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Vogel R, Versluis C, Frijsen R, Prins PT, Vogt ETC, Rabouw FT, Weckhuysen BM. The Coking of a Solid Catalyst Rationalized with Combined Raman and Fluorescence Lifetime Microscopy. Angew Chem Int Ed Engl 2024:e202409503. [PMID: 38973416 DOI: 10.1002/anie.202409503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 06/30/2024] [Accepted: 07/05/2024] [Indexed: 07/09/2024]
Abstract
The formation of carbon deposits is a major deactivation pathway for solid catalysts. Studying coking on industrially relevant catalysts is, however, often challenging due to the sample heterogeneity. That is especially true for zeolite-containing catalysts where fluorescence often hampers their characterization with Raman spectroscopy. We turned this disadvantage into an advantage and combined Raman and fluorescence (lifetime) microscopy to study the coking behavior of an equilibrium catalyst material used for fluid catalytic cracking of hydrocarbons. The results presented illustrate that this approach can yield new insights in the physicochemical processes occurring within zeolite-containing catalyst particles during their coking process. Ex situ analyses of single catalyst particles revealed considerable intra-sample heterogeneities. The sample-averaged Raman spectra showed a higher degree of graphitization when the sample was exposed to more hexane, while the sample-averaged fluorescence lifetime showed no significant trend. Simultaneous in situ Raman and fluorescence (lifetime) microscopy, used to follow the coking and the regeneration of single particles, gave more insights in the changing fluorescence dynamics. During the coking, the rise and decline of the average fluorescence lifetime suggested the prolonged presence of smaller coke species that are quenched more and more by adjacent larger polyaromatics acting as Förster-resonance-energy-transfer acceptors.
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Affiliation(s)
- Robin Vogel
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
| | - Caroline Versluis
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
| | - Rowie Frijsen
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
| | - P Tim Prins
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
| | - Eelco T C Vogt
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
| | - Freddy T Rabouw
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
- Soft Condensed Matter Group, Debye Institute for Nanomaterials Science, Utrecht university, Princetonplein 1, 3584, CC Utrecht, The Netherlands
| | - Bert M Weckhuysen
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG Utrecht, The Netherlands
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Zhang Y, Wang J, Xie X, Wang X, Wu WD, Chen XD, Wu Z. Deep Cracking of Bulky Hydrocarbons into Light Products via Tandem Catalysis over Uniform Interconnected ZSM-5@AlSBA-15 Composites. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309114. [PMID: 38233203 DOI: 10.1002/smll.202309114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/26/2023] [Indexed: 01/19/2024]
Abstract
Deep cracking of bulky hydrocarbons on zeolite-containing catalysts into light products with high activity, desired selectivity, and long-term stability is demanded but challenging. Herein, the efficient deep cracking of 1,3,5-triisopropylbenzene (TIPB) on intimate ZSM-5@AlSBA-15 composites via tandem catalysis is demonstrated. The rapid aerosol-confined assembly enables the synthesis of the composites composed of a continuous AlSBA-15 matrix decorated with isolated ZSM-5 nanoparticles. The two components at various ZSM-5/AlSBA-15 mass ratios are uniformly mixed with chemically bonded pore walls, interconnected pores, and eliminated external surfaces of nanosized ZSM-5. The typical composite with a ZSM-5/AlSBA-15 mass ratio of 0.25 shows superior performance in TIPB cracking with outstanding activity (≈100% conversion) and deep cracking selectivity (mass of propylene + benzene > 60%) maintained for a long time (> 6 h) under a high TIPB flux (2 mL h-1), far better (several to tens of times higher) than the single-component and physically mixed catalysts and superior to literature results. The high performance is attributed to the cooperative tandem catalytic process, that is, selective and timely pre-cracking of TIPB to isopropylbenzene (IPB) in AlSBA-15 and subsequently timely diffusion and deep cracking of IPB in nanosized ZSM-5.
