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Title: Drying of fiber webs

A process and an apparatus are disclosed for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquefied eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten mediamore » does not appreciatively stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers. 6 figs.« less
Inventors:
Issue Date:
OSTI Identifier:
462848
Assignee:
PTO; SCA: 320303; PA: EDB-97:061538; SN: 97001767254
Patent Number(s):
US 5,619,806/A/
Application Number:
PAN: 8-605,519
Contract Number:
FG03-95ER81982
Resource Relation:
Other Information: PBD: 15 Apr 1997
Research Org:
Harvest Technology
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; PAPER INDUSTRY; DRYERS; EVAPORATION; HEAT TRANSFER FLUIDS; HEAT RECOVERY; VAPOR CONDENSATION; ENERGY EFFICIENCY