Pickering

In January 2008 Bioflame finished commissioning their 0.5MW electrical output demonstration plant

The Problems

Although Bioflame has been marketing it's heat only products since 2001, it was clear that without a fully working demonstration site, it was going to be difficult to convince prospective partners that we had a credible technology.

The Pickering site was 3.5 miles away from the nearest grid connection, in a National Park and surrounded by neighbours - at first glance it seemed an unlikely place to site a power station.

The Bioflame Solution

 

The low grade woodchip biomass plant proving that it blends in with the stunning surrounding countryside.  Our rationale for persevering with this site was simple.  if we could get permission to build it here........... then we could get permission to build one anywhere.  Despite initial fierce local opposition to the planning application, The North Yorkshire Moors National Park planning authority nailed their sustainable colours to the mast and voted 8:2 in favour.    With exceptional help from a number of Government agencies including Yorkshire Forward and their spin-out renewable energy facilitation company FEY, the plant was finished in January 2008 and has now (September 2008) been used to demonstrated to over 1000 people - from school children to Parish Councillors to prospective partners and funders.  Our policy is open book and we are happy to show the plant to anyone who wants to see exactly what we are doing.  Some of our strongest objectors have become great advocates for us - although there are still a few yet to visit!.

 

Victor Buchanan Managing Director (left) and Matthias Grundmann, Technical Director, stand in front of their patented Advanced Thermal Treatment Unit (ATTU), which generates renewable electricity exported to the National Grid by processing locally sourcedlow-grade waste wood that would otherwise go to landfill.

 

Due to limited capacity of landfill sites and government restrictions on what can be tipped, the cost per tonne of general waste is expected to exceed UK£70.00.
Bioflame Ltd has entered into an agreement with a local waste management company who shred the wood before transporting it a short distance to the biomass plant. 

 

The low-grade waste wood contains MDF, chipboard, plywood, painted wood, laminated wood etc as well as clean timber such as old pallets and off-cuts from timber manufacture.  Because the system burns under Waste Incineration Directive (WID) conditions, the presence of these contaminants does not affect the ultimate 'clean' emission from the system

 

The woodchip is fed into a 50m3 hydraulic walking floor container. A ‘magic eye’ within the walking floor controls the flow of fuel into the combustion system ensuring a constant and controlled temperature is maintained inside the combustion unit.

The wood passes through a grader to sift out  pieces larger than 100mms in length.  The woodchip is fed up a conveyor belt into a distribution hopper and then into two augers which screw the wood into the combustion unit.




The woodchip is introduced onto the top of an actuated stepped grate within the primary combustion chamber. The combustion unit is encased in 150mm ceramic insulation to retain the heat and maximise electricity production.

The fuel gasifies at the top of the grate and the gas created is drawn by negative pressure and immediately burnt in a secondary combustion chamber.

The Waste Incineration Directive (WID) stipulates that low grade wood should be processed at a minimum temperature of 850 ºc and for that temperature to be held for a minimum of 2 seconds.

The patented Bioflame ATTU has a combustion temperature in excess of 1100ºc and uses the residence chamber to allow for 3.9 seconds of residence time for the combustion process.

 


The heat generated from the combustion unit is fed into a boiler which in turn generates steam to power a steam turbine. At this particular site the boiler produces around 6.5 tonnes of steam and the turbine and generator set will produce around 0.6

Megawatt of electrical power.  The resultant cooler off-gases then pass through a cyclone which uses centrifugal force to remove any residual fine particulates before entering a filter.

 

Finally, a Continuous Emission Monitoring System (CEMS) takes 100,000 readings every 24hrs to measure emission from the stack.  The following gases; Carbon Monoxide (CO), Oxygen (O2), Total Organic Compounds (TOCs), Nitrogen Oxides (NOx),

HydroChlorine (HCL) and Sulphur Oxides (SOx) are recorded to prove that WID limits on pollutants are being observed.

The Environmental Agency monitors the overall environmental performance of the plant set against strict WID limits stated in the Environmental Permit granted to the plant.

If the CEMS detects levels outside the permitted amounts, the automated control system can shutdown the entire plant under controlled conditions so that there is no danger from carbon or noxious emissions entering the atmosphere.

The ash by-product amounts to 2/3% that of the woodchip which enters the combustion unit. This is used as a second grade aggregate base in construction materials.