Conversão catalítica de clorometano em hidrocarbonetos
Autor(a) principal: | |
---|---|
Data de Publicação: | 2012 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFRN |
Texto Completo: | https://repositorio.ufrn.br/jspui/handle/123456789/15916 |
Resumo: | Amorphous silica-alumina and modified by incipient impregnation of iron, nickel, zinc and chromium were synthetized in oxide and metal state and evaluated as catalysts for the chloromethane conversion reaction. With known techniques their textural properties were determined and dynamics techniques in programmed temperature were used to find the acid properties of the materials. A thermodynamic model was used to determine the adsorption and desorption capacity of chloromethane. Two types of reactions were studied. Firstly the chloromethane was catalytically converted to hydrocarbons (T = 300 450 oC e m = 300 mg) in a fixed bed reactor with controlled pressure and flow. Secondly the deactivation of the unmodified support was studied (at 300 °C and m=250 g) in a micro-adsorver provided of gravimetric monitoring. The metal content (2,5%) and the chloromethane percent of the reagent mixture (10% chloromethane in nitrogen) were fixed for all the tests. From the results the chloromethane conversion and selectivity of the gaseous products (H2, CH4, C3 and C4) were determined as well as the energy of desorption (75,2 KJ/mol for Ni/Al2O3-SiO2 to 684 KJ/mol for the Zn/Al2O3-SiO2 catalyst) considering the desorption rate as a temperature function. The presence of a metal on the support showed to have an important significance in the chloromethane condensation. The oxide class catalyst presented a better performance toward the production of hydrocarbons. Especial mention to the ZnO/Al2O3-SiO2 that, in a gas phase basis, produced C3 83 % max. and C4 63% max., respectively, in the temperature of 450 oC and 20 hours on stream. Hydrogen was produced exclusively in the FeO/Al2O3-SiO2 catalysts (15 % max., T = 550 oC and 5,6 h on stream) and Ni/SiO2-Al2O3 (75 % max., T = 400 oC and 21,6 h on stream). All the catalysts produced methane (10 à 92 %), except for Ni/Al2O3-SiO2 and CrO/Al2O3-SiO2. In the deactivation study two models were proposed: The parallel model, where the product production competes with coke formation; and the sequential model, where the coke formation competes with the product desorption dessorption step. With the mass balance equations and the mechanism proposed six parameters were determined. Two kinetic parameters: the hydrocarbon formation constant, 8,46 10-4 min-1, the coke formation, 1,46 10-1 min-1; three thermodynamic constants (the global, 0,003, the chloromethane adsorption 0,417 bar-1, the hydrocarbon adsorption 2,266 bar-1), and the activity exponent of the coke formation (1,516). The model was reasonable well fitted and presented a satisfactory behavior in relation with the proposed mechanism |
id |
UFRN_59795f6a4dcf9b1099aecd94ade42942 |
---|---|
oai_identifier_str |
oai:https://repositorio.ufrn.br:123456789/15916 |
network_acronym_str |
UFRN |
network_name_str |
Repositório Institucional da UFRN |
repository_id_str |
|
spelling |
Rojas, Leopoldo Oswaldo Alcazarhttp://lattes.cnpq.br/1822123250893671http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783510Y4Benachour, Mohandhttp://lattes.cnpq.br/2445243904431423Santos, Luiz Carlos Lobato doshttp://lattes.cnpq.br/8891045064075199Oliveira, Jackson Araújo dehttp://lattes.cnpq.br/5058617634570704Ferreira, Sebastião Ribeirohttp://lattes.cnpq.br/7849019313801150Sousa, João Fernandes de2014-12-17T15:01:54Z2012-07-202014-12-17T15:01:54Z2012-03-02ROJAS, Leopoldo Oswaldo Alcazar. Conversão catalítica de clorometano em hidrocarbonetos. 