Research And Optimization On Performance Of Low-Temperature Adsorption Desiccant Material

The development of our life has created the demand for all kinds of fresh food. The problems of evaporator frosting and the high energy consumption are serious. Even more, the evaporator frosting could destroy internal structure of the evaporator and cold storage. Solid adsorption desiccant technology is the use of solid adsorbent cooling air inside the steam, saturated steam corresponding to the water vapor content is reduced to the heat exchange with the evaporator temperature pressure, so that the water vapor will not be liquefied, there would be no condensation and frost. Dehumidification technology with solid absorbent comes under increasing scrutiny.The research of solid, liquid, gas phase equilibrium system has be done, and the closed humidity control system is set up with solution, MH (metal halide) and the air. An experimental system of performance measurement of adsorption material with controlled temperature and relative humidity has been established. We tested and analyzed the absorption performance of Metal halide, molecular sieve, metal halide and molecular sieve composite adsorbent. Impregnation method has been taken to composite the chemical adsorption and physical adsorbent.According to the Clausius-Clapeyron equation of water vapor and adsorption, the chemical reaction enthalpy and entropy of sodium bromide, lithium bromide, lithium chloride were calculated. Through experiment, Molecular sieve and the adsorption performance of composite adsorbent would decrease with the decrease of temperature. At the same temperature, the adsorption quantity of5A is slightly larger than13X, and the adsorption quantity of composite adsorbent with13X is larger than that with5A. The reason is that, it is more likely to be blocked for the smaller pore5A by metal halide. Compared with the metal halide, although the adsorption capacity of the composite adsorbent has no advantage, the composite adsorbent has a fixed shape. Also, for the improvement of the heat and mass transfer, the study laid the foundation for the future of the adsorbent bed. Compared with the simple physical adsorption agent, adsorption tendency of composite adsorbent with similar, but the adsorption properties are greatly improved.13X-20%-NaBr at the temperature of-15℃,-10℃,-5℃, compared with13X, the adsorption amount increased by about3.3times,2.3times,1times.It is the proof of composite adsorbent prepared to play the good effect.Experimental study on preparation and dehumidification performance of composite adsorbent carried out in this paper, which provides the basic data and theoretical guidance used in cold frost system for the solid desiccant dehumidification technology, It plays a great role in saving energy and reducing consumption in cold storage.