FEATURE: Energy optimisation
Suppliers drive energy efficiency
For this issue’s energy optimisation feature, we asked a number of prominent suppliers what they were doing to reduce energy costs in South Africa’s mills – and what tricks they have up their sleeves with which to face mandatory energy cuts in the future
SKF
Putting Energy Efficiency into the Heart of Business
From a business perspective, SKF views energy conservation as both logical and a matter of self-interest. As Bengt-Olof Hansson who is both managing director of SKF in the UK and SKF Group vice president of Corporate Sustainability notes, “If the planet suffers, if poverty increases, if societies fail, business can’t succeed.”
Within SKF, there is consensus that the Group should be a leader in energy efficiency within its own business and should support its customers in reducing their own carbon footprints. So SKF has embarked upon a rigorous and sustained programme of environmental improvement measures. Dubbed BeyondZero™, this programme has the stated goal of not simply reducing its carbon footprint to zero but, ultimately, the Group should make a positive contribution to the environment. This is to be achieved by combining tough targets for its own operations with novel customer solutions that help others reduce their environmental impact.
Internally, the BeyondZero™ programme has a target for SKF’s own plants to make reductions in CO2 emissions of 5% annually. During the past two years, SKF has increased its production volumes by about 20% while achieving significant absolute reductions in CO2 emissions. This has been achieved by a variety of means including physical investment in more energy efficient equipment such pumps and motors, energy recovery systems, using energy saving lights and introducing solar power systems.
SKF has also placed the same emphasis on energy conservation in their products.
Energy saving bearings
In 2007, SKF introduced a new range of energy saving bearings. The development was focused on the two most widely used bearing types in the world; deep groove ball bearings and tapered roller bearings. For both types, SKF designers managed to reduce friction torque by 30% while maintaining the same service life of previous designs.
The initial application for the Energy Efficient deep groove ball bearing is expected to be in industrial motors, gearboxes, compressors and fans. Taking the US alone, some 16% of all energy consumed in industrial applications is related to such motors. Potential savings to the US and the EU if these bearings were used in all installed motor driven applications in 2007 adds up to 2 460 million kWh/year or 420,000 barrels of oil.
The initial applications for the Energy Efficient tapered roller bearing are expected to be wind turbines, hydraulic pumps, industrial transmissions, gearboxes for cranes, marine gearboxes, automotive gearboxes and heavy truck axles
Mechatronics
Mechatronics is an increasingly important area for SKF as it integrates mechanical components with electronic sensors to create intelligent systems that provide more functionality and value to customers. Robotic systems that use mechatronic actuators rather than pneumatic systems can be far more energy efficient. When SKF developed a compact electromechanical actuator for a welding robot used in automotive production, total energy consumption dropped by 90%. This energy saving was also combined with a faster welding capability and improved quality.
VOITH PAPER
Green Technology: Reduce costs and save resources
Approximately 400 million tonnes of paper, paperboard, and cardboard are produced annually worldwide, and the trend is increasing. Up to 75% of all production costs are comprised of raw material and energy expenses. "We can significantly reduce the use of resources in paper manufacturing and thus help our customers to save substantial costs," says Dr. Hans-Peter Sollinger, president of Voith Paper.
Up to 50% less primary energy, only one litre of fresh water per kilogram of paper produced, and maximum use of recovered paper are not a pipe dream at Voith Paper, but rather a clear concept for future paper production. Green Technology is certainly not a new invention. "Reductions in energy and fresh water use have always been our ambition, whether in new plants or conversions,” Dr. Sollinger says. “However, increased prices for raw materials and energy in recent years have shifted the focus worldwide. The paper industry is facing major challenges, and we want to make our contribution to environmentally friendly and cost-effective paper production." One example of these efforts is Atmos, an innovative Voith Paper technology that produces high-quality tissue paper from 100% recovered paper fibres.
Reusing valuable fibre stocks
If the use of recovered paper can be increased by the year 2020 from the current approximately 50% at 400 million tonnes of paper to 70% at an estimated global production volume of 500 million tonnes, fresh fibre and energy use can likewise be reduced substantially. Dr. Sollinger considers these ambitious plans to be realistic, based on Voith Paper’s results to date. Leipa in Schwedt, Brandenburg, Germany, is a good example. Since summer of 2004, 300,000 tonnes of first-class LWC paper have been produced annually on Leipa Schwedt PM 4 made by Voith, using up to 100% recovered paper. Then and now, the paper machine plays a leading role. For the first time, it was possible here to manufacture coated magazine paper varieties with such a high percentage of recovered paper, while maintaining a level of quality equal to primary fibre products in every relevant characteristic.
Lower water requirements thanks to the integrated paper plant concept
For Voith, Green Technology means the implementation of integrated paper plants, now more than ever. The integrated paper plant is a new resource-saving and environmentally friendly manufacturing concept. By using Voith Paper’s R2S Anaerobic Reactor and lime trap, virtually completely closed water circulation becomes possible. This concept has already been distinguished in Great Britain with the Green Apple Award environmental prize.
On average, 20,000 litres of water and up to 3,000 kWh of electricity are required today to produce one tonne of paper. Voith technology has enabled one kilogram of packaging paper can be produced using only three to four liters of fresh water. But Dr. Sollinger is pushing for more. He references Voith Paper’s Green Technology programme to the above-mentioned milestones: 1 litre of fresh water per kilogram of paper produced with a simultaneous maximum increase in the use of recovered paper, even in the production of high-quality graphic papers, and a halving of the primary energy used.
