还原碳化温度和CO浓度对工业级费托合成沉淀铁催化剂性能的影响

doi:10.16085/j.issn.1000-6613.2025-0346

摘要/Abstract

摘要：

采用自主研发的工业级费托合成沉淀铁催化剂CNFT-1，在尾气循环搅拌釜反应器中近工业反应条件下考察了还原碳化温度和反应器入口CO浓度对催化剂活性和选择性的影响。结果表明，在240~290℃内，随着还原温度升高，还原后催化剂的加氢能力增强，费托合成产物中低碳烃（C₂~C₄）选择性从2.9%增加至4.8%，高碳烃（C $5 +$ ）选择性从94.9%降低至92.0%，烃类产物分布向轻组分方向移动。从催化剂活性来看，较适宜的还原温度为270℃，还原温度太低（240℃和250℃）或过高（290℃）得到的催化剂活性都偏低。费托合成沉淀铁催化剂的还原反应和合成气在已还原的活性位点上发生费托反应是同步进行的，还原时反应器入口保持较低的CO浓度（≤2.6%）将得到较高的催化剂活性（CO转化率≥94.9%）和较低的副产物选择性（CO₂与CH₄选择性之和在20.3%~22.0%内）。

关键词: 催化剂, 还原, 一氧化碳, 温度, 费托合成

Abstract:

The effects of reduction-carbonization temperature and reactor inlet CO concentration on the activity and selectivity of a self-developed industrial Fe-based Fischer-Tropsch synthesis catalyst (CNFT-1) were investigated under near-industrial conditions in a tail-gas recycle continuous stirred tank reactor. The results indicated that within the temperature range of 240℃ to 290℃, the hydrogenation activity of the catalyst improved with increasing reduction temperature. The selectivity toward light hydrocarbons (C₂—C₄) increased from 2.9% to 4.8%, while the selectivity for heavy hydrocarbons (C $5 +$ ) decreased from 94.9% to 92.0%, demonstrating a shift in hydrocarbon product distribution toward lighter components. Regarding catalytic activity, an optimal reduction temperature of 270℃ was identified. Both lower reduction temperature (240℃ and 250℃) and higher temperature (290℃) resulted in an inferior catalytic activity. The reduction process of the precipitated iron catalyst and Fischer-Tropsch reaction of syngas on the reduced active sites proceeded simultaneously. Maintaining a lower CO concentration (≤2.6%) at the reactor inlet yielded superior catalyst performance, characterized by high CO conversion (≥94.9%) and low byproduct selectivity (CO₂ + CH₄ selectivity within the range of 20.3%—22.0%).

Key words: catalyst, reduction, carbon monoxide, temperature, Fischer-Tropsch synthesis

中图分类号:

O643

王涛, 张雪冰, 张琪, 陈强, 张魁, 门卓武. 还原碳化温度和CO浓度对工业级费托合成沉淀铁催化剂性能的影响[J]. 化工进展, 2025, 44(S1): 178-184.

WANG Tao, ZHANG Xuebing, ZHANG Qi, CHEN Qiang, ZHANG Kui, MEN Zhuowu. Effects of reduction-carburization temperature and inlet CO concentration on industrial precipitated iron-based catalyst for Fischer-Tropsch synthesis[J]. Chemical Industry and Engineering Progress, 2025, 44(S1): 178-184.

图/表 15

表1 催化剂CNFT-1的物性

参数	数值
堆密度/g·cm^-3	0.8
粒径范围/μm	30~120
孔体积/cm³·g^-1	0.53
比表面积/m²·g^-1	186
平均孔径/nm	11.5

图1 搅拌釜装置流程示意图1—H2气瓶；2—CO气瓶；3—气体净化系统；4—H2流量计；5—CO流量计；6—混合罐；7—搅拌釜；8—热分离罐；9—冷分离罐；10—压缩机；11—背压阀；12—气相色谱仪；13—尾气表

表2 还原期间不同反应器入口CO浓度实验条件

序号	新鲜气CO流量/mL·min^-1	循环气量/mL·min^-1	循环气CO体积分数/%	入口CO体积分数/%
1	16	1540	0.00	0.8
2	22	1547	0.16	1.3
3	32	1542	0.28	1.9
4	37	1553	0.34	2.2
5	43	1532	0.48	2.6
6	59	1547	0.74	3.6
7	105	1575	1.45	6.2
8	168	1538	3.34	10.6

图2 不同还原温度下反应器出口CO浓度随还原时间的变化趋势

图3 不同还原温度下还原恒温段反应器出入口CO浓度变化趋势

图4 不同还原温度下得到的催化剂性能随反应时间的变化趋势

图5 不同还原温度下催化剂烃类选择性随反应时间的变化趋势

图6 不同还原温度下催化剂加氢性能随反应时间的变化趋势

图7 不同还原反应器入口CO浓度条件下还原反应的CO转化率

图8 不同还原反应器入口CO浓度条件下还原反应的产物选择性

图9 还原期间不同入口CO浓度条件下的催化剂活性变化趋势

图10 还原期间不同入口CO浓度条件下的CO2选择性（100~200h平均值）

图11 还原期间不同入口CO浓度条件下的CH4选择性（100~200h平均值）

图12 还原期间不同反应器入口CO浓度条件下的催化剂CO2选择性变化趋势

图13 还原期间不同反应器入口CO浓度条件下的催化剂CH4选择性变化趋势

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