失活加氢裂化催化剂的研究

采用XRD、ESCA、FT-IR、TEM等技术对两种同类型工业运转失活的加氢裂化催化剂进行了表征。结果表明，碱性氮化物和积炭主要沉积在加氢裂化催化剂的L酸中心上，在B酸中心上积炭较少；引起催化剂失活的主要原因是积炭和有机硫、氮化合物覆盖催化剂的活性中心；导致再生催化剂比表面及酸性降低的主要原因是分子筛骨架坍塌。催化剂经长期使用后，活性金属发生聚集，晶粒长大，边角位活性中心数减少。     

工业加氢裂化催化剂失活原因分析

采用200 m L加氢评价装置对一种中油型加氢裂化催化剂和其在工业装置运转4年后的再生后催化剂进行对比评价。结果表明,失活催化剂经再生后加氢裂化活性明显降低,反应温度比新鲜催化剂高5℃,生成油产品分布和主要性能都略变差。采用XRD、IR和ICP等手段对再生前后催化剂性能进行表征,分析探讨催化剂的失活原因,结果表明,加氢裂化催化剂经工业应用后,炭的沉积使其暂时性失活,而重金属沉积、金属活性组分聚集和分子筛结构烧结使催化剂部分活性永久丧失。     

加氢裂化催化剂的失活与再生研究

为了研究催化剂失活原因,并为提高催化剂效率和使用寿命提供参考,对一种用于两段式加氢裂化工业装置的失活和再生后的加氢裂化催化剂进行了表征。结果表明,失活催化剂上有明显的积碳、有机硫氮吸附和金属沉积,活性金属团聚、分子筛结构破坏、金属沉积等造成的失活是无法恢复的。再生后,与新鲜催化剂相比,催化剂的比表面积、孔容、活性金属分散性和酸性均有明显下降。小试评价结果表明,再生催化剂的加氢裂化活性降低,反应温度比新鲜剂高2℃左右。原料性质较好、床层温度较低的二段再生催化剂,其理化性质和活性都优于一段再生催化剂。     

再生温度对FC-28型催化剂再生效果的影响

采用器外再生方法对工业失活的FC-28型催化剂进行再生,在不同再生温度制备系列催化剂,并利用TG、IR、XRD和TEM等手段考察再生温度对FC-28型加氢裂化催化剂再生效果的影响。结果表明,再生温度450 ℃时,失活催化剂可以烧掉绝大部分硫碳,金属元素基本得以恢复;催化剂表面酸性、催化剂比表面积和孔体积恢复到最大值。再生温度超过450 ℃时,开始出现少量的金属聚集,酸性降低,孔结构也不再恢复,适宜的再生温度才能使催化剂再生达到最好的效果。     

催化剂制备与研究 中低温煤焦油加氢裂化催化剂的表征与分析

通过对反应前后的煤焦油加氢裂化催化剂进行表征与分析,研究影响中低温煤焦油加氢催化剂失活的原因,以煤焦油组分特点为依据,分别考察加氢裂化催化剂的活性元素、积炭、金属沉淀、分散度和中心酸性等对催化剂寿命的影响。结果表明,煤焦油加氢催化剂的失活原因主要为积炭失活、金属沉积和水热失活;催化剂中较低的金属钙含量、良好的水热稳定性及较低的L酸含量有利于催化剂寿命的提高。     

中低温煤焦油加氢裂化催化剂的表征与分析

通过对反应前后的煤焦油加氢裂化催化剂进行表征与分析,研究影响中低温煤焦油加氢催化剂失活的原因,以煤焦油组分特点为依据,分别考察加氢裂化催化剂的活性元素、积炭、金属沉淀、分散度和中心酸性等对催化剂寿命的影响。结果表明,煤焦油加氢催化剂的失活原因主要为积炭失活、金属沉积和水热失活;催化剂中较低的金属钙含量、良好的水热稳定性及较低的L酸含量有利于催化剂寿命的提高。     

甲醇制芳烃催化剂失活特性研究进展

在系统分析甲醇制芳烃催化反应特性基础上,重点对影响催化剂长周期使用性能的失活原因及应对方案进行综述。催化剂失活是多因素共同影响的结果,主要包括可再生的积炭失活、可部分再生的分子筛骨架铝流失失活、及不可再生的活性金属迁移/聚并失活和杂质毒化失活。积炭导致的催化剂失活可通过调变ZSM-5的B酸强度、合成小晶粒ZSM-5分子筛及采用碱液预处理ZSM-5分子筛等方式减缓; ZSM-5分子筛骨架铝流失导致的催化剂失活可通过采用磷改性等方式降低;活性金属迁移导致的催化剂失活可通过引进稳定助剂、降低催化剂生产过程中铝的引入等方式解决;而杂质毒化导致的催化剂失活需要通过净化原料和反应体系的措施来避免。     

