熔铁催化剂活性相的调控及其费托反应性能

doi:10.16085/j.issn.1000-6613.2023-0300

摘要/Abstract

摘要：

采用水热合成法，在制备MIL-101(Fe)的过程中加入熔铁催化剂，使熔铁催化剂表面涂覆MIL-101(Fe)，通过碳化温度和碳化气氛的调变，制备了具有不同活性相组成（θ-Fe₃C和χ-Fe₅C₂）的熔铁催化剂，同时将其在340℃、1MPa和GHSV=12000h^-1反应条件下，进行费托合成反应性能评价，并运用XRD、SEM、CO-TPD、N₂-物理吸附等表征手段进行表征分析。结果表明，当催化剂中含有θ-Fe₃C时，具有更高的C₅₊选择性；在不同碳化气氛下，催化剂产生的活性相不同，且随碳化温度的升高，2种气氛下产生的活性相都可相互转化，但催化剂的反应性能相差显著。CO气氛下，当θ-Fe₃C部分转化为χ-Fe₅C₂，催化剂具有较高的活性，这是由于θ-Fe₃C和 χ-Fe₅C₂的协同作用更利于CO的解离吸附，提高了催化剂的活性；混合气氛（H₂+CO）下，当χ-Fe₅C₂部分转化为θ-Fe₃C，转变过程中由于χ-Fe₅C₂发生晶格畸变，抑制了CO的解离吸附，导致催化剂活性大幅下降。在CO气氛下，700℃碳化温度下所制得的催化剂具有最佳的催化反应性能，其CO转化率为74.4%，同时具有较高的C₅₊选择性，为65.6%。

关键词: 催化剂, 合成气, 一氧化碳, 金属有机骨架材料, 熔铁

Abstract:

MIL-101(Fe) was coated on the surface of fused iron catalyst by hydrothermal synthesis method. Fused iron catalysts with different active phase compositions (θ-Fe₃C and χ-Fe₅C₂) were prepared by adjusting the carbonization temperature and atmosphere. The catalytic performance of Fischer-Tropsch synthesis was evaluated at 340℃, 1MPa and GHSV=12000h^-1, and the catalysts were characterized by XRD, SEM, CO-TPD, and N₂-physisorption. The results showed that the catalysts with θ-Fe₃C had higher C₅₊selectivity. Active phases produced by the catalyst were different under different carbonization atmospheres. With the increase of carbonization temperature, the active phases produced by the two atmospheres could be converted to each other, but the difference in catalyst activity was significant. When θ-Fe₃C was partially converted to χ-Fe₅C₂ in CO, the synergistic effect of θ-Fe₃C and χ-Fe₅C₂ was more conducive to the dissociation and adsorption of CO, which improves the activity of the catalyst. When χ-Fe₅C₂ was partially converted to θ-Fe₃C in the syngas, the lattice distortion of χ-Fe₅C₂ occurs, which inhibits the dissociation adsorption of CO and leads to a significant decrease in the catalyst activity. The catalyst carbonized at 700℃ in CO had the best catalytic activity, which provided an CO conversion of 74.4%, and a C₅₊ selectivity of 65.6%.

Key words: catalyst, syngas, carbon monoxide, metal-organic frameworks, fused iron

中图分类号:

O643.36

杨霞珍, 彭伊凡, 刘化章, 霍超. 熔铁催化剂活性相的调控及其费托反应性能[J]. 化工进展, 2023, 42(S1): 310-318.

YANG Xiazhen, PENG Yifan, LIU Huazhang, HUO Chao. Regulation of active phase of fused iron catalyst and its catalytic performance of Fischer-Tropsch synthesis[J]. Chemical Industry and Engineering Progress, 2023, 42(S1): 310-318.

