05.01.2013 Views

Biofuels in Perspective

Biofuels in Perspective

Biofuels in Perspective

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

190 <strong>Biofuels</strong><br />

Biogas<br />

Desulfurization Desulfurization Gas upgrad<strong>in</strong>g<br />

Compress<strong>in</strong>g<br />

Gas upgrad<strong>in</strong>g Gas upgrad<strong>in</strong>g<br />

Boost<strong>in</strong>g<br />

Reform<strong>in</strong>g<br />

Boiler CHP Gas storage Odorization Fuel cell<br />

Heat Power<br />

Heat<br />

Figure 10.17 Alternatives for biogas utilization.<br />

Fuel<br />

Grid<br />

Power<br />

scrubb<strong>in</strong>g (Well<strong>in</strong>ger, 1998; Weiland, 2003). H2S can be removed <strong>in</strong>ternal to the digestion<br />

process by biological desulphurization performed by microorganisms of the family<br />

Thiobacillus or by iron chloride dos<strong>in</strong>g to the digester (Schneider, 2002). Us<strong>in</strong>g waterscrubb<strong>in</strong>g<br />

systems, H2S can be removed simultaneously with CO2, whereas for PSA<br />

systems adsorption columns with activated carbon are usually employed for H2S removal.<br />

If non-agricultural wastes are employed for biogas production, higher hydrocarbons, halogenated<br />

hydrocarbons and organic silicon compounds can also be present <strong>in</strong> biogas. They<br />

can be removed by adsorption with molecular sieves or absorption <strong>in</strong> a liquid medium.<br />

Raw<br />

biogas<br />

10 bar<br />

Absorption<br />

column<br />

Dryer<br />

2–4<br />

bar<br />

Wastewater<br />

Flash-tank<br />

Biomethane<br />

(upgraded biogas)<br />

Stripp<strong>in</strong>g column<br />

Figure 10.18 Pressure water scrubb<strong>in</strong>g with regeneration of applied water.<br />

Biofilter<br />

Air<br />

Water<br />

CO 2/Air<br />

Heat

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!