Shoe (Extended Nip) Press
Once the paper is formed, it is pressed to remove as much water as possible. Usually, pressing occurs between two felt liners pressed in between two rotating cylinders. Extended nip press uses a big concave shoe instead of one of the rotating cylinders. The additional pressing area increases residence time in the nip and allows for more water extraction (approximately 5 to 7% more water removal) to a level of 35 to 50% dryness. More water removal leads to decreased energy requirements in the dryer, which in turn leads to reduction in steam demand. Furthermore, reduced dryer loads allow plants to increase capacity up to 25% in cases where production is dryer limited. Extended nip pressing also increases wet tensile strength (Kramer et al., 2009. p.103).
Development Status | Products |
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Commercial
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Shoe (Extended Nip) PressCosts & Benefits
Parent Process: Papermaking | |
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Energy Savings Potential |
Achieveable energy savings through the installation of shoe press range from 2 to 15% depending on product and plant specifications. |
CO2 Emission Reduction Potential |
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Costs |
Capital costs have been estimated at $38/ton of paper. Additional maintenance costs are $2.24 /ton of paper(Kramer et al., 2009. p.103). |