%0 Conference Proceedings
%4 dpi.inpe.br/plutao/2013/05.31.19.34
%2 dpi.inpe.br/plutao/2013/05.31.19.34.30
%F lattes: 9823109938173087 1 SantosCrCaAuAu:2013:EfAdSt
%T Effect of adding steam to CH4 during chemical-looping processes with Ni-based oxygen carriers
%D 2013
%A Santos, Pedro Henrique Lopes Nunes Abreu dos,
%A Cruz, Gilberto Marques da,
%A Carneiro, Livia Melo,
%A Moure, Gustavo T.,
%A Ferreira, Marco Aurélio,
%A Rodrigues, Jose Augusto Jorge,
%@affiliation
%@affiliation
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Petrobras
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@electronicmailaddress henlonunes.ps@gmail.com
%@electronicmailaddress
%@electronicmailaddress
%@electronicmailaddress
%@electronicmailaddress marco@lcp.inpe.br
%@electronicmailaddress jajr@lcp.inpe.br
%B Congresso Brasileiro de CO2 na Indústria de Petróleo, Gás e Biocombustíveis, 2.
%C Rio de Janeiro
%8 abril de 2013
%P 1-10
%S Proceedings
%K Chemical Looping Combustion, CLC, Chemical Looping Reforming, CLR, oxygen carrier.
%X The chemical-looping combustion (CLC) and chemical-looping reforming (CLR) processes allow combustion to take place in fuel gases such as CH4 to generate energy and produce H2, impeding the emission of CO2 into the atmosphere and contributing to greenhouse mitigation. In this work, the effect of adding water steam to CH4 was investigated, using NiO/alpha-Al2O3 and NiAl2O4/gamma-Al2O3 as oxygen carriers in order to reduce or eliminate the formation of carbon deposits on these materials when using long reductions steps. After characterizing the oxygen carriers using different techniques, they underwent many redox sequences, proving themselves to be stable. However, when CH4 was employed as the only active component of the reaction mixture in argon, large carbon deposits were formed on both carriers. The carbon deposits were only removed by a subsequent oxidation step using oxygen in argon. In experiments carried out in which water steam was added to the CH4 during the reduction step, carbon deposits on NiAl2O4/gamma-Al2O3 were almost eliminated and on NiO/alpha-Al2O3 were totally eliminated. Since the results were different, two different reaction mechanisms were proposed: the first in which the addition of H2O impeded the formation of carbon deposits and the second in which the carbon formed was gasified by the water. Both of the mechanisms were evaluated thermodynamically and experimentally for each of the steps involved. It can be asserted that in the case of the NiO/alpha-Al2O3 oxygen carrier, the second mechanism is much more probable since it involves quick and irreversible steps and in which water steam acts directly on the carbon deposits. In the case of the NiAl2O4/gamma-Al2O3 carrier, both of the mechanisms are possible. Because they involve reversible reactions they dont result in the total elimination of carbon deposits, though the level of elimination is quite high.
%@language en
%3 EFFECT OF ADDING STEAM.pdf