This article was printed in CONTROL's October 2009 edition.
By Juan Jorge Caceres, Alejandro Erazo, Marco Vidal Cruz, Mauricio Quintana M, Gunars Luks Guzman
To compete in the global pulping industry, pulp manufacturers need world class mills producing high-quality pulp efficiently and reliably. Profitability is challenging as material, energy and transportation costs rise. The environment must be protected, leading to ever stricter environmental and other regulations.
Celulosa Arauco met these challenges head-on by turning to digital automation when it built the world's largest smart mill in Nueva Aldea, Chile, capable of producing 856,000 air-dried tons of kraft cellulose per year. The digitally integrated mill achieved 93.6% of targeted production in its first six months of operation, on a monthly basis, and haswe since ramped up to full production according to plan.
A key factor in the mill's success is the use of the latest digital architecture and bus technology, which contributed to the fast start-up and continues to provide predictive diagnostics. "The plant automation technology used on this project has enabled us to improve safety and reduce emissions," said Gunars Luks Guzman, Mill Manager at Nueva Aldea. "We've also managed to maintain production at the targeted levels."
Celulosa Arauco is one of the world's largest forestry companies measured by plantation area and production of kraft wood pulp and sawn timber and wood panels. The company has combined annual capacity of approximately 3.1 million metric tons of bleached and unbleached kraft pulp. Its 610,000 hectares constitute the largest holding of forest plantations in Chile.
The pulp mill is actually phase two of the Nueva Aldea project. Phase one, consisting of a wood processing plant that includes a sawmill and plywood manufacturing plant, was put into operation at the end of 2004. Of the total project cost of $1.4 billion, $150 million was spent on phase one, $850 million was invested in the pulp mill, and $400 million on forestry and other indirect items. The mill includes two fiber lines, one for radiata pine and the other for eucalyptus.
The mill has brought many jobs to the region. An average of 3,300 people were working on site during construction, and the entire project will provide permanent employment for 1,200 people including 200 at the pulp mill.
Environment, Safety and Quality Are Top Goals
"The three most important goals of this plant are the protection of the environment, safety of our employees, and production quality," Luks said. Arauco chose equipment that complies with the Best Available Technologies (BAT) Directive of the European Union, which is required for pulp mills operating in Europe as of September 2007. Safety and environmental concerns have also led the plant to obtain 1SO/IEC 14000 and 18000 auditing and certification. Underscoring its environmental commitment, the plant pioneered in performing tertiary treatment of its effluent stream, which is carried out by only five other pulp mills in the world.
The Nueva Aldea mill also includes a biomass power plant which generates 30,000 kilowatts of electricity and supplies power to the local electrical grid as well as the mill. The biomass power plant is expected to reduce greenhouse gas emissions by a approximately 2.2 million tons of carbon dioxide through 2025. The United Nation's CDM Executive Board has issued approximately 240,000 tons of certified emissions reduction (CER) credits for the project, representing the CO2 equivalent saved each year.
Automation strategy is critical to the Nueva Aldea plant. The plant's management selected Emerson Process Management's (www.emersonprocess.com) PlantWeb digital plant architecture and DeltaV digital automation system. Training, simulation, start-up and commissioning were managed through Emerson and Arauco teamwork.
"The whole plant from beginning to end was automated from the moment we feed the logs into the chipper until a bale of pulp emerges at the end," said Alejandro Erazo, distributed control systems project engineer for Arauco. "Our objective was to use the most modern technology in the market and use it in the best way possible, to make each part of the project easier, from engineering to configuration to startup up the plant."
Mauricio Quintana, systems supervisor, added, "The fact that the automation system is built for digital bus technology allowed us to interconnect several types of networking protocols. Foundation fieldbus, for instance, was used for all the instrumentation, comprising the world's largest pulp mill installation of this technology. We used DeviceNet for motor control center, motor controls and other devices. Profibus was used for discrete remote I/O points and also to interconnect many PLCs."
Complete Digital Automation Solution
Emerson automation and service experts from Argentina and Chile worked with Celulosa Arauco to provide a completely integrated digital solution. Emerson wrote a functional description specification (FDS) for managing the automation of the project; Arauco delivered the FDS to vendors, who returned their digital configuration data for entry into the systems database. This proved valuable in efficiently integrating the work of a number of suppliers.
Emerson supplied the smart mill infrastructure built around its PlantWeb digital architecture and Foundation fieldbus networking. The solution integrates 3,300 Foundation fieldbus devices including flow, level, pressure and temperature instruments and valves with digital valve controllers. Predictive diagnostics information is collected from intelligent devices throughout the mill by predictive maintenance software that delivers alarms and data to operations and maintenance personnel.