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As well as converting the wood resource from sustainable
yield forests to an upgraded product, the process of LVL production
is also environmentally friendly.
LVL production creates few emissions and complies with NPIL's existing
air discharge consent. The 20 megawatt energy plant burns wood waste
as fuel and was approved by the Tasman District Council.
The veneer drier emissions are contained and fed into the furnace,
providing the air needed for combustion removes any volatile organic
compounds generated in the veneer drier.
Water use
The hot water baths where the logs are soaked have increased NPIL
water use by only about 10%, with little increase in effluent load,
as the logs soak up water. The log conditioning baths need to be
cleaned out about twice a year, but the effluent can be processed
through existing on-site treatment systems.
The Furnace
The furnace grate is water cooled, with the water circulating back
into the steam circuit. This technology is familiar in coal burning,
but relatively new in burning waste wood and bark. It is CO2 neutral
- meaning it does not produce 'greenhouse gas'.
Lamination
At the LVL plant the press used to laminate the veneers is operated
at a significantly lower temperature than the MDF presses. Glue
is spread over the veneer and heated by microwave in a 1.2m wide
microwave oven, with LVL moving through it continuously. The lower
press temperature significantly reduces emissions from this operation.
Resin & Recycling
The Dynea plant is conveniently sited next door to NPIL. A pipeline
from Dynea carries phenolic resin glue to the LVL plant. This low
emission resin is spread onto sheets of veneer from a 'curtain coater'
- like a waterfall of resin. An even coat is essential, so this
machine is shut down and cleaned from time to time. The washdown
water is pumped back to Dynea and recycled as 'make up water' in
resin making. The recipe for the LVL resin is extended with imported
flour made from almond or walnut shells, and there is work going
on right now on using sander dust as a resin extender.
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Click here for more information
on:
Water
use
The furnace
Lamination
Resin and recycling
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