G—34型耐硫甲烷化催化剂的反应特性

报道了在钼系与氧化物系催化剂基础上开发的G-34型耐硫甲烷化催化剂的反应特性。它综合钼系和氧化物系二类催化剂的优点,获得了活性高、选择性好、对原料气中硫浓度不敏感,反应前可自然硫化,有良好稳定性的结果。此催化剂用于压力粗煤气提高热值较经济合理。可直接生产合格的城市煤气。     

可逆与不可逆氢在甲烷化反应中的作用

用自行设计和建立的加压动态分析装置研究了甲烷化催化剂上氢的吸附和反应行为．结果表明，在反应条件下吸附的氢可区分为不可逆吸附氢和可逆吸附氢两类，不可逆吸附氢又可分为能被ＣＯ顶替出来的和不能被顶替的两种．起甲烷化反应的是可逆吸附氢，而能被ＣＯ顶替出来的不可逆氢对吸附ＣＯ起促进作用，不能被ＣＯ顶替出来的不可逆氢是甲烷化催化剂必不可少的组分（或称“促进剂”）．     

Magnetically Induced CO2 Methanation Using Exchange‐Coupled Spinel Ferrites in Cuboctahedron‐Shaped Nanocrystals

Magnetically induced catalysis can be promoted taking advantage of optimal heating properties from the magnetic nanoparticles to be employed. However, when unprotected, these heating agents that are usually air‐sensitive, get sintered under the harsh catalytic conditions. In this context, we present, to the best of our knowledge, the first example of air‐stable magnetic nanoparticles that: 1) show excellent performance as heating agents in the CO₂ methanation catalyzed by Ni/SiRAlOx, with CH₄ yields above 95 %, and 2) do not sinter under reaction conditions. To attain both characteristics we demonstrate, first the exchange‐coupled magnetic approach as an alternative and effective way to tune the magnetic response and heating efficiency, and second, the chemical stability of cuboctahedron‐shaped core–shell hard CoFe₂O₄–soft Fe₃O₄ nanoparticles.     

Temperature hysteresis phenomena in heterogeneous catalysis

Temperature hysteresis is observed only in exothermic heterogeneous catalytic reactions (viz., oxidation and methanation of CO or propene hydrogenation) and is absent in the case of endothermic reactions (dehydrogenation of isobutane) or reactions with heat close to zero (viz., 2-butene isomerization). Temperature hysteresis in hydrogenation reactions was discovered for the first time. The concept of local overheating of catalyst active sites caused by poor removal of the reaction heat is proposed to provide a noncontradictory interpretation of the appearance of hysteresis loops. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1379–1385, August, 2000.     

外冷列管式耐硫煤气甲烷化反应器分析

使用Ｃｒａｎｋ－Ｎｉｃｏｌｓｏｎ隐格式差分法求解耐硫甲烷化固定床反应器的二维拟均相模型，通过模拟分析，考究管径、管数、反应气入口状态（压力、温度）、溶盐流量及入口温度对反应器操作的影响。对５万Ｎｍ＾３／ｄ煤气的反应器进行优化设计分析，为该工指导。     

Characterization of Ru/CeO2-Al2O3 catalysts and their Performance in CO2 Methanation

Ru/Al₂O₃ and Ru/CeO₂-Al₂O₃ samples were used as catalysts in CO₂ methanation. The catalysts were characterized by temperature-programmed reduction (TPR) and X-ray diffraction. The promoting effect of ceria on the cataytic activity of the catalysts under study in CO₂ methanation was observed.     

碳纳米管负载Cu-Co复合氧化物的富氢气氛中CO催化消除

采用超声处理辅助浸渍法制备了多壁碳纳米管负载的Cu-Co复合氧化物催化剂. 利用XRD、TEM、H₂-TPR、XPS和Raman光谱等表征了催化剂的结构性质. 在Cu和Co氧化物以及金属氧化物与碳纳米管载体间存在强相互作用. 催化剂在富氢气氛中CO催化消除反应中,与单一Cu或Co催化剂相比,Cu-Co复合氧化物催化剂表现出独特的反应特性,特别是在较高反应温度下可同时结合CO优先氧化和CO甲烷化的反应途径来实现高效CO消除. 当Cu/Co比为1/8时活性最优,可以实现在150～250 o和高反应空速 (120 L/(h·g))富氢气氛中CO的完全消除.     

合成气甲烷化反应积炭过程的热力学分析

建立了煤制替代天然气工艺中合成气甲烷化过程的热力学计算模型,并对该反应体系的10个反应进行了分析计算,得到了各组分的平衡组成和各反应的标准化学平衡常数.研究了反应温度、操作压力、原料气组分浓度和产品气循环比等对催化剂床层积炭的影响,发现容易导致积炭的热力学条件为550~800 ℃的反应温度和0.1~1.5 MPa的操作压力,且温度在700 ℃左右、操作压力低于1.0 MPa时催化剂床层积炭量最大.本研究针对催化剂床层积炭规律提出了低温、相对高压、合理的原料气组成是有利于缓解催化剂床层积炭、提高产品收率及保持催化剂活性的优化反应操作条件.     

等离子体技术对CO2甲烷化用Ni/SiO2催化剂的改性作用

采用浸渍法制备了Ni/SiO₂催化剂,应用等离子体技术对催化剂进行改性处理。以CO₂甲烷化为模型反应对催化剂进行活性评价,通过H₂程序升温还原(H₂-TPR)和CO₂程序升温脱附(CO₂-TPD)技术对催化剂进行表征。研究了等离子体技术强化处理对催化剂吸附性能和还原性能的影响。结果表明,与常规焙烧的催化剂相比,等离子体技术改性处理提高了催化剂活性组分的分散度,增加反应活性位并调变了活性位对吸附物种的吸附强度,改进了催化剂的还原性能,CO₂甲烷化反应活性和甲烷的时空产率显著提高。     

ZrO2晶型对Ni/ZrO2催化剂CO甲烷化性能的影响

采用浸渍法制备了四方相ZrO2(t-ZrO2)和单斜相ZrO2(m-ZrO2)负载的Ni含量为10%的催化剂,在连续流动微反装置上考察了Ni/m-ZrO2以及不同温度焙烧Ni/t-ZrO2催化剂的CO甲烷化催化活性.采用N2物理吸附-脱附、H2-TPR、XRD、CO-TPSR及原位漫反射傅里叶变换红外光谱等技术对催化剂进行了表征.结果表明,在CO体积分数为1%,空速为20 000 h-1,常压的反应条件下,当CO转化率为50%时,Ni/m-ZrO2-673和Ni/t-ZrO2-673催化剂的反应温度分别为445 K和488 K,Ni/m-ZrO2-673催化剂的CO甲烷化活性远高于Ni/t-ZrO2-673催化剂.随焙烧温度的升高,Ni/t-ZrO2催化剂的CO甲烷化活性评价显著升高,产生这一现象的原因是在高温焙烧过程中Ni/t-ZrO2催化剂表面的t-ZrO2已转化为m-ZrO2,以m-ZrO2为载体的催化剂因m-ZrO2表面具有较多的配位不饱和O2-碱性中心和配位不饱和Zr4+-O2-位点而表现出高的CO甲烷化活性.