Research On The Adsorption Performance Of Resin-based Solid Amine For CO₂ In Biogas

Biogas is a kind of renewable clean energy,which can alleviate the environmental problems resulted from fossil fuels（such as coal and oil）to a certain extent.It is produced by the biodegradation of organic matter such as waste or sludge in anaerobic digesters and landfills.Biogas is rich in CO₂,and CO₂ is a difficult-to-decompose gas.If the concentration is too high,it will reduce the calorific value of the biogas and limit its practical application.Therefore,the separation of CO₂ in biogas is very important.To solve this problem,this paper uses organic amine impregnating macroporous resin to prepare resin-based solid amine technology to purify biogas to remove CO₂ in biogas.The solid amine adsorbent was characterized by N₂ adsorption-desorption,fourier infrared spectroscopy（FT-IR）,scanning electron microscopy（SEM）,thermogravimetric analysis（TGA）.The adsorption performance of solid amine adsorbent for CO₂ in simulated biogas was tested by the dynamic separation method under the conditions of 25℃,0.2MPa,and 100ml/min.This study evaluated in detail the effects of the types of carriers and organic amines,the airflow rate,and the adsorption temperature on the adsorption performance of the adsorbent,as well as the regeneration and cycle stability.The main findings are as follows:（1）Use resin（AB-8,ADS-17,D1400,DM130,D3520,D4020）as the carrier,and use polyethylene（PEI）as the organic amine modifier.When the organic amine loading is 20%,the carriers with better adsorbent adsorption effect are AB-8,D1400,and ADS-17.（2）Use resins with better adsorption effects（ADS-17,D1400）as supports.When PEI or TEPA loading was 40%,It is found that the three solid amine adsorbents ADS-17-40%TEPA,ADS-17-40%PEI and D1400-40%TEPA have the largest CO₂ adsorption capacity compared to other solid amine adsorbents of the same series.Besides,the small molecule with different loading the CO₂adsorption capacity of TEPA impregnated resins was higher than that of PEI modified resins,but the PEI impregnated resins had better thermal stability.On the other hand,when the same organic amine was applied,the D1400 series solid amine adsorbents have a higher CO₂ adsorption capacity than the ADS-17 series solid amine adsorbents.（3）The resin-based solid amine ADS-17-40%TEPA,ADS-17-40%PEI,D1400-40%TEPA were selected to test the adsorption temperature and flow rate.Under the conditions of 0.2MPa and100ml/min,when the adsorption temperature changes from 25℃to 90℃,the amount of CO₂adsorbed by the solid amine adsorbent gradually decreases with the increase of adsorption temperature.When the pressure is 0.2MPa,the temperature is 25°C,and the gas flow rate increases from 100ml/min to 200ml/min,the CO₂ adsorption capacity of ADS-17-40%TEPA and ADS-17-40%PEI gradually increases.The CO₂ adsorption capacity of D1400-40%TEPA did not change significantly.（4）In the regeneration process,under the conditions of 0.2MPa and 200ml/min,the CO₂desorption time slows down with the increase of the organic amine loading.When the pressure is0.2MPa,the gas flow rate increases from 100ml/min to 200ml/min,the CO₂ desorption time of the solid amine adsorbent gradually slows down with the increase of flow rate.