焙烧镁铝水滑石脱除厌氧消化沼气中CO_(2)的效果及机制  

Calcined Mg/Al hydrotalcites for CO_(2) removal in anaerobic digestion biogas:Performances and mechanisms

作　　者：吴宇琦 李江涛 丁建智 宋秀兰 苏冰琴 WU Yuqi;LI Jiangtao;DING Jianzhi;SONG Xiulan;SU Bingqin(College of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;Taiyuan Design Research Institute for Coal Industry,Taiyuan 030000,Shanxi,China)

机构地区：[1]太原理工大学土木工程学院,山西太原030024 [2]煤炭工业太原设计研究院集团有限公司,山西太原030000

出　　处：《化工进展》2024年第9期5250-5261,共12页Chemical Industry and Engineering Progress

基　　金：山西省基础研究计划(自由探索类)青年项目(202103021223098);山西省高等学校科技创新项目(2021L035);太原理工大学2022年度校基金(2022QN088)。

摘　　要：厌氧消化沼气中含有的CO_(2)会降低沼气利用价值,高效去除CO_(2)是沼气利用领域的研究热点。焙烧镁铝水滑石具有良好的CO_(2)吸附性能,本文利用响应面法的Box-Behnken模型优化CO_(2)吸附条件,考察吸附剂剂量、焙烧温度和反应温度对吸附效果的影响;通过吸附材料表征、吸附过程测定分析吸附作用机制。实验结果表明,吸附剂剂量、焙烧温度和反应温度均对CO_(2)吸附有显著影响,最适宜的吸附条件为:投加量0.016g/m L、400℃焙烧、55℃反应。在此条件下,沼气中的CO_(2)体积分数从23.51%降至0,CO_(2)吸附容量为0.625mmol/g,CH4回收率为94.7%,经过6次循环吸附后,吸附剂仍具有良好的再生性能。吸附过程及吸附材料的X射线衍射、扫描电子显微镜、傅里叶变换红外光谱、比表面积、等电点及孔结构测试结果表明,焙烧镁铝水滑石的吸附过程十分迅速,表面碱性位点吸附及层间阴离子插层作用同时促进了CO_(2)吸附。Carbon dioxide(CO_(2))in the anaerobic digestion biogas can decrease the utility value of biogas,and removing CO_(2) efficiently is the research hotspot in the biogas utilization area.Calcined Mg/Al hydrotalcites(CLDHs)has desirable CO_(2) adsorption property.In this study,Box-Behnken model in the response surface methodology was applied to optimize the condition for CO_(2) adsorption by CLDHs,and the effects of adsorbents dosage,calcination temperature and reaction temperature on adsorption performances were investigated.The CO_(2) adsorption mechanisms were analyzed by adsorbents characterization and adsorption process test.Experimental results indicated that adsorbents dosage,calcination temperature and reaction temperature all showed significant effects on CO_(2) adsorption performance,and the optimal adsorption conditions were:CLDHs dosage of 0.016g/mL,calcination temperature of 400℃ and reaction temperature of 55℃.Under the optimal conditions,CO_(2) content decreased from initial 23.51% to 0,and CO_(2)adsorption capacity of 0.625mmol/g and CH_(4) recovery rate of 94.7%were achieved.Meanwhile,adsorbent had desirable regeneration property after 6 cycles of adsorption-desorption.The adsorption process test and adsorbents characterization results,including X-ray diffractometer(XRD),Scanning electron microscopy(SEM),Fourier transform infrared(FTIR),specific surface area,point of zero charge and pore structure,revealed that the CO_(2) adsorption process was very quick,and the surface basic sites adsorption as well as layer anion intercalation promoted CO_(2) adsorption simultaneously.

关 键 词：焙烧镁铝水滑石 厌氧消化沼气 CO_(2)吸附 响应面法优化设计 吸附机理 

分 类 号：X511[环境科学与工程—环境工程]