Structured silicalite-1 encapsulated Ni catalyst supported on SiC foam for dry reforming of methane

Structured silicalite-1 zeolite encapsulated Ni catalyst supported on silicon carbide foam (i.e., Ni@S1-SiC) was prepared using a new yet simple one-pot method, showing the significantly improved anti-sintering and anti-coking performance in comparison with the conventional supported and encapsulated Ni catalysts (i.e., Ni/S1, Ni/S1-SiC, and Ni@S1), in catalytic dry reforming of methane (DRM). The developed Ni_0.08@S1-SiC catalyst showed high CO₂/CH₄ conversions of >85% and H₂/CO molar ratio of >0.85 at 700°C, outperforming other control catalysts under investigation. Additionally, the Ni_0.08@S1-SiC catalyst demonstrated high turnover frequency (TOF) values of ~5.6 and ~2.1/s regarding to CO₂/CH₄ conversions at 400°C, exhibiting excellent stability and low pressure-drop during 100 hr on stream evaluation. Post-reaction characterization of the used catalysts demonstrated that the combination of zeolite encapsulated Ni catalysts and SiC foam enabled well-dispersed and ultrafine Ni nanoparticles, low pressure drop and intensified transfer steps, presented excellent anti-sintering and anti-coking abilities.     

Simulation of dry reforming of methane in a conventional downfired reformer

A model for industrial top‐fired dry reforming of methane (DRM) and for combined dry reforming and steam reforming of methane was developed for the first time. The model calculates and gives predictions on the temperature profiles for fuel gas, tube walls, and process gas, as well as the process gas composition profiles over the length of the tubes. Radiative heat transfer is modeled by Hottel Zone method. Material and energy balances are solved numerically using Newton‐Raphson solver. Kinetic models for two different DRM catalysts are applied in the model for comparison. Simulation results show that water–gas shift reaction is important in DRM and addition of steam in the feed of process gas is beneficial for industrial production. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2060–2071, 2017     

从反应温降波动分析重整催化剂活性变化

介绍了所用催化剂以及工艺流程的概况。详细讨论了正在运行的第八周期中重整反应器的有关情况。对重整反应器1在2002年初发生的催化剂失活，从失活的现象、可能的原因以及采取的措施进行了详细的分析。从生产效益考虑，应整体更换催化剂。     

Strontium carbonate supported cobalt catalyst for dry reforming of methane under pressure

Catalytic performance of Co–SrO catalyst for dry reforming of methane was investigated at 1 MPa, 1023 K. The catalyst prepared by oxalate co-precipitation method or citric acid method showed a steady activity for dry reforming of methane under pressure. The importance and stability of cobalt metal with strontium carbonate were suggested for the Co–SrO catalyst, and thus it should be denoted as Co–SrCO₃. In addition, cobalt supported on strontium carbonate prepared by impregnation method (Co/SrCO₃) showed the comparable activity with high tolerance to oxidative atmosphere under reaction conditions.     

干燥温度对Co/SiO2费托合成催化剂结构和性能的影响

采用浸渍法制备了钴负载质量分数15％的Co/SiO2催化剂,考察干燥温度对催化剂性能的影响.随着干燥温度升高,催化剂活性先增大后减小,但对产物选择性没有明显影响.BET、SEM、XRD和H2 - TPR测定结果表明,改变干燥温度可以影响钴在催化剂中的分布状态,从而使催化剂结构、晶粒度和还原性能发生相应变化,这些效应的叠...     

Modulating morphology and textural properties of ZrO2 for supported Ni catalysts toward dry reforming of methane

