逆水煤气变换催化剂的制备及反应性能

为解决逆水煤气变换反应环境下催化剂抗还原性和稳定性较差的问题,采用浸渍法和共沉淀法制备了Mn基催化剂,对逆水煤气变换反应进行了热力学分析和催化剂初步筛选,初步考察了不同反应温度、反应压力、氢碳体积比和气体空速下的催化活性和反应选择性,并进行了催化剂稳定性评价和物化表征。结果表明,与浸渍法相比,共沉淀法制备的催化剂性能较好。适宜的逆水煤气变换反应条件为550~600℃,常压~0.5 MPa,氢碳体积比1~1.5,空速10 000~15 000 h-1。在入口温度580℃,压力0.5 MPa,氢碳体积比1.5和气体空速6 000 h-1的条件下,CO2转化率达45%,CO选择性为90%。催化剂500 h稳定性良好,这主要是由于形成了稳定的Mn基尖晶石活性相。     

高浓度CO变换制氢催化剂本征动力学

采用石英玻璃管式反应器,考察B112型高温变换催化剂在高浓度CO(体积分率高于75%)氛围下的本征动力学特性,拟合实验数据并建立动力学模型,对幂函数动力学模型进行检验。结果表明:与传统铁系高温变换催化剂相比,该高温变换催化剂上变换反应活化能较低,其低温活性较好;该催化剂上CO对反应速率的影响偏小,是由反应组分中较高浓度的CO所导致;H_2O对反应速率的影响相对较大;CO_2对变换反应速率的抑制作用很大,因此为提高变换反应速率,应当减小CO_2的不利影响;H_2组分对反应速率的影响很小,实际应用中可以忽略。     

低水气比耐硫变换工艺及催化剂在HT-L煤气化制甲醇装置中的应用

介绍了低水气比耐硫变换工艺在首套HT-L煤气化制甲醇装置中的应用情况,以及在运行过程中出现的问题和解决的方法。生产实践证明,低水气比耐硫变换工艺和QDB-05/QDB-04变换催化剂,完全能适应HT-L煤气化生产甲醇的需求,其应用前景广阔。     

Co－Mo－K／Al_2O_3系耐硫变换催化剂硫化过程的研究

以工厂实用的加有ＣＳ２的半水煤气为硫化气源，采用ＴＧ、ＤＴＡ、ＳＥＭ、ＥＤＳ、ＸＲＤ等表征技术，对Ｃｏ－Ｍｏ－Ｋ／Ａｌ２Ｏ３系耐硫变换催化剂的各个组份及其组合试样进行了恒温硫化及程序升温硫化实验研究。全面考察了温度对硫化过程的影响．比较了不同活性组份的硫化行为，探讨了各组份在硫化过程中的作用。     

一种新γ相氧化铝负载的铁铝双金属催化剂用于反向水煤气转化反应(英文)

In reverse water gas shift (RWGS) reaction CO₂ is converted to CO which in turn can be used to produce beneficial chemicals such as methanol. In the present study, Mo/Al₂O₃, Fe/Al₂O₃ and Fe-Mo/Al₂O₃ catalysts were synthesised using impregnation method. The structures of catalysts were studied using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, inductively coupled plasma atomic emission spectrometer (ICP-AES), temperature programmed reduction (H₂-TPR), CO chemisorption, energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) techniques. Kinetic properties of all catalysts were investigated in a batch reactor for RWGS reaction. The results indicated that Mo existence in structure of Fe-Mo/Al₂O₃ catalyst enhances its activity as compared to Fe/Al₂O₃. This enhancement is probably due to better Fe dispersion and smaller particle size of Fe species. Stability test of Fe-Mo/Al₂O₃ catalyst was carried out in a fixed bed reactor and a high CO yield for 60 h of time on stream was demonstrated. Fe₂(MoO₄)₃ phase was found in the structures of fresh and used catalysts. TPR results also indicate that Fe₂(MoO₄)₃ phase has low reducibility, therefore the Fe₂(MoO₄)₃ phase signifificantly inhibits the reduction of the remaining Fe oxides in the catalyst, resulted in high stability of Fe-Mo/Al₂O₃ catalyst. Overall, this study introduces Fe-Mo/Al₂O₃ as a novel catalyst with high CO yield, almost no by-products and fairly stable for RWGS reaction.     

等温变换与绝热变换在高水气比粗煤气变换中的应用对比

不少新建合成氨装置采用粉煤加压气化工艺,其粗煤气中水气比高、CO含量高,介绍了与其配套的等温变换和绝热变换2种变换工艺,分别从工艺流程、占地面积、关键设备、公用工程消耗、催化剂用量和经济投资等方面对二者进行了对比。结果表明,等温变换在高水气比粗煤气变换中应用具有一定的优势,但也存在应用业绩不多、运行年限较短的问题。     

Pt and/or Pd Supported/Incorporated Catalyst on Perovskite-Type Oxide for Water Gas Shift Reaction

Catalytic properties of Pd and/or Pt supported/incorporated on/in perovskite-type oxides for water gas shift (WGS) reaction have been investigated. We found that the dominant reaction mechanism over these catalysts was redox mechanism by CO and steam, and their redox properties were controllable by the bulk structure of perovskite.     

