Liquid Desiccant Process Simulation And Investigation For Working Fluid Spray Regeneration

Liquid desiccant absorption dehumidification can utilize the low-grade energy, take the place of electricity power. The system also can control the temperature and the humidity independently, and improve the quality of the air. So, this system is a potential technique of adjustment of air condition in view of protecting environment and saving energyThis essay analyses the mechanism of dehumidify and regeneration process for liquid desiccant system with thermodynamics method on the basis of summarizing the physical properties of lithium chloride solution and humid air. Both of dehumidification and regeneration are heat and mass transfer process driven by pressure difference between vapour pressure of wet air and vapor pressure of LiCl solution. Low temperature and high concentration of the solution is beneficial for dehumidification process; high temperature and low concentration solution is beneficial to the conduct of regeneration.In this essay, the simulation of liquid desiccant system is available by ASPEN PLUS. In order to improve system performances, we introduce the splitter and intercooler on the basis of traditional technology. The results show that the introduction of splitter could reduce the solution circulation flow rate. Through this method, the heat load at the regeneration side has reduced by 5.5%, meanwhile the cold water of the regeneration process and device size is decreased. The introduction of multi-level dehumidification which works in the middle of the cooling wet system has helped the dehumidification increased greatly by 12.7% and regeneration wind reduced by 5.2%, indicating that appropriate heat (cold) compensation could make the mass transfer and heat transfer more matched in the process of dehumidification and regeneration, so that achieving better dehumidification effectiveness and energy efficiency. The structure of dehumidifier has been improved by cooling the side draw, which makes the dehumidify quality increase by 10.6% compared to ordinary adiabatic dehumidifier.This essay aims at researching the regeneration process, which is the key processes of the liquid desiccant system. In this research, we design and build laboratory-scale spray lithium chloride solution regeneration device, with 32%-33% of lithium chloride solution as the work fluid, and a pressure nozzle as the atomizer, which improves the maximum concentration of solution to 1%-3%. In this research, we investigated the influence of operating parameters such as preheating temperature, atomization pressure and renewable liquid to gas ratio on regeneration effect. The result are as follows:it is suitable to regenerate for the spray when the temperature is 70℃-85℃, the solution concentration increases with the increase of preheating temperature; The most suitable atomization pressure is 0.3MPa-1.0Mpa, the change in solution concentration increased with the increase of atomization pressure, but the increasing trend is getting smaller and smaller; the change of solution concentration reduces greatly with the increase of liquid to gas ratio, and the best ratio of liquid to gas is 0.8-1.2.