Zn对沉淀铁催化剂结构及其F-T合成性能的影响

王虎林; 杨勇; 王洪; 相宏伟; 李永旺

Zn对沉淀铁催化剂结构及其F-T合成性能的影响

王虎林^1,2,
杨勇^1,,
王洪^1,2,
相宏伟¹,
李永旺¹

1.
中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原 030001;
2.
中国科学院研究生院北京 100049;

基金项目: 国家杰出青年基金(20625620);国家自然科学基金重大项目(20590361)。

详细信息

作者简介:
王虎林(1977- ), 男, 陕西榆林人, 博士研究生, E-mail:wanghulin@sxicc.ac.cn。

通讯作者:
杨勇, Tel:0351-7560835; E-mail:yyong@sxicc.ac.cn。

中图分类号: TQ529.2
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出版历程
- 收稿日期: 2011-03-11
- 修回日期: 2011-05-29
- 刊出日期: 2012-01-31

Effects of Zn promoter on the structure and Fischer-Tropsch performance of iron catalyst

1.
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China;
2.
Graduate University of Chinese Academy of Sciences, Beijing 100049, China

摘要

摘要: 采用低温N₂吸附、XRD、MES、CO-TPR和H₂-DTG研究了Zn(100 gFe/x gZn, x=7～100)助剂对 Fischer-Tropsch (F-T) 合成Fe基催化剂的织构性质、还原行为以及相变结构的影响;在H₂/CO=2.0、260 ℃、1.5 MPa和4000 mL/(g·h) 条件下在固定床反应器上考察了Zn助剂含量对Fe基催化剂F-T合成反应活性、烃产物选择性和运行稳定性的影响。研究结果表明,随着Zn含量的增加,氧化态催化剂的物相由α-Fe₂O₃和ZnFe₂O₄逐渐向ZnFe₂O₄和ZnO转变,ZnFe₂O₄在催化剂中优先生成,只有在超出其计量比1∶2之后才有ZnO出现。由于ZnFe₂O₄较为稳定,能够促进催化剂中Fe物相的分散,导致比表面积增加。在还原和反应态催化剂中,ZnFe₂O₄一方面抑制催化剂的过度还原和碳化;另一方面表现为稳定活性相铁碳化物。催化剂的F-T反应性能评价结果表明,纯铁催化剂由于铁碳化物氧化而迅速失活,而Zn助剂催化剂却由于ZnFe₂O₄的稳定作用,活性较为稳定。同时,由于催化剂在反应初相变的影响,导致Zn助剂催化剂的初始烯烃选择性随着Zn含量的增加而增加,在相态稳定之后选择性趋于一致。
- 费托合成 /
- 铁锌催化剂 /
- 锌助剂
Abstract: The effects of Zn (100 gFe/x gZn, x=7～100) on the textural properties, reduction behavior and structural changes during reduction and reaction of the Fe-Zn catalysts were studied by using N₂ physical adsorption, X-ray diffraction (XRD), Mssbauer spectroscopy (MES), H₂ differential thermogravimetric analysis (H₂-DTG) and CO temperature-programmed reduction (CO-TPR). The F-T performances of the catalysts were investigated in a fixed-bed reactor under the conditions of H₂/CO=2.0, 260 ℃, 1.5 MPa and 4 000 mL/(g·h). The results show that, with the increase of Zn content in catalysts, the phases of catalysts transform from α-Fe₂O₃ and ZnFe₂O₄ to ZnFe₂O₄ and ZnO, where ZnO appears just beyond the stoichiometry of Zn/Fe (1∶2). The presence of ZnFe₂O₄ plays an important role in catalysts. In the fresh catalysts, ZnFe₂O₄ can enhance the dispersion of Fe phase and thus enlarge the surface area. For the reduced and used catalysts, ZnFe₂O₄ not only inhibits the excessive reduction and carbonization, but also improves the stability of the iron carbide phase. F-T tests show that the fast deactivation was observed in the un-promoted catalyst, but the catalytic activity was stabilized by ZnFe₂O₄ in Zn-promoted catalysts. In addition, high olefin selectivity is observed in Fe-Zn catalysts which gradually decreases to same content as that of un-promoted catalyst probably due to the change of phases at the beginning of reaction.
- F-T synthesis /
- Fe-Zn catalyst /
- Zn promoter

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参考文献(22)

DRY M E. Practical and theoretical aspects of the catalytic Fischer-Tropsch process[J]. Appl Catal A, 1996, 138(2):319-344.

HERRAN Z T, ROJAS S, PEREZ-ALONSO F J, OJEDA M, TERRERDS P, FIERRO J L G. Hydrogenation of carbon oxides over promoted Fe-Mn catalysts prepared by the microemulsion methodology [J]. Appl Catal A, 2006, 311:66-75.

相宏伟, 唐宏青, 李永旺. 煤化工工艺技术评述与展望:Ⅳ煤间接液化技术[J]. 燃料化学学报, 2001, 29(4):289-298. (XIANG Hong-wei, TANG Hong-qing, LI Yong-wang. Perspectives on R&D in coal chem ical industry:Ⅳ Synthesis of fuels from coal via Fischer-Tropsch reaction[J]. Journal of Fuel Chemistry and Technology, 2001, 29(4):289-298.)

BUKUR D B, LANG X. Highly active and stable iron Fischer-Tropsch catalyst for synthesis gas conversion to liquid fuels[J]. Ind Eng Chem Res, 1999, 38(9):3270-3275.

