Preksha Vichare

will propose a doctoral thesis entitled,

Mechanical role of porous mesh for improved dewatering

On

Thursday, April 23 at 10:00 am
EBB Krone 4029

And

Virtually via

https://teams.microsoft.com/meet/24976321543276?p=ANkvYNTOTzqcYcTy16

Meeting ID: 249 763 215 432 76

Passcode: dG9Y6Q9w

Committee
            Dr. Blair Brettmann – School of Materials Science and Engineering (Advisor)
            Dr. Victor Breedveld – School of Chemical and Biological Engineering (Co-advisor)
            Dr. Christopher Luettgen – School of Chemical and Biological Engineering

            Dr. Donggang Yao– School of Materials Science and Engineering

            Dr. Mary Lynn Realff– School of Materials Science and Engineering

Abstract

The papermaking process is highly energy-intensive, with the drying stage accounting for up to 50% of a paper mill’s total energy consumption. To reduce this energy demand, one promising approach is to maximize water removal during the forming and pressing stages prior to evaporation. During pressing, the wet paper is compressed against a felt to drive water out of the paper and into the felt. However, during decompression, the paper web undergoes pore expansion, leading to undesired return of water (rewet). Introducing a stiff, porous mesh layer between the paper and felt improves dewatering by disrupting the liquid bridges that flow back into the fibrous paper. This thesis investigates how the design and intrinsic properties of the mesh porous layer affect dewatering. This includes evaluating the role of mesh geometry, understanding how stress distribution from these porous layers affects the wet fibrous paper, and analyzing transient behavior during compression-decompression cycles.

In the first part of this thesis, I will investigate how the void volume of the mesh provides pathways for fluid to travel between the paper and the felt. I will also study how stacking multiple porous mesh layers between the paper and felt affects dewatering performance. In the second part, I will focus on the role of pressure distribution, specifically how uniform stress and compaction of the paper sheet affect the efficiency of the dewatering process. In the last part, I will examine time as a key process variable and evaluate its influence on the overall pressing system during cyclic pressing. Overall, this research seeks to develop a framework to optimize the mesh–felt system and improve dewatering efficiency by understanding the interactions among layered porous materials during press cycles.