Biogas steam and oxidative reforming processes for synthesis gas and hydrogen production in conventional and microreactor reaction systems

Izquierdo, U.; Barrio, V.L.; Lago, Natália de Macedo do; Requies, J.; Cambra, J.F.; Güemez, M.B.; Arias, P.L.

doi:10.1016/j.ijhydene.2012.04.077

Cited by 65 publications

(34 citation statements)

References 35 publications

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“…In addition to the above techniques, TPR profiles for all the catalysts have also been previously published [19,25] (see Figure A2), showing slight differences among the catalysts under investigation. One significant difference is that with the commercial catalyst, Katalco 57-5, four different reduction peaks were detected, the biggest one being at 1048 K. For the rest of the monometallic and bimetallic catalysts, the main reduction peaks appeared in the range 900 K to 1200 K. Different reduction peaks were observed for the promoted supports.…”

Section: Fresh and Reduced Catalysts Characterizationmentioning

confidence: 73%

Catalyst Deactivation and Regeneration Processes in Biogas Tri-Reforming Process. The Effect of Hydrogen Sulfide Addition

et al. 2018

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Abstract:This work studies Ni-based catalyst deactivation and regeneration processes in the presence of H 2 S under a biogas tri-reforming process for hydrogen production, which is an energy vector of great interest. 25 ppm of hydrogen sulfide were continuously added to the system in order to provoke an observable catalyst deactivation, and once fully deactivated two different regeneration processes were studied: a self-regeneration and a regeneration by low temperature oxidation. For that purpose, several Ni-based catalysts and a bimetallic Rh-Ni catalyst supported on alumina modified with CeO 2 and ZrO 2 were used as well as a commercial Katalco 57-5 for comparison purposes. Ni/Ce-Al 2 O 3 and Ni/Ce-Zr-Al 2 O 3 catalysts almost recovered their initial activity. For these catalysts, after the regeneration under oxidative conditions at low temperature, the CO 2 conversions achieved-79.5% and 86.9%, respectively-were significantly higher than the ones obtained before sulfur poisoning-66.7% and 45.2%, respectively. This effect could be attributed to the support modification with CeO 2 and the higher selectivity achieved for the Reverse Water-Gas-Shift (rWGS) reaction after catalysts deactivation. As expected, the bimetallic Rh-Ni/Ce-Al 2 O 3 catalyst showed higher resistance to deactivation and its sulfur poisoning seems to be reversible. In the case of the commercial and Ni/Zr-Al 2 O 3 catalysts, they did not recover their activity.

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Section: Fresh and Reduced Catalysts Characterizationmentioning

confidence: 73%

Catalyst Deactivation and Regeneration Processes in Biogas Tri-Reforming Process. The Effect of Hydrogen Sulfide Addition

et al. 2018

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“…H 2 S is then introduced from an N 2 cylinder containing 1052 ppm H 2 S. CH 4 A low S/C ratio is employed to ensure the participation of CO 2 in reforming reactions [9]. Nevertheless, it is worth mentioning here that S/C ratio may have some influence on the chemisorption equilibrium of H 2 S at temperatures above 700 o C [2].…”

Section: Stability Testsmentioning

confidence: 99%

“…Bio-gas is an alternate fuel for synthesis gas production containing 50-75% CH 4 , 50-25% CO 2 , 0-10% N 2 , and 0-3% H 2 S. Due to the trivial nature of the anaerobic digestion process by which it is produced it can serve as a decentralized source of energy. The bio-gas thus produced can be converted into synthesis gas either by dry reforming or by a combination of dry and steam reforming using appropriate catalysts [3,4].…”

Section: Introductionmentioning

confidence: 99%

“…The bio-gas thus produced can be converted into synthesis gas either by dry reforming or by a combination of dry and steam reforming using appropriate catalysts [3,4]. Since the CH 4 to CO 2 ratio in bio-gas is ∼1.5, dry reforming alone can lead to significant carbon deposition within the reactor [5]. Therefore, it is desirable to mix bio-gas with steam for reforming and generally the H 2 O to CH 4 ratio (S/C) is maintained at 3 to avoid any coke formation [6].…”

