CENTUM selected for copper smelter.
Project summary
Mopani Copper’s Mufulira smelter in Zambia originally processed over 400 000 tons per annum (tpa) of copper concentrates, most of which was sourced from its own mines. Some feed was obtained from surrounding operations in Zambia and the Democratic Republic of the Congo. The primary smelting furnace was a 36-MVA submerged arc, six-in-line electric furnace that had been installed in 1971 and rebuilt in 1991.
This furnace was approaching the end of its operating life and was due for replacement.
In addition, Mopani Copper was obliged to bring the gas emissions of its Mufulira smelter into compliance with Zambian environmental regulations. This necessitated the installation of an acid plant to process off-gas from the primary smelting furnace.
Increased copper mining activities in the Zambian copper belt and in the DRC presented an opportunity to process an increased quantity of copper concentrates. With surplus capacity in the Mufulira smelter and the need to replace the electric furnace, Mopani Copper’s management decided to install a new Xstrata Technology ISASMELT primary smelting furnace. Additionally, a purpose-built electric settling furnace, acid plant, oxygen plant – for the oxygen supply requirements of the ISASMELT – and associated infrastructure were installed.
The upgraded smelter was configured to process 650 000 tpa of copper concentrates, however, the design of the furnaces allowed for an increase to 850 000 tpa by increasing the level of oxygen enrichment in the ISASMELT process. In the redesign, gas from the ISASMELT furnace that has been cooled and cleaned of particulate matter is ducted to the acid plant for use in sulphuric acid production.
Challenges and solutions
The project was an excellent example of a brown-field site involving a wide number of engineering companies and vendors from different countries working together in a remote part of the world. Despite the logistical challenges of constructing a new smelter, in a land-locked country in the middle of Africa, this was one of the fastest ISASMELT projects completed to date. It took only 28 months from signing of the engineering and licence agreement to the first furnace feed.
In addition to completing engineering design of the ISASMELT plant and supplying key equipment such as the waste heat boiler, Xstrata designed and supplied a plant wide process control solution for the project based on a Yokogawa CENTUM CS 3000 system that had been built by Yokogawa Australia, tested and accepted by Xstrata Technology, and then exported to Zambia. The control system allows the acid plant, oxygen plant, and ISASMELT plant to be controlled from a central control room.
Mopani staff trained at Xstrata’s Mount Isa copper smelter for over three months prior to plant start-up, while Xstrata personnel with many years of operating experience on various smelters assisted with pre-operational training and hot commissioning of the Mufulira plant. Key process personnel remained on site for an extended period to assist with ramping up the plant and provide comprehensive training for Mopani operations staff. The Mount Isa plant also uses a Yokogawa control system, so the operation, engineering, and maintenance training went smoothly and was very effective.
System detail
Control architecture: CENTUM CS 3000, one plant resource manager (PRM), six dual screen human interface stations (HIS), one OPC and five field control
stations (FCS).
Customer satisfaction
The user wanted their control strategy implemented in a DCS they could trust, and one that could be maintained by the local Zambian workforce. Xstrata had used Yokogawa extensively in the past and trusted the reliability of the CS 3000 system; they also recognised the intuitive feel of the CS 3000 system and believed Yokogawa the best fit for the workers on site.
For more information contact Paulo De Sousa Gomes, Yokogawa South Africa, +27 (0)11 831 6300, [email protected], www.yokogawa.com/za
| Tel: | +27 11 831 6300 |
| Email: | [email protected] |
| www: | www.yokogawa.com/za |
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