A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units
The deterioration of refractories used in fluidized catalytic cracking units (FCC-units) is responsible for high costs of maintenance for the petrochemical industry. This is commonly associated with coke deposition during the production of light hydrocarbons. However, other mechanisms responsible fo...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Cerâmica
2014-09-01
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| Series: | Cerâmica |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132014000300019&lng=en&tlng=en |
| _version_ | 1818993753804767232 |
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| author | A. H. A. Pereira D. Y. Miyaji M. D. Cabrelon J. Medeiros J. A. Rodrigues |
| author_facet | A. H. A. Pereira D. Y. Miyaji M. D. Cabrelon J. Medeiros J. A. Rodrigues |
| author_sort | A. H. A. Pereira |
| collection | DOAJ |
| description | The deterioration of refractories used in fluidized catalytic cracking units (FCC-units) is responsible for high costs of maintenance for the petrochemical industry. This is commonly associated with coke deposition during the production of light hydrocarbons. However, other mechanisms responsible for causing damage may also occur, such as the generation of cracks by expansive phase transition. The aim of the work herein was to study the contribution of the a-b phase transition of quartz particles to the deterioration of a commercial aluminosilicate refractory used in a riser by the means of slow thermal cycles. Such damage may occur if the working temperature of the equipment fluctuates around the a-b transition temperature (573 °C). The current study considered the material with and without coke impregnation to evaluate the combined effect of coke presence and phase transition. To evaluate the damage, it was used the Young's modulus as a function of temperature by applying the Impulse Excitation Technique under controlled atmosphere. An equipment recently developed by the authors research group was applied. Specimens were prepared and submitted to slow thermal cycles of temperatures up to 500 °C and up to 700 °C, with a heating rate of 2 °C/min. Part of the specimens was previously impregnated with coke by a reactor using propen. To complete the evaluation, characterization by X-ray diffraction, as well as by dilatometry and scanning electron microscopy were performed. The findings of this study showed that the presence of quartz particles determine the thermo-mechanical behaviour of the material, as well as the thermocycling damage resistance. In spite of the fact that the a-b phase transition stiffens the material during the heating stage, it increases the damage by slow thermal cycling. The coke impregnation increases the resistance to slow thermal cycles, however it decreases the resistance to the damage evolution. |
| first_indexed | 2024-12-20T20:47:04Z |
| format | Article |
| id | doaj.art-7345108acb134b35a115f9ad7bd03cb4 |
| institution | Directory Open Access Journal |
| issn | 1678-4553 |
| language | English |
| last_indexed | 2024-12-20T20:47:04Z |
| publishDate | 2014-09-01 |
| publisher | Associação Brasileira de Cerâmica |
| record_format | Article |
| series | Cerâmica |
| spelling | doaj.art-7345108acb134b35a115f9ad7bd03cb42022-12-21T19:27:01ZengAssociação Brasileira de CerâmicaCerâmica1678-45532014-09-016035544945610.1590/S0366-69132014000300019S0366-69132014000300019A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking unitsA. H. A. Pereira0D. Y. Miyaji1M. D. Cabrelon2J. Medeiros3J. A. Rodrigues4Universidade Federal de São CarlosUniversidade Federal de São CarlosUniversidade Federal de São CarlosPETROBRÁSUniversidade Federal de São CarlosThe deterioration of refractories used in fluidized catalytic cracking units (FCC-units) is responsible for high costs of maintenance for the petrochemical industry. This is commonly associated with coke deposition during the production of light hydrocarbons. However, other mechanisms responsible for causing damage may also occur, such as the generation of cracks by expansive phase transition. The aim of the work herein was to study the contribution of the a-b phase transition of quartz particles to the deterioration of a commercial aluminosilicate refractory used in a riser by the means of slow thermal cycles. Such damage may occur if the working temperature of the equipment fluctuates around the a-b transition temperature (573 °C). The current study considered the material with and without coke impregnation to evaluate the combined effect of coke presence and phase transition. To evaluate the damage, it was used the Young's modulus as a function of temperature by applying the Impulse Excitation Technique under controlled atmosphere. An equipment recently developed by the authors research group was applied. Specimens were prepared and submitted to slow thermal cycles of temperatures up to 500 °C and up to 700 °C, with a heating rate of 2 °C/min. Part of the specimens was previously impregnated with coke by a reactor using propen. To complete the evaluation, characterization by X-ray diffraction, as well as by dilatometry and scanning electron microscopy were performed. The findings of this study showed that the presence of quartz particles determine the thermo-mechanical behaviour of the material, as well as the thermocycling damage resistance. In spite of the fact that the a-b phase transition stiffens the material during the heating stage, it increases the damage by slow thermal cycling. The coke impregnation increases the resistance to slow thermal cycles, however it decreases the resistance to the damage evolution.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132014000300019&lng=en&tlng=enconcreto refratáriotransformação de fasequartzodano por ciclo térmico lentoimpregnação por coqueUFCCtécnica de excitação por impulsomódulo de Youngamortecimento |
| spellingShingle | A. H. A. Pereira D. Y. Miyaji M. D. Cabrelon J. Medeiros J. A. Rodrigues A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units Cerâmica concreto refratário transformação de fase quartzo dano por ciclo térmico lento impregnação por coque UFCC técnica de excitação por impulso módulo de Young amortecimento |
| title | A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units |
| title_full | A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units |
| title_fullStr | A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units |
| title_full_unstemmed | A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units |
| title_short | A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units |
| title_sort | study about the contribution of the α β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units |
| topic | concreto refratário transformação de fase quartzo dano por ciclo térmico lento impregnação por coque UFCC técnica de excitação por impulso módulo de Young amortecimento |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0366-69132014000300019&lng=en&tlng=en |
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