This work presents a facile and efficient approach to modulate morphology and textural properties of ZrO₂ through ammonium fluoride‐urea assisted hydrothermal (FUAH) method with diverse parameters including molar ratio of NH₄F to zirconium (n_f/z), molar ratio of urea to zirconium (n_u/z), hydrothermal temperature (T_hydroth), and hydrothermal time (t_hydroth), which serve as support for supported Ni catalysts toward dry reforming of methane (DRM) to produce synthesis gas. The plausible mechanism for forming ZrO₂ supports with different morphologies under diverse hydrothermal conditions was proposed. Various characterization techniques were employed to investigate the effect of preparation parameters on the morphology and textural properties of the as‐synthesized ZrO₂ supports, as well as to reveal the structure‐performance relationship of the Ni/ZrO₂ catalysts prepared by L‐arginine assisted incipient wetness impregnation method toward DRM reaction. The developed supported Ni catalyst on hierarchically structured ZrO₂ with pinecone shape prepared by FUAH method (Ni/ZrO₂‐FUAH) demonstrates higher activity and stability for DRM than that on ZrO₂ prepared by traditional hydrothermal method (Ni/ZrO₂‐H). The higher activity of Ni/ZrO₂‐FUAH than Ni/ZrO₂‐H can be ascribed to the higher Ni dispersion, smaller Ni crystalline size, and enhanced reducibility of NiO, significantly affected by morphology of support, as well as the higher coke‐resistance catalytic stability can be ascribed to smaller Ni particle size and stronger Ni‐support interaction, strongly dependent on morphology and textural properties of ZrO₂ supports that affected by FUAH process parameters. The outstanding catalytic performance of the developed Ni/ZrO₂‐FUAH catalyst allows it to be a promising candidate for synthesis gas production through DRM reaction. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2900–2915, 2017     

Preparation of nanocrystalline Ni/Al2O3 catalysts with the microemulsion method for dry reforming of methane

Mesoporous nanocrystalline nickel‐alumina catalysts with high surface area were prepared by a microemulsion (ME) method and were employed in methane reforming with carbon dioxide for syngas production. The catalysts were characterized by X‐ray diffraction (XRD), Brunauer‐Emmett‐Teller surface area analysis (BET), temperature‐programmed reduction (TPR), temperature‐programmed oxidation (TPO), and scanning electron microscopy (SEM) techniques. The results showed that the catalysts possessed mesoporous structure with high surface area (> 250 m² · g^?1) and small crystallite size (～5 nm). The catalytic results revealed high activity and stability for the prepared catalysts. In addition, the effect of feed ratio and GHSV on catalytic performance was investigated.     

Cobalt–magnesia catalyst by oxalate co-precipitation method for dry reforming of methane under pressure

Catalytic performance of cobalt–magnesia catalyst prepared by oxalate co-precipitation method (Co–MgO) was investigated for dry reforming of methane at 1 MPa, 1023 K. Co–MgO (7 mol% Co) showed stable activity at such high space velocity as 400,000 cm³ h⁻¹ g⁻¹ whereas reactor was plugged during the reforming reaction with 10 mol% Co–MgO, and the activity of Co–MgO with Co content less than 6 mol% gradually decreased by the oxidation of cobalt species. Well-balanced cobalt content is essential for high and stable activity.     

Pt-Re催化剂重整高温F-T合成石脑油的催化性

选用SB粉制得γ-Al₂O₃载体,采用共浸渍法制备Pt-Re催化剂,并对其进行BET、XRD、NH₃-TPD、H₂-TPR和ICP表征。以高温F-T合成石脑油为原料,在反应温度500 ℃、反应压力1.0 MPa、空速2.0 h^-1和氢油体积比1 000条件下,考察Pt-Re催化剂的重整活性及其稳定性。结果表明,Pt-Re催化剂能高效催化重整高温F-T合成石脑油,240 h重整过程中,高温F-T合成石脑油液体收率79.89%,芳烃质量分数61.60%,直链烷烃质量分数降低了28.15%,重整转化率达200.53%,研究法辛烷值提高35个单位,表明Pt-Re催化剂能有效催化重整高温F-T合成石脑油,使之转化为汽油调和组分成为可能。     

The effects of stoichiometry on the properties of exsolved Ni-Fe alloy nanoparticles for dry methane reforming

