Obtaining bioenergy and nutrients from poultry slurry
Poultry slurry is a problem on farms as it accumulates, affecting the quality of life of poultry and involving significant costs in management and disposal.
Fluidised bed combustion produces heat energy, ash (which can be used as PK fertiliser) and electricity (when combined cycle technology is incorporated). The boiler is capable of generating a thermal output of 500 kWh, sufficient to provide hot water at 850°C required for distribution to the hatcheries.
After the birds have been removed, the slurry is collected and taken to a bio-secure fuel storage area, kept at low negative pressure. An innovative bulk handling system called the BHSL Toploader is then used to transfer the slurry from the storage area to the combustion plant at a rate of 5 tonnes/day. This low energy system is automated, minimising interaction with the slurry and farm personnel. Fluidised bed combustion uses a heated sand bed suspended (fluidised) within a rising air column to burn slurry (and potentially many different types of biomass) at 850°C for 2 seconds, even with varying moisture content. The surplus heat is available to produce renewable energy for on-farm use or export to the grid. The biggest savings come from the consumption of propane for heating the hatchery. By removing the slurry and providing the optimum temperature, the next batch of birds thrive in the warm, dry, optimally ventilated, low ammonia conditions, gaining weight for every kg of grain fed to them. Thus, the slurry produced is drier and less smelly.
Market deployment considerations