CO₂ Capture And Characterization Of Hollow Fiber Membrane-cryogenic Hybrid Technology

With the continuous improvement of production and life,a large number of greenhouse gases have been emitted.So the climate change represented by the greenhouse effect is more and more serious,which has already endangered the earth environment that people depend on.Therefore,the main greenhouse gas?such as CO₂?emissions should be strictly controlled.One of the main sources of CO₂ is coal-fired flue gas.So how to efficiently capture CO₂ in flue gas has become a research hotspot in the field of science and technology.It has important research significance and application value.This paper adopts hollow fiber membrane-cryogenic hybrid technology.The advantages of membrane separation and cryogenic distillation can be complementation.This hybrid technology does not need too low temperature of pure cryogenic distillation technology,so reduce energy consumption,also do not need membrane material with high performance,so reduce complex modification of membrane materials.In this paper,a set of membrane performance and gas separation efficiency evaluation device was built.The influence of temperature on membrane performance and gas separation effect was studied.Further study the other parameters?pressure,stage-cut,CO₂ concentration in flue gas?effect.In view of the actual industrial operation,it is the interaction of many factors.So I use the response surface method to analysis the interaction of multiple variables?temperature,pressure,CO₂ concentration in flue gas?and seek the optimal process parameters.The temperature dropped from 40?to-20?,CO₂ permeance,CO₂/N₂ selectivity,CO₂ purity and CO₂ recovery of polyimide membrane respectively reached 154 GPU,8.2,48%and 94%;CO₂ permeance,CO₂/N₂ selectivity,CO₂ purity and CO₂ recovery of polysulfone membrane respectively reached 17.4 GPU,18.9,73%and 26%.Low temperature does improve the performance of membrane and gas separation effect.It shows that the membrane-cryogenic hybrid system has advantages.According to response surface method,when the temperature was-16.54°C,the pressure was 0.7MPa,the CO₂ concentration in flue gas was 19.39%,polyimide membrane had optimal performance:CO₂ permeance was 160.2,CO₂/N₂ selectivity was10.1,CO₂ purity was61%and CO₂ recovery was 78%.When the temperature was 8.43°C,the pressure was0.7 MPa,the CO₂ concentration in flue gas was 20%,polysulfone membrane had optimal performance:CO₂ permeance was 17.4,CO₂/N₂ selectivity was 18.9,CO₂purity was 73%and CO₂ recovery was 26%.High pressure and high CO₂ concentration in flue gas resulted in good performance of membrane.The polyimide membrane was more suitable of the low temperature than the polysulfone membrane.The polyimide membrane had higher CO₂ permeance and CO₂ recovery.The polysulfone membrane had higher CO₂/N₂ selectivity and CO₂ purity.The results are consistent with the single factor experiment.