Performance Study On The Adsorption Of Carbon Dioxide From Biogas By Macroporous Resin-Based Solid Amines

The rational utilization of biogas not only has energy benefits,but also gains environmental benefits.However,the excessive CO₂ content in biogas reduces the calorific value of biogas and increases the difficulty of biogas utilization.In order to obtain high concentration of high quality biomethane,it is very important to remove CO₂ from biogas,and now the solid amine adsorbent for CO₂ removal has become the focus of research direction,but in the process of adsorbent application still faces the problems of unclear adsorption conditions and low regeneration performance.Therefore,this thesis explores the effects of adsorption process conditions and amine types on adsorbent performance and prepares a new type of solid amine adsorbent with high CO₂ adsorption capacity and high applicability.The following conclusions were drawn.（1）Different types of amines including Aminoethyl piperazine（AEP）,hydroxyethyl piperazine,polyethyleneimine（PEI）,tetraethylenepentamine（TEPA）and hydroxyethylenediamine（AEEA）were selected to modify the macroporous resins ADS-17 and D1400 with 30% loading,and the adsorption performance of PEI and TEPA was better when PEI and TEPA were used as modifiers.（2）The adsorption of CO₂ increased with the increase of amine loading（10%-40%）and decreased at 50% loading when the carrier D1400 and ADS-17 were modified with different loadings of amine polyethyleneimine（PEI）and hydroxyethylenediamine.The maximum CO₂ adsorption capacity of the adsorbent was obtained when the amine was 40% loading,162.5 mg/g and 134.896 mg/g,respectively.（3）The adsorbent was prepared with polyethyleneimine（PEI）modified resin carrier ADS-17 with different molecular weights（600,1800,10000）,and the adsorption performance decreased with the rise of PEI molecular weight,and the adsorption amounts were 202.75 mg/g,179.65 mg/g,169.18 mg/g with the rise of PEI molecular weight.low molecular weight 600 had the highest adsorption amount of PEI.（4）The effects of temperature and flow rate on D1400-40% PEI（1800）,ADS-17-40% PEI（600）and ADS-17-40% AEEA were tested and found that when the adsorption temperature was varied within 25°C-90°C and other adsorption conditions were constant,the adsorption amount of CO₂ was higher for solid amine adsorbent at low temperature,and the adsorption effect decreased with the increase of temperature,when the gas When the gas flow rate increased from 100 m L/min to 200 m L/min and other adsorption conditions remained unchanged,the adsorption amount increased and then decreased with the increase of gas flow rate.The regeneration performance of the above adsorbents was also tested,and they were all reusable.（5）When TEPA was used as the modifier,the CO₂ adsorption capacity of D1400-40% TEPA decreased significantly after five regenerations.When glycol diglycidyl etherwas（GDE）added to TEPA,the CO₂ adsorption amount after 5 regenerations of 40% GDE-TEPA4/D1400 varied in a small range,and the adsorption amounts were 166.05 mg/g、171.38 mg/g、172.62 mg/g、176.23mg/g and 176 mg/g,respectively.the adsorption amounts did not show This indicates that the stability of the GDE-modified TEPA has been enhanced,and it has not degraded after repeated use and has reached the requirement of reusability.