HRP-12型负载杂多酸催化剂的失活原因及预防措施

采用XRD、NMR、IR、MS等手段对长链烷基苯合成中失活负载型杂多酸催化剂进行了表征,结果表明,催化剂的失活主要是由于表面结焦引起的,原料中的双烯、烷基芳烃杂质以及反应生成的副产物重烷基苯是引起催化剂结焦的主要原因,对原料进行脱双烯和脱芳烃精制、提高苯烯比以及用苯洗涤催化剂等措施能够有效抑制催化剂的失活。     

工业氨肟化工艺失活HTS分子筛的结构特征和Ti物种状态

采用XRD及其Rietveld全谱拟合、低温N₂吸附-脱附、XPS、TEM（包括EFTEM和HRTEM）、UV-Vis等手段对失活HTS分子筛的晶胞参数、骨架结构、颗粒形貌和Ti物种的位置与状态进行分析。结果表明, HTS分子筛失活后,其拓扑结构保存完整,且晶胞参数未发生明显变化,但部分微孔结构发生溶解,介孔体积增大,比表面积略有下降。HTS分子筛失活后,部分骨架Ti物种转变为非骨架Ti物种,富集且高度分散于分子筛颗粒形成小碎片,可以初步判定该碎片为高度分散的无定型TiO₂或TiO₂-SiO₂氧化物。     

高硫渣油加氢反应动力学模型与失活模型的耦合应用

通过研究不同工艺条件(反应温度、压力和体积空速)对高硫渣油加氢处理反应的影响,构建了高硫渣油加氢脱硫、加氢脱氮、加氢脱残炭、加氢脱金属反应的动力学模型,并与颗粒活性区迁移模型(失活模型)进行耦合,从而利用耦合模型对渣油加氢装置的升温曲线、非常规操作及产品性质进行了模拟预测。模拟结果表明：经耦合模型模拟所得各反应转化率的预测值与试验值吻合度高;在加氢催化剂的整个评价周期内,随着加氢催化剂金属沉积比例增加,各反应转化率均呈现初期快速下降、中期缓慢下降、末期快速下降的规律;模拟产品性质恒定条件下加氢脱硫、加氢脱氮和加氢脱残炭反应的升温曲线,可以得到装置推荐的升温曲线。     

降低MTBE装置原料杂质的技术改造

原料轻C4中的杂质,导致MTBE装置催化剂失活较快。为减少杂质含量,将气体分馏装置碳四塔轻C4的出塔方式由塔顶馏出改为侧线抽出,延长了MTBE催化剂的使用寿命,提高了MTBE的产量,减少了催化剂的消耗量,降低了废催化剂处理成本。     

草酸二甲酯加氢制乙二醇Cu/SiO_2催化剂失活机理的研究

通过快速老化实验研究了草酸二甲酯加氢制乙二醇Cu/SiO2催化剂的失活。采用XRD、低温N2吸附、TEM及TG对失活前后催化剂进行了表征,发现催化剂失活原因为热烧结、积炭及活性组分铜的价态变化。还研究了各种失活原因之间的内在联系,并提出了较为合理的失活机理。     

Autothermal reforming of JP8 on a Pt/Rh catalyst: Catalyst durability studies and effects of sulfur

Autothermal reforming (ATR) of commercial grade JP8 was performed on a Pt/Rh catalyst deposited on a monolith. This study investigated catalyst performance under three test conditions: (i) 120 startup and shutdown cycles, (ii) 80 h of continuous operation with sulfur-free fuel, and (iii) 370 h of testing with JP8 containing 125 ppm of sulfur. Axial reactor temperature profiles and gas composition data showed that startup and shutdown cycling had no impact on catalyst performance. When durability testing was done with fuel containing 125 ppm of sulfur, the catalyst deactivated initially, which was reflected by a decrease in H₂ concentration and decrease in fuel conversion. However, after 250 h of operation the activity stabilized at 66% fuel conversion and product concentrations were constant for the remaining 120 h of testing. The presence of sulfur resulted in higher CO selectivity, lower H₂ concentrations, and lower fuel conversions compared to data with sulfur-free fuel. The data suggests that the presence of sulfur primarily affects steam reforming reactions, and CO oxidation. Regeneration was attempted with air and with fuel-lean combustion but initial H₂ yields and carbon selectivity were not achieved.     

工业渣油加氢失活催化剂上沉积金属及积炭研究

采用碳-硫元素分析、X射线荧光光谱、X射线衍射光谱、扫描电镜以及热重分析等手段对处理后的工业固定床渣油加氢失活催化剂进行表征.结果表明:保护剂、保护-脱金属过渡剂、脱金属剂、脱金属-脱硫过渡剂主要拦截杂质金属,并以NiV2 S4的形态存在于催化剂中,脱硫剂、降残炭剂积炭更多.沿物流方向,积炭从软炭向硬炭转变,积炭量增加...     

丙烯醛氧化制备丙烯酸催化剂失活原因浅析

针对目前国产丙烯酸催化剂在工业应用中出现的问题,分别对新鲜丙烯酸催化剂和工业应用2年后丙烯酸催化剂的物理和化学性能进行比较,采用XRD、X荧光、热重分析、孔吸附等分析方法对催化剂进行表征,认为丙烯酸催化剂失活的主要原因是主活性组分Mo、V和助剂组分Cu、Sr等的流失,Sb+3Sb+5O4相态向Sb2O3相态的转变也是催化剂活性下降的部分原因。     

丙酮一步法合成甲基异丁基酮催化剂的失活机理

为研究丙酮一步法合成甲基异丁基酮Pd/Al2O3催化剂的失活机理,采用BET,XRD,SEM,O2-TPO等方法,对反应前后的催化剂进行了表征。表征结果表明,反应前后催化剂中的Pd含量没有明显变化,而反应后的催化剂表面织构变化较大,反应后的催化剂孔体积减小、平均孔径增大,Al2O3载体形态由γ型转化为羟基氧化铝的形态;同时,反应后的催化剂表面存在一定的高沸物。因此,催化剂加氢能力降低的主要原因是载体Al2O3形态的变化和催化剂表面包覆的高沸物,造成加氢活性中心减少。     

生产超低硫柴油RTS技术的工艺优化

The RTS technology can produce ultra-low sulfur diesel at lower costs using available hydrogenation catalyst and device. However, with the increase of the mixing proportion of secondary processed diesel fuel in the feed, the content of nitrogen compounds and polycyclic aromatic hydrocarbons in the feed increased, leading to the acceleration of the deactivation rate of the primary catalyst and the shortening of the service cycle. In order to fully understand the reason of catalyst deactivation, the effect of mixing secondary processed diesel fuel oil on the operating stability of the catalyst in the first reactor was investigated in a medium-sized fixed-bed hydrogenation unit. The results showed that the nitrogen compounds mainly affected the initial activity of the catalyst, but had little effect on the stability of the catalyst. The PAHs had little effect on the initial activity of the catalyst, but could significantly accelerate the deactivation of the catalyst. Combined with the analysis of the reason of catalyst deactivation and the study of RTS technology, the direction of RTS technology process optimization was put forward, and the stability of catalyst was improved obviously after process optimization.