Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.

Proposed modifications in yankee hood

To increase production on Yankee paper machines.

  • Soyez le premier à commenter

Proposed modifications in yankee hood

  1. 1. Proposed Modifications inProposed Modifications in Yankee HoodYankee Hood Concept: D K Singhal deveshksinghal@gmail.com
  2. 2. Yankee HoodYankee Hood A lot of work has been done on design, optimization and control of yankee hood already. Still, there are few other possibilities toStill, there are few other possibilities to increase production from yankee hoods. The purpose of this presentation is to present first hand information about some of these possibilities. Proposed Modifications inYankee Hood, June 2015 2
  3. 3. Type of Heating MediumType of Heating Medium Yankee hoods can be of direct fire type, or may use alternate source of thermal energy like thermic fluid or steam to heat the air; which is impinged on the surfacethe air; which is impinged on the surface of paper over yankee dryer. Proposed Modifications inYankee Hood, June 2015 3
  4. 4. Type of Heating MediumType of Heating Medium Generally, it is the mills decision to decide upon the type of heating medium considering the expected production, cost and availability of fuel, amount ofand availability of fuel, amount of investment required etc. Proposed Modifications inYankee Hood, June 2015 4
  5. 5. Typical Hood DesignTypical Hood Design Typical hood design has two sections,WE (wet end) and DE (dryend) and DE (dry end) and the air system is a cascading one. Proposed Modifications inYankee Hood, June 2015 5
  6. 6. Overview ofYankee DryingOverview ofYankee Drying It has been found by many researchers that the paper moisture profile along the machine direction –or along yankee- reduces (almost) in a linear trend.reduces (almost) in a linear trend. A typical graph of the same is shown on the next slide. Proposed Modifications inYankee Hood, June 2015 6
  7. 7. Typical Drying CurveTypical Drying Curve Proposed Modifications inYankee Hood, June 2015 7
  8. 8. Moisture RemovalMoisture Removal From the curve shown on the previous slide, one can understand a major part of water vapor is removed from the wet end side of the hood.side of the hood. If we calculate, on the basis of linear trend of paper moisture profile, we may calculate that more than 75% of the water removal is being done in the wet end section of the hood. Proposed Modifications inYankee Hood, June 2015 8
  9. 9. Typical CalculationsTypical Calculations Position Moisture Water Removed Inlet to Wet End 65Inlet to Wet End 65 Wet End to Dry End 35 73% After Dry End 5 27% Proposed Modifications inYankee Hood, June 2015 9
  10. 10. Using a Three Segment HoodUsing a Three Segment Hood High moisture removal from wet end hood gives a clue to split a part of the wet end exhaust in two parts.This way, in place of two, hood will contain three sections with cascading arrangement.Thus, moisturecascading arrangement.Thus, moisture removal will be much lesser in last section thus meaning less humidity in hood and hence better production rates.A typical moisture removal pattern will look as shown on next slide. Proposed Modifications inYankee Hood, June 2015 10
  11. 11. Typical CalculationsTypical Calculations Position Moisture Water Removed Inlet to Wet End 65 Proposed Modifications inYankee Hood, June 2015 11 Middle of Wet End 45 58% Inlet to Dry End 25 27% Out from Dry End 5 16%
  12. 12. Reduced Air DrynessReduced Air Dryness As one can see less water vapor being removed from paper in the third section (16% against 27%), which means drier air and hence increased drying rate andand hence increased drying rate and production. Proposed Modifications inYankee Hood, June 2015 12
  13. 13. Use of PocketVentilationUse of PocketVentilation On most MF machines, PV has been used since long. However, the application of PV is limited in MG (Yankee) paper machines maybe because of space constraints.maybe because of space constraints. Next slide contains a sketch of a yankee machine. Proposed Modifications inYankee Hood, June 2015 13
  14. 14. Sketch of aYankee MachineSketch of aYankee Machine Proposed Modifications inYankee Hood, June 2015 14
  15. 15. Location of PV BoxLocation of PV Box In the next slide, a typical position of blow box (PV Box) has been shown. Normally, the vapor generation in this section is so high that several mills havesection is so high that several mills have mounted exhaust fans to spread away water vapors generated in this area. Position of proposed PV box is given in the next slide. Proposed Modifications inYankee Hood, June 2015 15
  16. 16. Proposed PV Box PositionProposed PV Box Position Proposed Modifications inYankee Hood, June 2015 16
  17. 17. Other PositionsOther Positions If space permits, another PV box can be positioned between the two touch rolls. In some cases, it may be required to reposition/redesign the felt circuits forreposition/redesign the felt circuits for the same. Such a position is shown on next slide. Proposed Modifications inYankee Hood, June 2015 17
  18. 18. Another PositionAnother Position Proposed Modifications inYankee Hood, June 2015 18
  19. 19. Please do share your experiences, knowledge and comments about this.knowledge and comments about this. Proposed Modifications inYankee Hood, June 2015 19
  20. 20. ThankYou. Proposed Modifications inYankee Hood, June 2015 20
  21. 21. About the Author: Born in 1968, D K Singhal is B.E., M.E. (Pulp & Paper, 1993) from Deptt. of Paper Technology, University of Roorkee (now IIT, Roorkee). He is a Certified Energy Auditor and Chartered Engineer also. With nearly 7 dozen publications, he has emphasized on development of low cost technologies and management practices for quality and profitability improvement. With publications on slideshare.net, energymanagertraining.com and paperonweb.com, he has been constantly contributing to IPPTA (Indian Pulp & PaperTechnical Association). He is also serving IPPTA as a member of Editorial Board.Board. An initiative by D K Singhal, a cyber campaign initiated against unjustified targeting of paper industry by “Idea” mobile, in their “Sirjee” advertisement campaign, after which this advertisement was taken off air. He also moderated aYahoo group,“PaperTechnology” with nearly 360 members from India and abroad to discuss problems related to pulp & paper making for five years. He can be contacted at deveshksinghal@gmail.com 21 Proposed Modifications inYankee Hood, June 2015

×