ALSCO Nelson Boiler Upgrade Significantly Cuts Discharge

ALSCO, supplier of rental linens, mats, uniforms and hygiene products, has completed the boiler upgrade at its Nelson Laundry, which will significantly reduce discharge from the plant.

According to ALSCO NZ chief executive Tony Colenso: `The reduction in emissions significantly exceeds the policy guidance for existing industrial discharges in the Nelson Air Quality Plan.  We are very pleased that the boiler conversion makes a positive contribution to the ongoing improvement of air quality in the city. 

`Our Nelson Laundry has operated a 1.95 megawatt coal-fired boiler for many years.  The boiler did not require a discharge permit prior to the development of the Nelson Air Quality Plan.  Once the Air Quality Plan became operative ALSCO lodged a consent application and we have worked very hard to upgrade the plant as quickly as possible. The consent application included a comprehensive assessment of the effects of the discharges from combustion of both the existing coal and the proposed wood pellet fuels.’

The conversion from coal to wood pellets will result in a significant improvement in local air quality. The assessment found that the change in fuel would result in a 54% reduction in maximum inhalable particulate matter (PM₁₀) concentrations at ground level in the valley, a 93% reduction in peak sulphur dioxide (SO₂) concentrations and an 80% reduction in nitrogen dioxide (NO₂) concentrations. The assessment concluded that any adverse effects of the boiler discharge would be minor and that no persons would be adversely affected. 

Tony Colenso explains: `The process of converting the boiler from coal to wood pellet fuel is now almost complete.  New fuel feed augurs have been installed and new heat sensors and safety equipment fitted.  ALSCO began operating the boiler on wood pellets at the beginning of May.’

A bunker is being installed to allow the long-term storage of dry pellet fuel.  In the meantime, pellets will be stored under waterproof covers. The change to the fuel feed system serving the boiler will enable improved control of the combustion process, with more consistent and efficient operation.  As a result, it is expected that operation on wood pellets will significantly reduce intermittent visible smoke emissions that have occurred at times when burning coal.  The boiler will be capable of operating on low steady load at times of low heat demand in the laundry, reducing the frequency cycling on and off that occurred when burning coal.

Overall the conversion of the laundry boiler from coal to wood pellets will significantly improve air quality and reduce the visual impact of smoke emissions.  Wood pellet fuel has the additional benefits that it is carbon neutral and can be obtained from a local supplier.