Integrated Study Of CO₂ Absorption And Flooding-Mineralization And Storage Based On Carbide Slag

Carbon dioxide capture,storage and utilization（CCUS）is the most effective and economically feasible way to reduce CO₂emissions in coal-fired boiler-based industries,and CCUS technology mainly includes CO₂capture,CO₂transport,CO₂utilization and storage.Reducing the energy consumption for desorption of CO₂absorption rich liquid and shortening the CCUS technology chain are important aspects of technology development.Currently,chemical absorption is the most widely used CO₂capture technology.CO₂utilization and storage is also a necessary measure to reduce CO₂emissions.However,the currently used mineralized CO₂sequestration technology has large limitations,and the technology also needs to compress and transport the CO₂separated from the desorption after absorption,which will increase the cost of carbon reduction.In view of this,this paper proposes an integrated CO₂absorption-rich liquid-mineralization storage technology using alcohol amine as the absorbent and carbide-rich carbide-rich carbide slag as the desorption mineralization raw material.The reaction device is designed to organically couple the desorption of absorbent rich liquid with CO₂mineralization and storage,and the mineralization raw material,carbide slag,is added to the absorbent rich liquid regeneration device to make the absorbent rich liquid react with carbide compounds in carbide slag to produce carbide carbonate（Ca CO₃）precipitate,and the absorber is desorbed and regenerated at the same time to realize CO₂mineralization and storage.mineralization sequestration.The effects of various influencing factors（reaction temperature,initial rich liquid CO₂loadinging,and the amount of carbide slag added）on the desorption effect and the mineralization rate of carbide slag were investigated for single and mixed absorption solutions.In a single absorber CO₂absorption enrichment-mineralization storage integration test,five single absorbents,namely,ethanolamine（MEA）,N-methyldiethanolamine（MDEA）,diethanolamine（DEA）,triethanolamine（TEA）,and space-site blocking amine（AMP）,were used as desorbents and mineralization raw materials for the study.The study showed that the desorption effect of each absorbent rich solution was from high to low under the optimal working conditions:AMP>MDEA>TEA>DEA>MEA,where the AMP absorbent rich solution showed the highest desorption effect at the reaction temperature of 30℃,the charge of carbide slag was 50 g/L,and the initial rich solution CO₂loading was 0.16 mol/mol,and showed the highest mineralization effect with the mineralization rate of 95.13%.The MEA absorption enrichment showed relatively poor desorption and mineralization effects during the integrated CO₂absorption enrichment-mineralization storage test,with a mineralization rate of only 68.07%.In addition,XRD and SEM characterization of the solid phases obtained before and after the integrated CO₂ absorption-enriched liquid-mineralization storage test conducted under optimal test conditions for AMP absorption-enriched liquid identified the product Ca CO₃crystalline type as calcite.In the mixed absorption solution CO₂rich liquid absorption-mineralization sequestration integration test,four mixed absorption solutions,MEA+MDEA,MEA+DEA,MEA+AMP and MEA+TEA,were tested with carbide slag as desorbent and mineralization raw material.The results showed that the desorption effect of each mixed absorption rich solution under the optimalworkingconditionswasfromhightolow:MEA+TEA>MEA+AMP>MEA+MDEA>MEA+DEA,where the MEA+TEA mixed absorption rich solution showed the highest desorption effect at a reaction temperature of30℃,a charge of 50 g/L of carbide slag,an initial rich solution CO₂loading of 0.20mol/mol,and solute ratio of 4:1.The highest desorption effect and showed the highest mineralization effect with a mineralization rate of 79.12%;the MEA+DEA mixed absorption enrichment solution showed relatively poor desorption and mineralization effect with a mineralization rate of 69.22%during the integrated CO₂enrichment absorption-mineralization sequestration test.The AMP absorption enrichment with the best desorption effect among the five single absorption enrichments and the MEA+TEA absorption enrichment with the best desorption among the four mixed absorption enrichments were selected for multiple cycle tests.The results showed that the desorption rate of the liquid-phase absorption enrichment was maintained at 98.75%for five times and the mineralization rate of the solid-phase was maintained at 95.13%for five times in the single absorption enrichment multiple cycle test,and there was no significant decrease in the cycle loading and the mineralization effect was stable;in the mixed absorption enrichment multiple cycle test,the desorption rate of the liquid-phase absorption enrichment was maintained at 80.83%for five times and the mineralization rate of the solid-phase was maintained at 79.12%for five times,and there was no decrease in the cycle loading.79.12%,with no significant decrease in cycle loading and stable mineralization effect.Finally,the integrated CO₂-rich liquid absorption-mineralization storage process was compared with the conventional MEA process（thermal desorption）in terms of energy consumption.The results show that compared with the energy consumption of the conventional desorption process,the energy consumption required for the integrated CO₂-rich liquid absorption-mineralization storage process is significantly reduced,saving approximately 1108.0 k Je/kg CO₂.