dried sodium sulphite particles. The residual gas stream passes into the outlet chimney at at least 100 deg.C. The Na sulphite particles are sepd. by physical means, converted into sodium sulphate, and discharged into environmental water, esp. the sea. C.F. prior art processes using calcium hydroxide to scrub the gas stream, the process gives sodium sulphate in the effluent stream, which can be discharged directly into environmental waters.