Energy from Waste (EFW)
What we do ...
Our Energy from waste (EFW) plants’ use mainly municipal solid waste (MSW) as a fuel to keep the furnaces under fire in order to incinerate the waste. This then heats up water in the boilers that produce high pressurised steam, that is used to turn blades in a turbine that feeds that energy into a generator to convert that energy into electrical power.
The excess electricity produced is distributed to the national grid to power businesses and homes.
Our EFW plants consist of 2 parallel incineration streams, each comprising a furnace, boiler and flue gas treatment. The common systems to both incineration streams consist of cranes, water treatment plants, steam turbine generator, air cooled condenser, ash and lime systems.
Waste is fed by overhead cranes into 2 feed chutes, one for each incinerator stream. A ram-feeder pushes the waste into the furnace, where it is burnt as it travels down the inclined moving grate system. The residue ash on the grate system is discharged into a water quench system, where it is cooled. This bottom ash is transported on a conveyor system through a ferrous belt magnet to extract ferrous metal for recycling. The remaining bottom ash is transported to a bottom ash recycling facility.
Air for combustion of the waste is taken from waste bunker area which provides combustion for the waste but also at the same time provides negative pressure that helps reduce waste odours from building up around the waste reception area and bunkers.
In terms of emissions control then NOx emissions are controlled using a process called selective non-catalytic reduction (SNCR) using dry urea powder. The hot gasses then pass through our flue gas treatment system where the hot gasses are treated through various abatement systems and a bag filter system. The gases finally pass through the chimney stack which is monitored by a calibrated automated measuring system (AMS) that ensure our emissions are legally compliant.