Effect of ZrO2 on catalyst structure and catalytic methanation performance over Ni-based catalyst in slurry-bed reactor

Meng, Fanhui; Li, Zhong; Ji, Fangkui; Li, Minhan

doi:10.1016/j.ijhydene.2015.05.057

Cited by 30 publications

(25 citation statements)

References 46 publications

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“…Nevertheless, it cannot be discarded that the addition of Ca enhances the formation of carbon. Finally, it can be concluded that promotion with ZrO 2 can diminish the carbon formation rate, as suggested in previous studies [19][20][21][22]. The results encourage the performance of long tests in order to confirm that Zr inhibits carbon formation and reduces the catalyst deactivation rate.…”

Section: Carbon Formationsupporting

confidence: 83%

“…Moreover, none of these promoters led to a decent improvement of the catalyst thermal resistance. The results may be surprising since previous studies [19,21,22] claimed that Zr, for instance, and atoms of C β formed per Ni active site (right). The latter was calculated using the metallic dispersion obtained from H 2 -static chemisorption enhanced the catalyst thermal stability.…”

Section: Thermal Sinteringmentioning

confidence: 81%

“…For instance, several researchers [19][20][21][22] have found that addition of ZrO 2 can reduce the formation of carbon and enhance the thermal resistance of both the carrier and the Ni particles. Rotgerink et al [23] found that the addition of La 2 O 3 can restrain the growth of Ni particles.…”

Section: Introductionmentioning

confidence: 99%

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Deactivation of Ni/γ-Al2O3 Catalysts in CO Methanation: Effect of Zr, Mg, Ba and Ca Oxide Promoters

et al. 2017

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reserves [1,2]. The SNG production process involves two steps: gasification of the carbon-containing feedstock and subsequent catalytic methanation of the resulting synthesis gas. Methanation of synthesis gas involves the two following reactions [3][4][5]:These reactions are thermodynamically favored at low temperature and high pressure [6]. It is therefore that the methanation process is designed to effectively remove the heat of reaction and thus maximize the methane yield [1,7]. There are currently two main methanation concepts: single fluidized bed reactors and series of adiabatic fixed bed reactors with intercooling [1]. The latter, also known as high temperature methanation, has already found commercial application [8,9].Alumina-supported nickel catalysts are usually employed in this application due to their high activity, selectivity to methane and relatively low price [7]. However, their stability is threatened by the severe conditions of the high temperature methanation process [10,11]. In this process, the catalyst at the inlet of the reactor is exposed to low temperatures and high CO partial pressures, fact that favors the formation of polymeric carbon and sintering via nickel carbonyl formation [4,[12][13][14]. The exothermic reactions cause a significant temperature rise. As a result, the major part of the catalyst in these reactors is exposed to high temperatures and high steam partial pressures fact that promotes sintering of the nickel nanoparticles and the support [11,15]. In order to limit the temperature rise and thus, catalyst deactivation, a high gas recycle is used in these reactors. Catalysts with improved stability at low andAbstract Catalyst deactivation is one of the major concerns in the production of substitute natural gas (SNG) via CO methanation. Catalysts in this application need to be active at low temperatures, resistant to polymeric carbon formation and stable at high temperatures and steam partial pressures. In the present work, a series of aluminasupported nickel catalysts promoted with Zr, Mg, Ba or Ca oxides were investigated. The catalysts were tested under low temperature CO methanation conditions in order to evaluate their resistance to carbon formation. The catalysts were also exposed to accelerated ageing conditions at high temperatures in order to study their thermal stability. The aged catalysts lost most of their activity mainly due to sintering of the support and the nickel crystallites. Apparently, none of these promoters had a satisfactory effect on the thermal resistance of the catalyst. Nevertheless, it was found that the presence of Zr can reduce the rate of polymeric carbon formation.

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Section: Carbon Formationsupporting

confidence: 83%

Section: Thermal Sinteringmentioning

confidence: 81%

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Deactivation of Ni/γ-Al2O3 Catalysts in CO Methanation: Effect of Zr, Mg, Ba and Ca Oxide Promoters

et al. 2017

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“…Greek symbols a ik Number of atoms of the k element present in each molecule of species i l i Chemical potential of species i (J/mol) / i Fugacity coefficient of species i k k Lagrange multiplier 1 Introduction Natural gas is a highly efficient and clean fossil fuel due to its high calorific value, low sooting tendency and slag free products, leading to its increasing consumption year by year (Gao et al 2015;Meng et al 2015a;Rönsch et al 2016). In 2014, the consumption of natural gas in China increased to 197.3 billion cubic meters, with a growth rate of 30.9% every year in the last decade (BP 2016).…”

