SULPHURIC ACID / OLEUM UPSTREAM OF INTERMEDIATE ABSORBTION TOWER OR FINAL ABSORBTION TOWER OR SINGLE ABSORBTION TOWER

PROCESS INFORMATION
In a sulphur burning or metallurgical double absorbtion H2SO4 plant where no Oleum is produced upstream, SO3 gas exits the third catalyst pass, is cooled down and enters the first ( = intermediate ) absorbtion tower, where H2SO4 is distributed over ceramic packing to absorb the SO3 . When the gas exits the I.A.T. it returns to the converter to go into the fourth catalyst pass after being reheated in a gas/gas heat exchanger.Due to the high inlet gas temperature and the relatively low inlet acid temperature, mist is formed thermodynamically and acid droplets are mechanically entrained from the acid distribution system or packing, combining typically as a load of 2,000 – 4,000mg/m3. The particle size spectrum will be sub-micron to small sized ( 0.3 to 3 micron ), average & majority 1 micron.

PROBLEMS TO SOLVE
Protect expensive and critical heat exchanger downstream from corrosion, so ideally exit mist load should not exceed 20mg/m3.

DESIGN SOLUTION

• High Efficiency, Brownian Diffusion ‘Becofil’ Candle Filters, hanging type HT or standing type F, with Glass Fibre elements and 316L Stainless Steel structure.