Process control and automation: drivers for the pulp and paper industry

In Australia and many other parts of the world, global competition, mergers and acquisitions and advances in pulping, production and process technology are placing pressure on operating procedures and profit margins in the pulp and paper industry. Mills and manufacturers are under constant pressure on a local and international scale to produce more, in less time at less cost.

One of the keys to staying successful in these conditions is to apply sound process control and automation strategies that can help the business run smoothly. Pulp and paper production is highly capital intensive and relies heavily on automated, efficient processes. Producers must consider environmental sustainability, reduce wastage, recycle energy, adhere to strict safety standards in all operations, produce high quality product and keep up to date with the latest paper machine, printing and pressing technology and do all of this while spending the least amount of money on operations.

The industry is facing a number of challenges including:

• The advent of new production and control technology.
• Fewer experienced operational staff.
• Competition from low cost suppliers.
• The need to ensure operations do not adversely affect the environment, produce unnecessary waste or use energy inefficiently.
• Producing a quality product.
• Managing a significant asset base.

New technology and fewer experienced staff

The industry has seen the advent of larger, higher capacity paper production units. As with other industries it is also facing reduced mill headcounts and a difficulty in attracting qualified staff, particularly in Australia. This extends to a reduction in engineering capacity at mill sites and a larger reliance on vendors to provide turnkey solutions. Whether it is the vendors or the mills themselves though, there is a distinct need for more people with actual experience in the overall plant operations.

Competition from low cost suppliers

Mills are also faced with significant competition from a number of low cost suppliers who are driving profit margins down.

Environmental sustainability

Governments and environmental groups have an expectation that paper producers will take measures to minimise negative impacts on the environment. Water and energy are precious resources and paper producers must have strategies in place for hazard identification, risk assessment and risk control. Applying the latest process control and automation technology and strategies is important to mitigate these risks by reducing unplanned down time, ensuring optimum production conditions and reducing wastage.

Quality product

Output these days must adhere to even more stringent quality requirements. High-speed printing presses and modern office machines, for instance, require top quality paper in order to operate without interruption. This is a key consideration for manufacturers and therefore they must have the processes and controls to support high-speed operations without compromising quality.

Asset management

Pulp and paper plants must also consider carefully their methods of asset management. Pulp and paper is an extremely capital intensive industry and so the ability to visualise end-to-end operations is critical for plant operators to do a good job. The issues outlined above are just a few of the challenges facing paper producers today. In fact, the issues above are not dissimilar to similar, process-intensive production industries. Paper producers therefore need to streamline their operations, keep up with developments in technology, upgrade their process controls and automation strategies, take cost out of the business and increase the yield and quality of paper production.

To do this, paper producers and their vendors need to have a complete understanding of their overall plant operations right through from wood handling to pulping (chemical or mechanical), production, packaging and delivery. From a process control and automation perspective, they then need to ensure they have the most appropriate, modern technology for their plants and the process controls and automation strategies to support the most effective use of technology and optimal operating efficiency.

So if you are planning on building a new mill, upgrading a paper machine or upgrading your process control technology, there are a few key things to consider when it comes to process control:

1. Invest in one process control system plant-wide and ensure all of the plant uses only this control platform. This will support the introduction of advanced strategies later and reduces the confusion and or training demands of multiple control platforms. If you run a brown-field operation with a number of different systems, it is recommended that the plant takes a phased approach to eventually standardise on a consistent control platform plant-wide.
2. If performing an upgrade in a brown-field plant it is imperative that all current operations and processes are fully understood by the project teams from the plant and third-party vendors. Thorough planning and design will go a long way to mitigating risk and minimising unplanned down time during an upgrade of an operating mill.
3. A single control system implementation standard is recommended for all suppliers. This will benefit operators, maintenance and engineering in the future.
4. Ensure a full understanding of the life cycle of the preferred process control platform and ensure it is acceptable to future production plans. Obviously, the selected control system should also support all of the functionality necessary to effectively control the processes of the plant.
5. Ensure there are enough people on the project with not only process control experience but also real-world plant operations experience. There is no substitute for real plant operating experience.
6. Select a control system solutions and engineering services provider with a view to a medium- to longer-term partnering relationship. The right partner with the right values will actively work with the paper producer to reduce operating costs and increase production output through proactive planning of minor and significant upgrades.
7. Invest in a plant historian platform. This will give real foundations to productivity improvements and will prove a valuable investment. What gets measured and reported can be improved.

