Green automation: Manufacturer of high-voltage cables cuts 50% in cooling process
Saving energy, a challenge many businesses face, has to be balanced with the requirements of processes with sensitive operating parameters. Lamifil n.v., in Hemiksem, Belgium, invested new automation technologies for 50% energy savings in one process, for a return on investment (ROI) of less than one year. Variable speed drives control cooling pumps used in production of aluminum and aluminum alloys, and 5,000 tons of copper and copper alloys. Also, engineers and personnel involved in the product development now can consult critical production data, such as the temperature of the blast furnaces and annealing furnaces, in real time. Lamifil manages the liquid metal production process, through to semifinished goods and end products, which it sees as providing market flexibility.
Founded in 1929 and manufacturing continuously from the same location at Hemiksem near the Port of Antwerp in Belgium, Lamifil develops, produces, and sells high-quality and specialized copper and aluminum as well as aluminum alloy and copper alloy wire and conductors. Its wire rod, drawn wire, sector-shaped wire, and conductors are designed to improve efficiency and capacity as well as to solve customer issues and fulfill customer needs.
The company produces a range of overhead conductors for electrical transmission and distribution networks, including a range of high-conductivity all-aluminum alloy conductors (AAAC); high-temperature, low-sag gap conductors; and the new high-efficiency aluminum conductor composite core (ACCC) conductors. Lamifil also produces a full range of high-speed railway overhead electrification systems, including those based on copper, copper silver, copper magnesium, copper tin, and copper cadmium alloys.
The company is among Europe’s biggest independent aluminum wire and conductor manufacturers, and a prominent supplier of copper alloys and railway electrification
products. Lamifil produces 40,000 tons of wire and conductors from aluminum and aluminum alloys, and 5,000 tons of copper and copper alloys.
Lamifil melts metal within the factory and hot-rolls it into rod. After heat treatment the m
etal is drawn into wires of the appropriate thickness and shape. Six furnaces (four for aluminum and two for copper) support a range of wire-drawing and stranding lines—with new lines being added annually.
Opportunity for savings
Etienne De Block, L
amifil engineering and maintenance manager, explained the processes and renovations.
Each hot-rolling line and wire-drawing line is equipped with a cooling circuit that runs through one or more cooling towers. A study conducted within the scope of the Energy Covenant (an agreement with the government regarding CO2 reduction) showed that energy could be saved in these cooling units by achieving a greater difference in temperature (delta T°) between the supplied and discharged cooling water.
The first cooling circuits to be examined were those of the wire-drawing works, including the cooling circuit for the three aluminum wire-drawing machines and the cooling circuit for the two copper wire-drawing machines. Each cooling circuit was equipped with two pumps, one of which was operational (redundant design). The first had 27 kW pumps, the second 7.5 kW pumps. The first circuit had a constant capacity of 90 m³/h on two cooling towers of 7.4 kW. The second circuit had a capacity of 13 m³ on a cooling tower of 7.5 kW.
Within the cooling circuits, the pumps are operated at high speed, yielding an average delta T° of 2°C. The optimum difference between the inlet and outlet pipes in a cooling circuit lies around the 4°C mark. Initial ideas on how to increase this delta T° included suppressing the flow rate using valves. Reducing the flow rate by 20% in this way delivers a 10% energy saving.
Installing a variable frequency drive on the pump allows energy savings of up to 50%, seen as an enormous amount, since the lines run day and night.
Pumps for the cooling circuits were equipped with new drives. Measurements were first taken with the drive operating at 50 Hz, which delivered a pump capacity of 27 kW and 5.8 kW, respectively. The settings were then adjusted such that the motor operated at 50 Hz at a delta T° of 4°C, at which point the frequency was scaled back to 40 Hz at a delta T° of 0°C. Tests have not yet ventured lower, to ensure that the motor continues to retain sufficient cooling capacity, even without an additional ventilator. At 40 Hz, the consumption of the pump was 13.8 kW and 3 kW, respectively. At the same time, the cooling towers were equipped with an on/off switch, based on the cooling temperature.