图/表 15

参考文献 26

1	BAO Jun, YANG Guohui, YONEYAMA Yoshiharu, et al. Significant advances in C₁ catalysis: highly efficient catalysts and catalytic reactions[J]. ACS Catalysis, 2019, 9(4): 3026-3053.
2	ZHOU Wei, CHENG Kang, KANG Jincan, et al. New horizon in C₁ chemistry: breaking the selectivity limitation in transformation of syngas and hydrogenation of CO₂ into hydrocarbon chemicals and fuels[J]. Chemical Society Reviews, 2019, 48(12): 3193-3228.
3	巩守龙. 铁基高温费托合成催化剂研究与应用进展[J]. 中国石油和化工标准与质量, 2020, 40(8): 171-172.
	GONG Shoulong. Research and application progress of iron-based high temperature Fischer-Tropsch synthesis catalyst[J]. China Petroleum and Chemical Standard and Quality, 2020, 40(8): 171-172.
4	OPEYEMI OTUN Kabir, YAO Yali, LIU Xinying, et al. Synthesis, structure, and performance of carbide phases in Fischer-Tropsch synthesis: a critical review[J]. Fuel, 2021, 296: 120689.
5	LU Fangxu, CHEN Xin, WEN Lixiong, et al. The synergic effects of iron carbides on conversion of syngas to alkenes[J]. Catalysis Letters, 2021, 151(7): 2132-2143.
6	WANG Di, CHEN Bingxu, DUAN Xuezhi, et al. Iron-based Fischer-Tropsch synthesis of lower olefins: the nature of χ-Fe₅C₂ catalyst and why and how to introduce promoters[J]. Journal of Energy Chemistry, 2016, 25(6): 911-916.
7	杨霞珍, 张红, 霍超, 等. Fe_1- _x O基熔铁催化剂物相及结构变化对其催化合成气制低碳烯烃性能的影响[J]. 石油化工, 2018, 47(8): 775-780.
	YANG Xiazhen, ZHANG Hong, HUO Chao, et al. Effects of phase and structure of Fe_1- _x O-based fused iron catalyst on its performance for producing light olefins from syngas[J]. Petrochemical Technology, 2018, 47(8): 775-780.
8	WANG Jian, HUANG Shouying, HOWARD Shaun, et al. Elucidating surface and bulk phase transformation in Fischer-Tropsch synthesis catalysts and their influences on catalytic performance[J]. ACS Catalysis, 2019, 9(9): 7976-7983.
9	TANG Lei, HE Lei, WANG Yang, et al. Selective fabrication of χ-Fe₅C₂ by interfering surface reactions as a highly efficient and stable Fischer-Tropsch synthesis catalyst[J]. Applied Catalysis B: Environmental, 2021, 284: 119753.
10	CHANG Qiang, ZHANG Chenghua, LIU Chengwei, et al. Relationship between iron carbide phases (ε-Fe₂C, Fe₇C₃, and χ-Fe₅C₂) and catalytic performances of Fe/SiO₂ Fischer-Tropsch catalysts[J]. ACS Catalysis, 2018, 8(4): 3304-3316.
11	LIU Qianyu, SHANG Cheng, LIU Zhipan. In situ active site for CO activation in Fe-catalyzed Fischer-Tropsch synthesis from machine learning [J]. Journal of the American Chemical Society, 2021, 143(29): 11109-11120.
12	HERRANZ Tirma, ROJAS Sergio, PÉREZ-ALONSO Francisco J, et al. Genesis of iron carbides and their role in the synthesis of hydrocarbons from synthesis gas[J]. Journal of Catalysis, 2006, 243(1): 199-211.
13	DE SMIT Emiel, BEALE Andrew M, NIKITENKO Sergey, et al. Local and long range order in promoted iron-based Fischer-Tropsch catalysts: a combined in situ X-ray absorption spectroscopy/wide angle X-ray scattering study[J]. Journal of Catalysis, 2009, 262(2): 244-256.
14	MA Caiping, ZHANG Wei, CHANG Qiang, et al. θ-Fe₃C dominated Fe@C core-shell catalysts for Fischer-Tropsch synthesis: roles of θ-Fe₃C and carbon shell[J]. Journal of Catalysis, 2021, 393: 238-246.
15	LIU Yi, LU Fangxu, TANG Yu, et al. Effects of initial crystal structure of Fe₂O₃ and Mn promoter on effective active phase for syngas to light olefins[J]. Applied Catalysis B: Environmental, 2020, 261: 118219.
16	ZHANG Juan, ABBAS Mohamed, ZHAO Wentao, et al. Enhanced stability of a fused iron catalyst under realistic Fischer-Tropsch synthesis conditions: insights into the role of iron phases (χ-Fe₅C₂, θ-Fe₃C and α-Fe)[J]. Catalysis Science & Technology, 2022, 12(13): 4217-4227.
17	LIU Huazhang, YANG Xiazhen, CEN Yaqing, et al. A novel Fe_1- _x O-based fused iron catalyst for Fischer-Tropsch synthesis with the high olefine selectivity[J]. Advanced Materials Research, 2012, 512-515: 2207-2211.
18	GECGEL Cihan, SIMSEK Utku Bulut, GOZMEN Belgin, et al. Comparison of MIL-101(Fe) and amine-functionalized MIL-101(Fe) as photocatalysts for the removal of imidacloprid in aqueous solution[J]. Journal of the Iranian Chemical Society, 2019, 16(8): 1735-1748.
19	邢建东. 晶体定向生长[M]. 西安: 西安交通大学出版社, 2008.
	XING Jiandong. Crystal directional growth[M]. Xi'an: Xi'an Jiaotong University Press, 2008.
20	LI Juan, WANG Liangjie, LIU Yongqiang, et al. Removal of berberine from wastewater by MIL-101(Fe): performance and mechanism[J]. ACS Omega, 2020, 5(43): 27962-27971.
21	杨霞珍. 熔铁催化剂费-托合成制低碳烯烃构效关系研究[D]. 杭州: 浙江工业大学, 2018.
	YANG Xiazhen. Study on structure-activity relationship of fused iron catalyst for producing light olefinsvia Fischer-Tropsch synthesis[D]. Hangzhou: Zhejiang University of Technology, 2018.
22	CHEN Yao, LI Xin, LI Zhenhua, et al. Highly efficient iron based MOFs mediated catalysts for Fischer-Tropsch synthesis: effect of reduction atmosphere[J]. Journal of the Taiwan Institute of Chemical Engineers, 2020, 107: 44-53.
23	WU Xian, MA Hongfang, ZHANG Haitao, et al. High-temperature Fischer-Tropsch synthesis of light olefins over nano-Fe₃O₄@MnO₂ core-shell catalysts[J]. Industrial & Engineering Chemistry Research, 2019, 58(47): 21350-21362.
24	LIU Xiaoling, MA Cailian, ZHAO Wentao, et al. Effects of promoters on carburized fused iron catalysts in Fischer-Tropsch synthesis[J]. Journal of Fuel Chemistry and Technology, 2021, 49(10): 1504-1512.
25	HAN Zhonghao, QIAN Weixin, MA Hongfang, et al. Effects of Sm on Fe-Mn catalysts for Fischer-Tropsch synthesis[J]. RSC Advances, 2019, 9(55): 32240-32246.
26	HAN Zhonghao, QIAN Weixin, ZHANG Haitao, et al. Effect of rare-earth promoters on precipitated iron-based catalysts for Fischer-Tropsch synthesis[J]. Industrial & Engineering Chemistry Research, 2020, 59(33): 14598-14605.

