Churning out 350,000 metric tons of copper per year is impressive, but doing it with 20-year-old process controls in an almost 70-year-old plant is even more amazing. However, after such long and faithful service, even the most durable process controls need an upgrade.
For instance, the Hernan Videla Lira (HVL) copper-smelting plant operated by Empresa Nacional de Minería (ENAMI) in Copiapo, Chile, needed a new distributed control system (DCS) because its Bailey controls and obsolete automation networks lacked spare parts, didn’t provide access to production data and couldn't be supported, according to Manuel Parra, chief consulting engineer for planning and maintenance, ENAMI. Located in Chile's arid Atacama desert region, HVL started its upgrade project in 2015 and completed it this past June.
"Process areas controlled by the Bailey systems included our electric smelting furnace, water/wastewater plant and teniente converter for cleaning slag, but our operational challenge was that these areas and their 8,000 I/O points were only connected at the HMI level, not at the database for handling critical information, and were in silos that weren't connected to each other," said Parra.
Parra and Andrés Sammartino, process sales lead, Rockwell Automation Argentina S.A., presented "Bailey DCS modernization to PlantPAx" at this week’s Rockwell Automation Process Solutions User Group in Philadelphia.
Specification to installation
Beginning in 2010, ENAMI's upgrade team began researching process control system (PCS) solutions and suppliers that could replace its legacy Bailey controls, eventually settling on the PlantPAx DCS, including human machine interface, database and historian.
"ENAMI needed a modern control system with easy maintenance, strong diagnostics and alarm capabilities, data management to support business decisions, and support for operational improvement," said Sammartino. "These requirements were used to develop technical specs for the project, which helped keep all the vendors on the same page."
The specs covered operations stations, cabinets and data processing control units (DPCU), historian replacement, engineering drawings and services, factory acceptance test (FAT), site acceptance test (SAT), configuration of HMI and controls, fiber-optic network installation, commissioning and startup, as well as operations and maintenance training.
Migration of the HVL copper smelting plant to the PlantPAx DCS was carried out in three main phases:
Phase 1 involved removing the old HMIs, but allowing them to run in parallel with the new ones for a period of time, so operators could get used to them. This stage included adding fiber-optic networking in preparation for the PlantPAx DCS.
Phase 2 consisted of implementing the PlantPAx DCS, including nine redundant ControlLogix controllers and OPC-based communications between the PlantPAx DCS and some Bailey devices still in use at the plant.
Phase 3 included removal of more legacy devices, completing the transition to PlantPAx DCS, and connecting all control system components to a redundant Ethernet ring.
"We identified all the Bailey cabinets and wires, added the new PlantPAx cabinet and cabling, and conducted real operating runs during commissioning," added Parra.
Now, everything can be commissioned using the Rockwell Automation Library of Process Objects.
“This means users and system integrators can make small changes, but do them in a standardized way, instead of everyone having different ideas about how they should be done,” he said.
"I come front the IT side originally, so we tried to have this migration to PlantPAx DCS match the seven-layer Open Systems Interconnect (OSI) model,” he said. “We believe this is important for maintenance, and finding and fixing problems more quickly."
Viewing is optimizing
Sammartino added that ENAMI's preparation enabled its smelting operation to end up with an integrated system based on the PlantPAx DCS that provides:
Holistic plant view of its process, real-time data, key performance indicators (KPI) ad dashboards;
Maintenance efficiency, including asset management, preventive/predictive maintenance, and maintenance cost reductions; and,
Standard applications, such as standardized automation projects, correct technology applications and efficient return on investment (ROI).
"This new, modern DCS delivers a more holistic plant view that sees everything,” added Sammartino. “PlantPAx makes maintenance more efficient and less costly, and unifies all control on the same platform with the same development tools plantwide."