基于改进型吸附等温线模型的空气预纯化TSA双层床模拟

Simulation for air pre-purification by TSA in a two-layer bed based on a modified adsorption isotherm model

为了掌握空气中CO2和水蒸气在空分装置双层床变温吸附(TSA)纯化器中的动态吸附特性,通过LDF传质假设及非绝热假设,建立了一维二元稀组分系统的双层床TSA过程数学模型。一种改进型的多组分等温线模型用于描述水蒸气的Ⅱ型吸附等温线以及水蒸气和CO2混合物的吸附平衡关系。通过对比模拟结果与TSA纯化器的现场监控数据发现,基于改进型等温线模型的模拟结果与现场数据吻合良好。最后对多种工况下的TSA纯化器中的温度、浓度及吸附量床层分布和穿透曲线进行了数值模拟和分析。

The adsorption and thermal desorption dynamics of water vapor and carbon dioxide in a temperature swing adsorption （TSA）purification system with a two-layer bed of zeolite 13X and activated were studied in this work.The simulation was based on the linear driving force mass transfer approximation and non-adiabatic model for the one dimensional and dilute system.The modified model,which can describe Type Ⅱ isotherm of water vapor,was used to fit the adsorption equilibrium data and estimate the adsorption equilibrium for the mixture of water vapor and carbon dioxide.The simulation results were in good agreement with the data from a commercial scale TSA unit.Under a wide range of operation conditions,the bed temperature and concentration profiles,the effluence and breakthrough of adsorption were studied.