Experimental investigation on the separated gasification chemical looping combustion performance of phytoremediation plant and retention of heavy metals
Experimental investigation on the separated gasification chemical looping combustion performance of phytoremediation plant and retention of heavy metals
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DOI：
10.1016/j.fuel.2023.127880
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发表时间：
2023-07
期刊：
影响因子：
7.4
通讯作者：
Xudong Wang;Y. Shao;Rongjuan Wang;Baosheng Jin
中科院分区：
文献类型：
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作者：
Xudong Wang;Y. Shao;Rongjuan Wang;Baosheng Jin
植物修复技术已成为治理土壤重金属污染的重要途径之一。然而，如果收获的植物修复植物不能得到适当的处理，植物修复植物中的重金属可能会再次污染环境。在两段式反应器中研究了植物修复植物分离气化化学链燃烧（SG-CLC）技术，以减少重金属向气体中的排放。该技术具有传统化学链燃烧的优越性。通过改变一段反应器温度、床料和水蒸汽质量流量，考察了它们对燃烧性能、底渣重金属截留率和载氧体特性的影响。在每种条件下进行了五个氧化还原实验循环。结果表明，当温度从450℃升高到650 ℃时，碳转化率从44.4%提高到66.7%，Mn、Ni、Zn和Pb的保留率分别从44.16%、69.82%、73.42%和49.46%下降到18.86%、13.56%、38.42%和6.18%。增加蒸汽流量和使用CaO作为床料也有利于提高碳转化率。这也影响了第二段反应器中氧载体的微观形态。在650 °C或以CaO为床料时，用过的载氧体表面出现明显的颗粒形貌。当蒸汽流量从0.36 g/min增加到0.60 g/min时，对重金属的截留效果不同，Mn、Ni、Zn和Pb的截留率分别从24.87%、10.42%、57.32%和25.06%增加到22.32%、17.70%、50.97%和21.38%。
Phytoremediation technology has been one of the important ways to treat soil heavy metal contaminant. However, if the harvested phytoremediation plant cannot be properly disposed, the heavy metals in phytoremediation plant may pollute the environment again. Separated gasification chemical looping combustion (SG-CLC) of phytoremediation plant is investigated in a two-stage reactor to reduce the emission of heavy metals into gas. And this technology has the superiority of traditional chemical looping combustion (CLC). The first-stage reactor temperature, bed material and steam mass flow are changed to investigate their effects on the combustion performance, retention of heavy metals in bottom residue and characteristics of oxygen carrier. Five redox experiment cycles are carried out under each condition. Results show that increasing the temperature from 450℃ to 650 ℃, the carbon conversion increases from 44.4% to 66.7%, and the retention rates of Mn, Ni, Zn and Pb decrease from 44.16%, 69.82%, 73.42% and 49.46% to 18.86%, 13.56%, 38.42% and 6.18% respectively. Increasing steam mass flow and using CaO as bed material are also beneficial to enhance the carbon conversion. This also affects the microscopic morphology of oxygen carrier in second-stage reactor. There appears obvious granular morphology on the surface of used oxygen carrier at 650 °C or using CaO as bed material. Rising the flowrate of steam from 0.36 g/min to 0.60 g/min has divergent effects on retention of heavy metals as retention rates of Mn, Ni, Zn and Pb change from 24.87%, 10.42%, 57.32% and 25.06% to 22.32%, 17.70%, 50.97% and 21.38%.