THE EVAPORATION OF VISCOSE PROCESS LIQUORS
A programme of work aimed at producing designs for an energy efficient process for the evaporation of water from viscose process liquors has been completed. The process uses mechanical vapour recompression in conjunction witha thin plastic heat transfer surface. Physical properties of the process liquors have been measured. Thermal and long term mechanical properties of the plastic, which is a cross-linkable polyethylene, have been determined. A bench laboratory evaporation rig was built to prove the technical viability of the process. This was followed by the construction of a research plant at a viscose production site. The capacity of this plant was 100-150 kg/hour of water evaporated. The engineering of the research plant produced a number of technical challenges. Among these, the construction and operation of a plastic heat exchanger with thin walled plastic tubes, was achieved with considerable success. The lining of the concrete containment vessel proved more difficult, and the technique employed may not be the best for commercial units. Heat transfer coefficents of up to 550 WmRU-RU2 K**-1 were measured on the research plant. These agreed well with results obtained from a mathematical model developed for the process. Values of around 750 Wm**-2 K**-1 should be achievable on a commercial plant. An optimum design for a commercial unit has been costed and the financial parameters determined. Simple payback times of around 1.2 years are possible. These figures are very attractive, and Courtaulds considers that the construction of a demonstration plant is justified.
Bibliographic Reference: EUR 9403 EN (1984) MF, 24 P., BFR 120, BLOW-UP COPY BFR 150, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989123016100 / Last updated on: 1987-01-01
Available languages: en