Demag crane system with a bale grab
Automated travelling crane for biomass logistics
Drax Power Ltd. is one of the largest operators of power stations in Great Britain. To boost its capacities to generate power from biomass, Drax invested in a prototype plant to process pellets at its location in Goole, East Riding. The pellets are then employed in a CO2-neutral co-firing operation at the company's nearby coal-fired power station.
Efficient supply process design
We support Drax in the handling and transport of bales of raw straw with Demag state-of-the-art crane systems – thus playing a major role in enhancing supply processes for an improved carbon footprint.
To meet the specific requirements of the application, we installed a double-girder overhead traveling crane equipped with a sophisticated grab in the new, 1,700 m² storage area to serve the production process efficiently and effectively.
Logistics for biomass
Helping to safeguard the future
The scheduled annual production of 100,000 tonnes of pellets at the Goole plant replaces around 60,000 tonnes of coal in the power generation process. In this way, annual CO2 emissions are reduced by some 120,000 tonnes. The storage building covers an area of 1,700 m² and offers a storage capacity of up to 936 bales, each measuring up to 2,500 x 1,300 x 1,200 mm (L x W x H), which can be stacked in a pyramid up to a height of 8 m.
Flexible grab unit with sophisticated sensor system
The 24-hour production process involves the receipt of up to 400 tonnes of raw straw delivered to the plant in Goole every day. To store the material, the double-girder overhead traveling crane is positioned above the delivery vehicle. Six grabs that can travel in the longitudinal direction and which can simultaneously pick up 12 bales serve as the load handling attachment. The advantage of this grab, which is divided up into two groups, is that it can be specifically adjusted to the relevant load to achieve optimum handling of the straw bales.
When the sensors have checked the moisture level and the load has been accepted, the crane switches into automatic mode and transports the bales to the allocated storage location, where they are deposited with a positioning accuracy of +/- 15 mm. Frequency-inverter controlled drives provide for smooth travel and variable speeds.
A travel mission is triggered as soon as the production installation sensors indicate that replenishment is necessary. In accordance with a defined routine, the crane automatically picks up the required number of bales and transfers them to a conveyor line, which transports them to the production plant.
Process crane: efficient solution
The crane installation has a load capacity of 22 t on the hoist ropes and travels with a span of 28.28 m on a crane runway at a height of 11.26 m. The variable-speed travel drives are fed by frequency inverters and are rated for cross-travel speeds of between 2 and 40 m/min and from 3 to 60 m/min for the long-travel motion.
Efficient lifting motions
The loads are lifted by a multi-purpose open winch unit (MPW). MPW units feature a high level of versatility. At the same time, these hoist units are engineered to meet the most demanding quality requirements of the specific application in terms of functionality and efficiency.
Load-dependent lifting speeds
With a maximum load of 12 bales of straw, the system lifts with a speed of 16 m/min. For loads that weigh less than 50 percent of the maximum load, the hoist operates in the partial load range at 24 m/min. Integrated electronic overload detection with an automatic cut-off system provides for increased operating reliability.