Sustainable Production of Syngas from Biomass‐Derived Glycerol by Steam Reforming over Highly Stable Ni/SiC

Abstract

The production of syngas was investigated by steam reforming glycerol over Ni/Al(2)O(3), Ni/CeO(2), and Ni/SiC (which have acidic, basic, and neutral properties) at temperatures below 773 K. The complete and stable conversion of glycerol with a yield (higher than 90 %) of gaseous products (mainly syngas) was achieved over Ni/SiC during a 60 h reaction, whereas the conversion of glycerol continually decreases over Ni/Al(2)O(3) (by 49.8 %) and Ni/CeO(2) (by 77.1 %). The deactivation of Ni/Al(2)O(3) and Ni/CeO(2) is mainly caused by coke deposition because of the C-C cleavage of the byproducts produced by dehydration over acidic sites and condensation over basic sites. Gaseous products with a 1.0-1.9 syngas ratio (H(2)/CO) are produced over Ni/SiC. This ratio is required for the Fischer-Tropsch synthesis. However, a syngas ratio of more than 3.0 was observed over Ni/Al(2)O(3) and Ni/CeO(2) because of the high activity of the water-gas-shift reaction. Any dissociative or associative adsorption of water on Al(2)O(3) and CeO(2) promotes a water-gas-shift reaction and produces a higher syngas ratio. H(2) and CO were mainly produced by decomposition of glycerol through dehydrogenation and decarbonylation over Ni sites. Thus, SiC promotes an intrinsic contribution of nickel (dehydrogenation, and decarbonylation) without any byproducts from the dehydration and condensation.

Hydrogen Production via Glycerol Steam Reforming over Ni/Al2O3: Influence of Nickel Precursors

“…Similar distribution of condensable products were observed for the four catalysts at the same reaction condition, and the main products were trace amounts of acetaldehyde, methanol, ethanol, propanal, acetone, allyl alcohol, 1-hydroxy-2-propanone, and 1,2-propandiol. This result suggests that the reaction pathway of GSR over nickel-based catalysts could be similar, which has also been proposed in previous work. , Therefore, only hydrogen molar yield and selectivities of C-containing gas-phase products were presented to compare the activity of difference Ni/Al 2 O 3 catalysts. ,, …”

“…Glycerol is totally converted at the chosen reaction conditions. The increase in S/ C ratio from 1 to 3 promotes H 2 yield significantly over all Ni/ Al 2 O 3 catalysts because the increase in water content in the feed promotes a forward reaction of WGSR, and more H 2 and CO 2 are produced 53. With a further increase in S/C ratio from 3 to 5, H 2 yield goes up slightly, in agreement with the thermodynamic analysis.…”

Hydrogen Production via Glycerol Steam Reforming over Ni/Al2O3: Influence of Nickel Precursors

“…Similar distribution of condensable products were observed for the four catalysts at the same reaction condition, and the main products were trace amounts of acetaldehyde, methanol, ethanol, propanal, acetone, allyl alcohol, 1-hydroxy-2-propanone, and 1,2-propandiol. This result suggests that the reaction pathway of GSR over nickel-based catalysts could be similar, which has also been proposed in previous work. , Therefore, only hydrogen molar yield and selectivities of C-containing gas-phase products were presented to compare the activity of difference Ni/Al 2 O 3 catalysts. ,, …”

“…Glycerol is totally converted at the chosen reaction conditions. The increase in S/ C ratio from 1 to 3 promotes H 2 yield significantly over all Ni/ Al 2 O 3 catalysts because the increase in water content in the feed promotes a forward reaction of WGSR, and more H 2 and CO 2 are produced 53. With a further increase in S/C ratio from 3 to 5, H 2 yield goes up slightly, in agreement with the thermodynamic analysis.…”

Efficient hydrogen production from ethanol steam reforming over La-modified ordered mesoporous Ni-based catalysts

“…It can also be found that with the higher H 2 selectivity, higher CO 2 selectivity and lower CO selectivity are also exhibited. Since the CO 2 /CO ratio has been considered as an indicator for water gas shift reaction (WGSR, CO + H 2 O → CO 2 + H 2 ) activity, the enhanced H 2 selectivity is probably related to the catalysts' capability to facilitate WGSR reaction [72,74]. Combined with the characterization results, it can be clearly observed that the trend of the catalytic performance matches well with that of the active nickel surface areas and nickel metal dispersion.…”

Enhancing the catalytic performance of Ni based catalysts in toluene reforming at low temperature by structuring on SiC extrudates

“…54 As aforementioned, the structuration leads to some changes in the phases deposited, generating individual oxides as well as cobalt and nickel silicates, which may explain the differences in catalytic performance found between (Ru)Ni/LSCF and (Ru)Ni/LSCF/SiC. Moreover, it has been reported that SiC is quite inactive in WGS when compared with other mixed oxides, 18 which can also explain the low catalytic activity in WGS of the structured catalysts.…”

