Methane in biogas

Porpatham, E., Ramesh, A., Nagahngam, B. 2008. Investigation on the effect of concentration of methane in biogas when used as a fuel for a spark ignition engine. Fuel 87(8-9) 1651-1659. 

Anaerobic decolorization of azo dyes was started back in the 1970s. Reticulated sintered glass was used as immobilization of anaerobic bacteria for the decolorization of wastewater and transformation of the azo dye to degradable products [58], Full decolorization was achieved in less than 4 h HRT, and in addition to it, methane as biogas was also produced. 

The percentage of methane in the biogas was 60.1% for a retention time of 30 days and 56.8% for a similar retention time in the mixed waste study. 

Nevertheless, the added metal ions under these conditions sho ved a positive influence on methane formation, increasing the rate of formation and the amount of methane. Figure 8.4 sho vs the composition of biogas produced after the addition of (a) iron, (b) nickel and (c) cobalt in all cases, an increase in the percentage of methane in the gas phase vas observed. 

FIGURE 7.2 Stages in biogas and methane production from Jerusalem artichoke. 

Non-woody biomass may be converted into methane contained in biogas (cf. Sorensen, 2004a), followed by the methane-to-methanol conversion process mentioned above, e.g. using steam reformation. 

Hence, conversion of acetic acid should produce an effluent gas with a composition of 50% CH4 and 50% COj. However, in all experiments they observed more than 60% methane in the effluent biogas. Consequently, some reduction of COj to methane must also occur. 

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