钴基费托合成催化剂失活机理及再生研究进展

综述了钴基费托合成催化剂的失活机理、催化剂再生工艺及如何延长催化剂寿命的研究进展,通过分析催化剂失活原因,认为中毒、Co颗粒烧结、积炭、氧化、固相反应、晶相重构、表面阻塞和催化剂磨损等因素造成催化剂不同程度失活,其中积炭和Co颗粒烧结是催化剂失活的最主要原因,延长催化剂寿命的关键是提高催化剂的抗烧结能力和抑制积炭生成。增强活性金属Co和载体间的相互作用,保持Co晶粒分布均一或采用包覆、限域等策略可提高催化剂的抗烧结能力,通过添加助剂、调整氢碳比和空速等工艺参数亦可抑制积炭的生成。采用氢处理、脱蜡-氧化-还原和脱蜡-氧化-溶液处理-还原等工艺可实现催化剂的再生,对催化剂进行再生时要结合催化剂失活的主要原因,选择合适的再生工艺来最大限度地恢复催化剂活性。今后,提高催化剂的稳定性以及开发催化剂再生工艺技术路线是提高钴基费托合成技术竞争力的关键。     

新书推荐

“工业催化剂的失活与再生”一书系北京化学工业出版社近期出版的现代催化技术丛书中的第一本书。该书共分9章，主要介绍了目前工业上所用催化剂的失活情况及其再生方法。全书按工业催化剂中所含主要金属组分的品种进行了分类介绍。第一章介绍了工业催化剂的构成、发展沿革和分类等基本情况，并介绍了工业催化剂失活和再生的特性和共性的问题。从第二章到第九章分别介绍了贵金属催化剂，含钴、镍、钼、铜、铁、钒及硅铝催化剂的失活原因及再生方法。     

锰系低温脱硝催化剂失活与再生研究进展

氨选择性催化还原(NH_(3)-SCR)是有效的烟气脱硝技术之一,技术核心是脱硝催化剂。近年来,锰系脱硝催化剂在低温SCR反应中优良的催化活性得到国内外学者的关注。介绍锰系低温脱硝催化剂失活原因及再生方法。重点针对锰系低温脱硝催化剂的化学中毒详细介绍了失活原因及失活机理,包括SO_(2)、H_(2)O、碱(土)金属、重金属As、Zn、Pb及非金属Cl、P、F等。根据不同化学失活原因提出了相应的再生方法,比较不同再生方法的再生效果。最后对未来锰系低温脱硝催化剂失活与再生研究方向进行了展望。     

Catalyst pore plugging effects on hydrocracking reactions in an Ebullated bed reactor operation

This paper analyzes the deactivation effects of NiMo/Al₂O₃ catalyst during the operation in an Ebullated bed reactor for Heavy residue hydrocracking. The spent catalysts were characterized by chemical analysis, ¹³C NMR, ESM, DRX, and by using thermal programmed oxidation and diffusion studies in a shallow bed micro-reactor. The deactivations were performed in a 5 l continuously stirred tank reactor, while the spent catalysts were tested in a 0.05 l micro-reactor. The study focused on determining the properties of the external layer of the catalyst and on evaluating the internal coke and metal deposition. The results indicated that initial deactivation is mainly due to coke depositions, while its impact on mass transfer reaction control depends on temperature. In long-term deactivation, the metal deposition plays a more important role in blocking the internal micro- and meso-structures and in building up the external layer of the pellets.     

渣油加氢裂化反应中油溶性催化剂的抑焦性能

以辽河常压渣油为研究对象,通过高压釜模拟渣油加氢裂化反应,对不同油溶性催化剂体系反应后的生焦量、生焦状况及产物进行分析,深入研究渣油加氢裂化反应中油溶性催化剂的抑焦性能.研究表明,随着活性金属含量的增大,油溶性单金属Co催化剂和Ni催化剂的生焦量减少,Co - Fe或Ni - Fe复配体系具有协同效应,抑焦性能增强,由...     

