THROUGH DRYING

• Through drying is a process in which a hot, unsaturated gas is forced through a wet, porous material by imposing a pressure differential across the material.
• As the gas passes through the porous material, the gas heats the material and supplies energy to evaporate the water. The gas leaves at a reduced temperature and increased water vapor concentration.
• In the paper industry, this process has found its greatest application in the drying of lightweight, permeable webs, such as tissue, toweling, filter paper, and Nonwovens . In such applications, the through dryer may be of either the flat bed or the rotary design.
• The gas can be heated either indirectly through a heat exchanger or directly by mixing with the products of combustion of a clean fuel.
• The drying of paper and packaging grades is defined (TIP 0404-07 “Paper Machine Drying Rate”), in terms of the total cylinder area, even though the actual heat transfer to the sheet takes place over the contact area of the cylinder.

It Provides information on:

• Thermodynamic description of the drying process.
• Energy consumption.
• Permeability.

It Benefits:

• Engineers.
• Researchers.
• Laboratory Personal.