Research on carbon fixation and alkali reduction process of fly ash absorbents
The carbon fixation and alkali reduction process of fly ash absorbent is of great significance in reducing carbon dioxide(CO2)emission,comprehensive utilization of resources and treatment of alkaline wastewater.Using the solid waste fly ash from Sandaogou Fugu Power Plant in Yulin,Shaanxi as raw materials,fly ash CO2 absorbents("absorbent"for short)were prepared by modification treatment.The effects of different pretreatment agents(acetic acid(CA),sodium chloride(NaCl)and sodium hydroxide(NaOH)solution,respectively,all the mass fractions are 85%)on the carbon fixation and alkali reduction performance and carbonation and leaching property of absorbent were studied,and the effects of temperature and CO2 injection rate on the carbon fixation and alkali reduction process were analyzed.The results show that NaOH can effectively destroy the spherical vitreous structure of fly ash and release the active components.Increasing the temperature can increase the ion leaching rate in fly ash and make the reaction move forward.Increasing CO2 injection rate can improve the dissolution rate of CO2 in the absorber,but too high CO2 injection rate will shorten the gas-liquid contact time,resulting in lower absorption efficiency.With NaOH solution as pretreatment agent,under the conditions that temperature is 60℃,CO2 injection rate is 40 mL/min and absorption time is 5 h,the carbon fixation and alkali reduction process has the best effect.The absorption efficiency of the absorber can reach 27.89%,and the carbon fixation capacity is 30.16 kg/t.
fly ashabsorbentcarbon dioxidecarbon fixation and alkaline reductionprocess optimization
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