2012. 125 f. Tese (Doutorado em Pesquisa e Desenvolvimento de Tecnologias Regionais) - Universidade Federal do Rio Grande do Norte, Natal, 2012.https://repositorio.ufrn.br/jspui/handle/123456789/15916Amorphous silica-alumina and modified by incipient impregnation of iron, nickel, zinc and chromium were synthetized in oxide and metal state and evaluated as catalysts for the chloromethane conversion reaction. With known techniques their textural properties were determined and dynamics techniques in programmed temperature were used to find the acid properties of the materials. A thermodynamic model was used to determine the adsorption and desorption capacity of chloromethane. Two types of reactions were studied. Firstly the chloromethane was catalytically converted to hydrocarbons (T = 300 450 oC e m = 300 mg) in a fixed bed reactor with controlled pressure and flow. Secondly the deactivation of the unmodified support was studied (at 300 °C and m=250 g) in a micro-adsorver provided of gravimetric monitoring. The metal content (2,5%) and the chloromethane percent of the reagent mixture (10% chloromethane in nitrogen) were fixed for all the tests. From the results the chloromethane conversion and selectivity of the gaseous products (H2, CH4, C3 and C4) were determined as well as the energy of desorption (75,2 KJ/mol for Ni/Al2O3-SiO2 to 684 KJ/mol for the Zn/Al2O3-SiO2 catalyst) considering the desorption rate as a temperature function. The presence of a metal on the support showed to have an important significance in the chloromethane condensation. The oxide class catalyst presented a better performance toward the production of hydrocarbons. Especial mention to the ZnO/Al2O3-SiO2 that, in a gas phase basis, produced C3 83 % max. and C4 63% max., respectively, in the temperature of 450 oC and 20 hours on stream. Hydrogen was produced exclusively in the FeO/Al2O3-SiO2 catalysts (15 % max., T = 550 oC and 5,6 h on stream) and Ni/SiO2-Al2O3 (75 % max., T = 400 oC and 21,6 h on stream). All the catalysts produced methane (10 à 92 %), except for Ni/Al2O3-SiO2 and CrO/Al2O3-SiO2. In the deactivation study two models were proposed: The parallel model, where the product production competes with coke formation; and the sequential model, where the coke formation competes with the product desorption dessorption step. With the mass balance equations and the mechanism proposed six parameters were determined. Two kinetic parameters: the hydrocarbon formation constant, 8,46 10-4 min-1, the coke formation, 1,46 10-1 min-1; three thermodynamic constants (the global, 0,003, the chloromethane adsorption 0,417 bar-1, the hydrocarbon adsorption 2,266 bar-1), and the activity exponent of the coke formation (1,516). The model was reasonable well fitted and presented a satisfactory behavior in relation with the proposed mechanismSílica alumina amorfa e modificada por impregnação incipiente de precursores de ferro, níquel, zinco e cromo foram sintetizados na forma de óxido e reduzidos, tendo sido posteriormente avaliados como catalisadores na conversão de clorometano em hidrocarbonetos. Propriedades texturais e técnicas dinâmicas em temperatura programada foram usadas para a determinação das propriedades ácidas dos materiais. Um modelo termodinâmico para representar a capacidade de adsorção e dessorção de clorometano foi avaliado. Dois tipos de reações foram abordados. No primeiro, o clorometano foi convertido cataliticamente a hidrocarbonetos (T = 300 450 oC e m = 300 mg) em um reator de leito fixo catalítico com controle de fluxo, pressão e vazão mássica e, no segundo, com o suporte puro (T = 300 oC e m = 250 mg) foi estudado a reação de desativação do catalisador pelo coque em