接枝PVDF膜吸收器中CO2吸收特性和传质规律的研究

CO2 Absorption Characteristics and Mass Transfer Performance in Grafted PVDF Hollow Fiber Membrane Contactor

摘要:

本文以CO2为吸收气体，NaOH为吸收液，研究了N－异丙基丙烯酰胺（PNIPAM）接枝的PVDF中空纤维膜吸收器吸收二氧化碳的吸收特性以及传质规律，并建立膜吸收器中二氧化碳的传质模型。研究结果表明：PNIPAM接枝PVDF中空纤维膜吸收器的CO2吸收率随吸收液浓度和吸收液的流量的升高而升高，随气体流量升高而降低；在实验操作条件下，较佳吸收二氧化碳的工艺参数为：吸收液浓度为0.4 mol/L，吸收液流量为16 L/h，气体流量为250 L/h，气液两相流动方式采用逆流方式。此时，二氧化碳的吸收率接近100%；而对二氧化碳气体吸收过程中传质的研究得出，总传质系数KG=17.5?26.3×10-5 mol?m-2?s-1?KPa-1，传质通量NCO2=3.8?7.6×10-6 mol?m-2?s-1；采用PNIPAM接枝PVDF中空纤维膜吸收器，NaOH水溶液吸收CO2具有良好的吸收效率。

Abstract:

In this paper, CO2 absorption characteristics and mass transfer performance in N-isopropyl acrylamide (PNIPAM) grafted PVDF hollow fiber membrane contactor using NaOH solution as absorbing liquid to absorb carbon dioxide were studied, and then mass transfer model of CO2 absorption was established. The absorption rates of carbon dioxide in PVDF hollow fiber membrane contactor was improved by the increase in the concentration and flow rate of absorbing liquid, while decreased with gas flow. The optimal processing parameters for absorbing CO2 via grafted PVDF hollow fiber membrane contactor were: 0.4 mol/L of absorbing liquid concentration, 16 L/h of flow rate of absorbing liquid, and 250 L/h of gas flow rate at a counter flow of gas against absorbing liquid. Under the above operating conditions, the absorption rate of carbon dioxide was nearly 100% and total mass transfer coefficient is KG=17.5?26.3×10-5 mol?m-2?s-1?KPa-1. The mass transfer flux was about NCO2=3.8?7.6×10-6 mol?m-2?s-1. The characteristics of absorption of CO2 for grafted PVDF membrane contactor were of good efficiency of absorption.