“We know that significant investments will be necessary and that a lot of work will have to be done by us as well as our customers. But if we work resolutely on our concept of the integrated paper plant, these milestones can be achieved by 2020."
HERCULES
Saving energy in boiler sample cooler systems
Ashland Hercules Water Technologies (AHWT), a commercial unit of Ashland Inc. (NYSE: ASH), is dedicated to helping pulp and paper mills operate more efficiently and profitably. One area where AHWT’s expertise has helped bring substantial cost savings to customers is the subject of boiler sample cooler systems.
Within the utility area, solutions are aimed at avoiding and solving problems that, when left unchecked, lead to inefficiencies, production losses, or even loss of assets. Through the combination of application expertise and state-of-the-art chemical technology and support, AHWT treatment programs are engineered to protect systems against the problems that can affect operations and equipment life.
Many paper mill boiler houses worldwide continue to utilize hot pressurized water sampling points to assess chemical treatment needs. As many know, this is not the best sampling method and can often lead not only to inaccurate readings that contribute to inefficiencies, but it can also place operators in less than optimum safety positions. An example of how the AHWT Boiler Sample Cooler System provides substantial savings in water, fuel and additives is illustrated below.
The initial approach begins with basic thermodynamic principles and the relationship between pressure, boiling temperature, liquid heat content, evaporation heat content and total heat content of saturated steam.
System Parameters:
| • Steam production: | 20 T/h |
| • Conductivity: | Boiler Feed Water: 500 µS/cm |
| Boiler: 6,500 µS/cm set point | |
| • Pressure: | 10 bar |
| • Gas: | 31,650 kJ/N m3 |
| • Estimated gas price: | €0.26/N m3 |
| • Water: | €1.00/ m3 |
| • Efficiency: | 80% |
| • Operation hours: | 8,760 hours/year |
Assuming 1 m3/h blow down:
• Boiler water sampling at 781.6 KJ/kg (pressure temperature, heat)
• Steam to atmosphere (1 bar) 2,675.5 kJ/ kg : X m3/h
• Condensate sample water (1 bar) 417.46 kJ/kg: Y m3/h
Stripping calculation provides 16.1% of steam loss
Measured boiler water conductivity:
• Flashing of 16.1%
• All salts will be concentrated in 6,500 x 83.9 = 5,453.5 µS/cm
• Real cycles are then: 5,453.5/500 = 10.9 instead of 13
• Real cycles can be raised from 10.9 to 13
Savings generated:
Based on measured conductivity of 6,500 µS/cm, the example boiler yields savings (gas & MU water only) of €24,000.00, assuming a cost of €3,000 including installation. Calculated ROI* of 710% means that in less than two months the AHWT Boiler Sample Cooler System will have paid for itself. Qualitative results include more accurate measurement of conductivity and lower Total Cost of Ownership (TCO) based on improved analyses.
*ROI achieved is dependant on system parameters
ABB
ABB now an accredited Eskom energy efficient motor supplier
ABB South Africa has joined the list of Eskom approved suppliers of subsidised energy efficient motors to the South African industrial sectors.
This means that, in future, companies looking to replace old electric motors with energy efficient motors through ABB will qualify for an Eskom subsidy on each new efficient motor purchased. In South Africa, the ABB group has a strong local manufacturing capability with seven manufacturing sites around the country. The company is known for introducing technologies such as FACTS (Flexible AC Transmission Systems) that help make the transmission and distribution of electricity more energy efficient. It has also developed technologies that reduce losses in distribution.
Commenting on ABB’s future role in the Eskom energy efficient motors programme, Oren Prato of Eskom DSM said that since the commencement of Eskom’s Energy Efficient Motors Programme, suppliers who are registered on the programme have found a huge increase in demand for EFF1 motors. Their stock holding in EFF1 motors has increased by approximately 30%. This is great news for the programme, Eskom and the country.
Prato further explained that the Eskom subsidy scheme, which applies to registered suppliers of energy efficient motors, enables the cost of these motors to be reduced. Any added costs are quickly amortised by the significant savings that can be achieved by running energy efficient motors in plants.
Motors that qualify for the subsidy range from 1.1 kW units to 90 kW motors. The 1.1kW units will qualify for a subsidy of R400. At the top of the range, the 90kW unit subsidy will be R 3 500. Added to this direct subsidy, must be the significant operating savings that are achieved. A 22kW energy efficient motor will include a R 1 400 once-off subsidy on the catalogue price and produce energy savings of 9,056kWh/ a year or R5 071 a year.
Companies taking advantage of the offer are required to return their old EFF2 or EFF3 motor- with all components (stator and rotor) intact- to the suppliers when they make the purchase of a new EFF1 motor. The old motors are then scrapped in a process monitored by independent auditors appointed by Eskom.
Anton Henning, Sales Manager (LV motors) ABB, said that ABB felt strongly about the use of energy efficient motors in South Africa and was working hard to educate users about their benefits.
“There is a need for the message that Eskom is serious about the subsidy programme to be constantly heard. We are doing our best to be an active part of the process,” Henning said.
Commercial and industrial criteria apply to all suppliers wishing to participate in the programme. Once approved, a supplier’s details will appear on Eskom’s Demand Side Management website at www.eskom.co.za/dsm. The site also carries full subsidy details. Potential suppliers and those wishing to obtain more information can do so through contacting the EE Motors Help Desk on (011) 800 4744 for details
