Heat And Mass Transfer Process Research Of Liquid Desiccant System (Droved By Low Temperature Flue Gas)

In the existing industrial air dehumidification project, refrigerationdehumidification technology has been widely applied to remove moisture aftercooling the air temperature to the dew point. Refrigeration dehumidificationtechnology has the advantages of widely-used, but the need for power (compressionrefrigeration) or steam (absorption chiller) high-grade energy as the driving force. Itnot only consumes high-grade energy, but also the cooling air need reheated, that willcost further part of the energy consumption. This paper presents a self-use style LiBrliquid desiccant system，to recover the low temperature flue waste heat of furnacesand other emissions of metallurgical and other industrial enterprises. Use these heat toget the solution regenerated, and then the system is applied to the furnaces themselvesblast dehumidification to achieve the production of low temperature flue waste heatfor their own consumption. This paper carried out the following work:First, the dehumidification and regeneration experiments were carried out on theliquid desiccant experimental system, and the parameters affecting the performance ofdehumidification and regeneration were analyzed. The dehumidifier volume masstransfer coefficient can reach up to2.4to4.0kg/m3s, with the solution temperature of20to39℃, concentration of49%to54%; The regenerator volume mass transfercoefficient can reach up to3.0to6.0kg/m3s, with solution temperature of40to62℃,concentration of49%to54%. Better regeneration performance will be got under theliquid-gas ratio of4.0. The energy balance error of dehumidification and regenerationprocess does not exceed30%, and it being basically conserved. The expression of airhumidity and enthalpy of phase interface were analyzed by least squares. By usingmultiple regression approach, the functional relations were got between thedehumidification capacity, regeneration capacity and the air inlet parametersrespectively and also conducted a regression analysis on the mass transfer coefficient,and got the calculation expression of the Sherwood number, providing a reference fortheoretical research and system applications.Secondly, on the one hand, on the basis of the theory of heat and mass transfer,a counter-flow heat and mass transfer model was established by discrete numericalsolving method, The other hand, the constant coefficient differential equations weregot by simplifying the basic relationship of heat and mass transfer process, andsolving the equations to get the description of the distribution law of the internalsolution and air parameters of the dehumidifier (renewable) analytical solution.Compare the numerical solution, the analytical solution and regenerationexperiments, and get the numerical solution fits the experimental value well than theanalytical solution. However, due to the tower body and pipes without insulation andother reasons, numerical solution and experimental data have a certain bias, thenumerical solution of the model needs to consider the boundary heat transfer. Improvenumerical solution by introducing boundary heat transfer item in the model of heattransfer equation to get the numerical solution closer to the experimental value thatare used to be applied in following-up system circulation research.Finally, use the numerical solution model to analysis the level of concentration corresponds to the dehumidification and regeneration cycle respectively. Thenanalysis the level of the steady state parameters in the liquid desiccant system withinternal circulation under different circulation flow. And provide a reference to studiesof liquid desiccant dehumidification system cycle.Low-temperature waste heat Self-use style LiBr liquid desiccant system can notonly save the high-grade energy such as electricity and steam, but also broaden thescope of low temperature waste heat recovery. Using the liquid desiccant system torecover waste heat has great application prospects for industrial low-temperature fluegas heat recovery, and has great significance for the industrial areas of "energyconservation".