China’s economic growth and its pervasive urbanization requires immense new living space for the second largest national economy on earth. The key raw material for the steel consumption coming along is iron ore. Thereby China’s hunger for raw material becomes a mainspring for growing needs in countries as Indonesia, Australia and Chile.
The Chilean export economy is the strongest in South America. One of the participating companies is the Compañia Mineara del Pacifico (CAP), Chile’s leading producer and export firm of iron ore and ore pellets. The mine operator is planning to increase his production from 12 up to 30 million tons per year in 2018. 75 % of his export is destined for China.
Pellets for the steel production
At Los Colorados site in the Atacama region CAP mines about 539 Mio. tons of iron ore per year to produce pellets of different qualities for the steel production. For this purpose the hand sized iron ore peaces first of all have to be broken and grinded in one of numerous process steps.
One of the successful global players in the field of ore grinding technology is Humboldt Wedag GmbH (KHD), located in Cologne, Germany. Their High Pressure Grinding Roller Presses (HPGR) are applied amongst others in copper, gold and iron mines worldwide.
On the Bauma fair 2012 KHD and Weir Minerals signed a license contract for HPGR Technology. This agreement is an unlimited license contract to assign Weir Minerals the direct control about planning, production and marketing of HPGR equipment for mineral preparation using KHD technology.
HPGR technology can optimize conventional cone crusher technology in terms of process engineering. It is in use by a Chilean KHD customer already since 1998. The technology has proven to be obviously more energy-efficient. In addition the grinding capacity could be increased by about 30% due to the special patent-registered texture of the roller surface. In 2012 CAP placed an order of three more HPGR plants to be delivered by KHD.
MCC for high availability
In addition to the systems engineering CAP expected from KHD in the tendering phase also the electrical equipment. For two of the plants KHD assigned the system integrator Trips with the delivery of switchgears for parts of the controls. These switch gears needed to ensure a high availability as well as strict safety standards, which especially have to prevent arc faults.
For this purpose the application of a motor control center (MCC), carried out in withdrawable technology, became obvious. “The withdrawable technology ought to be figurehead for KHD in terms of the quality and innvotion of our grinding plants”, told Alexander Haroske, head of project at KHD.
The presentation of the Trips MCC solution TRIMOT promptly pointed out, that the technology would ideally integrate into the KHD plant design. TRIMOT motor control center is a low voltage switchgear concept, designed and developed by Trips. The highly available system is integrated in Rittal Ri4Power switchgears.
Trips has constructed the system in close cooperation with the world’s leading systems provider for enclosures, power distribution, climate control, IT infrastructure and software & services.
Thanks to the patent-registered contacting system TRIMOT is designed arc fault free. Up to 22 withdrawable units à 75 mm are applicable in the device compartment. They are safely changeable even under voltage.
Thus Trips could meet the requirements and specifications of KHD entirely. “As expected we also have been competitive in price”, declared TRIMOT Product Manager Walter Kochenburger. “So in April 2012 KHD ordered from Trips the hardware engineering and switchgear construction of the MCC panels.”
Subsequently the technical details of the plant design have been clarified. The CAP roller press consists of a fix and a lose roller. The space between the rollers and thereby the grinding pressure is adjusted hydraulically. The rollers have an oil-lubricated bearing. The main drives possess an electrical power of 1.200 kW each.
TRIMOT controls all heating feeders of the central grease lubrication, the oil lubrication, the trace heating, the hydraulic pump and the cable feeders for the control cabinet.
The available mains voltage of 400 V required the mounting of a current transformer to control the 120 V based heatings. As defined by the Trips engineering and production standards, the bus lines were consistently carried out with shielded plug-in connections to prevent impacts by external signals.
In August 2012 an inspector of the end customer CAP passed the technical approval of the plant at Trips in attendance of the responsible KHD engineer. The inspector took a sight check as well as functional check under voltage. Subsequently the plant has been shipped from Hamburg to Chile where it has been commissioned in the mid of 2013.
TRIMOT MCC – Advantage overview
- Meets high personnel safety standards
- Assures reliable safety and availability of the switchgear, especially for continuous processes
- Is flexibly modificable without breakdown
- Allows a high packing density in the switchgear cabinets
- Minimizes maintenance costs
- Works cost efficiently and economically