Automated Cranes for Oman Aluminium Rolling Mill
27 July 2012
SCX Special Projects have created a highly complex crane automation system for an Aluminium Rolling Mill in Oman, designed to process around half a million tonnes of rolled aluminium product a year.
Molten aluminium brought in from the adjacent smelting plant is processed into coils, which are then distributed around the plant by 12 Street Cranes ranging from 7.5 tonnes to 80 tonnes SWL.
The hoists, end carriages and control panels have already been shipped, the bridge steelwork has been sourced locally, and the final piece of the puzzle, SCX Special Projects' complex automation system, is about to be sent out to the Middle East for installation.
SCX Special Projects are automating two of the plant's 25 tonne cranes that will take hot coils into and out of storage, as well as between a variety of other process lines. Easily switched from manual to automatic, SCX's complex Crane Management System (CMS) will record information on type, date/time of any movement and what onward processes are required for each and every roll.
The CMS will then use this information to organise the coils' predetermined process paths into the most efficient network possible; getting the coils to their destinations in the shortest time, sharing the workload equally between the two cranes and of course, ensuring they do not obstruct each other.
As the hot coils enter the cooling area, the cranes' initial responsibility is to accurately position them onto 45 stands in front of the coil cooling air fans. A coil in the cooling area that has reached a temperature of less than 80°C is automatically moved to one of 120 stands in the storage area. This assessment is initially based on cooling time, but is verified by temperature sensors mounted on the grab. Optical and pressure sensors on the grabs also determine whether the coils have been accurately seated and it is safe to move them on.
The cranes' responsibilities do not end there: they must also move the coils between the cooling area and an annealing furnace, between the cooling area and the general store, between the general store and tension line, into a slitting line or onto transfer cars to be removed from the mill, or even back into the cold rolling area for adjustments. The CMS is able to use the details on each coil's process path and cross-reference this with all the other tasks the cranes must complete, in order to safely and accurately move all the coils through the plant using the most optimum route possible.
The cranes are linked back to the CMS via a Siemens SCALANCE wireless communication network which also provides an approved E-stop, ensuring complete shutdown of the crane system in the event of emergency stop activation. Because of the extreme operating environment which can be up to 60°C, air-con units keep the thermally insulated control cabinets at a suitable temperature.
Initially, the CMS will act as the overall brain of the storage operations, but has been specifically created so that it can integrate into a complete Plant Management System (PMS) when that is installed in the future.
The SCX Group provides a full spectrum of service and product based mechanical handling solutions from specialist lifting equipment and bespoke crane installations, through to crane servicing, planned preventative maintenance, repairs, refurbishment, breakdown and spare parts.