🌱 Environment & EcologyUPSC 2019Sustainable Development

In the context of which one of the following are the terms ‘pyrolysis and plasma gasification’ mentioned?

aExtraction of rare earth elements
bNatural gas extraction technologies
cHydrogen fuel-based automobiles
dWaste-to-energy technologies
✓ Correct answer: d) Waste-to-energy technologies
ExplanationWaste-to-Energy (WTE) technologies consist of any waste treatment process that creates energy in the form of electricity or heat from several types of waste: from the semi-sol- id (e.g. thickened sludge from effluent treatment plants) to liq- uid (e.g. domestic sewage) waste.Landfill gas recovery, Gasifi- cation, Pyrolisis, Thermal Depolymerisation are examples of Waste-to-Energy (WTE) technologies.Option (d) is correct: Pyrolysis is a process of chemical de- composition of organic matter brought about by heat.In this process, the organic material is heated in the absence of air until the molecules thermally break down to become a gas compris- ing smaller molecules (known collectively as syngas).Gasifi- cation can also take place as a result of partial combustion of organic matter in the presence of a restricted quantity of oxygen or air.The gas, so produced, is known as producer gas.The gases produced by pyrolysis mainly comprise carbon monoxide (25%), hydrogen and hydrocarbons (15%), and carbon dioxide and nitrogen (60%).It is used commercially as a waste to energy system th

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