Waste to Energy (WTE), is a term that is used to describe various technologies that convert non-recyclable waste into usable forms of energy including heat, fuels and electricity. WTE can occur through a number of processes such as incineration, gasification, anaerobic digestion, and landfill gas recovery.
Biogas production from anaerobic digestion: Anaerobic digestion is a biological conversion process which is carried out in the absence of an electron acceptor such as oxygen. The main products of this process are an effluent (or digest) residue and an energy-rich biogas. The entire conversion chain can be broken down into several stages to drive the required chemical reactions. The obtained biogas can be used either to generate power and heat or to produce biofuels. The digest can also be utilized in many different ways depending on its composition. Several technologies utilizing this process have been developed throughout the years but are still considered to be immature and not economically competitive compared to other WTE technologies.
Biogas production from landfills: Other than in an anaerobic digester, it is possible to extract biogas directly from landfill sites, because of the natural decomposition of waste. In order to do so, it is necessary to construct appropriate collecting systems for the produced biogas. Biogas in landfills is generally produced by means of complex bio-chemical conversion processes, usually including different phases like Initial Adjustment, Transition Phase, Acid Phase, Methane Fermentation and Maturation Phase.
Biogas generated have maximum proportion of Methane content which varies from 40 to 75% and other gases like Hydrogen Sulphide, Carbon Dioxide etc. The most common use of biogas fuels inTurbineis in Combined Heat and Power (CHP) unit to produce electricity and heat. The uniqueness of Capstone Microturbine is that biogas can be combusted directly to produce heat& power. In Microturbine, there is no need to scrub the hydrogen sulphide(handling capacity up to 7%) in the biogas.