Largest cement works in UK increases its sustainability targets


CEMEX benefits from Integrated Architecture approach from Rockwell Automation

CEMEX, a global building materials company, provides high-quality products and reliable service to customers and communities throughout the world. Its operations network produces, distributes and markets cement, ready-mix concrete, aggregates and related building materials in more than 50 countries, and maintains trade relationships with more than 100 nations.

Founded in Mexico in 1906, CEMEX has grown from a local player to one of the top global companies in the industry, with nearly 50,000 employees worldwide. It has annual production capacities of close to 97 million metric tons of cement, approximately 54 million cubic metres of readymix concrete and more than 168 million metric tons of aggregates.

The company’s impressive sustainability strategy has seen it switch to more environmentally friendly production processes; one of which is the use of Climafuel® at its UK production plants. Climafuel is a waste-derived fuel, which is made using household residual and commercial waste. Similar in look to that of shredded paper, it consists of paper, cardboard, wood, carpet, textiles and plastics and can therefore substantially reduce what is sent to landfill. At CEMEX’s UK cement plants it replaces fossil fuels, such as coal, used to heat the cement kilns, depending on the cement plant permits.

With its use of Climafuel expanding – from 30 to 60 percent – CEMEX’s Rugby plant, the largest cement works in the UK, needed additional unloading and conveyor capacity to complement the pair of bays already in existence. The loading bays use a combination of screw conveyors and walking floors to transport the Climafuel from the lorry unloading area to the kiln. As well as the automation demands, the new loading bay also needed a safety infrastructure to help protect employees and fuel delivery drivers.

The company originally specified an Allen-Bradley® ControlLogix® programmable automation controller (PAC)-driven solution from Rockwell Automation, but with automation and safety components supplied by different third parties. It had also considered an intelligent-motorstarter approach but could not justify it on the grounds of cost – that was until Westbury Controls, a Rockwell Automation Recognised Systems Integrator, introduced CEMEX to the concept of a complete automation and safety suite from Rockwell Automation.

Westbury Control’s solution was still based on the ControlLogix PAC, but all the other primary components were also from Allen-Bradley – running on an EtherNet/ IP network. In addition to the PAC, the automation and safety solution comprised of PowerFlex® 755 drives for driving the motors, E1Plus solid-state overload relays, Stratix switches, SmartGuard™ 600 Programmable Safety Controller, GuardShield™ safety light curtain, SensaGuard™ RFID Coded non-contact safety switches and actuators, RightSight™ photoelectric sensors and 440T ProSafe® coded key exchange switches.

Of particular note is the use of the E1Plus relay, as it is believed to be one of the first applications connecting a Motor Control Centre (MCC) onto an EtherNet/IP network. This intelligence-lead approach, formulated by Westbury Controls, helped reduce the wiring costs considerably (LAN rather than hard wired) meaning that CEMEX could now justify an intelligent infrastructure on a cost basis.

According to Daron Shaw, Electrical Plant Development Engineer at CEMEX’s Rugby plant: “The unloading pod, which resembles a large cube with one open face, could have potentially been a dangerous place to be because of the exposed screw conveyors, hence our requirement for the safety solution. What is more it had to be automatic and not reliant on the actions of the drivers.”

Paul Knott, from Westbury Controls, explains the principal: “In operation, lorries are reversed into the bay and the drivers enter via side doors to undo the clasps on the back of the trailer. The safety solution, driven by the SmartGuard 600, uses a safety light curtain to detect personnel and photoelectric sensor array across the open face of the cube to detect the presence of a lorry. If either the safety light curtain is operated or the side doors are opened (protected by the 440T Prosafe coded switches and monitored by the SensaGuard switches), the system shuts down by interrupting the power to the motors. The safety logic dictates that the system only re-activates when a lorry is present, both side doors are shut and a restart button is pressed by the driver. The unloading pod side doors are also fitted with a trapped-key interlocking system to make sure that the driver cannot become locked inside the pod while undoing the trailer clasps.”

Westbury Controls has also written all the software for the installation. “Using Premier Integration we were able to easily map the Rockwell Automation solution into CEMEX’s SCADA system,” Knott proudly proclaims.

“After a visit to Rockwell Automation’s UK headquarters in Milton Keynes for a demonstration of the technology we became convinced that this was the way to go,” Shaw elaborates. “The E1Plus is a revelation, as it will allows us to easily justify the investment of intelligent components on a cost basis.

We have been using Rockwell Automation’s hardware and software since the plant was commissioned in 1999 and I cannot fault them. In all this time we have had very few failures, their support has been excellent and the spares and service agreement in place suits our needs. I can also see us making more use of the E1 Plus in future installations.”

“The intelligence now available to CEMEX will allow them to target specific timeslots for downtime,” Knott elaborates. “As motor performance details can now be collated, historic data will allow them to identify trends and formulate maintenance plans accordingly.”


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