FPE Global delivers ship discharge systems
Posted on December 2011
For the past decade, FPE Global has supplied numerous processing systems into West Africa, particularly Nigeria, where we have a permanently manned office staffed by our own engineers. So when the opportunity arose to quote for an entire ship discharge and conveying system for Flour Mills of Nigeria Plc at their facility at Apapa Wharf, Port of Lagos, we were ideally placed to service and eventually win the contract.
The contract covers two distinct phases: The design and manufacture of the four self-contained ship discharge units and the design and manufacture of the conveying system which takes sugar from the ship discharge units to a storage warehouse and associated sugar melt station.
The design for the ship discharge units came about after visits to the recently refurbished, deep water dock at Apapa which is wholly owned by Flour Mills of Nigeria Plc. Our design engineers are more used to dealing with large shore based factory process systems which are very securely bolted to high quality, dead flat concrete floors. A dock is a different matter altogether; the chances of docking dry-cargo ships weighing many thousands of tonnes consistently in the same place is zero. The obvious solution therefore, was a system of four mobile units, mounted on rails which could be pushed into place by any suitable vehicle and then locked into place once the ship had docked.
The really impressive part of the design of the discharge units is the mounting for the screw conveyors. The screw conveyors are platform mounted, fully retractable and can be moved through a twenty degree arc. The balance is such that it takes just one man to push – or pull – the screw conveyor into the correct position; there is no need for powered adjustment of any kind. Also, because the screw conveyors are designed with just two end bearings, maintenance is kept to a minimum.
Once the contract had been awarded, work started on building the units in our factory in the UK for shipping out to Lagos.
Large dry-cargo ships have derrick mounted cranes fitted with grabs. So at Apapa Wharf, the ship-mounted crane fitted with a grab deposits up to 3 tonnes of product at a time into a 25 tonne stainless steel hopper which forms part of each discharge system. From the hopper, the product is conveyed by the screw conveyor which is rated at 150 tph. Each assembly, which measures 10 metres in height and weighs in at around 35 tonnes, was erected on site by local skilled labour supervised by our project engineers.
The second part of the contract, which had to be delivered and assembled at the same time as the ship discharge system, covers the way that sugar is conveyed to a new dockside warehouse and the sugar melt station.
The platform mounted screw conveyors sited on each ship discharge unit, feeds directly into the boot of one of four 150tph rated bucket elevators sited at regular intervals along an already existing 200 metre long gantry. These bucket elevators feed a 200 metre belt conveyor, rated at 600 tph, which we have installed along the top of the gantry.
At the discharge end of the belt conveyor, a vibratory screen removes any non-sugar product that could have been collected from the ship. From here, the sugar is then conveyed via a belt conveyor and bucket elevator up into the roof of the new warehouse facility by a further bucket elevator. A 200 metre long tripper belt conveyor then takes the sugar into the warehouse where it is deposited and stored prior to being conveyed directly to the melt station. A reverse jet dust collector removes dust from the vibratory screen and elevator boots.
FPE Global engineers devised an ingenious yet simple method of conveying the sugar from the warehouse to the melt station. Inside the warehouse, we have installed a row of 18 floor mounted hoppers each with a special, pneumatically activated clam-shell discharge valve. These valves allow a controlled feed to a below-floor belt conveyor. This belt conveyor directs the sugar to a further bucket elevator and inclined belt conveyor which feeds the sugar melt station. Wheeled loading shovels feed the floor mounted hoppers within the warehouse.
In addition to the hoppers, screw conveyors, bucket elevators and vibratory screen FPE Global also supplied the full SCADA control systems.
A number of safeguards have been built-in. Should the main sugar intake system to the melt station and warehouse fail, there is the facility for trucks to be filled directly from the ship discharge units where it can be then tipped directly on to the tail end the below floor belt conveyor.
An additional benefit is the ability to discharge the sugar from the ship and deliver it to the melt station at the same time as delivering it to the warehouse; thereby saving considerable energy.
In addition to the hoppers, screw conveyors, bucket elevators, belt conveyors and vibratory screen, FPE Global also supplied all the necessary steel framework, control systems and the electrical installation.
FPE Global is renowned for its static, factory based processing systems. Adapting these systems for dock use was the responsibility of the Project Manager, Derek Wood who said:
“As with all our systems, care has been taken to ensure ease of maintenance and cleaning – especially important where different products are to be discharged.”
FPE Global is the umbrella company for FPE Process Equipment who manufacture a huge range of mechanical conveying systems including screw conveyors, bucket elevators, belt conveyors, bin activators and dosing units. FPE Neu Solutions manufactures pneumatic conveying systems and Flomat Bagfilla International has a world-wide reputation for FIBC filling and discharging systems. FPE Site Operations is a specialist in structural steelwork and system installation.