Norske Skog paper machine automation systems upgrade

Norske Skog is an excellent example of a company that has experienced these pressures on its business and has made important strategic decisions that are resulting in a business that puts quality, efficiency, profitability, safety and the environment as top business priorities.

In 2002, Norske Skog Albury initiated the automation upgrade project to provide a new plant-wide control system and integrated automation platform. The goals of the project were to:

• Provide plant operators with a single user interface to the control system;
• Replace ageing and/or unsupported control system hardware; and to
• Improve the control strategies and alarm management.

Project scope and methodology

Norske Skog appointed MIPAC to manage the design, implementation and commissioning of the new control system. The scope included design, procurement support, configuration, contractor supervision, commissioning and start-up support. Consolidation of control system types and the replacement of obsolete systems to facilitate central control of the plant was the fundamental aim of the project.

This required MIPAC to ensure knowledge of the current Norske Skog operations in Albury. MIPAC had to be aware of any constraints to implementing the project as well as gaining a full understanding of future requirements.

Beginning in 2003, MIPAC set about a phased upgrade of the automation systems for the whole mill which included more than 15,000 inputs and outputs (I/O). This included the paper machine, steam plant, water treatment and TMP pulp mill. The scope included:

• Assisting Norske Skog in the selection of the new control system.
• Management of project design, commissioning and implementation.
• Development of specifications and standards for electrical, instrumentation and control scope.
• Updating instrumentation, wiring and control documentation as a foundation to the engineering to be undertaken.
• Detailed design for electrical, instrument and control requirements in all plant areas.
• Application programming for the water treatment plant, steam plant and paper machine (stock preparation and broke systems).

The project involved replacing the existing control system which consisted of Honeywell TDC 2000, TDC 3000, Siemens programmable logic controller (PLC) and relay logic. After consideration of various options, Norske Skog chose the Metso DCS for the plant-wide system and MIPAC replaced all existing systems with Metso equipment in a phased approach.

Key outcomes

As a result of the automation upgrade, Norske Skog has realised a number of benefits which have directly contributed to improved operations and process controls. This creates distinct improvements for profit margins, environmental outputs, production yields and quality. These include:

• Better process visibility;
• Better operational tools - trends, alarm logs, etc;
• Improved control strategies;
• Group starts;
• Sequencing;
• Alarm masking;
• Duty/standby systems;
• Current instrumentation and control system documentation.

Most importantly, the Albury plant now has a single process control platform that reaches across most of the plant and can support process and operational strategies that extend beyond the scope of the original system.

The following two sections highlight key outcomes related to minimising lost production time during the shutdown as well as advanced alarm management and sequencing techniques.

Minimising lost production time/revenue

The biggest challenge for the teams on this project was to minimise down time and generally decrease lost production time during the upgrade. As there is only one paper machine, any down time of that machine directly contributes to lost production and, therefore, lost revenue for Norske Skog. The upgrade of the Albury paper machine and related controls and automation processes could therefore be likened to 'open heart surgery' as the overall operations of the plant had to be kept running while the upgrade occurred in parallel.

A considerable amount of planning and engineering was paramount to ensure minimal unplanned down time. This included preliminary work during scheduled maintenance shuts and close cooperation between MIPAC and the Norske Skog employees at the Albury mill.

This careful planning proved invaluable in assisting MIPAC to complete the upgrade project in line with Norske Skog's expectations.

Attention to detail, thorough planning and process knowledge reduced the risks on a very complex project. Control strategies that allow operators to visualise the end-to-end processes of the plant, reduce unplanned down time and improve ongoing production output.

Alarm management and advanced sequencing

For the Albury installation, MIPAC incorporated a number of high-level alarm minimisation strategies and advanced sequencing techniques into the Metso control system.

A feature of the new process controls has seen high-level alarm minimisation strategies and advanced sequencing techniques used in a Metso system for the first time.

A failure in one part of the plant normally means that alarms ripple through. The installed systems can capture the first alarm and minimise the ripple effect by pinpointing exactly which piece of equipment has caused the problem. MIPAC also simplified the alarm procedures, taking out unnecessary alarms, such as those on the end of pumps: if the operator shuts down the pump you know it is off - there is no need for an alarm.

Advanced sequencing techniques are used for starting up equipment in groups rather than each piece individually. This creates consistency in start-up and minimises the start-up time. The mill had also discovered that some shifts start-up better than others: another reason for using the sequencing techniques. The aim was to take out as much of the human element as possible.