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Affiliation(s)
- Yali Zhang
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Jiaren Wang
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Xianglin Xie
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Xiaoning Wang
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Winston Duo Wu
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Xiao Dong Chen
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
| | - Zhangxiong Wu
- Particle Engineering Laboratory, School of Chemical and Environmental Engineering, and Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices, College of Chemistry Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu, 215123, P. R. China
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Bian J, Wang B, Niu X, Zhao H, Ling H, Ju F. Migration and emission characteristics of metal pollutants in fluid catalytic cracking (FCC) process. JOURNAL OF HAZARDOUS MATERIALS 2024; 462:132778. [PMID: 37844495 DOI: 10.1016/j.jhazmat.2023.132778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/01/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
Fluid catalytic cracking (FCC) is the core unit for heavy oil conversion in refineries. In the FCC process, the metal contaminants from the feedstock are deposited on the catalysts, causing catalyst deactivation and metal particulate matter (PM) emission. However, the migration and emission characteristics of metal pollutants in FCC units are still unclear. Here, the stack tests of three FCC units were carried out to monitor metal PM emissions, and the metal contents of the feedstock oil and spent catalyst were detected. For the metal migration from the feedstock to the catalysts, Ni, Fe, and V have high concentrations and migration rates while other metals perform much lower. The metal distribution on the spent catalysts profoundly determines the metal mobility to the flue gas and the regeneration process affects the catalyst attrition, leading to metal PM emissions discrepancy. The migration rate and emission concentration of V in the deeper layers of the catalysts are much lower than those of Ni at the particle's exterior. Finally, the stack data was used to calculate the emission factors and ratio factors of the metal PM. This work is expected to advance metal migration cognition and metal pollutants emissions estimation in FCC units.
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Affiliation(s)
- Jiawei Bian
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Bohan Wang
- Key Laboratory of Specially Functional Polymeric Materials and Related Technology of the Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ximing Niu
- Shanghai Research Institute of Chemical Industry CO., LTD, Shanghai 200333, China
| | - Hai Zhao
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Hao Ling
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Feng Ju
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, the Netherlands.
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Wang W, Zhao J, Jia D, Fu Z, Xing E, Zhu Z, Yan R, Tao Z, Luo Y, Shu X. Highly Efficient Hydroisomerization of Endo-Tetrahydrodicyclopentadiene to Exo-Tetrahydrodicyclopentadiene over Pt/HY. ACS OMEGA 2021; 6:17173-17182. [PMID: 34278104 PMCID: PMC8280701 DOI: 10.1021/acsomega.1c00212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/23/2021] [Indexed: 06/13/2023]
Abstract
The fast deactivation caused by serious formation of coke is a major challenge in catalytic isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) into exo-tetrahydrodicyclopentadiene (exo-THDCPD) over the HY zeolite. In order to suppress the coke formation for the isomerization process, the conventional HY zeolite was modified with Pt at 0.3 wt %. Then, the hydroisomerization of endo-THDCPD into exo-THDCPD was evaluated over a fixed-bed reactor. The catalytic stability of Pt/HY was greatly enhanced in comparison to that of the HY zeolite. The Pt/HY catalyst provided 97% endo-THDCPD conversion and 96% selectivity for exo-THDCPD without deactivation after 100 h. Moreover, the formation mechanism of coke on the HY zeolite during the isomerization process was proposed based on the results of the coke analysis. It was indicated that the coke was generated from the oligomerization and condensation of olefin species, which originated from the β-scission reaction or hydride transfer reaction of intermediates. The lower coke formation over Pt/HY was attributed to the lower amount of coke precursors, which could be hydrogenated by activated H2 over Pt sites. Therefore, Pt on Pt/HY and H2 were two crucial factors in efficiently enhancing the catalytic stability of the HY zeolite for this isomerization reaction.
