固定床吸附分离过程数学模型研究及其在变压吸附CO的应用

Study of Modeling for Fixed-Bed Adsorption Process and Simulation in Experimental CO Separation Through PSA

变压吸附分离过程以其能耗小和高产率的特点日益受到重视,在提纯分离和资源化利用工业尾气部分成分方面为环境工程所利用.本文针对Skarstrom变压吸附的吸附、解吸循环,在线性驱动力和Langmuir组成的传质动力学模型的基础上建立了较为完整的传质、动量和热量的传输耦合模型.模型以固定床吸附提纯工业尾气中CO为实验背景,对吸附、均压以及解吸实验过程作了模拟.模型提出固定床截面面积函数概念,在轴向一个维度上建立模型.模型含有对固态吸附剂吸附量的量化描述.模型分别对吸附和均压两个阶段做了模拟.解吸过程中床层出口流速直接决定解吸速率,模拟结果与实验一致,模型能够正确刻画变压循环的复杂流态动态过程,比静态活塞流假设更加适用于复杂Skarstrom循环,为理论研究和工艺设计提供有力工具.

The Pressure Swing Adsorption （PSA） process is generally preferable in industrial application inclu-ding environmental engineering, due to its high productivity and low energy consuming in gas separation. In this paper a math model is developed for Skarstrom Cycling of PSA operation, coupling with the adsorption kinetics composed by Linear Driving Force （LDF） and Langmnir equation. A relatively complete model considering the integration of mass, momentum and heat dynamic transfer is then proposed, then a simulation of adsorption step and pressure equilibrium step in Skarstrom is carried on. The introduction of the section area variable as a func- tion of axial length of the fixed bed helps model this PSA cycling in one dimension in an objective and accurate manner. The absorbed mass amount on solid particle in fixed bed is dynamically depicted in this model. The ex- perimental background of this simulation is a CO separation process via PSA technique from industrial tail gas. In validation, this simulation yields an agreeable numerical result with the testing data. Compared with fixed bed models based on static plug flow assumption, this model fitting for the variable pressure condition is an effective tool in process optimizing design and researches for PSA technique.