MCM-41/ZSM-5 composite particles for the catalytic fast pyrolysis of biomass

Lei, Yu; Farinmade, Azeem; Ajumobi, Oluwole; Su, Yang; John, Vijay T.; Valla, Julia A.

doi:10.1016/j.apcata.2020.117727

Cited by 37 publications

(30 citation statements)

References 52 publications

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“…Yu et al [25] limited fast deactivation of HZSM-5 by the formation of MCM-41/ZSM-5 composite with ZSM-5 crystallites encapsulated in the MCM-41 mesoporous matrix. It is known that in the case of ZSM-5, large diameter pyrolysis intermediates may polymerize on the catalyst surface and block access to the micropores, decreasing the yield of valuable products.…”

Section: Formation Of Coke Depositmentioning

confidence: 99%

“…Although, the MCM-41 matrix can act as a layer protecting against the rapid deactivation of ZSM-5 due to the fact that a considerable part of coke was deposited on the surface of the mesoporous material. Yu et al [25] limited fast deactivation of HZSM-5 by the formation of MCM-41/ZSM-5 composite with ZSM-5 crystallites encapsulated in the MCM-41 mesoporous matrix. It is known that in the case of ZSM-5, large diameter pyrolysis intermediates may polymerize on the catalyst surface and block access to the micropores, decreasing the yield of valuable products.…”

Section: Formation Of Coke Depositmentioning

confidence: 99%

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Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

Grams

Ruppert

2021

Catalysts

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The pyrolysis of lignocellulosic biomass is one of the most promising methods of alternative fuels production. However, due to the low selectivity of this process, the quality of the obtained bio-oil is usually not satisfactory and does not allow for its direct use as an engine fuel. Therefore, there is a need to apply catalysts able to upgrade the composition of the mixture of pyrolysis products. Unfortunately, despite the increase in the efficiency of the thermal decomposition of biomass, the catalysts undergo relatively fast deactivation and their stability can be considered a bottleneck of efficient pyrolysis of lignocellulosic feedstock. Therefore, solving the problem of catalyst stability is extremely important. Taking that into account, we presented, in this review, the most important reasons for catalyst deactivation, including coke formation, sintering, hydrothermal instability, and catalyst poisoning. Moreover, we discussed the progress in the development of methods leading to an increase in the stability of the catalysts of lignocellulosic biomass pyrolysis and strengthening their resistance to deactivation.

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Section: Formation Of Coke Depositmentioning

confidence: 99%

Section: Formation Of Coke Depositmentioning

confidence: 99%

Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

Grams

Ruppert

2021

Catalysts

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“…Alternate ways of introducing the metal will result in the metal being deposited in the lumen and will not lead to a direct comparison of the reaction with and without the straws that is necessary for this study, although perhaps inconsequential for application. Our earlier work on integrating zeolites into the matrix of MCM-41 23 , 24 indicates that the aerosolization process is entirely feasible for this objective, and the current work expands on this concept to introduce halloysites with the objective of improving access to interior catalytic sites. The following sections of this paper address this focused objective using the liquid phase reduction of nitrophenol as a model reaction.…”

Section: Introductionmentioning

confidence: 99%

Integrating Halloysite Nanostraws in Porous Catalyst Supports to Enhance Molecular Transport

Ajumobi

Farinmade

et al. 2021

ACS Appl. Nano Mater.

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In many porous catalyst supports, the accessibility of interior catalytic sites to reactant species could be restricted due to limitations of reactant transport through pores comparable to reactant dimensions. The interplay between reaction and diffusion in porous catalysts is defined through the Thiele modulus and the effectiveness factor, with diffusional restrictions leading to high Thiele moduli, reduced effectivess factors, and a reduction in the observed reaction rate. We demonstrate a method to integrate ceramic nanostraws into the interior of ordered mesoporous silica MCM-41 to mitigate diffusional restrictions. The nanostraws are the natural aluminosilicate tubular clay minerals known as halloysite. Such halloysite nanotubes (HNTs) have a lumen diameter of 15–30 nm, which is significantly larger than the 2–4 nm pores of MCM-41, thus facilitating entry and egress of larger molecules to the interior of the pellet. The method of integrating HNT nanostraws into MCM-41 is through a ship-in-a-bottle approach of synthesizing MCM-41 in the confined volume of an aerosol droplet that contains HNT nanotubes. The concept is applied to a system in which microcrystallites of Ni@ZSM-5 are incorporated into MCM-41. Using the liquid phase reduction of nitrophenol as a model reaction catalyzed by Ni@ZSM-5, we show that the insertion of HNT nanostraws into this composite leads to a 50% increase in the effectiveness factor. The process of integrating nanostraws into MCM-41 through the aerosol-assisted approach is a one-step facile method that complements traditional catalyst preparation techniques. The facile and scalable synthesis technique toward the mitigation of diffusional restrictions has implications to catalysis and separation technologies.

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“…The majority of the work has been performed on microreactors, known as pyrolysis-GC/MS systems, where a very small amount of biomass (milli-or micrograms) was pyrolysed in the presence of catalysts and the evolved products are analysed using GC/MS. [1][2][3][4][5][6] This technique is very useful for catalyst screening or comparison with different process parameters, but it may not be representative of a fullscale production as no real bio-oil or liquid is produced. A comprehensive review on catalytic pyrolysis of biomass by Yildiz et al 2016 (ref.…”

Section: Introductionmentioning

confidence: 99%