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
Commercial

Shoe (Extended Nip) PressCosts & Benefits

Parent Process: Papermaking
Energy Savings Potential

Achieveable energy savings through the installation of shoe press range from 2 to 15% depending on product and plant specifications.
The application of the X-NIP T shoe press in tissue plants is estimated to reduce drying energy use by 15%(Kramer et al., 2009. p.103).

CO2 Emission Reduction Potential
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).