Blogical Desulphurization

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BIOLOGICAL SCRUBBER

Desulphurization is a difficuγ✘♥lt part for all biogas engineering proj☆✔↑ects. Normally, the chemical©∑ scrubber process consumes many NA"δ↕OH with expensive operation cos©βt.The dry type desulphurization requires frequen£‍§"t replacement of the filling mass wi§δ✔th a lot of manpower at παdangerous working condition EnvironTec ha€¥✘s completed many projects wit $h Biological Desulphurization (BDS). U ®‌sing microbial metabolic principle γ πwithout consuming any chemicals, BDS has pr←₹oved its low operating cost and th€•§÷e Best Practice Technology$∏£. A typical project >↕shows that the operating c✘↑"ost of biological scrubberis less than R✔₽¶MB 2 cent per m3 biogas.

PRINCIPLE

A certain amount of air£<↕™ is added into the bioga÷∞§☆s. Then the mixture of raw gas passes throu•€gh the EnvironTec BDS reactor for H2S ​₹¥"removal. Inside this★₹∞ reactor a big amount of filling mass mat&☆<≤erials (10,000 ~ 40,000≠♣ pieces) are installed inside to pro★♦• vide sufficient growth area for bacteri♣Ωa. Nutrient and water solution is recycled over t•​↔he package continuously. In most cases, the nu&'trient supply can be from natural source or man®$∑×-made fertilizer i.e. :

Digested waste water
Liquid phase of digested sludge or man₽↕ure
Landfill leachate
Artificial fertilizer NPKE

Special aerobic bacte£₹ria (i.e. Thiothrix or Th¥§♣≥iobacillus), starts growing in the nuλδtrient solution and also on‍© the surface of the ♦×£filling mass materials. The ba‌δ>cteria takes up the H2S ¶♥εfrom the gas and converts it into elemental ←≥sulfur and sulfuric acid according to the fol ∏σ§lowing chemical reaction:

H2S + 2O2 → H2SO4

2 H2S + O2→2 S + 2 H2O

S + H2O + 1.5 O2→H2SO4

The sulfuric acid is neutralized by the b♥§←uffering capacity of the nutrient solution. It is₹∏ then removed out of the system with liqΩ✔uid waste water automat&₽ically.