Test period results
A test period of 1,244 operating hours was conducted. A consumption of 17.74 kWh, equal to a gain of 16,000 kWh, showed a drop in consumption in pump one from 27 kW to an average of 13.7 kW. In the case of the second pump, the consumption dropped from 5.7 to 3.7 kW. An astonishing result was also achieved in relation to the operating hours of the cooling tower: the first cooling tower had 670 operating hours to spare, the second had operated for just two hours. The test was carried out during the winter, one of the reasons for the vast difference. It is, however, expected that a major energy reduction will occur during summer (and most certainly over an entire year), more than enough to time to recover the costs of the materials used and within a period of less than one year.
The process is closely monitored via new human-machine interfaces (HMIs) in the system; offices were equipped with new supervisory control and data acquisition (SCADA) software that allows all engineers and personnel involved in the development of the product to consult all critical production data, such as the temperature of the blast furnaces and annealing furnaces, in real time in their offices. Those are used for cooling circuits and for tracking the temperature of the annealing furnaces, which is highly important because annealing determines the quality of the wire. The drives are linked via an industrial network to programmable logic controllers (PACs), connected to the company network by Ethernet.
The project used Allen-Bradley PowerFlex 700 drives, PanelView HMIs, CompactLogix PACs, and RSView products from Rockwell Automation, and DeviceNet, an industrial device protocol managed by ODVA. Since sustainability and environmental responsibility have increased in importance for many manufacturing companies, in a mandate to be more green, this example shows that sustainable manufacturing solutions positively impact the bottom line.
View more Lamifil shop and machine pictures.
Photo gallery – CAPTIONS – See attached file – link above
Top left – The first Lamifil cooling circuits to be examined were those of the wire drawing works, including the cooling circuit for the three aluminum wire machines and the cooling circuit for the two copper wire drawing machines. Photos courtesy of Rockwell Automation.
Top right – The pumps for the Lamifil cooling circuits were equipped with Allen-Bradley PowerFlex 700 drives from Rockwell Automation.
Second row, left – Mainly targeting electrical utilities and railways, Lamifil’s wire rod, drawn wire, sector shaped wire and conductors are designed to improve efficiency and capacity as well as to solve customer issues and to fulfill their needs.
Second row, right – Lamifil produces 40,000 tons of wire and conductors from aluminum and aluminum alloys, and 5,000 tons of copper and copper alloys.
Third row, left – Founded in 1929 and manufacturing continuously from the same location at Hemiksem near the Port of Antwerp in Belgium, Lamifil n.v. develops, produces and sells high quality and specialized copper and aluminum as well as aluminum alloy and copper alloy wire and conductors.
Third row, right – Lamifil produces a range of overhead conductors for electrical transmission and distribution networks, including a range of high-conductivity All Aluminum Alloy Conductors (AAAC); high-temperature, low-sag Gap conductors and the new high-efficiency Aluminum Conductor Composite Core (ACCC) conductors.
Bottom, left – The PanelView HMIs from Rockwell Automation are used to monitor Lamifil cooling units and for tracking the temperature of the annealing furnaces, important because annealing determines the quality of the wire.
Bottom, right – The entire process at Lamifil is closely monitored via Allen-Bradley PanelView HMIs from Rockwell Automation, installed directly into the system.
– Information was provided by Rockwell Automation and edited by Mark T. Hoske, CFE Media, Control Engineering, www.controleng.com.
- Sustainability tips: How manufacturing can become more energy efficient – Manufacturers should consider energy as a cost component of manufacturing production, measure where and how energy is used, and create an implementation plan for using energy more efficiently.
- Cover story: Energy-Efficient Electric Motors – How to get the most out of energy-efficient motors: You have to do more than just look at the motor nameplate to get maximum energy savings.
- Why Choose Medium-Voltage Drives? – Energy savings and other benefits of more common, low-voltage ac drives are becoming well known. Medium-voltage drives, operating from higher electric supply, bring ‘heavy lifting’ capability and further economies of scale to rugged applications. This is the August 2010 Control Engineering cover story.