摘要 |
Non-aqueous solvents are removed from a web material, e.g., paper, by contacting the material with a condensable, heat transfer vapor, e.g. saturated steam, in countercurrent fashion. The heat transfer vapor is employed in the process in amounts of at least 50% by weight of the solvent to be removed. The process allows effective and efficient total removal and recovery of the solvent without damage to the web material. The condensable heat transfer vapor, as well as being the source of energy for evaporating the solvent, acts as a solvent vapor carrier. Condensation of the mixture in a recovery apparatus, e.g., condenser or still, allows easy recovery of the solvent.
|