The dry reforming of methane has received notable attention as a chemical process to convert natural gas into value-added chemicals and fuels. Ni-based exsolution catalysts using perovskite oxides supports have been used for their attractive sinter-resistance and coke-resistance properties. The perovskite oxide in itself has unique defect chemistry that can be used to manipulate and control the properties of the catalyst nanoparticles exsolved on the surface, therefore influencing both the nanoparticle and support characteristics. In this study, the La:Fe ratio of Ni-doped LaFeO₃ was used to manipulate and control the properties of exsolved Ni-Fe alloy nanoparticles. The Ni-Fe nanoparticles consisted of different sizes ranging from 10 to 380 nm. Temperature programmed surface reaction studies along with materials characterization with SEM, STEM-HAADF, XRD, and BET showed that the Ni-Fe nanoparticles from different solid precursors have the same active sites for methane activation but differ in performance and stability because of size effects, metal-support strength, composition and support basicity. A mechanism is proposed to decipher the merits of the Ni-Fe nanoparticles with the best activity, selectivity, and stability in this study.     

Mn-Mg-O_x催化剂低温NH_3选择性催化还原NO的性能的研究

采用低温固相法制备了系列Mn-Mg-Ox催化剂,考察了催化剂的低温NH3选择性催化还原(NH3-SCR)NO的性能。结果表明,当Mn/Mg摩尔比为1,氨氮体积比为1,空速为30 000 h-1时,催化剂表现出优异的低温催化活性和抗硫性。在100~175℃温度范围内,无硫时,NO催化转化率能保持在99%以上;加入100μg/g SO2后,催化剂脱硝性能变化不大,仍可维持在95%以上。     

Intrinsic kinetics of nickel/calcium aluminate catalyst for methane steam reforming

A new catalyst for steam reforming of methane based on nickel/calcium aluminate is prepared. The new catalyst has shown stability and high activity at low steam to methane ratios. In this paper the intrinsic rate equations are derived and parameters estimation made. The rate equations show non-monotonic dependence on steam partial pressure. The rate equations also show that the primary product is CO₂ while CO is formed via the reverse water-gas shift reaction. The mechanism proposed and the rate equations obtained indicate that it may be essential to propose specific rate models for any given catalyst rather than generalized mechanism and rate models.     

O-846型合成气低温脱氧催化剂的性能研究

开发了一种用于合成气的O-846型低温脱氧催化剂,该催化剂以氧化铝为载体,以贵金属Pd为主活性组分,采用浸渍工艺制备,使用前无需活化。在贵金属和多种非贵金属氧化物助剂协同催化作用下,于空速3 500 h-1、反应压力0.5 MPa和反应温度63℃条件下,将合成气中体积分数为0.2%的O2脱至0.5×10-6以下。1 032 h寿命试验结果表明,O-846型合成气低温脱氧催化剂的活性及稳定性良好,具有工业应用前景。     

RC011连续重整催化剂的工业试生产

石油化工科学研究院研制的一种新型连续重整催化剂PS Ⅵ（研究型号），具有低积炭速率和高选择性，适用于各种类型新建连续重整装置，特别适用于受再生能力限制的连续重整装置的扩能改造。2000年11月在建长公司化工厂进行了PS Ⅵ型连续重整催化剂的吨级工业放大试验, 得到了吨级放大的RC011（生产型号）催化剂成品，取得了工业放大的成功。     

An efficient technique for improving methanol yield using dual CO2 feeds and dry methane reforming

Steam methane reforming (SMR)-based methanol synthesis plants utilizing a single CO₂ feed represent one of the predominant technologies for improving methanol yield and CO₂ utilization. However, SMR alone cannot achieve full CO₂ utilization, and a high water content accumulates if CO₂ is only fed into the methanol reactor. In this study, a process integrating SMR with dry methane reforming to improve the conversion of both methane and CO₂ is proposed. We also propose an innovative methanol production approach in which captured CO₂ is introduced into both the SMR process and the recycle gas of the methanol synthesis loop. This dual CO₂ feed approach aims to optimize the stoichiometric ratio of the reactants. Comparative evaluations are carried out from a techno-economic point of view, and the proposed process is demonstrated to be more efficient in terms of both methanol productivity and CO₂ utilization than the existing stand-alone natural gas-based methanol process.     

