The Burning Issue of Renewable Energy

 

News – draperHEAT and BHSL reach agreement for supply, installation and maintenance of the FBC manure combustion systems throughout the UK. Jules Marris director of draperHEAT comments “drawing on our many years’ experience in the renewables sector and close working relationship with BHSL over the past 5 years, the Fluidised Bed Combustion (FBC) manure combustion systems offer unrivalled operational experience and give us the confidence to incorporate into our heating systems. Unlike the other mainstream biomass fuels, poultry manure poses many challenges to ensure smooth operation in the field. Successful combustion of 100% manure with moisture contents varying from 25-45% takes years to perfect, the devil is in the detail!”

Adrian Walker, Sales Director for BHSL in Western Europe, also commented, “Over the last 5 years our Fluidised Bed Combustion technology has been running on several farms in the UK and quietly proving itself, year after year, in terms of operational durability and delivery of ‘free heat’ regardless of the ever-changing cost of purchased heating fuel. Draper were alongside us for these installs in the beginning and are with us now as we roll out further installs across the country. We share common values championing technical innovations and ecological sustainability in the poultry sector.”

For those of you using or considering using Poultry Manure as a renewable energy source, be aware that because it is an animal by-product, the moving, storing and combustion aspects need to fully comply to EU regulation 592/2014.

 

Key points are:

  • Fuel to be 100 % manure, un-altered or processed in any way. Non pre-combustion drying is allowed under the regulations.
  • Stored in bio-secure store adjacent to the boiler plant with minimal human intervention to prevent possible contamination
  • Combustion gasses to be held at 850O C for 2 seconds to control pathogens
  • Strict emission limits to be met

Poultry manure varies in consistency, texture and moisture levels, so in order to comply with these strict emission levels and processing parameters, any equipment used must be fit for purpose, which is why draperHEAT  have confidence  the BHSL Fluidised Bed Combustion (FBC) system.

This system utilises 100 % poultry litter, which enters the furnace at a high level into a combustion chamber of suspended sand, fuel and air. The suspension of the fuel cocktail is provided by a low level fan system with no internal moving parts to jam, wear, clinker up etc, and it means it can burn more efficiently than step grate systems.

Cleaning and Maintenance Considerations

Due to the corrosive nature of the manure and the varying consistencies, the BHSL fluidised bed copes well with these anomalies, and has been specifically designed to allow removal and cleaning/replacement with minimal interruption.

Combustion Control, Continuity and Clinker

Keeping temperatures consistent is vital and totally achievable in the fluidised bed system. The unit is required to run at above 850O C at all times for 2 seconds residence while burning the manure. The regulator can arrive for an unannounced visit at any time, so make sure that your records can demonstrate this.

To ensure this continuity and consistency, your system needs to be able to cope with the wide range of moisture content in this material, which increases significantly if manure is stored for several weeks. Adding other fuels to help the combustion process is non-compliant, hence the BHSL system is designed to cope with this fluctuation seamlessly.

In addition, clinker formation occurs very readily at temperatures below 600O C and above 940O C. Hence the ability to tightly control the combustion between these ranges avoids major clinker formation and subsequent poor combustion performance, illegal emissions and lower kW output.

Emissions

Again, strictly monitored – plumes are never to be visible from a stack if the proper filtering system is in place, less than 10mg/Nm3.

NOx emissions are prevented in the fluidised bed system by strictly controlling a low and consistent combustion temperature around 650O C. Unlike a step grate system, this is easily achieved within the fluidised bed as the fuel is in suspension.

Ash Fouling

10% of the manure will fall out as a sticky fly ash through the system. Bag filtration is often used to remove the fine particulates from the flue gasses before exit, but they are very vulnerable to blockage and damage if the combustion parameters deviate from the perfect conditions. So again, the combustion process is crucial to ensure bag filtration systems perform efficiently and provide long life between services.

Installing an energy production system is a major investment decision for any farmer, and there is a great deal of confusion and misleading information out there, so please do consult with us here at draperHEAT to ensure you get the best impartial  advice.

 

Please follow link below for more information about fluidised combustion:

http://www.bhsl.com/fluidised-bed-combustion-new/