Section: Introductionmentioning

confidence: 99%

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Deactivation and regeneration of Ni catalyst during steam reforming of model biogas: An experimental investigation

Appari

Janardhanan

Bauri

et al. 2014

International Journal of Hydrogen Energy

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This paper presents detailed study of biogas reforming. Model biogas with different levels of H 2 S is subjected to reforming reaction over supported Ni catalyst in a fixed bed reactor at 700 o C and 800 o C. In order to understand the poisoning effects of H 2 S the reactions have been initially carried out without H 2 S in the feed stream. Three different H 2 S concentrations (20, 50 and 100 ppm) have been considered in the study. The H 2 O to CH 4 ratio is maintained in such as way that CO 2 also participates in the reforming reaction. After performing the poisoning studies, regeneration of the catalyst has been studied using three different techniques i) removal of H 2 S from the feed stream ii) temperature enhancement and iii) steam treatment. Poisoning at low temperature is not recoverable just by removal of H 2 S from the feed stream. However, poisoning at high temperature is easily reversed just by removal of H 2 S from the feed stream. Unlike some previous reports [1,2], catalyst regeneration is achieved in shorter time frames for all the regeneration techniques attempted.

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“…The composition of biogas depends on the biomass source and duration of digestion process. Generally it contains 50-75% CH 4 , 50-25% CO 2 , 0-10% N 2 , and 0-3% H 2 S. Biogas may be combusted to produce electricity or can be converted to synthesis gas by reforming over Rh or Ni catalyst [1,2,3,4]. However, the presence of H 2 S or other sulfur containing compounds is a major problem for reforming of biogas due to its poisoning effect on most transition metals [5].…”

Section: Introductionmentioning

confidence: 99%

A detailed kinetic model for biogas steam reforming on Ni and catalyst deactivation due to sulfur poisoning

Appari¹,

Janardhanan²,

Bauri³

et al. 2014

Applied Catalysis A: General

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This paper deals with the development and validation of a detailed kinetic model for steam reforming of biogas with and without H 2 S. The model has 68 reactions among 8 gasphase species and 18 surface adsorbed species including the catalytic surface. The activation energies for various reactions are calculated based on unity bond index-quadratic exponential potential (UBI-QEP) method. The whole mechanism is made thermodynamically consistent by using a previously published algorithm. Sensitivity analysis is carried out to understand the influence of reaction parameters on surface coverage of sulfur. The parameters describing sticking and desorption reactions of H 2 S are the most sensitive ones for the formation of adsorbed sulfur. The mechanism is validated in the temperature range of 873-1200 K for biogas free from H 2 S and 973-1173 K for biogas containing 20-108 ppm H 2 S. The model predicts that during the initial stages of poisoning sulfur coverages are high near the reactor inlet; however, as the reaction proceeds further sulfur coverages increase towards the reactor exit. In the absence of sulfur CO and H atoms are the dominant surface adsorbed species. High temperature operation can significantly mitigate sulfur adsorption and hence the saturation sulfur coverages are lower compared to low temperature operation. Low temperature operation can lead to full deactivation of the catalyst. The model predicts saturation coverages that are comparable to experimental observation.

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Biogas steam and oxidative reforming processes for synthesis gas and hydrogen production in conventional and microreactor reaction systems

Cited by 65 publications

References 35 publications

Catalyst Deactivation and Regeneration Processes in Biogas Tri-Reforming Process. The Effect of Hydrogen Sulfide Addition

Catalyst Deactivation and Regeneration Processes in Biogas Tri-Reforming Process. The Effect of Hydrogen Sulfide Addition

Deactivation and regeneration of Ni catalyst during steam reforming of model biogas: An experimental investigation

A detailed kinetic model for biogas steam reforming on Ni and catalyst deactivation due to sulfur poisoning

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