Advanced cracking catalysts for the conversion of naphtha into light olefins
<p>To meet the current global warming limit of 1.5℃ above pre-industrial levels, an urgent requirement is to develop advanced technologies fully- able to decarbonise the energy industry and other sectors. It is also expected that the demand for fossil of derived fuels will start declining in t...
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| Format: | Thesis |
| Language: | English |
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2022
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| _version_ | 1797109040557326336 |
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| author | Almuqati, NS |
| author2 | Edwards, P |
| author_facet | Edwards, P Almuqati, NS |
| author_sort | Almuqati, NS |
| collection | OXFORD |
| description | <p>To meet the current global warming limit of 1.5℃ above pre-industrial levels, an urgent requirement is to develop advanced technologies fully- able to decarbonise the energy industry and other sectors. It is also expected that the demand for fossil of derived fuels will start declining in the coming years. Thereby, a significant fraction of the still vast resources of fossil hydrocarbons will be targeted towards the production of petrochemicals, notably to the production of light olefins, especially propene, and aromatics within an environmentally–friendly, climate-conscious perspective. The main scope of the project is to design and develop highly selective solid based catalysts and also to optimize the reaction conditions for converting the relatively high molecular weight hydrocarbons present in naphtha into the desired compounds.</p>
<p>ZSM-5 is the most efficient catalyst for naphtha cracking to light olefins. Our initial studies reveal that, for these catalytic processes, the SiO2/Al2O3 ratio is not perhaps the primary criterion for the assessment of the performance of the zeolite catalyst.</p>
<p>When compared to the catalyst formulation that was created by the impregnation approach, Cr2O3 loading on HZSM-5 (SiO2/Al2O3 = 80) zeolite using the mechanical mixing (MM) method results in a better n-heptane conversion (i.e., 95 wt.%) than the impregnation method (IMP). The inclusion of Cr had an effect on the physicochemical parameters of the catalysts, as well as their catalytic activity and selectivity. The optimum amount of Cr loading, which was 10% by weight, resulted in an increase in selectivity toward olefins, especially ethylene. In order to gain an understanding of the interaction mechanisms of the catalyst components and the role of support in the catalytic cracking of n-heptane over a hybrid of zeolite-matrix catalysts, it was investigated the effect of different matrix over ZSM-5 zeolite.</p>
<p>The advance made in this thesis is based on the designed combination of HZSM-5 with kaolin, the latter being a highly versatile catalyst and support matrix. This inert, inexpensive and earth-abundant material significantly improves the catalyst's sustainable features alongside the effective production of light olefins from n-heptane (a model compound) and naphtha (the actual petrochemical feedstock). The matrix alters the texture, morphology, surface density and strength of acid sites of HZSM-5 zeolite hence, enhancing
the production of light olefins, particularly propene, followed by ethene and in minor extension C4H8 compound.</p>
<p>This work highlights the favourable impact of carefully tuning the strength and surface density of acid sites in HZSM-5 by combining it with a natural clay! This strategy enhances the production of light alkenes, particularly propene, and even aromatics via the catalytic cracking of naphtha.</p> |
| first_indexed | 2024-03-07T07:36:30Z |
| format | Thesis |
| id | oxford-uuid:7200163d-6856-4d93-a8c8-082291966602 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:36:30Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | oxford-uuid:7200163d-6856-4d93-a8c8-0822919666022023-03-14T10:20:50ZAdvanced cracking catalysts for the conversion of naphtha into light olefinsThesishttp://purl.org/coar/resource_type/c_db06uuid:7200163d-6856-4d93-a8c8-082291966602Heterogeneous catalysisEnglishHyrax Deposit2022Almuqati, NSEdwards, PHayward, M<p>To meet the current global warming limit of 1.5℃ above pre-industrial levels, an urgent requirement is to develop advanced technologies fully- able to decarbonise the energy industry and other sectors. It is also expected that the demand for fossil of derived fuels will start declining in the coming years. Thereby, a significant fraction of the still vast resources of fossil hydrocarbons will be targeted towards the production of petrochemicals, notably to the production of light olefins, especially propene, and aromatics within an environmentally–friendly, climate-conscious perspective. The main scope of the project is to design and develop highly selective solid based catalysts and also to optimize the reaction conditions for converting the relatively high molecular weight hydrocarbons present in naphtha into the desired compounds.</p> <p>ZSM-5 is the most efficient catalyst for naphtha cracking to light olefins. Our initial studies reveal that, for these catalytic processes, the SiO2/Al2O3 ratio is not perhaps the primary criterion for the assessment of the performance of the zeolite catalyst.</p> <p>When compared to the catalyst formulation that was created by the impregnation approach, Cr2O3 loading on HZSM-5 (SiO2/Al2O3 = 80) zeolite using the mechanical mixing (MM) method results in a better n-heptane conversion (i.e., 95 wt.%) than the impregnation method (IMP). The inclusion of Cr had an effect on the physicochemical parameters of the catalysts, as well as their catalytic activity and selectivity. The optimum amount of Cr loading, which was 10% by weight, resulted in an increase in selectivity toward olefins, especially ethylene. In order to gain an understanding of the interaction mechanisms of the catalyst components and the role of support in the catalytic cracking of n-heptane over a hybrid of zeolite-matrix catalysts, it was investigated the effect of different matrix over ZSM-5 zeolite.</p> <p>The advance made in this thesis is based on the designed combination of HZSM-5 with kaolin, the latter being a highly versatile catalyst and support matrix. This inert, inexpensive and earth-abundant material significantly improves the catalyst's sustainable features alongside the effective production of light olefins from n-heptane (a model compound) and naphtha (the actual petrochemical feedstock). The matrix alters the texture, morphology, surface density and strength of acid sites of HZSM-5 zeolite hence, enhancing the production of light olefins, particularly propene, followed by ethene and in minor extension C4H8 compound.</p> <p>This work highlights the favourable impact of carefully tuning the strength and surface density of acid sites in HZSM-5 by combining it with a natural clay! This strategy enhances the production of light alkenes, particularly propene, and even aromatics via the catalytic cracking of naphtha.</p> |
| spellingShingle | Heterogeneous catalysis Almuqati, NS Advanced cracking catalysts for the conversion of naphtha into light olefins |
| title | Advanced cracking catalysts for the conversion of naphtha into light olefins |
| title_full | Advanced cracking catalysts for the conversion of naphtha into light olefins |
| title_fullStr | Advanced cracking catalysts for the conversion of naphtha into light olefins |
| title_full_unstemmed | Advanced cracking catalysts for the conversion of naphtha into light olefins |
| title_short | Advanced cracking catalysts for the conversion of naphtha into light olefins |
| title_sort | advanced cracking catalysts for the conversion of naphtha into light olefins |
| topic | Heterogeneous catalysis |
| work_keys_str_mv | AT almuqatins advancedcrackingcatalystsfortheconversionofnaphthaintolightolefins |