Sulphuric acid mfr. using air to oxidise sulphur dioxide - at controlled temp. and pressure in the presence of nitric acid (NL231176)

摘要

Sulphuric acid is mfd. by oxidn. of SO2 with atmospheric oxygen in the presence of a catalyst, and sepn. of the end prod. The mfr. occurs at 2-80 atmos. and 40-200 degrees C. in an aq. medium contg. (by wt.) not >95% H2SO4 and not >15% catalyst consisting of NHO3 or its salts. The nitric acid salts are pref. cerous nitrate or AgNO3 and the oxidn. pref. occurs at 10-20 atmos. and 150-200 degrees C. in an aq. medium contg. 0.5-2 wt.% NHO3. The reaction temp. is pref. maintained by using circulating SO3 as a coolant to remove the heat of reaction. The raw material may be (a) 100% SO2; (b) a gas mixt. contg. 0.1-96% SO2; or (c) SO2 obtd. by the combustion of a sulphur-bearing material at 2-80 atmos. and 800-2000 degrees C. The process gives increased output from the reactor; a redn. in catalyst costs; and a redn. in environmental pollution.