镍基催化剂上甲烷三重整制合成气的研究
文献类型：学位论文
| 作者 | 姜洪涛 |
| 学位类别 | 博士 |
| 答辩日期 | 2007-08-18 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 张懿 |
| 关键词 | 甲烷 三重整 合成气 Ni基催化剂 床层温度 |
| 其他题名 | Tri-reforming of Methane to Syngas over |
| 学位专业 | 化学工艺 |
| 中文摘要 | CH4化工利用是非石油基路线合成燃料或大宗化工产品的重要组成部分之一。CH4三重整（Tri-Reforming，TRM）是利用CO2、H2O和O2同时重整CH4来生产合成气的过程，具有能效高、合成气的n(H2)/n(CO)适宜（1.5~2.0）和缓解催化剂积碳的优点。TRM过程对CO2减排具有重要贡献，在重要的工业生产过程、环境保护以及新能源上具有广阔的应用前景。本论文对CH4三重整制合成气（TRM）Ni基催化剂、工艺条件以及催化剂床层温度分布进行了研究。采取两种手段对Ni基催化剂进行改性：修饰载体和修饰金属活性组分。系统地研究了Ni/Al2O3、Ni/MgxTi1-xO和Pt修饰的Ni/MgO三种催化剂体系在TRM反应中的催化性能。主要研究内容和创新点如下： 1、制备了新型γ-Al2O3载体上负载的Ni/Al2O3催化剂，重点考察催化剂制备过程中焙烧温度对催化剂结构、性质和催化性能的影响。结果表明，650 ℃下焙烧的催化剂具有较高的金属分散度（11.5%）和较好的催化性能，在优化的工艺条件下，连续运行50 h未见活性下降，发现产物的n(H2)/n(CO)可以通过改变原料的组成进行调节。考察了反应过程床层温度分布情况，将催化剂床层中的反应区域划分为三个区域：富氧区、贫氧区和无氧区，自供热式的重整反应发生在贫氧区内。 2、制备了新型载体MgxTi1-xOy复合氧化物负载的Ni基催化剂，向Ni/MgO体系中添加Ti，调节催化剂中金属-载体的相互作用，在不改变催化剂还原度的前提下，改善催化剂的氧化-还原性能，提高了催化剂在TRM反应中的稳定性。Ni/Mg0.75Ti0.25Oy催化剂在n(CH4):n(CO2):n(H2O):n(O2)=1:0.48:0.54:0.1、850 ℃、1.0 MPa和1.78 g•h• mol-1的加压反应条件下，连续运行50 h未见活性下降，具有较好的稳定性。 3、向Ni/MgO催化剂中添加微量的贵金属Pt，修饰了催化剂的金属活性组分，改善了Ni/MgO催化剂在TRM反应中的催化性能。考察了Pt修饰的Ni/MgO催化剂在TRM反应中的床层温度分布，发现采用分步浸渍法制备的NiPt/MgO和PtNi/MgO催化剂，可以消除床层入口处的热点，使富氧区和贫氧区合并成为一个自供热反应区，并使得该自供热反应区在整个床层中所占的比例增加。 |
| 英文摘要 | Activation of mathane is a part of synthesizing fuel or chemicals through non-petroleum route. Tri-reforming of methane (TRM) to syngas is most energy-efficient. In the reaction system, O2 and H2O help to reduce the carbon deposition on the refrorming catalyst. The n(H2)/n(CO) of syngas from TRM ranges from 1.5 to 2.0 and is very suitable to produce other chemicals. In terms of CO2 produced based on relative energy requirements, trireforming process generates considerably less CO2 per unit amount of desired syngas (CO + 2H2), than the industrial steam reforming process and the well-known CO2 reforming process. TRM process is a promising process for environmental protection and development of new sources of energy. The study on the TRM reaction over Ni-based catalysts was conducted in this paper. Ni-based catalysts were prepared through a wet impregnation method and catalytic performance was improved by modifying support or metal. Three series catalysts were prepared through wet impregnation-Ni/Al2O3, Ni/MgxTi1-xO and Pt modified Ni/MgO system. The TRM reaction was carried out in a continuous flow fixed bed reactor. The influence of reaction conditions, including temperature, pressure, feed composition and W/F (W = catalyst weight, F = total flow rate) on the catalytic performance was investigated. Temperature profiles in fixed catalyst bed in TRM reaction were also investigated. The important results are as follows. 1. Ni/Al2O3 catalysts were prepared by dispersing Ni on new γ-Al2O3 obtained by H2O2-precipitated boehmite from sodium aluminate solution, followed with azeotropic distillation. The influence of calcined temperature on properties and catalytic performance of Ni/Al2O3 was investigated. The dispersion of Ni/Al2O3-650 wass 11.7%, higher than catalysts calcied at other temperature. The activity of Ni/Al2O3-650 did not decrease for a reaction period of 50 h under condition of n(CH4):n(CO2):n(H2O):n(O2)=1:0.48:0.54:0.1, 850 ℃, 1.0 MPa and 1.78 g•h•mol-1, indicating that the catalyst calcined at 650 ℃ possesses excellent performance. It was concluded that n(H2)/n(CO) of syngas could be adjusted by varying feed composition. According to thermal distribution of the catalyst bed, the catalyst bed can be divided into three zones orderly-oxygen adequate zone, oxygen inadequate zone, and oxygen absent zone. In oxygen inadequate zone, proceeds auto-thermal reforming reaction. 2. Ni/MgxTi1-xOy catalysts were prepared by dispersing Ni on new MgxTi1-xOy composite oxides obtained via a sol-gel technique. Adding Ti to the NiO-MgO system obstructed the formation of solid solution, and thus increased the reducibility of the catalysts. The prepared MgxTi1-xOy composite oxides had the same ability to disperse Ni as TiO2 and MgO. Due to the moderate interaction between metal and support and the moderate ability to be reduced, the Ni/Mg0.75Ti0.25Oy and Ni/Mg0.5Ti0.5Oy catalyst possess high stability. For example, the activity of Ni/Mg0.75Ti0.25Oy did not decrease for a reaction period of 50 h under condition of n(CH4):n(CO2):n(H2O):n(O2)=1:0.48:0.54:0.1, 850 ℃, 1.0 MPa and 1.78 g•h•mol-1. 3. Catalytic performance of Ni/MgO was improved by adding Pt to Ni/MgO system through co-impregnation or sequential impregnation method. It was found that in thermal distribution of NiPt/MgO and PtNi/MgO, prepared through sequential impregnation method, hot spot in inlet of catalyst bed was eliminated and auto-thermal zone was extended. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 123 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1107]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 姜洪涛. 镍基催化剂上甲烷三重整制合成气的研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2007. |
入库方式： OAI收割
来源：过程工程研究所
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