Filter › Tail Gas Scrubber

SULPHURIC ACID PLANT SO₂ TAIL GAS / NH₃ / SO₂ TAIL GAS SCRUBBER TOWER

Tail Gas Scrubber PROCESS INFORMATION

The SO₂ conversion rate of single absorption plants is lower than double absorption, and many single absorption plants installed tail gas scrubbers to reduce this SO₂ content rather than convert the plant to double absorption. Scrubbing the tail gas (tail gas scrubbing) to acceptable SO₂ emission values can be done with seawater, caustic, lime slurry, hydrogen peroxide or ammonia. After exiting the absorber tower, the gas enters a tail gas scrubber tower where ammonia (NH₃) is injected and contacts the SO₂. Ammonium Sulphite and Bi-sulphite are formed and some of these salts are entrained in the exit air.

These salts are soluble, but can be emitted in quite large volumes, e.g. 2,000 – 15,000 mg/m³ and are generally < 3 microns in size, with a large amount < 1 mircron.

PROBLEMS TO SOLVE

Air pollution

Prevent blockage of fibre bed by salts solidification.

Occasional risk of weak acid mist emission

DESIGN SOLUTION

• High Efficiency, Brownian Diffusion ‘Becofil’ Candle Filters, hanging type HT or standing type F, with TGW15 or B14W Glass Fibre elements and Polypropylene or GRP/FRP structure. Option of concentric bed Xtra-Flow F design.
  Notes : Pre-wet the inlet gas to solubilise the ammonia salts. Use an irrigation spray system to wash fibre when pressure loss increase indicates blockage is happening.