Study of accelerated deactivation of hydrotreating catalysts by vanadium impregnation method

The main causes of catalysts deactivation for hydrotreating are coking and metals deposition. In this present work, accelerated deactivation of hydrotreating catalysts was studied. In this respect, vanadium which is deposited with nickel during hydrotreating reaction was impregnated into the fresh hydrotreating catalyst. Different percentage of vanadium was impregnated and their hydrodemetalization (HDM) and hydrodesulfurization (HDS) activities were studied in bench-scale reactor of heavy crude oil. Accelerated deactivations for both HDM and HDS were observed on vanadium impregnated catalysts. The rate of HDS deactivation was faster than that of HDM reaction. The rapid deactivation of HDS may be due to the coverage of active sites by impregnated vanadium atom. The deactivation is slower when the V loading is low; but above 10 wt% loading a rapid deactivation is observed. A comparison of deactivation is made in between normal deactivation and the deactivation by vanadium impregnation. It was found that deactivation by vanadium impregnation is lower than that of normal deactivation. It suggests that at initial stage the formation of coke causes deactivation of the catalyst whereas at later stage when metals sulfides deposition is quite high, these sulfides take part in deactivation.     

Deactivation of a platinum reforming catalyst in a tubular reactor

This work concerns the methodology of characterizing the deactivation of a catalyst by coke deposition. The isomerization of n.pentane on a platinum reforming catalyst was studied in a tubular reactor permitting easy sampling of the gas phase at several positions in the reactor. Runs with high ratios of hydrogen to pentane did not show any deactivation and served to determine the kinetics of the main reaction and the principal side reaction, hydrocracking. At low ratios of hydrogen to pentane the catalyst was deactivated by carbonaceous deposits. At the end of the run the coke was determined in sections of the reactor and was found to be deposited according to a profile. Additional insight into the coking phenomenon was obtained from experiments on a thermobalance. A mathematical model for the performance of the tubular reactor subject to coking was set up and the parameters were determined from the experimental data. The parameters were found to be significantly determined and to obey the Arrhenius temperature dependence. The values of the parameters of the main reaction and of the hydrocracking side reaction which were derived from the experiments in the presence of coking were in agreement with those obtained from the runs in the absence of coking.     

Deactivation Analysis of Industrial Spent Catalysts Applied to Lube Oil Hydrotreating in a Pilot Plant

Industrial spent catalysts taken from different beds of industrial lube oil hydrotreating reactors were investigated in a pilot plant. Experiments to quantify the catalytic activity loss for hydrodesulfurization, hydrodenitrogenation, and aromatic hydrogenation reactions were carried out using an industrial feedstock under operational conditions similar to the industrial ones. Characterization of the spent catalysts was performed to demonstrate the relative influence of different possible deactivation causes. Depending on the position of the catalyst inside the industrial reactor, different deactivation causes were evaluated. At the top of the reactor, poisoning by silicon, arsenic, and iron was the main cause, while at the bottom, coke deposition was predominant.     

分子筛催化剂积炭失活行为探讨

反应过程中生成的重质副产物积炭堵塞孔道是造成酸性分子筛催化剂失活的主要因素.影响积炭的因素有催化剂的孔道结构、酸性以及操作条件.对分子筛催化剂积炭失活机理、积炭表征技术、影响因素和抑制措施进行了综述,并介绍了一种积炭分离方法,对分子筛催化剂积炭研究的发展趋势进行了分析.     

Deactivation of metal catalysts in liquid phase organic reactions

The paper gives a general survey of the factors contributing to the deactivation of metal catalysts employed in liquid phase reactions for the synthesis of fine or intermediate chemicals. The main causes of catalyst deactivation are particle sintering, metal and support leaching, deposition of inactive metal layers or polymeric species, and poisoning by strongly adsorbed species. Weakly adsorbed species, poisons at low surface coverage and solvents, may act as selectivity promoters or modifiers. Three examples of long term stability studies carried out in trickle-bed reactor (glucose to sorbitol hydrogenation on Ru/C catalysts, hydroxypropanal to 1,3-propanediol hydrogenation on Ru/TiO₂ catalysts, and wet air oxidation of paper pulp effluents on Ru/TiO₂) are discussed.     

Z417/Z418蒸汽转化催化剂的应用及积炭中毒失活原因分析

对中国石油西安石化分公司新建制氢装置蒸汽转化催化剂的使用进行了总结，剖析转化催化剂积炭和中毒失活的原因，提出了防止积炭和中毒失活的预防措施及保证装置长周期运行的方法。