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 example, 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).
ENAMI’s 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 in 2018.
ENAMI’s process control areas, run by legacy Bailey systems, included their electric smelting furnace, water/wastewater plant and teniente converter for cleaning slag. Para explained they faced operational challenges with their process control areas in siloes. Their 8,000 I/O points were only connected at the HMI level, not at the database level for handling critical information.
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.
Andrés Sammartino, Process Industry Manager at Rockwell Automation Argentina S.A., explained 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.
They developed technical specs for the project based on these requirements, keeping all 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.
Three Phase Approach
Modernization of the HVL copper smelting plant to?the DCS?was implemented 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 DCS.
Phase 2 consisted of implementing the 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 the DCS, and connecting all control system components to a redundant Ethernet ring.
ENAMI identified all Bailey cabinets and wires, added the new PlantPAx cabinet and cabling, and conducted real operating runs during commissioning.
Para explained, now everything can be commissioned using the Rockwell Automation Library of Process Objects allowing users and system integrators to make small changes in a standardized way, instead of everyone having different methods.
Para, having a background in IT, made a point to have the migration match the seven-layer Open Systems Interconnect (OSI) model, making it easier for IT maintenance and resolving problems more quickly.
Viewing is Optimizing
ENAMI's integrated smelting operation, based on the PlantPAx DCS, provides:
- A holistic plant view of its process, real-time data, key performance indicators (KPI) and 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).
Sammartino added that the modern DCS delivers a more holistic plant view that sees everything, and it makes maintenance more efficient, less costly, and unifies all control on the same platform.