Experimental Study On Zeolite/Hygroscopic Salt Composite Adsorbent For High-temperature Heat Pump

As a kind of system to recycle industrial waste heat effectively,adsorption heat pump can provide unlimited possibilities for solving energy and environmental problems.In this thesis,the adsorptive steam generation system based on direct contact heat exchange method is improved from the aspects of adsorbent material and process enhancement.The main work and conclusions are summarized as follows:?1?Zeolite 13X-CaCl₂ and zeolite 13X-MgSO₄ composite adsorbent were prepared by impregnation method,and the highest contents of the two hydroscopic salts in composite adsorbent are 22.55%and 13.38%,respectively.Then the prepared composite adsorbents were characterized by using different methods.XRF confirmed the presence of inorganic salt in the composite adsorbent.SEM determined the adherence of CaCl₂ to the zeolite 13X after the composite process.BET judged that the composite process has a great influence on the internal pores inside zeolite 13X.Measured equilibrium water uptake and adsorption heat of 13X-CaCl₂ are greatly improved by 56.16%and 13.14%compared with zeolite 13X,and an increase of 29.76%and 6.13%of 13X-MgSO₄.?2?The prepared composite adsorbent was applied to the adsorption system to investigate the effect of inorganic salt type and compound degree on the system performance.Cyclic stability of prepared adsorbents was tested.The experimental and testing results show that:i.Steam above 200°C was generated under the inlet water at80°C and inlet gas temperature of 130°C when composite adsorbent was employed.ii.Steam generation time is prolonged leading to the rise in steam mass under the same regeneration condition.The steam mass produced by zeolite 13X-CaCl₂ and zeolite13X-MgSO₄ are 12.97%and 8.85%higher than that of the zeolite 13X.System heating power is elevated by 12.46%.iii.It is found that zeolite 13X-MgSO₄ composite adsorbent has better durability after 10 cycles of test.The CaCl₂ content stabilizes at67.62%of initial value after 3 cycles,while the content of MgSO₄ needs 6 cycles to stabilize,and the final remaining value is 72.38%.?3?Heat and mass recovery process was introduced to the adsorption system with zeolite 13X-CaCl₂ composite adsorbent and the influence of different recovery temperature on system performance was investigated.Based on the analysis of the experimental results under two recovery temperatures of 80°C and 90°C,it is concluded that:i.The introduced recovery process can effectively prolong the steam generation time and elevate the mass of steam generated.The steam generation time is extended by 5.00%and 18.33%,respectively,and the steam mass is increased by 6.06%and 9.12%,respectively,under the two temperatures.ii.System performance is greatly improved with heat and mass recovery process.The system exergy efficiency and specific heating power are raised by 7.02%and 9.23%.iii.Increasing the recovery temperature can improve the system performance effectively.