Streamline unloading at coal terminal
21 February 2011
ABB control products are being used to improve the operation of coal unloaders at a dockside terminal in Liverpool and give better overall control and scheduling.
The terminal is operated by E.ON UK and unloads imported coal intended to feed several UK power stations. Up to 65,000 tonnes of coal needs to be unloaded from each ship. To improve the efficiency and reliability of the terminal equipment and avoid the danger of penalties for exceeding scheduled unloading times, E.ON decided to upgrade its control methods and deploy a modern, integrated Terminal Operation System.
The company asked an ABB Automation Solution Provider, JMS Automation & Drives of Birkenhead, to deliver an enhanced control system that would improve operations at the terminal.
To improve the ship unloading time, JMS upgraded the two 40 tonne ship unloaders with ABB’s Crane Management System (CMS). Using software that takes account of the layout of the ships’ holds and superstructure, the system guides the grabs along an optimum path. This gives a fast yet safe unloading sequence that avoids straining the ship’s hull. The system also features special control algorithms that prevent motor overloading when high water content is encountered at the bottom of the hold. Over 25,000 tonnes of coal per day can now be unloaded.
JMS also completely upgraded the drives to a bus connected 260 kW inverter with 14 motors and a DC multidrive for the hoist.
The other major aspect of the system is control of coal stocks in the yard and scheduling of train loads for delivery to the power stations. The discharged coal is fed to the stockyard by conveyor and then stacked on the terminal’s stockyard according to who owns the coal. When the coal is reclaimed it is conveyed to the train loading hopper over a belt weigher.
To run the terminal efficiently, the terminal’s managers must know the status of discharge, stockpile tonnage, reclamation performance and planned movement of machinery and match all this with the overriding schedule. To do this they require real time information about coal movement and the status and condition of all machinery and equipment.
To meet this challenge, JMS updated the whole data acquisition scheme with an ABB AC800 system that acquires data and presents operations information on screens in a control room. Specific screens show the changing levels of stockyard coal stocks as they are stacked and reclaimed, and the amount of coal being conveyed. The rate of coal movement by weight is also displayed, allowing managers to see over or under achievement against targets.
Other areas of the facility, including the stacker and reclaimer control and the handling of a significant amount of surface water, will form part of a further stage of the project. JMS is considering the use of ABB’s 800xA DCS to provide a complete terminal wide operations system that will ensure all facilities are integrated.
Ken Jones, E.ON Terminal Manager, says: “We run a safe, clean and reliable operation here. The upgraded system provided by JMS has significantly contributed to operational efficiency, allowing us to meet a tight schedule. This benefits all stakeholders and delivers a modern terminal operation.”
John McGuigan, E.ON Terminal Team Leader commented: “The new system gives us insight into what is happening at all times. ABB technology underpins the upgraded coal terminal.”
The improved reliability and performance of the ship unloaders means that penalty charges are minimised, leading to the terminal acquiring a reputation for fast discharge and on-schedule dispatch to power stations.
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