Waste to Energy – making the most of landfill gas

Published by Graham Wilkins on

Many New Zealand and Australian landfill operators collect landfill gas (LFG, or biogas) but much of it is flared.  While this helps landfills meet their carbon destruction or abatement targets, the opportunity to utilise the LFG in a waste to energy project should not be overlooked.

Options include power generation with gas engines or microturbines and both are widely used to generate electricity either to support local electricity needs or to feed into the local grid.  Microturbines offer minimal moving parts, low maintenance, low noise and vibration and where there’s a nearby application for the heat generated by the microturbine, this meaningfully supports microturbine project economics.  However both microturbines and gas engines require LFG to be cleaned up before use.  Gas engine manufacturers typically require the high H2S content in LFG to be removed or reduced and siloxanes in newer landfills damage gas engine components and lead to excessive maintenance costs.  Microturbines often require complete removal of siloxanes prior to combustion to avoid early failure of expensive turbine components.

Pressure Worx have developed a variety of gas conditioning and biogas clean up solutions. We find no two sites are the same and biogas constituents will vary depending on many factors including the type and mix of organic waste. We can help you with designing and supplying a gas conditioning or clean up solution to match your raw biogas and meet the specifications for your end use requirements.

Another option for LFG is to use it in gas fired boilers.  While this comes with some challenges, the gas cleanup requirement prior to combustion is reduced.  Landfill gas emerges with variable pressures, volumes and methane content during a day and over time and boilers on LFG need to include gas trains designed and sized to accommodate this variability.  Combustion controls can provide for in operation adjustments for fluctuations in the LFG composition.  A well-designed LFG fired gas boiler installation provides stable heat for many applications, especially when combined with a LNG fuel train.  In some critical applications, dual gas trains with LFG and LNG options can allow uninterrupted operation.  Pressure Worx can offer custom designed dual gas trains for your requirements.

Contact us at sales@pressureworx.co.nz if you want to talk about your waste to energy project to better utilise biogas on your landfill.