低温变换催化剂结盐的原因分析及处理

我公司硝铵厂CO变换系统采用加压中温变换串低温变换流程,低变炉操作压力在1．25—1．7MPa,装填的是LB204铜锌铝型低温变换催化剂,装填量48t,分2层装填。2003年以来,公司对硝铵厂净化系统的部分装置进行了改造,改造后生产负荷大幅度提高,但出现了低变炉催化剂结盐现象（20多年来的第1次）,严重影响了装置的正常运行。     

Deactivation, Regeneration, and Stable Performance of a PtMoRe Water Gas Shift Catalyst for On-Site Hydrogen Generation: Part 2

This paper analyzes the mechanism of deactivation and methods of regeneration of a PtMoRe water gas shift catalyst supported on a stabilized zirconia. Although this catalyst initially possesses high activity below 250 °C, a decrease in CO conversion ranging from 10 to 50% was observed over a period of 60 h. To determine the mechanism responsible for the decay, a series of activity tests and high resolution transmission electron microscopy analyses were done. Experimental results revealed the existence of stable and unstable operating regimes that depend on the reaction temperature, CO concentration, and H₂O/H₂. The high initial activity of this catalyst relies upon a synergetic relationship between the platinum, molybdenum, and rhenium which form an alloy generating the catalytically active phase. Based on our experimental results, we have concluded water contained in the feed gas oxidizes the Mo/Re metals, disrupts this synergy (de-alloys), and deactivates the catalyst. While not completely understood, CO is required for this oxidation mechanism to occur and possible explanations are discussed. Heating the catalyst in a hydrogen or reformate gas reduces the oxides back to metals, reforms the PtMoRe alloy, and restores the activity of the catalyst. Conditions for stable performance are consistent with use as a mid-temperature range water gas shift catalyst for on-site hydrogen generation.     

NDC纳米催化湿法脱硫技术在变换气脱硫中的应用

我国氮肥行业中半水煤气和变换气脱硫主要采用湿式氧化脱硫工艺,该工艺中所使用的催化剂有100多种,其中实用的有20多种,主要有ADA法、栲胶法、酞氰钴法等。湿法脱硫技术主要亟待解决的问题有如下几个方面：     

Effect of Catalyst Supports on Water‐Gas Shift Reaction at Ultrahigh Temperatures Using Syngas

Monometallic and bimetallic catalysts (Pt, Ni, and Pt‐Ni) with single support (Al₂O₃, TiO₂) and composite support (CeO₂/Al₂O₃, CeO₂/TiO₂) were prepared and tested for water‐gas shift reaction in a tubular quartz reactor. Syngas and steam with different steam‐to‐carbon ratios served as feedstock. The operating pressure was fixed while the reaction temperature was varied. The measured results indicated that the monometallic Ni/Al₂O₃ catalyst exhibits the lowest CO conversion and H₂ yield as compared with other catalysts. About the same CO conversion can be obtained from Pt and Pt‐Ni catalysts with single or composite support. However, higher H₂ yield can be achieved from the TiO₂‐supported catalyst compared with those supported by Al₂O₃. The experimental data also indicated that good thermal stability can be reached for the Pt‐based catalysts studied.     

丙醛常压气相催化加氢制正丙醇催化剂的研究

采用浸渍法制备一系列Cu催化剂,在固定床小粒度连续流动反应器中评价了Cu催化剂的催化性能。主要考察了Cu、Zn等含量和反应条件对丙醛催化加氢制备正丙醇反应的影响。实验结果表明,Cu、Zn等含量对该反应有明显的影响;催化剂适宜组分(m%)为:催化剂中含铜8.0%～12.0%、锌10.0%、Na2O 0.8%～1.0%,竞争吸附剂选择a;得出了适宜的反应条件:氢/醛物质的量比为10.0、温度100～130℃、反应压力0.05～0.10 MPa,原料液体空速:0.1～0.3 h-1;在该反应条件下,丙醛转化率≥99.0%,正丙醇选择性大于99.0%。     

低汽气比高温变换催化剂的表征及应用

通过对ICI71－4和LB型低汽气比高温变换催化剂在侧线试验装置上使用前后的结构进行测定，探讨适用于低汽气比合成氨工艺流程的催化剂的表征特性。     

Low-Temperature Water Gas Shift Reaction on Combustion Synthesized Ce1−x Pt x O2−δ Catalyst

Catalytic activity of Pt²⁺ ion substituted CeO₂ synthesized by solution combustion method was tested for low-temperature water gas shift reaction in H₂ rich steam reformate. XPS studies show that Pt is dispersed as ions and there is no change in Pt oxidation state after the reaction. CO conversion is found to be maximum at 200 °C over Ce_1?x Pt _x O_2?δ catalysts without any methanation. The values of rate are 1.86 and 4.66 μmol/g/s at 125 and 150°C respectively with a dry gas flow rate of 6 Lh^?1 over 2% Pt/CeO₂.     

加压下填料塔中液相轴向反混的研究

Liquid phase axial mixing was measured with the tracer technique in a packed column with inner diameter of 0.15m,in which the structured packing,Mellapak 350Y,was installed.Tap water as the liquid phase flowed down through the column and stagnant gas was at elevated pressure ranging from atmospheric to 2.0MPa.The model parameters of Bo andθwere estimated with the least square method in the time domain.As liquid flow rate was increased,the liquid axial mixing decreased.under our experimental conditions,the effect of pressure on Bo number on single liquid phase was negligible,and eddy diffusion was believed to be the primary cause of axial mixing in liquid phase.     

Catalysis at Metal/Oxide Interfaces: Density Functional Theory and Microkinetic Modeling of Water Gas Shift at Pt/MgO Boundaries

Topics in Catalysis - The impact of metal/oxide interfaces on the catalytic properties of oxide-supported metal nanoparticles is a topic of longstanding interest in the field of heterogeneous...