um micro adsorvedor com monitoramento gravimétrico. O teor de metal no suporte (2,5 %) e o percentual de clorometano na mistura (10 %) foram mantidos constantes durante os experimentos. Com os resultados obtidos foram avaliadas a conversão e a seletividade dos produtos gasosos, ou seja, H2, CH4, C3 e C4 bem como a energia da etapa de dessorção (75,2 KJ/mol para o Ni/Al2O3-SiO2 e 684 KJ/mol para o catalisador Zn/Al2O3-SiO2), considerando a taxa de adsorção do gás em função da temperatura. A presença do metal no suporte mostrou uma importância significativa em termos de atividade na reação de condensação do clorometano. Os catalisadores na forma de óxido apresentaram melhor desempenho para obtenção de hidrocarbonetos. É possível destacar o ZnO/Al2O3-SiO2 que , em termos de constituinte gasoso, produziu apenas C3 (Máx. de 83 %) e C4 (Máx. de 63%), respectivamente, na temperatura de 450 oC e 20 horas de reação,. O gás hidrogênio foi formado exclusivamente com os catalisadores FeO/Al2O3-SiO2 (Máx. de 15 %, T = 550 oC e tempo de reação de 5,6 h) e Ni/SiO2-Al2O3 (Máx. 75 %, T = 400 oC e tempo de reação de 21,6 h). Todos os catalisadores produziram o gás metano (10 à 92 %), salvo os do tipo Ni/Al2O3- SiO2 e CrO/Al2O3-SiO2. No estudo com o suporte puro foram propostos dois modelos de iii desativação, do tipo paralelo, onde a formação do produto compete com a formação de coque e o sequencial, onde a etapa de dessorção é a competidora. Com as equações do balanço de massa baseadas no mecanismo proposto foram determinados duas constantes cinéticas (a primeira de valor 8,01·10-4 min-1, relacionada à etapa da formação de hidrocarbonetos e a segunda, 1,46·10-1 min-1, ao coque depositado no sítio do material), três constantes de equilíbrio (a global 0,003, relativa ao clorometano 0,417 bar-1, e a de formação de hidrocarbonetos 2,266 bar-1) e o do perfil do fator de atividade (1,516). Em termos de ajustes, o modelo representou um comportamento satisfatório em relação ao mecanismo propostoapplication/pdfporUniversidade Federal do Rio Grande do NortePrograma de Pós-Graduação em Engenharia QuímicaUFRNBRPesquisa e Desenvolvimento de Tecnologias RegionaisClorometano, sílica-alumina, modelo de desativação, reator de leito fixo, hidrocarbonetos, catalisadoresChloromethaneSilica-aluminaDeactivation modelFix bed reactorHydrocarbonsCatalystsCNPQ::ENGENHARIAS::ENGENHARIA QUIMICAConversão catalítica de clorometano em hidrocarbonetosinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRNinstname:Universidade Federal do Rio Grande do Norte (UFRN)instacron:UFRNORIGINALLeopoldoOAR_TESE.pdfapplication/pdf2477409https://repositorio.ufrn.br/bitstream/123456789/15916/1/LeopoldoOAR_TESE.pdf8a0937fc273e62c20239012357028d11MD51TEXTLeopoldoOAR_TESE.pdf.txtLeopoldoOAR_TESE.pdf.txtExtracted texttext/plain183639https://repositorio.ufrn.br/bitstream/123456789/15916/6/LeopoldoOAR_TESE.pdf.txt81e114cf1c0bc4a179a66127b68b72adMD56THUMBNAILLeopoldoOAR_TESE.pdf.jpgLeopoldoOAR_TESE.pdf.jpgIM Thumbnailimage/jpeg2995https://repositorio.ufrn.br/bitstream/123456789/15916/7/LeopoldoOAR_TESE.pdf.jpg9526d29f9786ebb8c48a264eee8c89d5MD57123456789/159162017-11-02 05:58:56.519oai:https://repositorio.ufrn.br:123456789/15916Repositório de PublicaçõesPUBhttp://repositorio.ufrn.br/oai/opendoar:2017-11-02T08:58:56Repositório Institucional da UFRN - Universidade Federal do Rio Grande do Norte (UFRN)false |
dc.title.por.fl_str_mv |
Conversão catalítica de clorometano em hidrocarbonetos |
title |
Conversão catalítica de clorometano em hidrocarbonetos |
spellingShingle |
