Experimental Study On Deep Dehumidification In Microchannel With Copper Nanowire

Deep dehumidification or ultra-low humidity control plays a very important role in material preparation,chemical industry and microelectronics.For the traditional adsorption dehumidification process,the diffusion process of water molecules to the active sites of adsorbents limits the adsorption rate,and the adsorption quantity of adsorbents to water molecules determines the dehumidification limit of the materials.Therefore,the traditional dehumidification process can not accord with the requirements of low humidity environment in the above areas under the two restriction.Using the advantages of rapid diffusion of microchannels and abundant hydrophilic sites on the surface of copper nanowires,deep dehumidification of moisture was achieved by combining condensation phase transition and adsorption process.The moisture generation system,dehumidification system and dew point detection system were constructed.The dehumidification system was composed of multiple dehumidification unit in series and parallel coupling with temperature controlling system,and the single channel of dehumidification unit was 0.5 mm high,2 mm wide,150 mm effective length.The above units were combined to form a microchannel condensation and adsorption dehumidification system.The visualization of condensation phase transition process was studied by high-speed camera technology and the results showed that the rapid condensation phase transition of wet air occured at the entrance of the microchannel,which made the humidity of wet air decrease preliminarily.Attenuated total reflection Fourier transform infrared spectrum(ATR-FTIR)was used to understand the trapping mechanism of water molecules with copper nanowires under low humidity,demonstrating that the deep dehumidification was achieved by physisorption.The effects of inlet humidity,operating temperature,Re and residence time on dehumidification were investigated.The results showed that the performance of the condensation phase change dehumidification system can be controlled by controlling operating temperature,and the reduction of operating temperature and Re,and the increase of residence time will enhance the deep dehumidification ability of copper nanowires.A condensation-adsorption cascade dehumidification system was constructed.The humidity can be reduced by condensation system primarily,and further dehumidification can be achieved by the adsorption of copper nanowires.Finally,deep dehumidification was achieved by controlling the process parameters,and the dehumidification performance can be further improved by enhancing the diffusion process.