钙基工业固废循环捕集CO2性能研究进展
A review on cyclic CO2 capture performance of calcium⁃based industrial solid waste
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摘要: 随着能源需求增长,煤炭、石油、天然气等化石燃料的大量开采,人为产生的CO2排放量不断升高。如何控制CO2排放、减缓全球变暖速度是亟待解决的难题。钙循环技术利用CaO的碳酸化/煅烧反应实现CO2的捕集,具有成本低、工艺简单、效率高等优点,被认为是具有前景的大规模脱碳技术之一。每年我国会产生大量钙基工业固体废弃物,填埋、露天堆积等不当的处置手段对环境和人体健康造成极大的危害。将钙基工业固废作为CO2吸收剂用于钙循环过程,不仅实现工业固废的资源化利用,还节约石灰石矿资源,进一步降低CO2捕集成本。本文对钙基工业固废循环捕集CO2的国内外研究现状进行了综述,总结了电石渣、冶炼渣(钢渣、高炉渣)、造纸白泥等工业固废的CO2捕集性能。电石渣、冶炼渣、造纸白泥等工业固废具有一定捕集CO2性能,粉煤灰、铝土矿尾矿等工业固废可作为添加剂提高钙基材料捕集CO2性能。与石灰石相比,电石渣、酸浸取后的冶炼渣和造纸白泥的循环捕集CO2稳定性更好。针对钙基工业固废捕集CO2性能较低的问题,重点介绍了多种提高钙基工业固废捕集CO2性能的方法,主要包括化学改性、添加支撑体/添加剂以及成型造粒等。钙铝酸盐(如Ca2Al2O6、Ca12Al14O33等)和MgO作支撑体能够提高钙基工业固废的捕集CO2性能和循环稳定性,具有工业应用前景。最后,对钙基工业固废捕集CO2的未来研究方向进行了展望。Abstract: With the growth of energy demand and surging exploitation of fossil fuels such as coal, petroleum, and nat⁃ ural gas, human⁃induced CO2 emissions have been elevating continuously. How to control CO2 emissions and slow down the rate of global warming is a big challenge. With the advantages of low cost, simple process, and high ef⁃ ficiency, a calcium looping technology achieves CO2 capture by using the cyclic carbonation / calcination reactions of CaO, which is currently considered to be one of the most promising technologies for a large⁃scale CO2 capture. Lots of calcium⁃based industrial solid wastes are produced in China annually. Improper disposal ways such as landfill and accumulation in the open⁃air cause serious damage to the environment and human health. Using some calcium⁃based industrial solid wastes as CO2 sorbents in the calcium looping process can not only realize the utilization of wastes and save the limestone resource, but also reduce the cost of CO2 capture. In this study, the current status of research pro⁃ gress on the CO2 capture by calcium⁃based industrial solid wastes was reviewed. The CO2 capture performance of calci⁃ um⁃based industrial solid wastes such as carbide slag, smelting slag (steel slag and blast furnace slag), lime mud, etc. was summarized. Coal fly ash and bauxite tailings could be used as additives to improve the CO2 capture perform⁃ ance of calcium⁃based materials. Compared with limestone, carbide slag, smelting slag after acid leaching and lime mud showed a higher cyclic stability in the calcium looping process. Many methods to improve the CO2 cap⁃ ture capacities of calcium⁃based industrial solid wastes were highlighted, involving chemical modification, addition of support/additive, and granulation. Calcium aluminates (Ca2Al2O6, Ca12Al14O33, etc.) and MgO were efficient sup⁃ ports, which were promising for industrial applications. In addition, some future research directions for the CO2 cap⁃ ture by calcium⁃based industrial solid wastes were prospected.