甲烷干重整Ni基催化剂失活及抑制失活研究进展

使用甲烷和二氧化碳为原料,通过甲烷干重整反应可以将其转化为合成气。由于此反应可以利用甲烷和二氧化碳这两种温室气体,因而近年来受到了研究人员广泛的关注。其中,反应所使用的Ni基催化剂由于其较高的活性和较低的成本得到了较为深入的研究。针对甲烷干重整Ni基催化剂,本文简要介绍了几种常用的制备方法,并指出了在反应条件下存在的活性组分Ni的烧结和积炭的生成这两个问题,还详细分析了其各自的影响因素。另外,还从使用特殊载体、添加助剂以及构造特殊结构三方面阐述了甲烷干重整Ni基催化剂的失活解决方案,并指出解决催化剂的烧结和积炭问题是当前该领域的研究重点。     

双金属Ni-Co/HZSM-5催化剂上甲烷二氧化碳重整反应

采用等体积浸渍法制备一系列双金属Ni-Co/HZSM-5催化剂,考察反应温度和Ni与Co质量比对甲烷二氧化碳催化重整性能的影响。采用BET和H2-TPR表征催化剂的孔结构和还原性能,结果表明,负载的活性组分均匀分散在HZSM-5载体孔道内。Ni与Co之间存在协同作用,促进了Ni-Co/HZSM-5催化剂的还原性能。单金属Co催化剂几乎对甲烷没有转化活性,双金属Ni-Co催化剂催化活性明显提高,Ni与Co质量比6∶4时,催化剂甲烷二氧化碳重整反应的催化活性和稳定性优于单金属Ni催化剂。     

低温甲醇水重整制氢催化剂研究进展

甲醇具有结构简单、含氢量高、产能大等优点,利用甲醇与水蒸气进行重整是一种节能高效的现场制氢方式。甲醇水蒸气重整(MSR)与燃料电池联用能够实现多场景应用,但由于反应温度较高(250~300℃),存在启动速度较慢、副产CO含量较高和热效率较低等问题。低温甲醇水重整(LT-Methanol Water Reforming, LT-MWR)包括低温甲醇水蒸气重整(LT-MSR)与液相甲醇水重整(Aqueous-phase Reforming of Methanol, APRM),反应通常在200℃以下进行,同时保持较高的反应活性,进而能够减少预热时间、减弱副反应发生,且能与燃料电池实现更强的热耦合。本工作首先介绍了商用催化剂优异的性能与存在的缺陷,然后对低温甲醇水重整制氢催化剂,诸如Cu基催化剂、贵金属催化剂与光协同催化剂的研究进展进行了回顾。归纳了低温铜基催化剂的改性策略,包括合成方法、结构设计与元素掺杂。对国内外商用CuZnAlOx催化剂结构与性能的测试表明,其转化率高和稳定性好,存在的缺陷是价格较贵且在低温区催化活性急剧下降。Cu基催化剂活性受温度影响较大,在低温区活性很低,但通过适当的改性能够实现其应用价值,其改性策略包括合成方法、结构设计与元素掺杂。贵金属催化剂低温下活性较高,但存在价格昂贵、合成复杂等缺点。光协同催化剂则是在光照条件下进行催化重整,尚处于研究阶段。对于Cu基催化剂,合成方法的改进能够大大改善催化剂的微观混合程度与可重现性。适当的结构设计可提升催化剂的比表面积与热稳定性。元素掺杂则能够提升活性组分的分散度,修饰催化剂表面结构。三种改性策略能够有效提升Cu基催化剂低温下甲醇重整制氢的性能,在保持较高活性的同时,降低CO副产物的含量。展望了低温甲醇水重整制氢催化剂的发展前景和挑战,对催化剂的开发与应用有指导意义。     

Z型甲烷蒸汽转化催化剂用于补碳制合成甲醇合成气的研究

选择工业应用效果较好的CNYQ、Z-2和Z-3型催化剂，并补加CO₂,对在其上的甲烷水蒸汽转化制合成气催化反应过程进行了测试研究。结果表明，在适当补加CO₂、反应温度600～850 ℃下，制得的合成气适合于甲醇合成。Z型催化剂用于CH₄-H₂O-CO₂转化制合成甲醇合成气，在当前情况下可满足某些合成甲醇厂的需要。