催化剂	X(CO)/%	S(CO₂)/%	烃类分布/%
催化剂	X(CO)/%	S(CO₂)/%	CH₄	C₂~C₄	C₅₊
CO-600	63.2	35.5	16.0	13.2	70.8
CO-700	74.4	36.1	19.5	14.9	65.6
HC-550	69.7	37.1	22.8	15.5	61.7
HC-650	19.8	22.9	22.6	17.1	63.3

催化剂	X(CO)/%	S(CO₂)/%	烃类分布/%
催化剂	X(CO)/%	S(CO₂)/%	CH₄	C₂~C₄	C₅₊
CO-600	63.2	35.5	16.0	13.2	70.8
CO-700	74.4	36.1	19.5	14.9	65.6
HC-550	69.7	37.1	22.8	15.5	61.7
HC-650	19.8	22.9	22.6	17.1	63.3

催化剂	元素相对质量分数/%
催化剂	C	O	Fe	K	Al	Ca
CO-600	57.23	8.06	33.60	0.09	0.46	0.55
CO-700	49.50	6.01	43.17	0.05	0.41	0.86
HC-550	31.02	4.97	62.81	0.07	0.45	0.68
HC-650	43.58	1.68	53.23	0.15	0.59	0.77

催化剂	元素相对质量分数/%
催化剂	C	O	Fe	K	Al	Ca
CO-600	57.23	8.06	33.60	0.09	0.46	0.55
CO-700	49.50	6.01	43.17	0.05	0.41	0.86
HC-550	31.02	4.97	62.81	0.07	0.45	0.68
HC-650	43.58	1.68	53.23	0.15	0.59	0.77

催化剂	比表面积/m²·g^-1	孔容/cm³·g^-1	平均孔径/nm
MIL-101(Fe)-熔铁	6.4	0.02	15.4
CO-600	177.4	0.26	5.75
CO-700	136.5	0.25	7.39
HC-550	86.5	0.13	5.95
HC-650	146.1	0.26	7.31