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Pore Blocking by Phenolates as Deactivation Path during the Cracking of 4-Propylphenol over ZSM-5. Catalysts 2021. [DOI: 10.3390/catal11060721] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cracking of propyl side chains from 4-propylphenol, a model compound for lignin monomers, is studied for a commercial ZSM-5 zeolite catalyst. The decline of 4-propylphenol conversion with time on stream can be delayed by co-feeding water. FTIR spectroscopy shows the formation of chemisorbed phenolates during reactions and significant amounts of phenolics are detected by GC-MS of the extract from the spent catalysts. Thus, chemisorbed phenolates are identified as the main reason for deactivation in the absence of water. Regardless of the amount of co-fed water, substituted monoaromatics and polyaromatic species are formed. Comprehensive characterization of the spent catalysts including Raman and solid-state 27Al NMR spectroscopy, and thermogravimetric analysis points to a combination of deactivation processes. First, phenolates bind to Lewis acid sites within the zeolite framework and hinder diffusion unless they are hydrolyzed by water. In addition, light olefins created during the cracking process react to form a polyaromatic coke that deactivates the catalyst more permanently.
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Briggs NM, Crossley SP. Equilibrium catalyst from a fluidized catalytic cracking unit separated by metal content by using carbon nanotubes and a biphasic system. AIChE J 2021. [DOI: 10.1002/aic.17260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Nicholas M. Briggs
- School of Chemical, Biological and Materials Engineering University of Oklahoma Norman Oklahoma USA
| | - Steven P. Crossley
- School of Chemical, Biological and Materials Engineering University of Oklahoma Norman Oklahoma USA
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Liao Y, Liu T, Du X, Gao X. Distribution of Iron on FCC Catalyst and Its Effect on Catalyst Performance. Front Chem 2021; 9:640413. [PMID: 33763407 PMCID: PMC7982838 DOI: 10.3389/fchem.2021.640413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
The effects of different iron contamination content on the formation of iron nodules and the performance of FCC catalysts have been studied by cyclic deactivation treatment using iron naphthenate. The catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, and SEM. The catalysts’ performance was evaluated by the Advanced Cracking Evaluation device. It has been found that there will be obvious nodulation on the catalyst when the iron concentration exceeds 7,400 μg/g. With the iron deposition from 53 μg/g to 11,690 μg/g, the crystal structure of zeolite will not be destroyed by iron. The surface area and pore volume of the catalyst decreased significantly; the surface area decreased from 125.3 m2/g to 91.0 m2/g, and the pore volume decreased from 0.21 cm3/g to 0.16 cm3/g. The studies also showed that the increase of iron deposition will lead to the decrease of catalytic reaction efficiency. With the iron deposition from 53 μg/g to 11,690 μg/g, the conversion decreased by 4.83%. Under the same 78 wt.% conversion, bottoms yield and coke yield increased by 2.15% and 1.31%, while gasoline yield and LCO yield decreased by 2.59% and 2.16%, respectively. The real state of the industrial iron contaminated equilibrium catalyst can be mimicked by using the cyclic deactivation method.
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Affiliation(s)
- Yitao Liao
- College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, China.,Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou, China
| | - Tao Liu
- Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou, China
| | - Xiaohui Du
- Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou, China
| | - Xionghou Gao
- Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina, Lanzhou, China
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A Comparison of Laboratory Simulation Methods of Iron Contamination for FCC Catalysts. Catalysts 2021. [DOI: 10.3390/catal11010104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Two different methods of simulating iron contamination in a laboratory were studied. The catalysts were characterized using X-ray diffraction, N2 adsorption–desorption, and SEM-EDS. The catalyst performance was evaluated using an advanced cracking evaluation device. It was found that iron was evenly distributed in the catalyst prepared using the Mitchell impregnation method and no obvious iron nodules were found on the surface of the catalyst. Iron on the impregnated catalyst led to a strong dehydrogenation capacity and a slight decrease in the conversion and bottoms selectivity. The studies also showed that iron was mainly in the range of 1–5 μm from the edge of the catalyst prepared using the cycle deactivation method. Iron nodules could be easily observed on the surface of the catalyst. The retention of the surface structure in the alumina-rich areas and the collapse of the surface structure in the silica-rich areas resulted in a continuous nodule morphology, which was similar to the highly iron-contaminated equilibrium catalyst. Iron nodules on the cyclic-deactivated catalyst led to a significant decrease in conversion, an extremely high bottoms yield, and a small increase in the dehydrogenation capacity. The nodules and distribution of iron on the equilibrium catalyst could be better simulated by using the cyclic deactivation method.
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