A Principle of Producing Multi-ply Paper Using a Wire in an Inclined Wire Machine

In this study,we improved the dispersibility of the stocks in the headbox of an inclined wire machine to produce a distinct paper,and analyzed some factors affecting paper formation in the production of multiply paper.We used FLUENT6.3 to analyze the flow of the stocks in the headbox and select the structure of the diffusion part required for improving the dispersibility of fibers.Moreover,based on a simulation experiment,the optimal rational angle of the diffusion part(g)was found to be approximately 8°~10°,and it improved the paper formation in the case of usage of two plates.Using the equation for the formation of paper layers in the headbox of an inclined wire machine,we obtained a paper with the given basic weight by controlling the inclined angle of the wire(a),initial height of water(H),and concentration of the stocks.We considered the effect of a and H of the stocks in the headbox on the fiber distribution,and according to the results,a should be set as approximately 20°~30°and H should be maximally high.When producing multi-ply paper by a wire,the line pressure of the couch roll should be maintained at 1.8~2.0 kN/m to avoid the damage to the paper sheets.In addition,we found the optimal structure parameter of the dehydrated roll was as follows:hole ratio of approximately 30%of the dehydrated roll surface area,width of 1.5~2.0 mm,slot pitch of 5~6 mm,slot depth of 2~3 mm,and inclined angle of diffusion part(b)of 5°.

CFD modeling of a headbox with injecting dilution water in a central step diffusion tube

For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to examine the predictability of CFD model for the headbox in industrial scale,two pulp suspensions before mixing were treated as homogeneous flows separately.Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations.A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure–velocity coupling.Results show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube,and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.

Efficient Management of Fines in the Stock Flow prior to Headbox in Paper,Board,and Tissue Production

Fines represent a significant volume of biobased wood material and filler,which is of significant importance to sheet quality.New imaging technology reveals the true nature of the behavior of fines in the retention process.This study illustrates new chemical mixing systems,novel and efficient flash mixing methods,and active measurement and automation systems pertaining to efficient management of fines in the stock flow prior to headbox in paper,board,and tissue production,which can reduce additive,fresh water,energy consumption,and the carbon footprint of production to improve sustainability and provide novel opportunities for fines and filler management.