Resistance to poisoning by nitrogen compounds of NiMo/Al-MCM-41 hydrocracking catalysts

Barbosa, Francisco Assis; Santos, Ana Carlota B. dos; Silva, Maria Isabel Pais da; Stumbo, Alexandre M.

doi:10.1016/j.cattod.2004.07.025

Cited by 18 publications

(8 citation statements)

References 17 publications

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“…The diffractogram of the Al-MCM-41 catalyst shown in Figure 1b presented a strong reflection at 2θ = 2.1 • , characteristic of the MCM-41 structure. The two peaks of lower intensity and greater width observed at 2θ = 3-4 • suggest a loss of homogeneity and hexagonal symmetry of the crystalline structure due to the incorporation of aluminum in the structure of MCM-41 [18][19][20]. and a much larger pore volume than SAPO-5 [16].…”

Section: X-ray Diffractionmentioning

confidence: 99%

Thermal and Catalytic Pyrolysis of Dodecanoic Acid on SAPO-5 and Al-MCM-41 Catalysts

et al. 2019

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In this study, dodecanoic acid was decomposed during fast pyrolysis experiments either thermally or in the presence of SAPO-5 and Al-MCM-41catalysts. The catalysts were synthesized by a hydrothermal route and subsequently characterized by XRD, TPD-NH3, and TGA, and dodecanoic acid was characterized by TGA and DSC. Analysis of the post-pyrolysis products was performed online by gas chromatography coupled with mass spectrometry (GC-MS). The results from pyrolysis at 650 °C indicated that the nature of the catalysts strongly influences the composition of the products. Linear alkenes were standard products for all pyrolysis experiments, but with Al-MCM-41, various alkene isomers with a linear and cyclic structure formed, as well as saturated and aromatic hydrocarbons. As a whole, Al-MCM-41 led to a much higher dodecanoic acid conversion and higher deoxygenation than SAPO-5. As these catalysts present small differences in strong acid site density, the difference in the global conversion of dodecanoic acid could be attributed to textural characteristics such as pore volume and surface area. In this case, the textural properties of the SAPO-5 are much lower when compared to Al-MCM-41 and, due to a lower accessibility of the reactant molecule to the acidic sites of SAPO-5, partially blocked for fatty acid molecules by the considerable amount of amorphous material, as detected by XRD.

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Section: X-ray Diffractionmentioning

confidence: 99%

Thermal and Catalytic Pyrolysis of Dodecanoic Acid on SAPO-5 and Al-MCM-41 Catalysts

et al. 2019

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“…A peneira molecular Al-MCM-41 foi sintetizada com razão sílica/alumina (SAR) igual a 20 segundo adaptação quanto ao tempo de reação de acordo com a metodologia proposta por BARBOSA e colaboradores [16] . O uso de atmosfera inerte impede a queima do composto orgânico que agiu como direcionador, com a consequente produção de vapor d'água, que poderia remover todo ou parte do alumínio incorporado à estrutura da Al-MCM-41.…”

Section: Síntese Do Catalisadorunclassified

Pirólise rápida de biomassa de eucalipto na presença de catalisador Al-MCM-41

Félix

Júnior²,

Freitas³

et al. 2018

Matéria (Rio J.)

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A América Latina possui um considerável potencial na produção de biomassa, se destacando principalmente pela utilização de seus resíduos, sendo o Brasil um dos representantes mais importantes na geração de energia proveniente dessas fontes renováveis. Nesse sentido, esse trabalho aborda a biomassa de eucalipto, na forma de resíduo, como uma fonte promissora e de baixo custo para produção de energia e de produtos quí-micos. O objetivo do trabalho é realizar a pirólise rápida a temperatura de 500 °C na presença de catalisador mesoporoso Al-MCM-41 visando avaliar o rendimento das fases (bio-óleo, bio-gás e bio-carvão), bem como analisar os produtos gerados na fase líquida utilizando um cromatógrafo a gás com um espectrômetro de massas acoplado. Foram realizadas caracterizações por microscopia eletrônica de varredura (MEV) e fluorescência de raios X (FRX) para o catalisador e a biomassa, além de análise elementar, imediata, poder calorífi-co e análise termogravimétrica (ATG) para o eucalipto. Foram obtidos rendimentos de bio-óleo, bio-gás e bio-carvão, compatíveis com a literatura, além de comprovar que a presença do catalisador influencia de forma direta nesta distribuição. Os principais compostos identificados foram o ácido acético, 1-hidroxi -2-propanona, 1-1-dietoxi-etano, furfural, confirmando a importância do processo para obtenção de produtos químicos. Palavras-chave:Resíduo, Processo Térmico, Bio-óleo. ABSTRACTLatin America has considerable potential in the production of biomass, mainly for the use of its waste, Brazil being one of the most important representatives in the generation of energy from these renewable sources. In this sense, the paper approaches eucalyptus biomass, in the form of residue, as a promising source of low cost for the production of energy and chemical products. The objective of this work is to perform the fast pyrolysis at 500 °C in the presence of mesoporous Al-MCM-41 catalyst to evaluate the performance of the phases (bio-oil, biogas and bio-coal), as well as to analyze the products generated in the liquid phase using a gas chromatograph with a coupled mass spectrometer. The catalysts and the biomass were characterized by scanning electron microscopy (SEM) and X-ray fluorescence (FRX). Elemental analysis, immediate analysis, calorific value and thermogravimetric analysis were performed for eucalyptus. Bio-oil, bio-gas and biocarbon yields were obtained, compatible with the literature, besides proving that the presence of the catalyst influences directly in this distribution. The main compounds identified were acetic acid, 1-hydroxy-2-propanone, 1-1-diethoxyethane, furfural, confirming the importance of the process for obtaining chemical products.

