| Capturing carbon dioxide in the flue gas streams from coal-fired power plants is a key measure to reduce CO2 emissions.The main challenge is to develop cost-effective adsorbents with low-energy consumption and excellent adsorption performance.Owing to its low-energy consumption,high selectivity and high adsorption capacity,the solid amine adsorbent is considered as an alternative.However,how well can these adsorbents perform has only been recognized in the lab-and bench-scale,and has not been really demonstrated in related process or on related equipment.Therefore,basing on the porous polymer beads applied to fluidized bed for CO2 adsorption,this thesis mainly focuses on amine-based adsorbents with high adsorption capacity,adsorption and desorption rates,cycling stability and large-scale production capacity.The following are the main contents:(1)Porous poly(t-butyl acrylate)beads by emulsion suspension polymerization were prepared.The effects of initiator amount,dispersed phase volume fraction,stirring speed,high speed dispersion conditions and co-emulsifier on the sphericity and pore structure of the material were investigated.Polymer spherical adsorbent with a particle size distribution of 0.6-1.2 mm and a pore size mainly concentrated at 0.8-2 ?m was synthesized.(2)The above obtained porous beads were physically impregnated PEI(MS=600)to prepare solid amine adsorbent.The sample(PTBA-PEI-55)with PEI loading of 55 wt.%reached the optimum adsorption temperature at 70?,and the adsorption amount reached 3.58 mmol/g under the pure CO2 conditions.The selective adsorption capacity of the sample was 242,and the time to reaching 90%adsorption amount was 11 mins under the simulated flue gas conditions.The 90%desorption time for pure CO2 conditions was 12 mins.After 50 cycles,the adsorption capacity decreased by 9.8%.This adsorbent exhibits good capacity,but the adsorption and desorption rates and cycling stability have yet to be improved.(3)Preparation of solid amine adsorbent by amine-based implant loads to achieve uniform and firm loading of PEI.The effects of different PEI additions on pore structure,nitrogen content and adsorption performance were studied.The results showed that when the PEI addition amount was 30 wt.%,the nitrogen content was 8.775 wt.%,and the uniform of the pore structure was obtained.The adsorption capacity reached 2.14mmol/g under 60?.The adsorbent achieved 90%adsorption under the simulated flue gas conditions and completed 90%desorption under pure CO2 conditions within 5.5 mins and 8.5 mins respectively.After 50 cycles,the adsorption amount decreased by 8.6%.The sample shows good absorption and desorption kinetics and cycles stability.(4)A solid amine adsorbent was prepared by a new method combining amine-based implant loads and physical impregnation.The adsorbent showed excellent adsorption capacity at 90? and adsorption amount reached 3.77mmol/g,and the time for the sample to complete 90%adsorption and 90%desorption was 7 mins and 9.5mins,respectively.The sample also exhibited good stability after 50 cycles and adsorption capacity lost 8.7%.Therefore,compared with the other two amine loading methods,the solid amine adsorbent prepared by combining amine implant loads and physical impregnation has the best comprehensive adsorption performance.(5)The adsorbent(PTBA-2)was prepared by using industrial raw materials and its adsorption properties were tested in a fluidized bed.The results showed that the adsorption amount reached 1.545 mmol/g in 500 seconds under the condition of simulated flue gas,the adsorption amount reached 93%in 400 seconds.After five cycles,the adsorption capacity dropped by 8.02%. |
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