Fe-ZSM-5 outperforms Al-ZSM-5 in paraffin cracking by increasing the olefinicity of C3-C4 products

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F24%3A10487016" target="_blank" >RIV/00216208:11310/24:10487016 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=IcMeXjx8Yo" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=IcMeXjx8Yo</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.cej.2024.156032" target="_blank" >10.1016/j.cej.2024.156032</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Fe-ZSM-5 outperforms Al-ZSM-5 in paraffin cracking by increasing the olefinicity of C3-C4 products

Popis výsledku v původním jazyce

Iron-modified Al-ZSM-5 increases selectivity to propene, a key petrochemical resulting from fluid catalytic cracking (FCC). However, the type and role of active iron species remain unclear, hindering efforts to streamline the design of selective FCC additives. Here, we investigated Al-free Fe-ZSM-5 catalysts containing iron species in the form of framework Fe(3+), extra-framework Fe(3+), oxidic clusters, and oxide micro aggregates in n-octane cracking (FCC model) to assess their effect on catalytic cracking. DR-UV-Vis spectroscopy, (57)Fe Mössbauer Spectroscopy, FTIR studies of pyridine adsorption, and n-octane cracking tests at 500 °C revealed that framework-associated coordinatively unsaturated Fe(3+) species, which induce strong Lewis acidity, are responsible for paraffin cracking initiation, whereas bulk iron oxides on the zeolite surface are inactive. In comparison with Al-ZSM-5, Fe-ZSM-5 increases the olefinicity of the valuable C(3)-C(4) fractions (selectivity to propene and butenes) and promotes aromatization reactions due to the lower relative strength of Fe-induced Bronsted acid sites and dehydrogenation properties. As shown by our (57)Fe Mössbauer study (performed at -269 °C) of the catalyst in calcined, spent, and regenerated states, Fe-ZSM-5 deactivation is associated with the loss of tetrahedrally coordinated Fe(3+) species. Therefore, tuning Fe-ZSM-5 C(3)-C(4) selective FCC additives requires stabilizing framework Bronsted and framework-associated Lewis acid sites while decreasing the concentration of iron oxide species. Ultimately, these findings may enable us to meet the demand for propene derived from FCC cracking, which is expected to grow in the foreseeable future.

Název v anglickém jazyce

Fe-ZSM-5 outperforms Al-ZSM-5 in paraffin cracking by increasing the olefinicity of C3-C4 products

Popis výsledku anglicky

Iron-modified Al-ZSM-5 increases selectivity to propene, a key petrochemical resulting from fluid catalytic cracking (FCC). However, the type and role of active iron species remain unclear, hindering efforts to streamline the design of selective FCC additives. Here, we investigated Al-free Fe-ZSM-5 catalysts containing iron species in the form of framework Fe(3+), extra-framework Fe(3+), oxidic clusters, and oxide micro aggregates in n-octane cracking (FCC model) to assess their effect on catalytic cracking. DR-UV-Vis spectroscopy, (57)Fe Mössbauer Spectroscopy, FTIR studies of pyridine adsorption, and n-octane cracking tests at 500 °C revealed that framework-associated coordinatively unsaturated Fe(3+) species, which induce strong Lewis acidity, are responsible for paraffin cracking initiation, whereas bulk iron oxides on the zeolite surface are inactive. In comparison with Al-ZSM-5, Fe-ZSM-5 increases the olefinicity of the valuable C(3)-C(4) fractions (selectivity to propene and butenes) and promotes aromatization reactions due to the lower relative strength of Fe-induced Bronsted acid sites and dehydrogenation properties. As shown by our (57)Fe Mössbauer study (performed at -269 °C) of the catalyst in calcined, spent, and regenerated states, Fe-ZSM-5 deactivation is associated with the loss of tetrahedrally coordinated Fe(3+) species. Therefore, tuning Fe-ZSM-5 C(3)-C(4) selective FCC additives requires stabilizing framework Bronsted and framework-associated Lewis acid sites while decreasing the concentration of iron oxide species. Ultimately, these findings may enable us to meet the demand for propene derived from FCC cracking, which is expected to grow in the foreseeable future.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Chemical Engineering Journal

ISSN

1385-8947

e-ISSN

1873-3212

Svazek periodika

499

Číslo periodika v rámci svazku

November

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

14

Strana od-do

156032

Kód UT WoS článku

001327754400001

EID výsledku v databázi Scopus

2-s2.0-85204936203