The Port of Tauranga had installed a large shed for the storage of coal prior to shipment. Both the load in and load out operations generate significant amounts of dust, which must be contained within the shed to prevent egress from the building. The internal shed environment must also be maintained at reasonable dust levels to allow out loading operations to proceed with a safe degree of visibility.
Luehr received an order to provide an exhaust system to achieve the above objectives. An exhaust rate of 36,000m3/h was selected based on the size of the shed and the fact that the shed was a sealed construction design and the access doors would be closed during the in and out loading operations.
For the design to work, air distribution within the shed was critical. To ensure good circulation a series of stirrer fans were positioned strategically at roof level to remove the problem of dead areas around the stockpiles. The air was moved to one end of the shed where exhaust ductwork were connected at the building apex. From there it was taken to ground level and into a Trema ZK 200 Cyclonic Scrubber complete with a recirculation tank, recirculation pump and integral pipe work.
The scrubber was also supplied with its own ID fan and drive positioned at ground level and discharging to atmosphere via an exhaust silencer and outlet weather protection cowl.
The system has now been running since 2004 and is achieving the design objectives.