Hydrogen Production via Glycerol Steam Reforming over Ni/Al2O3: Influence of Nickel Precursors

“…Similar distribution of condensable products were observed for the four catalysts at the same reaction condition, and the main products were trace amounts of acetaldehyde, methanol, ethanol, propanal, acetone, allyl alcohol, 1-hydroxy-2-propanone, and 1,2-propandiol. This result suggests that the reaction pathway of GSR over nickel-based catalysts could be similar, which has also been proposed in previous work. , Therefore, only hydrogen molar yield and selectivities of C-containing gas-phase products were presented to compare the activity of difference Ni/Al 2 O 3 catalysts. ,, …”

“…Glycerol is totally converted at the chosen reaction conditions. The increase in S/ C ratio from 1 to 3 promotes H 2 yield significantly over all Ni/ Al 2 O 3 catalysts because the increase in water content in the feed promotes a forward reaction of WGSR, and more H 2 and CO 2 are produced 53. With a further increase in S/C ratio from 3 to 5, H 2 yield goes up slightly, in agreement with the thermodynamic analysis.…”

Efficient hydrogen production from ethanol steam reforming over La-modified ordered mesoporous Ni-based catalysts

“…It can also be found that with the higher H 2 selectivity, higher CO 2 selectivity and lower CO selectivity are also exhibited. Since the CO 2 /CO ratio has been considered as an indicator for water gas shift reaction (WGSR, CO + H 2 O → CO 2 + H 2 ) activity, the enhanced H 2 selectivity is probably related to the catalysts' capability to facilitate WGSR reaction [72,74]. Combined with the characterization results, it can be clearly observed that the trend of the catalytic performance matches well with that of the active nickel surface areas and nickel metal dispersion.…”

Enhancing the catalytic performance of Ni based catalysts in toluene reforming at low temperature by structuring on SiC extrudates

“…54 As aforementioned, the structuration leads to some changes in the phases deposited, generating individual oxides as well as cobalt and nickel silicates, which may explain the differences in catalytic performance found between (Ru)Ni/LSCF and (Ru)Ni/LSCF/SiC. Moreover, it has been reported that SiC is quite inactive in WGS when compared with other mixed oxides, 18 which can also explain the low catalytic activity in WGS of the structured catalysts.…”

Hydrogen Production via Glycerol Steam Reforming over Ni/Al2O3: Influence of Nickel Precursors

“…Similar distribution of condensable products were observed for the four catalysts at the same reaction condition, and the main products were trace amounts of acetaldehyde, methanol, ethanol, propanal, acetone, allyl alcohol, 1-hydroxy-2-propanone, and 1,2-propandiol. This result suggests that the reaction pathway of GSR over nickel-based catalysts could be similar, which has also been proposed in previous work. , Therefore, only hydrogen molar yield and selectivities of C-containing gas-phase products were presented to compare the activity of difference Ni/Al 2 O 3 catalysts. ,, …”

“…Glycerol is totally converted at the chosen reaction conditions. The increase in S/ C ratio from 1 to 3 promotes H 2 yield significantly over all Ni/ Al 2 O 3 catalysts because the increase in water content in the feed promotes a forward reaction of WGSR, and more H 2 and CO 2 are produced 53. With a further increase in S/C ratio from 3 to 5, H 2 yield goes up slightly, in agreement with the thermodynamic analysis.…”

Efficient hydrogen production from ethanol steam reforming over La-modified ordered mesoporous Ni-based catalysts

“…It can also be found that with the higher H 2 selectivity, higher CO 2 selectivity and lower CO selectivity are also exhibited. Since the CO 2 /CO ratio has been considered as an indicator for water gas shift reaction (WGSR, CO + H 2 O → CO 2 + H 2 ) activity, the enhanced H 2 selectivity is probably related to the catalysts' capability to facilitate WGSR reaction [72,74]. Combined with the characterization results, it can be clearly observed that the trend of the catalytic performance matches well with that of the active nickel surface areas and nickel metal dispersion.…”

Enhancing the catalytic performance of Ni based catalysts in toluene reforming at low temperature by structuring on SiC extrudates

“…54 As aforementioned, the structuration leads to some changes in the phases deposited, generating individual oxides as well as cobalt and nickel silicates, which may explain the differences in catalytic performance found between (Ru)Ni/LSCF and (Ru)Ni/LSCF/SiC. Moreover, it has been reported that SiC is quite inactive in WGS when compared with other mixed oxides, 18 which can also explain the low catalytic activity in WGS of the structured catalysts.…”