To upgrade or replace : The challenge facing pulp and paper manufacturers

The pulp and paper manufacturing industry faces many of the same issues that all manufacturing industries face. The need to better utilise or to increase total plant capacity to remain competitive is no different in this industry than in any other. Production rates need to be increased, downtime reduced, quality and yields need to be improved and unscheduled shutdowns need to be eliminated.

In many manufacturing industries the development of new products based on modern materials, such as plastics, has seen new production facilities built from the ground up, delivering the cost-effective products from day one. These new plants are also facilitated by the consolidation of major players, who often move to new facilities as part of mergers and acquisitions.

Unlike many of these industries, consolidation of the pulp and paper manufacturing industry has been quite slow on an international scale. Also, as the actual raw materials have basically remained the same over many years and original hardware is often in excellent working order, alternative cost-effective solutions need to be sought out.

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Legislation of international environmental standards also adds another level of complexity. The pulp and paper industry now has to comply with strict reporting and performance standards brought about by new wide ranging environmental regulations.

As the original equipment can still meet all required output metrics, to remain competitive and to meet the requirements that face modern manufacturers automation specialists are being engaged to upgrade many of the mills, from materials supply through to paper production and printing and then on to packing, palletising and distribution. With the design and implementation of fully automated systems incorporating total process control, new integrated production solutions can be achieved delivering significant productivity gains.

The range of skills required to upgrade an older plant can be extremely diverse, including automation and robotics design specialists, mechanical, electrical and mechatronic engineers, project managers and programmers skilled in Windows, Networks, SCADA, DeviceNet, HMIs - and the list goes on. This is where an automation/robotic specialist/integrator can be employed.

Starting at the mechanical level, the paper winder is an extremely sophisticated piece of machinery that is required to deal with rolls that weigh upwards from 10 tonnes and winders that need to accelerate and decelerate quickly while maintaining speeds upward of 2000 m/min. At the same time as the roll decreases in diameter, real-time tensioning is required ensuring no issues with the feeder. This is where new technology in the form of advanced drives and drive controls can be integrated with existing equipment, available from leading manufacturers such as Rockwell/AB or Siemens.

As part of this integration, digital outputs and controls need to be installed, which often require conversion from analog to digital. This enables monitoring, management and reporting to be integrated into the total system. There are many different systems, such as Rockwell's ControlLogix, which provide flexible control architectures that allow multiple types of control, networks and I/O to be combined into a single system - a solution that fits the requirements identified.

On top of this SCADA (real-time supervisory control and data acquisition) systems that utilise PCs, Windows multitasking and DDE capabilities are ideal when coupled with off-the-shelf software and instruments that integrate remote management and monitoring systems. This enables other standard plant facilities such as boiler operation and effluent treatment to also be integrated. Citect's SCADA delivers simplified installation, a common programming environment and HMIs to be installed with minimal downtime.

This also enables sophisticated reporting due to real-time data acquisition capabilities to also be built in, enabling regulatory requirements to be met. A typical installation will include a LAN which also delivers a high degree of security, environmental modelling and simulation. From the control room, operators monitor information continually collected from remote data gathering devices on their PCs.

Robotics

In conjunction with bringing the original equipment up to date, automation of all upstream and downstream processes need to be addressed to maximise the outputs being gained. From material supply through to packaging and palletising, integrating robotics into the automation solution can deliver efficiencies previously unheard of.

Robots are able to handle the weights of the rolls required as part of the material supply chain upstream that previously required extensive equipment and manpower. With careful planning and design and assuming suitable space is available, the same robots can be utilised in the warehouse management downstream such as where multiple size rolls are wrapped, barcoded and shipped based on an integrated EDI ordering system.