Report

In

Energy Savings Potential at Ship Discharge

, the reports’ authors, Christoph Tilke and Stefan Rakitsch, presented their findings on data they had collected from 16 European grain handling companies operating various unloading equipment.

They found that the absorbtion of material, minimum material height in the hold, restrictions by statutory provisions and the efficiency of the unloader all play an important role in establishing whether an unloader is suitable for the job in hand.

Tilke and Rakitsch found that for Phase One operation – normal removal by the unloader in one position, with capacity near the maximum – the chain and screw type systems were optimum.

For Phase Two operations, where the unloader has to change position, where capacity decreases and/or where the use of a wheel loader/bulldozer is profitable, the chain and screw type systems again were favoured, when kick-in and kick-out and feeding are allowed.

When an unloader has to be fed by a wheel loader/bulldozer and capacity is influenced by the feeding and not the unloader (Phase Three) then the chain and screw types were found to be less suitable if the conveyor has a high capacity, due to low efficiency.

Pneumatic systems were found to be less suitable in Phases One and Two, due to less capacity, but optimal for final clean up in Phase Three unloading operations. Grab type systems worked in all phases but were deemed not the optimum solution. However, an optimum solution for Phase Three operations was deemed to be the use of one big wheel loader/bulldozer and in Phase Two, use of a feeding device for a mechanical unloader.

The conclusions were based on the speed of removal, energy consumption, personnel costs and profitability. According to the results of the survey, efficiency of ship discharge was influenced by: the driving route on the quay; the number of breaks employees had; the number of interruptions, due to breakdown of silo of quay conveyor; and the strategy employed when using the unloader in the hold.