Conversão catalítica de clorometano em hidrocarbonetos Rojas, Leopoldo Oswaldo Alcazar Clorometano, sílica-alumina, modelo de desativação, reator de leito fixo, hidrocarbonetos, catalisadores Chloromethane Silica-alumina Deactivation model Fix bed reactor Hydrocarbons Catalysts CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
title_short |
Conversão catalítica de clorometano em hidrocarbonetos |
title_full |
Conversão catalítica de clorometano em hidrocarbonetos |
title_fullStr |
Conversão catalítica de clorometano em hidrocarbonetos |
title_full_unstemmed |
Conversão catalítica de clorometano em hidrocarbonetos |
title_sort |
Conversão catalítica de clorometano em hidrocarbonetos |
author |
Rojas, Leopoldo Oswaldo Alcazar |
author_facet |
Rojas, Leopoldo Oswaldo Alcazar |
author_role |
author |
dc.contributor.authorID.por.fl_str_mv |
|
dc.contributor.authorLattes.por.fl_str_mv |
http://lattes.cnpq.br/1822123250893671 |
dc.contributor.advisorID.por.fl_str_mv |
|
dc.contributor.advisorLattes.por.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783510Y4 |
dc.contributor.referees1.pt_BR.fl_str_mv |
Benachour, Mohand |
dc.contributor.referees1ID.por.fl_str_mv |
|
dc.contributor.referees1Lattes.por.fl_str_mv |
http://lattes.cnpq.br/2445243904431423 |
dc.contributor.referees2.pt_BR.fl_str_mv |
Santos, Luiz Carlos Lobato dos |
dc.contributor.referees2ID.por.fl_str_mv |
|
dc.contributor.referees2Lattes.por.fl_str_mv |
http://lattes.cnpq.br/8891045064075199 |
dc.contributor.referees3.pt_BR.fl_str_mv |
Oliveira, Jackson Araújo de |
dc.contributor.referees3ID.por.fl_str_mv |
|
dc.contributor.referees3Lattes.por.fl_str_mv |
http://lattes.cnpq.br/5058617634570704 |
dc.contributor.referees4.pt_BR.fl_str_mv |
Ferreira, Sebastião Ribeiro |
dc.contributor.referees4ID.por.fl_str_mv |
|
dc.contributor.referees4Lattes.por.fl_str_mv |
http://lattes.cnpq.br/7849019313801150 |
dc.contributor.author.fl_str_mv |
Rojas, Leopoldo Oswaldo Alcazar |
dc.contributor.advisor1.fl_str_mv |
Sousa, João Fernandes de |
contributor_str_mv |
Sousa, João Fernandes de |
dc.subject.por.fl_str_mv |
Clorometano, sílica-alumina, modelo de desativação, reator de leito fixo, hidrocarbonetos, catalisadores |
topic |
Clorometano, sílica-alumina, modelo de desativação, reator de leito fixo, hidrocarbonetos, catalisadores Chloromethane Silica-alumina Deactivation model Fix bed reactor Hydrocarbons Catalysts CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
dc.subject.eng.fl_str_mv |
Chloromethane Silica-alumina Deactivation model Fix bed reactor Hydrocarbons Catalysts |
dc.subject.cnpq.fl_str_mv |
CNPQ::ENGENHARIAS::ENGENHARIA QUIMICA |
description |
Amorphous silica-alumina and modified by incipient impregnation of iron, nickel, zinc and chromium were synthetized in oxide and metal state and evaluated as catalysts for the chloromethane conversion reaction. With known techniques their textural properties were determined and dynamics techniques in programmed temperature were used to find the acid properties of the materials. A thermodynamic model was used to determine the adsorption and desorption capacity of chloromethane. Two types of reactions were studied. Firstly the chloromethane was catalytically converted to hydrocarbons (T = 300 450 oC e m = 300 mg) in a fixed bed reactor with controlled pressure and flow. Secondly the deactivation of the unmodified support was studied (at 300 °C and m=250 g) in a micro-adsorver provided of gravimetric monitoring. The metal content (2,5%) and the chloromethane percent of the reagent mixture (10% chloromethane in nitrogen) were fixed for all the tests. From the results the chloromethane conversion and selectivity of the gaseous products (H2, CH4, C3 and C4) were determined as well as the energy of desorption (75,2 KJ/mol for Ni/Al2O3-SiO2 to 684 KJ/mol for the Zn/Al2O3-SiO2 catalyst) considering