Desorption performance of CO2-rich ammonia aqueous via CO2 mineralization using biomass ash
In the ammonia-based CO2 chemical absorption process,CO2-rich ammonia aqueous solution is generally regenerated at the high temperature and pressure conditions for inhibiting the ammonia volatilization,in which a high energy input is necessary.To minimize the energy inputs,biomass ash was adopted into the CO2-rich ammonia aqueous solution(i.e.,rich ammonia solution)in this study for CO2 desorption and CO2 fixation through CO2 mineralization.The feasibility of CO2 desorption by adding biomass ash,CO2 reabsorption performance of CO2-lean ammonia aqueous solution and cyclic stability of ammonia during CO2 absorption-CO2 desorption induced by biomass ash addition were experimented.The results showed that the rich ammonia solution can be desorbed effectively through adding biomass ash to form the CO2-lean ammonia aqueous solution with a maximum net CO2 absorption capacity of 0.32mol/mol.Under the ambient pressure,the decrement of CO2 loading of rich ammonia solution increased with the biomass ash dosage and reaction temperature.When the dosage of biomass ash added into the rich ammonia solution with an initial CO2 loading of 0.6mol/mol varied from 50g/L to 250g/L,the decrement of CO2 loading of rich ammonia solution increased gigantically from 18.83％to 94.17％.Compared to the case adopting CaO,adopting biomass ash to desorb rich ammonia solution could achieve a relatively lower cyclic CO2 absorption performance.However,an averaged net CO2 absorption capacity of ammonia with 0.24mol/mol could still be achieved in five"absorption-desorption"cycles.
CO2 captureabsorptiondesorptionbiomass ashbiogas upgrading
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