How does the process work? 

The Bioflame process comes from an agricultural rather than an industrial pedigree.  The system is designed to be robust, simple and efficient.  Fuel is delivered to the Thermal Treatment Unit (TTU) in a number of different ways but for wood waste, we use a 50m3 hydraulic 'walking floor' that delivers chip into a screw conveyor. This conveys into the TTU through a rotary valve.

Fuel is introduced onto the top of an actuated stepped grate within the primary combustion chamber.  The fuel gasifies at the top of the grate and the gas created is then immediately burnt in a secondary combustion chamber.  The products of combustion the pass through a device to extend the flame path and ensure burn-out of any gas bourne particulates before then passing into a residence chamber.  Each model in our range is computer modeled by The University of Sheffield to ensure that the residence chamber complies with WID (Waste Incineration Directive) and retains the combustion for at least two seconds, this ensures complete oxidation of the off-gases.  At the exit of the residence chamber the temperature will be in excess of 850 degrees centigrade - another stipulation of WID.

Here the interface between the raw thermal energy and method of energy recovery and heat exchange takes place.  That may be in the form of a hot water boiler, steam generation or indeed an absorption chiller.

For an electrical power application we favour a steam boiler with traditional steam turbine.  In this instance the boiler produces around 6 to 16 tonnes of steam and the turbine and generator set will produce anywhere between 1 Megawatt and 3 Megawatts of electrical power depending on the exact specification of the site.  Electrical energy is then exported to the grid through standard switch gear.

After the raw thermal energy has been 'used' the resultant cooler off-gases then pass through a cyclone to remove any residual fine particulates before entering a reverse pulse bag filter with organic filter medium.  From the filter, the clean off gases escape to atmosphere up a standard stack.  In most cases the Environment Agency will insist that constant electronic monitoring of the off-gases takes place. Sophisticated equipment typically measures Carbon Monoxide (CO), Oxygen (O²) Volatile Organic Compounds (VOCs) Nitrogen Oxides (NOx) and Sulphur Oxides (SOx).  The emissions levels are monitored on a half-hour moving average basis.  If the sensors detect levels outside the permitted amounts the electronics will shut-down the entire system so that there is no danger from emission and so that the problem can be rectified.  Bioflame is so confident about it's equipment that in the near future, real time emission levels will be published directly to this web site.