Ship unloading trends
October 16, 2007
by Arvin Donley
With reports of increasing vessel congestion at many of the world’s largest ports, having efficient and reliable ship unloading systems has perhaps never been more important to companies operating port grain terminals.
Global grain trade was up 3% in the 2006-07 crop year, and during the next four years it is projected to grow 11%, fueled largely by the need for China and India to feed their growing populations.
With that in mind, the world’s leading manufacturers of ship unloading and conveying equipment face the challenge of making equipment that not only can move vast amounts of grain quickly, but is also durable, energy efficient and designed with environmental and safety concerns in mind.
Alain de Visscher of Nivelles, Belgium-based Vigan Engineering, SA, said today’s ship unloaders are being designed with the goal of increasing unloading capacity. Among other developments, Vigan, has redesigned its suction nozzle to improve its adjustment capabilities according to the specific characteristics of each product.
Jonas Fack, sales director for Gothenburg, Sweden-based MacGREGOR Bulk AB, said the trend toward bigger tonnage is causing port grain terminal operators to closely examine their hourly unloading capacity, since grain traders wish to have the lowest possible accumulated cost for the sea voyage and the port handling. "Any port installation that cannot provide an unloading rate that matches the ship size will risk losing business," he said.
The unloading rate is one of the factors port terminals must consider in their quest for cost-efficiency. They are interested in getting a fast return on investment, which means low operation costs, unloading efficiency across the vessel to ensure minimum demurrage charges and the safe handling of their product.
MECHANICAL VERSUS PNEUMATIC Ultimately, the decision must be made whether to use mechanical or pneumatic unloaders, as each have their advantages and disadvantages when it comes to cost.
Buhler AG, which sells both mechanical and pneumatic unloaders, said although the initial investment costs are lower for pneumatic unloaders, mechanical systems are more cost-efficient in the long run if the unloading capacity is rated above 400 tph. "The pneumatic system requires two to three times more power and has increased maintenance requirements," said Robert Haymoz, head of product design and development in Buhler’s grain handling division.
He added that the unloading efficiency of pneumatic systems is more dependent on the equipment operator’s skills.
But there are several distinct advantages to using pneumatic conveyors, said Tomas Kisslinger, president of Melle, Germany-based Neuero Corporation. He said the development of frequency inverter software control for the turbo blower rotation speed in pneumatic unloaders as well as using longer booms to reach hatch corners results in better overall unloading performance than mechanical unloaders with high-peak unloading capacities. Kisslinger said the physical characteristics of pneumatic unloaders allow them to do a better job of picking up material from the bottom of the ship that mechanical unloaders cannot reach. "If the system cannot work at the end and clean up efficiently, this will cost time and, as a consequence, money," he said.
Another aspect of cost-efficiency is equipment maintenance, with an emphasis on "preventive" maintenance. Computerized preventive maintenance schemes included with the control system have been developed to assist the operator in providing proper and costefficient maintenance in a timely manner. Systems have also been created that continuously monitor and log a number of operating parameters during operation. "Any trends that might indicate eventual upcoming malfunctions in any parts of the equipment can be observed, and rectifying measures can be taken at an early stage," Fack said.
Also, as a preventive measure, de Visscher said new materials are being used that increase the shelf life of parts subject to wear and tear such as the elbow between vertical and horizontal telescopic suction pipes.
Adhering to a growing list of environmental rules and regulations is also on the minds of port terminal operators.
Suppliers of grain handling equipment at port terminals say they are responding by designing more "environmentally friendly" equipment.
"Reducing dust emissions, lowering energy consumption and noise reduction are at present influencing the design and overall concepts or our units," said Haymoz, noting that Buhler’s ship unloaders can be equipped with newly designed dust suppressors.
Enclosed conveying systems with dust aspiration at transfer points to prevent dust escape are also being used by the industry, Fack said.
IMPACT OF OIL, BIOFUELS Fuel energy issues such as the high price of oil, the increase in the trade of biofuels and material made to produce biofuels, may have a profound impact on the industry.
The soaring cost of oil, which was hovering around a record-high $80 per barrel in mid-September, could have the biggest impact in developing countries, de Visscher said, by making it "even more difficult to allocate adequate financial resources in order to invest in modern port infrastructure." He added that oil prices are also making companies more sensitive to energy costs, which can have an impact on pneumatic equipment sales.
"Pneumatic equipment is indeed an excellent alternative in many projects, but due to its questionable reputation of energy consumption, it is even more challenging to convince the buyers about the pneumatic system advantages," he said.
Likewise, the biofuels boom is also having an indirect effect on the industry, because the demand for grain and oilseed products that can be used to produce ethanol and biodiesel is pushing up agricultural commodity prices, making it more difficult for countries with limited financial resources to import larger amounts of these agribulk products.