Industrialized Application Research On Infrared Drying In Silk Re-reeling Process

During the silk re-reeling process, re-reeled silk slices were dryed by infrared dryingtechnology instead of conventional steam pipes radiation drying, the aim of it was to overcomethese shortcomings existed in the steam pipes radiation drying, such as large steam consumption,low thermal efficiency, high quantity of sulfur dioxide emissions, and poor working environmentfor workers(the temperrature of the workshop in summer can reach around42℃), ect. Theobjective of this investigation was to provide a reference to seek a new non-polluting dryingmethod which possesses high thermal efficiency, low energy consumption and can improve theworking environment of workers.Firstly, re-reeling prototype machine with infrared heating and drying system was designedand processed in laboratory scale. The silk of specification20/22D was dried by infrared andsteam pipes respectively. The microstructure and properties of the silk which have been driedwere measured, analyzed and compared by FTIR, SEM, XRD and tensile tester, observing theeffect of infrared drying on the structure and propertied of the raw silk and exploring thefeasibility of infrared in the drying process. Secondly, two kind of raw silk (20/22D,40/44D)were used and dried by infrared on the basis of the feasibility of infrared drying on the raw silk,studying the optimal processing parameters of infrared drying system such as temperature andhumidity. The energy consumption was measured by the meter and the energy-efficient ofinfrared drying was evaluated comparing with conventional steam drying. Quality indicators ofraw silk which have been treated by infrared drying were evaluated via authoritative testorganization. Lastly, fundamental to the success of small scale prototype, middle scale pilot ofinfrared drying equipment was researched. Under the premise of well operation of middle scaleequipment and the stability of produce quality, industrialization equipment would be furtherdesigned and applied to produce.The results showed that infrared drying had no effect on the micro-structure andphysico-chemical performance of raw silk, which proved the feasibility of using infrared dryingas an alternative to conventional steam drying for re-reeled silk slices drying in practical production. For raw silk of22/22D and40/44D, the best temperature and humidity by infrareddrying are32-35℃,45-48%and36-39℃,44-48%, respectively. Compared with conventionalsteam pipes drying, the temperature of the re-reeling machine compartments using infrareddrying can be lowered about15°C, the energy consumption dropped by more than50%and theenergy-saving effect was significant, thus reducing the production costs considerably andimproving the working environment in summer effectively. Furthermore, for re-reeled silk slices,the heating effect of medium infrared was better than that of far infrared. Raw silk dried bypilot-scale and industrialization equipments was tested for quality inspection by Silk InspectionCenter of Zhejiang Inspection and Quarantine Burenu, the grade of infrared-dried raw silk wasidentical to the one that was dried by steam pipes, and they all reached the5A grade which metthe practical production requirements compeletely.The new re-reeled infrared drying technologyshowed a good demonstration effect and promotion value in the actual production, and theprospects for industrial application was promising.