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“…[8][9][10] The inhibitory effect induced by strongly basic pyridine type compounds; which possess an electron-pair donor ability, is broadly documented. [10][11][12] Nonetheless, the effect of nitrogen heteroaromatics such as indoles (pKa Indole-H + /Indole = À 3.6), carbazoles, benzocarbazole over hydrocracking catalysts has only been recently put in evidence. [4,9] Indeed, a previous work confirmed that weakly basic nitrogenates are the most abundant nitrogenates in a hydrotreated vacuum gas oil (ca.…”

Section: Introductionmentioning

confidence: 99%

“…They are recognized to exert inhibitory or poisoning effects over the activity and selectivity of zeolite‐based catalysts employed in hydrocracking units . The inhibitory effect induced by strongly basic pyridine type compounds; which possess an electron‐pair donor ability, is broadly documented . Nonetheless, the effect of nitrogen heteroaromatics such as indoles (pKa Indole‐H + /Indole=−3.6), carbazoles, benzocarbazole over hydrocracking catalysts has only been recently put in evidence .…”

Section: Introductionmentioning

confidence: 99%

In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

et al. 2019

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In the present work, the liquid‐solid interaction of liquid N‐heteroaromatic compounds, commonly present in the petroleum feedstocks of the refineries, with Y zeolites used as hydrocracking catalysts was followed using IR‐ATR spectroscopy. The inhibition of the zeolitic acid sites by strongly basic pyridine and weakly basic indole was highlighted using a continuous flow IR‐ATR cell. Results were assessed by Density Functional Theory calculations to compute the vibrational frequencies of pyridine and indole according to the nature of the interaction sites: silanol groups or acidic OH groups. The study points out that IR‐ATR spectroscopy opens the way for investigating the interaction modes of low vapor pressure molecules (e. g. indole) that present an inherent difficulty to be operated in the gas phase. Moreover, the IR‐ATR makes possible the analysis of the little‐explored low wavenumber zone (<800 cm−1), that presents informative vibrational modes on the adsorption mode of N‐molecules. Hence, this work points out that for pyridine, the bands at 686 and 727 cm−1 are characteristic of pyridinium species formed over zeolitic OH groups, meanwhile, the signals at 703 and 750 cm−1, are associated to pyridine in interaction with silanol groups. The IR‐ATR study reveals that indole, a weakly basic compound, can be protonated on acidic Y zeolites as unambiguously evidenced by the formation of the bands at 1617, 1608, 1543 and 705 cm−1. Findings here exposed are crucial for studying inhibitory effects exerted by weak nitrogenated compounds on acidic materials during hydrocracking processes.

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Resistance to poisoning by nitrogen compounds of NiMo/Al-MCM-41 hydrocracking catalysts

Cited by 18 publications

References 17 publications

Thermal and Catalytic Pyrolysis of Dodecanoic Acid on SAPO-5 and Al-MCM-41 Catalysts

Thermal and Catalytic Pyrolysis of Dodecanoic Acid on SAPO-5 and Al-MCM-41 Catalysts

Pirólise rápida de biomassa de eucalipto na presença de catalisador Al-MCM-41

In Situ IR‐ATR Study of the Interaction of Nitrogen Heteroaromatic Compounds with HY Zeolites: Experimental and Theoretical Approaches

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