Photo courtesy of Cargotec.
Growing grain exports and increasing vessel size are placing big demands on dry bulk handling systems. This is not only because they need to meet the ensuing increase in cargo quantities, they also need to load and discharge vessels as quickly as possible to minimize port costs.
A key consideration for handling grain is cargo degradation. Any successful dry bulk handling system must offer extremely low degradation and crushing rates, minimizing the production of fines, which are defined as material smaller than the grain particles themselves.
Fines are problematic for many types of cargo, but in grain handling they can make the grain more difficult to aerate, increase spoilage rates and increase dust emissions. Under some circumstances high levels of fines may result in a dusty atmosphere with a raised risk of fire and explosions.
Fines have to be removed before milling, therefore their presence has a significant knock-on effect on grain processing as a whole. A high level of fines in a grain shipment may mean that the quality of the shipment is downgraded. Grain terminal operators must therefore think carefully when considering the handling systems they should employ.
Making an informed choice
To determine the optimum grain handling arrangements for its specific needs, a terminal operator must seek out as much relevant, reliable information as possible to make a properly informed decision.
So, as someone with responsibility for a terminal’s commercial performance, where should one look for this information? Comparison of manufacturers’ published specifications and performance claims is a reasonable starting point. But, just as no one should choose a new car solely on the basis of an advertising brochure, the same goes for a major industrial plant. It is vital to dig down to get the real story. Industry references and recommendations offer the next step in building a picture of the pros and cons associated with different technologies and manufacturers.
Talk to as many other operators as you can. When it comes to assessing important factors such as reliability, customer support and aftersales services, there is no need to limit your contacts to those handling the same material. The bigger your sample, the better the outcome. Visit terminals that use the technologies that interest you. Talk to your counterparts face to face.
However, you also need solid information about a system’s performance when handling your particular bulk commodity, especially if levels of cargo degradation are critical to your trade. This is where genuinely independent tests carried out under strictly controlled conditions are vital.
All grain handling systems should be independently tested by third-party specialists to ensure unbiased reports. Claims about extremely low degradation rates are no exception to this standard, particularly as fines production has such a critical impact on the quality of the grain shipment.
Handling grain — along with many other dry bulk cargoes — raises environmental concerns, including atmospheric pollution, cargo spillage, high energy consumption and unacceptably high levels of noise.
Terminals ideally need a grain handling system that can achieve the specified handling capacity, while incurring minimal environmental impact. These requirements are not mutually exclusive. A totally enclosed system may deliver high capacity and excellent environmental performance.
In fact, fully-enclosed conveying lines are needed to achieve compliance with even the least onerous environmental impact criteria.
The efficiency of unloading systems is also a key environmental consideration. This applies not only to the power demands of individual pieces of machinery, but also to the combination of equipment that transfers grain from the ship’s hold into storage and even onward to final distribution. Designing a complete terminal, where every efficiency avenue is explored, can offer an extremely cost-competitive solution, where the individual components work together to deliver optimum overall performance.
A further consideration is noise pollution. This is particularly important today as many commercial operations are located close to heavily populated waterfronts.
Every port has its own dry-bulk handling demands, in some cases handling a single commodity, in others a mix of commodities that may well have differing handling requirements, so there is no single solution that fits all. Some manage very well with a single technology, others require a combination of technologies that might, for example, include elements such as complex conveyor systems in combination with pneumatic and screw-type unloaders and conveyors.
Siwertell believes totally-enclosed screw-type technology is firmly established as the “go to” technology for efficiency and environmental protection.
Meeting changing market needs
The needs of ports change over time. Commodity mixes may vary, along with capacity demands and, of course, rising environmental standards pose a significant challenge to some operators.
In Australia, the privately-owned Newcastle Agri Terminal (NAT) in New South Wales needed to address unacceptably high levels of dust emissions and noise generation, and needed to increase ship unloading times. As a result, it commissioned a new operating system. The terminal features a Siwertell SBL 1600 TT rail-mounted loader with a rated capacity of 2,000 tph for ships up to 60,000 dwt.
In the U.K., Peel Ports Group’s Seaforth grain terminal in Liverpool also needed to improve efficiency rates and power consumption demands and looked to state-of-the-art technology to meet these needs.
In the Port of Klaipéda in Lithuania, stevedoring company Bega showcases a complex agri-bulk handling terminal solution. Prior to the new terminal, Bega had no dedicated storage areas, making it impossible to store agricultural products arriving at the port. It now has two linked warehouses with a combined storage capacity of 160,000 cubic meters.
Since commissioning in 2012, the terminal handles more than 5 million tonnes of cargo each year. Ships of up to 70,000 dwt may be loaded at a rate of 1,200 tph by the rail-mounted ship loader, served by a system of totally-enclosed conveyors. A traveling belt conveyor transfers material from the pier conveyors to the loader, allowing loading at any position along the length of the vessel.