the desorption rate as a temperature function. The presence of a metal on the support showed to have an important significance in the chloromethane condensation. The oxide class catalyst presented a better performance toward the production of hydrocarbons. Especial mention to the ZnO/Al2O3-SiO2 that, in a gas phase basis, produced C3 83 % max. and C4 63% max., respectively, in the temperature of 450 oC and 20 hours on stream. Hydrogen was produced exclusively in the FeO/Al2O3-SiO2 catalysts (15 % max., T = 550 oC and 5,6 h on stream) and Ni/SiO2-Al2O3 (75 % max., T = 400 oC and 21,6 h on stream). All the catalysts produced methane (10 à 92 %), except for Ni/Al2O3-SiO2 and CrO/Al2O3-SiO2. In the deactivation study two models were proposed: The parallel model, where the product production competes with coke formation; and the sequential model, where the coke formation competes with the product desorption dessorption step. With the mass balance equations and the mechanism proposed six parameters were determined. Two kinetic parameters: the hydrocarbon formation constant, 8,46 10-4 min-1, the coke formation, 1,46 10-1 min-1; three thermodynamic constants (the global, 0,003, the chloromethane adsorption 0,417 bar-1, the hydrocarbon adsorption 2,266 bar-1), and the activity exponent of the coke formation (1,516). The model was reasonable well fitted and presented a satisfactory behavior in relation with the proposed mechanism |
publishDate |
2012 |
dc.date.available.fl_str_mv |
2012-07-20 2014-12-17T15:01:54Z |
dc.date.issued.fl_str_mv |
2012-03-02 |
dc.date.accessioned.fl_str_mv |
2014-12-17T15:01:54Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
ROJAS, Leopoldo Oswaldo Alcazar. Conversão catalítica de clorometano em hidrocarbonetos. 2012. 125 f. Tese (Doutorado em Pesquisa e Desenvolvimento de Tecnologias Regionais) - Universidade Federal do Rio Grande do Norte, Natal, 2012. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufrn.br/jspui/handle/123456789/15916 |
identifier_str_mv |
ROJAS, Leopoldo Oswaldo Alcazar. Conversão catalítica de clorometano em hidrocarbonetos. 2012. 125 f. Tese (Doutorado em Pesquisa e Desenvolvimento de Tecnologias Regionais) - Universidade Federal do Rio Grande do Norte, Natal, 2012. |
url |
https://repositorio.ufrn.br/jspui/handle/123456789/15916 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal do Rio Grande do Norte |
dc.publisher.program.fl_str_mv |
Programa de Pós-Graduação em Engenharia Química |
dc.publisher.initials.fl_str_mv |
UFRN |
dc.publisher.country.fl_str_mv |
BR |
dc.publisher.department.fl_str_mv |
Pesquisa e Desenvolvimento de Tecnologias Regionais |
publisher.none.fl_str_mv |
Universidade Federal do Rio Grande do Norte |
dc.source.none.fl_str_mv |
reponame:Repositório Institucional da UFRN instname:Universidade Federal do Rio Grande do Norte (UFRN) instacron:UFRN |
instname_str |
Universidade Federal do Rio Grande do Norte (UFRN) |
instacron_str |
UFRN |
institution |
UFRN |
reponame_str |
Repositório Institucional da UFRN |
collection |
Repositório Institucional da UFRN |
bitstream.url.fl_str_mv |
https://repositorio.ufrn.br/bitstream/123456789/15916/1/LeopoldoOAR_TESE.pdf https://repositorio.ufrn.br/bitstream/123456789/15916/6/LeopoldoOAR_TESE.pdf.txt https://repositorio.ufrn.br/bitstream/123456789/15916/7/LeopoldoOAR_TESE.pdf.jpg |
bitstream.checksum.fl_str_mv |
8a0937fc273e62c20239012357028d11 81e114cf1c0bc4a179a66127b68b72ad 9526d29f9786ebb8c48a264eee8c89d5 |
bitstream.checksumAlgorithm.fl_str_mv |
MD5 MD5 MD5 |
repository.name.fl_str_mv |
Repositório Institucional da UFRN - Universidade Federal do Rio Grande do Norte (UFRN) |
repository.mail.fl_str_mv |
|
_version_ |
1797776965640388608 |