TECHNICAL SHOWCASE

Energy reduction an ongoing process at Metso

New process solutions and energy efficient equipment have helped Metso reduce total energy consumption in tissue lines by 20% from 2850 kWh/ton to 2280 kWh/ton since 2007, the company says. The target, when running at 100% energy efficiency, is to operate below 2000 kWh/ton or at about 30-35% less than most machines operate today.

Smart design in stock preparation, an optimized layout of the building and process solutions with fewer pumps and smaller chests have cut energy consumption. Eliminating gear boxes for refiners and a new type of refiner segment also contribute to energy reduction in this area.

The elimination of secondary screening and an improved headbox design are the main reasons for reduced energy consumption in short circulation. Increasing of after press dryness, yankee head insulation and increased exhaust humidity has trimmed energy consumption in drying. New drive systems and reduced drag load have diminished consumption in drives. Replacing conventional water-ring pumps with turbo blowers has reduced consumption in the vacuum system.

NEW FOREFRONT TECHNOLOGIES

NTT press technology is designed to improve solids content to as much as 47%, which gives an additional 12-14% reduction in drying energy consumption. A turbine positioned in the forming section can reduce electric power consumption by about 10%, when at least 50% of the energy from the slice jet flow is recovered to produce electricity. Positioning a steam generator directly after the hood, but before the air/air heat exchanger enhances the overall efficiency of the heat recovery system. Further information: Jan Erikson, vice president sales, Metso, Tissue Business Line - +46 5417 1490; or Börje Sandgren, senior product manage energy, Metso, Tissue Business Line - +46 5417 1265.