吴宝山, 白亮, 张志新, 相宏伟, 李永旺, 易凡, 徐斌富. 不同沉淀剂制备的铁基催化剂对浆态床FT合成反应的催化性能[J]. 催化学报, 2005, 26(5):371-376. (WU Bao-shan, BAI Liang, ZHANG Zhi-xin, XIANG Hong-wei, LI Yong-wang, YI Fan, XU Bin-fu. Catalytic performance of iron-based catalysts prepared using different precipitating agents for Fischer-Tropsch synthesis [J]. Chinese Journal of Catalysis, 2005, 26(5):371-376.)

YANG Y, XIANG H-W, TIAN L, WANG H, ZHANG C-H, TAO Z-C, XU Y-Y, ZHONG B, LI Y-W. Structure and Fischer-Tropsch performance of iron-manganese catalyst incorporated with SiO₂[J]. Appl Catal A, 2005, 284(1/2):105-122.

YANG Y, XIANG H-W, XU Y-Y, BAI L, LI Y-W. Effect of potassium promoter on precipitated iron-manganese catalyst for Fischer-Tropsch synthesis[J]. Appl Catal A, 2004, 266(2):181-194.

ZHANG C-H, YANG Y, TENG B-T, LI T-Z, ZHENG H-Y, XIANG H-W, LI Y-W. Study of an iron-manganese Fischer-Tropsch synthesis catalyst promoted with copper[J]. J Catal, 2006, 2(2):405-415.

JIN Y, DATYE A K. Phase transformations in iron Fischer-Tropsch catalysts during temperature-programmed reduction[J]. J Catal, 2000, 196(1):8-17.

LI T, YANG Y, ZHANG C, AN X, WAN H, TAO Z, XIANG H, LI Y, YI F, XU B. Effect of manganese on an iron-based Fischer-Tropsch synthesis catalyst prepared from ferrous sulfate[J]. Fuel, 2007, 86(7/8):921-928.

QIN S D, ZHANG C, XU J, WU B, XIANG H, LI Y. Effect of Mo addition on precipitated Fe catalysts for Fischer-Tropsch synthesis[J]. J Mol Catal A, 2009, 304(1/2):128-134.

杨雁南, 钟炳, 彭少逸, 王琴. 无载体Fe/Zn超细粒子催化剂的磁学研究[J]. 煤炭转化, 1997, 20(3):84-90. (YANG Yan-nan, ZHONG Bing, PENG Shao-yi, WANG Qin. Magnetic study of Fe/Zn ultrafine particle catalysts[J]. Coal Conversion, 1997, 20(3):84-90.)

杨雁南, 钟炳, 彭少逸, 王琴, 陈义龙, 徐斌富. 铁/锌催化剂的物相结构及其还原行为的穆斯堡尔谱研究[J]. 分子催化, 1993, 7(6):425-431. (YANG Yan-nan, ZHONG Bing, PENG Shao-yi, WANG Qin, CHEN Yi-long, XU Bin-fu. A Mossbauer study on Fe/Zn catalysts for Fischer-Tropsch synthesis[J]. Journal of Molecular Catalysis (China), 1993, 7(6):425-431.)

LI S, LI A, KRISHMAMOORTHY S, IGLESIA E. Effects of Zn, Cu, and K promoters on the structure and on the reduction, carburization, and catalytic behavior of iron-based Fischer-Tropsch synthesis catalysts[J]. Catal Lett, 2001, 77(4):197-205.

LIU X-M, LU G Q, YAN Z-F, BELTRAMINI J. Recent advances in catalysts for methanol synthesis via hydrogenation of CO and CO₂[J]. Ind Eng Chem Res, 2003, 42(25):6518-6530.

NASR ISFAHANI M J, MYNDYK M, SEPELAK V, AMIGHIAN J. A Mossbauer effect investigation of the formation of MnZn nanoferrite phase[J]. J Alloys Compd, 2009, 470(1/2):434-437.

PRIETO F, BARRADO E, MEDINA J, LOPEZ-GOMEZ F A. Characterisation of zinc bearing-ferrites obtained as by-products of hydrochemical waste-water purification processes[J]. J Alloys Compd, 2001, 325(1/2):269-275.

DING M, YANG Y, XU J, TAO Z, WANG H, WANG H, XIANG H, LI Y. Effect of reduction pressure on precipitated potassium promoted iron-manganese catalyst for Fischer-Tropsch synthesis[J]. Appl Catal A, 2008, 345(2):176-184.

SATTERFIELD C N, HANLON R T, TUNG S E, ZOU Z M, Papaefthymiou G C. Effect of water on the iron-catalyzed Fischer-Tropsch synthesis[J]. Ind Eng Chem Prod Res Dev, 1986, 25(3):407-414.

PEREZ-LOPEZ O W, FARIAS A C, MARCILIO N R, BUENOET J M C. The catalytic behavior of zinc oxide prepared from various precursors and by different methods[J]. Mater Res Bull, 2005, 40(12):2089-2099.

DING M, YANG Y, WU B, XU J, ZHANG C, XIANG H, LI Y. Study of phase transformation and catalytic performance on precipitated iron-based catalyst for Fischer-Tropsch synthesis[J]. J Mol Catal A, 2009, 303(1/2):65-71.

RIEDEL T, SCHULZ H, SCHAUB G, JUN K-W, HWANG J-S, LEE K-W. Fischer-Tropsch on iron with H₂/CO and H₂/CO₂ as synthesis gases:The episodes of formation of the Fischer-Tropsch regime and construction of the catalyst[J]. Top Catal, 2003, 26(1/4):41-54.

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