Section: List Of Symbolsmentioning

confidence: 99%

CO hydrogenation combined with water-gas-shift reaction for synthetic natural gas production: a thermodynamic and experimental study

Meng

et al. 2017

Int J Coal Sci Technol

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The hydrogenation of CO to synthetic natural gas (SNG) needs a high molar ratio of H 2 /CO (usually large than 3.0 in industry), which consumes a large abundant of hydrogen. The reverse dry reforming reaction (RDR, 2H 2 ? 2CO $ CH 4 ? CO 2 ), combining CO methanation with water-gas-shift reaction, can significantly decrease the H 2 /CO molar ratio to 1 for SNG production. A detailed thermodynamic analysis of RDR reaction was carried out based on the Gibbs free energy minimization method. The effect of temperature, pressure, H 2 /CO ratio and the addition of H 2 O, CH 4 , CO 2 , O 2 and C 2 H 4 into the feed gas on CO conversion, CH 4 and CO 2 selectivity, as well as CH 4 and carbon yield, are discussed. Experimental results obtained on homemade impregnated Ni/Al 2 O 3 catalyst are compared with the calculations. The results demonstrate that low temperature (200-500°C), high pressure (1-5 MPa) and high H 2 /CO ratio (at least 1) promote CO conversion and CH 4 selectivity and decrease carbon yield. Steam and CO 2 in the feed gas decrease the CH 4 selectivity and carbon yield, and enhance the CO 2 content. Extra CH 4 elevates the CH 4 content in the products, but leads to more carbon formation at high temperatures. O 2 significantly decreases the CH 4 selectivity and C 2 H 4 results in the generation of carbon.Keywords Synthetic natural gas Á Reverse dry reforming of methane Á Gibbs free energy minimization Á Experimental study Á CO conversion List of symbols A k Total mass of k element in the feed f i H Standard-state fugacity of species i (Pa) f i

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“…It is also very challenging because the high concentration of CO on the catalyst surface may lead to the formation of Ni(CO) 4 and further catalyst deactivation. At present, research on low-temperature methanation is mainly focused on hydrogen-rich systems and slurry-bed reactors [32][33][34][35][36][37], while that for syngas (H 2 /CO = 3/1) in fixed beds has rarely been reported.…”

Section: Introductionmentioning

confidence: 99%

Highly Dispersed Ni Nanocatalysts Derived from NiMnAl-Hydrotalcites as High-Performing Catalyst for Low-Temperature Syngas Methanation

Lü

Zhuang

et al. 2019

Catalysts

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Increasing the low-temperature performance of nickel-based catalysts in syngas methanation is critical but very challenging, because at low temperatures there is high concentration of CO on the catalyst surface, causing formation of nickel carbonyl with metallic Ni and further catalyst deactivation. Herein, we have prepared highly dispersed Ni nanocatalysts by in situ reduction of NiMnAl-layered double hydroxides (NiMnAl-LDHs) and applied them to syngas methanation. The synthesized Ni nanocatalysts maintained the nanosheet structure of the LDHs, in which Ni particles were decorated with MnOy species and embedded in the AlOx nanosheets. It was observed that the Ni nanocatalysts exhibited markedly better low-temperature performance than commercial catalysts in the syngas methanation. At 250 °C, 3.0 MPa and a high weight hourly space velocity (WHSV) of 30,000 mL·g−1·h−1, both the CO conversion and the CH4 selectivity reached 100% over the former, while those over the commercial catalyst were only 14% and 76%, respectively. Furthermore, this NiMnAl catalyst exhibited strong anti-carbon and anti-sintering properties at high temperatures. The enhanced low-temperature performance and high-temperature stability originated from the promotion effect of MnOy and the embedding effect of AlOx in the catalyst.

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Effect of ZrO2 on catalyst structure and catalytic methanation performance over Ni-based catalyst in slurry-bed reactor

Cited by 30 publications

References 46 publications

Deactivation of Ni/γ-Al2O3 Catalysts in CO Methanation: Effect of Zr, Mg, Ba and Ca Oxide Promoters

Deactivation of Ni/γ-Al2O3 Catalysts in CO Methanation: Effect of Zr, Mg, Ba and Ca Oxide Promoters

CO hydrogenation combined with water-gas-shift reaction for synthetic natural gas production: a thermodynamic and experimental study

Highly Dispersed Ni Nanocatalysts Derived from NiMnAl-Hydrotalcites as High-Performing Catalyst for Low-Temperature Syngas Methanation

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