Landfill gas is a natural byproduct of the decomposition of organic materials which are put into landfill. The gas is composed of roughly 50% methane (CH4) and 50% carbon dioxide (CO2) and a small amount of non-methane organic compounds. Methane is a potent greenhouse gas and is harmful to the environment.
When organic waste is first deposited into landfill, it goes through the initial stages of decomposition where small amounts of methane are generated. As the conditions change during the subsequent stages of decomposition, an increase in methane is generated. After a period of time, the generation of methane slows down. These fluctuations in the organic waste and the amount of methane generated means the ventilation equipment needs to adapt to continue the extraction of methane effectively.
Various fume extraction processes are available with certain systems being designed to capture methane for use in generating power. Other equipment may be designed to burn the methane to stop it from entering into the atmosphere. This depends on the rate methane is generated from the decomposition of the organic waste.
Axair Fans supplies polypropylene fans for fume extraction systems in landfill applications. One such customer in the landfill gas renewable energy industry is Landfill Systems Limited. Based in Suffolk, the company manufactures bespoke landfill and biogas gas flares, installing plant worldwide. Andrew Ward, product sales engineer at Axair Fans, specified the ‘S’ range of fans designed to provide high air flow rate against medium system pressures. Due to the potentially flammable nature of landfill gases, the ATEX (Atmospheres Explosibles) certified version of the ‘S’ range was required. The fans are constructed from a polypropylene type material that is certified for ATEX Zone 2 applications with the fan pedestals manufactured in steel. Likewise, the fan motors are also made to an ATEX specification to conform to the European equipment directive.
To achieve better energy efficiencies, an inverter was used to control the fans. This facilitates speed control, meaning the fan will only do its required duty. As the fan only uses the minimum energy required, savings were made on running costs. The fan motors were also fitted with thermistors which are wired into the inverter to shut the system down if the motor starts to overheat. This failsafe is a regulation requirement.
In addition to the ‘S’ range, Axair Fans also offer ‘ST’ fans available in ATEX versions suitable for Zone 2 applications. These ranges of fans are both suitable for extracting corrosive air from a wide range of applications other than landfill gases, such as biomass systems and odour control systems. Download the industrial fume extraction brochure.
For more information or to ask one of Axair’s specially trained ATEX fume extraction product sales engineers to specify fans for your application, contact us or call 01782 349 430.
Please note prior to fan selection, if you are not sure whether you need an explosion proof ATEX fume extraction fan or need to know the zone in which your application is classified, please consult an official authority.