工业钙基废弃物催化餐饮业废油脂酯交换特性研究与机理分析

It is significant to develop biodiesel technology using waste cooking oil as feedstocks to solve energy crisis and trackle environmental pollution. Limited by surface area, traditional calcium oxide performs poorly during transesterification and it needs long reaction period and large quantity catalyst. In this project, the developed microstructure materials of industrial calcium based slags, such as carbide slag, are mentioned as transesterification catalyst. In tentative researches, carbide slag shows stronger catalytic properties than calcium oxide. However, the action mechanism has not been ascertained because of the complicated composition, and especially, the influence of impurities in slag needs to be explored. To research characteristic and analysis mechanism of waste cooking oil transesterification that is catalyzed by industrial calcium based slags, both batched and continuous transesterification experimental systems are mentioned, and instruments for physical-chemical properties indicators determinations of waste cooking oil, characterization of catalyst, composition analysis of biodiesel are also included. This project principally researches the function mechanism of impurities on slag catalyst activity and subsequently analysis selection basis and mixing standard of industrial calcium based slags for catalyzing transesterification. At the same time, effect of low carbon chain molecules of alcohol on phase interface heat-mass transfer of heteropical methanol transesterification reaction is emphasized. Also, effect mechanism of composition and activation conditions on lixiviation characteristic and acid resistant ability of slag catalyst will be revealed. On the whole, this project is for the purpose of broadening resource utilization of industrial calcium based slags and establishing theoretical basis for waste cooking oil transesterification to produce biodiesel with catalytic action by industrial calcium based slag.

发展餐饮业废油脂生物柴油技术对于解决能源危机和治理环境污染有重要意义。受限于比表面积等因素，普通氧化钙催化酯交换制备生物柴油时间长、催化剂量大。本项目提出采用微观结构发达的电石渣等工业钙基废弃物作为酯交换催化剂。探索实验表明，电石渣具有比氧化钙更强的催化性能，但其成分复杂，作用机制还不明确，特别是杂质存在的影响，有待进一步考证。项目通过间歇式和连续式酯交换实验系统，结合废油脂理化指标测定、催化剂表征等设备，进行工业钙基废弃物催化餐饮业废油脂酯交换特性研究与机理分析，探讨杂质对废弃物催化剂活性的影响机制，并由此分析适于催化酯交换的废弃物选取依据和掺配标准，同时研究低碳链大分子醇对异相甲醇酯交换相界面热质传递的作用规律、揭示组成成分和活化条件对废弃物催化剂流失特性及抗酸能力的影响机制。项目有望拓展钙基工业废弃物资源化利用的新途径，并为建立废弃物催化餐饮业废油脂酯交换制备生物柴油理论奠定基础。

（1）制备了基于电石渣CS、造纸白泥LM等含钙工业废弃物的固体碱，获得了原料油酸值的限定范围和适宜的醇剂，论证了含钙工业废弃物催化低酸值原料油甲酯化生产生物柴油的可行性。650oC煅烧CS所得固体碱CS-650主体成分为CaO，碱性强度为9.8<H_<15.0、比表面积为22.63m2/g，在γ=15、ζ=3%、Tr=60oC、τr=110min条件下，CS-650催化酸值为0.44mgKOH/g的花生油PO甲酯化效率为92.98%，活化能为68.45kJ/mol。LM经800oC活化后，LM-800的主体成分为CaO，碱性强度为9.8<H_<15.0、比表面积为7.45m2/g，在γ=12、ζ=6%、Tr=65oC、τr=3h条件下，催化PO甲酯化效率为92.56%。RSM计算CS-850催化PO甲酯化的最优工况是γ=13.8、ζ=6.7%、Tr=60oC。.（2）阐明了钠、钾等杂质的作用机制，获得了含钙工业废弃物固体碱的抗H2O及CO2性能；通过有机酸调质及活性位负载，强化了含钙工业废弃物固体碱催化酯交换的能力。LM经700oC煅烧并吸收H2O和CO2以后（LM700-H），比表面积和比孔容均较小，但碱密度高、均相催化效应明显、催化酯交换诱导期短，在ζ=8%、γ=15、Tr=64oC和τr=2h时，LM700-H催化PO甲酯化效率为88.53%。CS经醋酸调质、800oC活化后，主体成分为CaO，19.07m2/g的比表面积和0.0814cm3/g的比孔容均大于CS-800的值，传质阻力降低，γ=15、ζ=4%、Tr=59oC和τr=2h条件下，CSA-800催化酯交换效率可达96.79%。负载KF降低了KF/LM-600的比表面积和比孔容，但碱性强度显著提高，在ζ=5%、γ=12、Tr=64oC和τr=2h条件下，催化PO甲酯化效率高达99.09%。.（3）获得了生物柴油热解的动力学及热力学参数，掌握了生物柴油热解的气体产物分布，奠定了构建生物柴油燃烧化学反应机理的理论基础。经过酯交换反应，PO所得生物柴油POB分子量约降低2/3，POB热解过程提前。PO和POB热解的活化能分别约为120kJ/mol和50kJ/mol，生物柴油热解的气体产物主要包括烷烃、烯烃、醛、酮、醚类等有机物。.基于以上工作，本课题共发表SCI论文12篇、EI论文4篇。