After the kind of long and arduous tender exercise which befits Australasia’s largest timber processing company, Living Energy were successful in securing the contract to install a 22.5MW energy centre for Carter Holt Harvey at their Fortress Sawmill project in Whangerei, New Zealand.  Utilising the proven technology of the Bio T- burner and Visdamax’s first-rate engineering skills, the energy centre provides water at 188 deg C 24/7 for the new high temperature kilns at the sawmill site.

Fuelled by waste sawdust from the sawmill, the three 7.5MW Bio T-burners have made it possible for Carter Holt Harvey to cost effectively dry the sawn lumber produced by the Whangerei mill for the first time.  Prior to the installation, the lumber was trucked down to kilns in the Central North Island for kiln-drying prior to delivery to domestic and overseas markets.  The savings in direct costs, road miles and carbon dioxide emissions are huge when you consider the distances and quantities involved – a 400km one-way trip for the lumber and over 100,000 cubic metres processed each year.

     

The Visdamax pile-bed Bio T-burners deliver flexible performance with low running costs and very low emissions to atmosphere.  A key factor for CHH in selecting this equipment was the flexibility offered by the modular format of three burners.  It allows output of less than 5MW when heat demand is low or markets are depressed, whilst combustion remains smokeless at low output even on the green sawdust.  The modular approach also allows more burners may be added in the future when the mill ramps up to full production.

Inside the Bio T-Burner the fuel pile itself is a drying zone, removing the need for external drying loops or other complex methods of pre-drying the wood fuel.  The wood is fed through the bottom of the burner and by the time it reaches the top of the pile it is pre-dried and ready to combust.  This means that wet fuels, including Radiata sawdust (up to 56% MC on a wet basis) can be used without the costs and hassles of pre-drying at the same time as achieving class-leading emissions levels.

The Bio T-burner has been designed to need only one combustion air fan.  Other burners have two or more fans which translate to higher maintenance costs and substantially more electricity consumption.  The Bio T-burner uses just 20-30% of the electricity of most other comparable woodfuel burners, delivering savings of hundreds of thousands of dollars each year at this site.