Energy saving

Biogas, biofuels from anaerobic digestion


Thebiogasit's abiofuelcomposed mainly of methane and carbon dioxide. Inbiogasit is easy to find traces of other gases such as hydrogen, oxygen, nitrogen, carbon monoxide, ammonia and hydrogen sulfate.

Biogas production
Thebiogasis produced by anaerobic digestion (in the absence of oxygen) with a biological process which, starting from organic substance, leads to the formation of different intermediate metabolites which are gradually transformed up to the production ofmethaneand carbon dioxide. In schematic terms we can thus summarize the biogas production:

Organic substance + Water + nutrients = bacterial flora + residual sludge +biogas(methane and other gaseous substances)

The entire process is operated by a very specific anaerobic bacterial flora and can be obtained almost from the totality of organic matter, thereforeOrganic waste, mowing, animal sewage, crop residues…. Based on the starting substance, specific enzymes capable of carrying out anaerobic digestion with different percentage composition of thebiogasobtained.

For thebiogas productionthe organic substance is collected in suitable silos (calleddigestersortubs), where, thanks to the metabolism of the bacterial flora, it is producedmethane. With suitable suction and monitoring systems, the quality and quantity of the products are kept under controlbiogasissued. Thebiogasproduct can be used directly in turbines for the production ofelectric energyor accumulated and destined for sale. The better the qualities of the starting materials used for thegasification, the better the characteristics of thebiogasobtained. The best sources ofbiogasare the lignocellulosic materials derived - ideally - from forest residues or pruning waste. In reality, the lignocellulosic materials used for the production ofbiogasderive, in large part, from dedicated crops.

Biogas, pollution and impact on the environment
Anaerobic digestion, operated from organic waste, can make a significant contribution to the disposal of domestic, industrial and agricultural waste, potentially harmful to the environment. The only non-gaseous element produced by the production process is theresidual sludge from decomposition activity, this substance can be used as a low carbon and nitrogen fertilizer in a rapidly absorbed form.

As for theissuerelated to combustion of biogas, we see that these are far less harmful to all other fossil and renewable fuels. Only thenatural methanehas atmospheric emissions capable of keeping up with those ofbiogas(which we remember is equallymethanebut produced with a renewable process and mixed with low percentages of other gases), but it must be said that methane derives from fossil carbon and, however abundant, is destined to run out.

In this article we talked aboutbiogasproduced from organic substrates, not to be confused withbiogas from municipal solid waste (RSU). ThebiogasRSU is produced by a different mechanismgasificationand the product obtained is a said synthesis gassyngas.

In the photo above, a BTS Biogas plant


Video: How sustainable is biogas? Anaerobic dry digestion of waste biomass the climate-friendly energy (October 2020).