Landfill waste for methane gas
LANDFILL waste produces significant amounts of methane gas, which promotes the idea of collecting the potentially harmful emissions and converting it to electricity. Landfill gas energy generation is environmentally friendly and a way to reduce reliance on fossil fuels. It has certain distinct advantages over wind and solar energy, such as not depending on windy and sunny days.
Landfill gas, caused by the degradation of solid waste by anaerobic microorganisms, can be collected via different methods, a popular one of which is a series of wells drilled into a landfill and connected by a plastic piping system to an extraction site. The gas in the system is processed and then used directly in reciprocating engines or further refined into a higher BTU (British Thermal Unit) gas for such uses as powering boilers for manufacturing processes or electricity generation via gas turbines.
This multistep process includes compression, chilling, absorption, and membranes to remove impurities, such as sulfur, carbon dioxide, nitrogen and alcohols, from the gas stream. The purified stream is then fed into a natural gas liquefier, where it is cooled to below the natural gas boiling point of -260 degrees to produce liquefied natural gas (LNG). Once liquefaction takes place in an aluminum heat exchanger, refrigerants flow through one side while natural gas flows through the other side, cooling the natural gas into a liquid state so the LNG can be stored in a tank and delivered to filling stations – after all the impurities, such as sulfur dioxide, are scrubbed out, you have pipeline-quality gas, which is high-enough quality to be blended with existing natural gas systems.