高馏分油选择性钴基费托合成催化剂的开发及催化工艺研究

QIBEBT-IR > 热化学转化研究组

	高馏分油选择性钴基费托合成催化剂的开发及催化工艺研究
	李琢
	2015-06
关键词	费托合成钴基催化剂 Zsm-5/sba-15复合载体汽柴油馏分
学科分类	化学工程
报告类别	专题报告
中文摘要	Fischer-Tropsch (F-T) synthesis is an important means to convert coal, natural gas, biomass and other carbonaceous resources into high quality liquid hydrocarbon fuels free of sulfur and nitrogen and low in aromatics. However, the traditional F-T synthesis is featured by the Anderson-Schultz-Flory (ASF) distribution with the wider carbon number distribution of the products. How to suppress the formation of methane and light hydrocarbons and increase the proportion of middle distillates (gasoline and diesel fractions) is not only one of the most important direction to improve the F-T synthesis technology, but also the most difficult challenges in the F-T synthesis research. Co-based catalyst is considered to be the best F-T synthesis catalyst for middle distillate products due to its high activity, high stability, high selectivity towards alkanes and low water-gas shift reaction.This report focuses on the influences of support properties (SBA-15 and ZSM-5), promoter of Zr and preparation methods on the structure, surface physical and chemical properties of the catalysts and product distribution. The main bodies of the work included the following aspects:The influence of the addition of several zeolites (such as ZSM-5, USY and Hβ) and the incorporation manner of ZSM-5 on the catalytic performance of the Co-based catalysts was studied. The preparation method of the catalyst with Co impregnated on the composite support of SBA-15 and ZSM-5 mechanically mixed was established. And the catalysts prepared by this method showed a moderate size of cobalt particles, favorable cobalt-support interaction and moderate acidity, leading to the maximum selectivity to gasoline and diesel distillate.The effect of the amount of ZSM-5 addition in the composite support on the structure, surface physicochemical properties of the catalyst and the product distribution was subsequently researched. It was found that the catalyst with 20% ZSM-5 in the composite support was shown to have the maximum pore volume and degree of cobalt particle dispersion, as well as the moderate reduction of the catalyst and acidity, which facilitated to the production of the gasoline and diesel fractions. This catalyst also showed well stability during 600 hr continuous run with the CO conversion and C5+ selectivity remaining stable after a 50 hr induction period, and the ratio of n-alkanes in the product was gradually increased.A series of Co-Zr-SBA-15 F-T catalysts were prepared using the co-impregnation method, stepwise-impregnation method and in-situ synthesis method to incorporate Zr as a promoter. It was shown that the CO conversion (80%) and chain growth probability (α=0.78) were lower on the catalysts prepared by in-situ synthesis method due to the stronger interaction between cobalt and zirconium. Conversely, higher selectivity of diesel distillate (C12-C22) and higher chain growth probability (α=0.84) were observed on the catalysts prepared by stepwise-impregnation method, which could be attributed to the larger pores, larger particle size of cobalt, weaker interaction between cobalt and zirconium. While the higher selectivity of gasoline distillate (C5-C11) and moderate chain growth probability (α=0.81) were observed on the catalysts prepared by co-impregnation method.
英文摘要	Fischer-Tropsch合成(F-T合成)技术是将煤、天然气、生物质等含碳资源转化为无硫、无氮和低芳烃的优质液体燃料的重要途径。然而，传统的F-T合成产物碳数分布遵循Anderson-Schultz-Flory（ASF）分布。如何最大限度的抑制甲烷及轻质烷烃的生成和提高中间馏分油（汽油和柴油馏分）的比例，是改进F-T合成技术的重要方向之一，也是F-T合成研究中最有挑战性的科学技术与问题。在F-T合成催化剂中Co基催化剂以其高活性、高稳定性、高重质烃选择性及低水煤气变换等特点被认为是最佳的合成中间馏分油的F-T合成催化剂。采用共浸渍法、分步浸渍法和原位合成法引入Zr助剂，制备了系列Co-Zr-SBA-15费托合成催化剂。其中，原位合成法制备的催化剂钴锆作用较强，CO转化率(80%)和链增长因子(α=0.78)较低；分步浸渍法制备的催化剂孔径较大，钴颗粒较大，钴锆相互作用较弱，还原度较高，柴油馏分（C12-C22）选择性最高，具有最高的链增长因子(α=0.84)；而共浸渍法制备的催化剂具有较高的汽油馏分（C5-C11）选择性，链增长因子居中(α=0.81)。
文献类型	研究报告
条目标识符	http://ir.qibebt.ac.cn/handle/337004/9797
专题	热化学转化研究组
作者单位	中科院青岛生物能源与过程研究所
推荐引用方式 GB/T 7714	李琢. 高馏分油选择性钴基费托合成催化剂的开发及催化工艺研究. 2015.

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