天然气膜法脱碳过程中节流降温行为的研究

Investigation on throttling and cooling behavior caused by CO_(2) permeation from natural gas in membrane process

采用实验室自制的聚酰亚胺(PI)中空纤维膜组件,通过气体节流渗透降温实验装置,系统考察了天然气中主要气体组分、膜渗透速率、组件填充率、操作压力以及放空比等参数对于膜法脱碳过程中气体节流渗透降温规律的影响.实验结果表明,CO_(2)气体表现出最为显著的节流渗透降温现象;膜渗透速率、组件填充率、操作压力等参数的提高会加剧组件内CO_(2)气体节流渗透降温程度,即降温速率变快且降温程度更严重;操作压力为1.5 MPa、进气温度为24.0℃时,膜组件内产生近20℃温降;放空比的提高在一定程度上有利于缓解组件内的温降现象.这些结果揭示了相关参数对膜组件内CO_(2)节流渗透降温行为规律性的影响,为天然气膜法脱碳过程中CO_(2)节流渗透降温行为的预判提供了科学有效的理论依据.

Using polyimide(PI)hollow fiber membrane modules self-made in laboratory,through the gas throttling permeation and cooling experimental device,the influences of main components of natural gas,membrane permeation rate,module packing density,operating pressure and vent flow ratio on CO_(2) throttling permeation and cooling phenomena during carbon dioxide removal by membrane were investigated and analyzed systematically.The experimental results showed that CO_(2) exhibited the most obvious cooling phenomenon,increasing membrane permeation rate,module packing density and operating pressure will aggravate the cooling behavior,that is,the faster cooling rate and the more serious cooling degree.When operating pressure is 1.5 MPa and feed temperature is 24.0℃,the temperature in membrane module generated a maximum drop around 20℃;on the other hand,the cooling behavior will be alleviated to some extent with the increase of vent flow ratio.These results reveal the influences of relevant parameters on the regularity of CO_(2) throttling permeation and cooling behavior in membrane module and provide a scientific and effective theoretical basis for the prediction of CO_(2) throttling permeation and cooling effect during carbon dioxide removing from natural gas by membrane separation.