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CO hydrogenation combined with water-gas-shift reaction for synthetic natural gas production: a thermodynamic and experimental study.
- Source :
- International Journal of Coal Science & Technology; Dec2018, Vol. 5 Issue 4, p439-451, 13p
- Publication Year :
- 2018
-
Abstract
- The hydrogenation of CO to synthetic natural gas (SNG) needs a high molar ratio of H<subscript>2</subscript>/CO (usually large than 3.0 in industry), which consumes a large abundant of hydrogen. The reverse dry reforming reaction (RDR, 2H<subscript>2</subscript> + 2CO ↔ CH<subscript>4</subscript> + CO<subscript>2</subscript>), combining CO methanation with water-gas-shift reaction, can significantly decrease the H<subscript>2</subscript>/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<subscript>2</subscript>/CO ratio and the addition of H<subscript>2</subscript>O, CH<subscript>4</subscript>, CO<subscript>2</subscript>, O<subscript>2</subscript> and C<subscript>2</subscript>H<subscript>4</subscript> into the feed gas on CO conversion, CH<subscript>4</subscript> and CO<subscript>2</subscript> selectivity, as well as CH<subscript>4</subscript> and carbon yield, are discussed. Experimental results obtained on homemade impregnated Ni/Al<subscript>2</subscript>O<subscript>3</subscript> catalyst are compared with the calculations. The results demonstrate that low temperature (200-500 °C), high pressure (1-5 MPa) and high H<subscript>2</subscript>/CO ratio (at least 1) promote CO conversion and CH<subscript>4</subscript> selectivity and decrease carbon yield. Steam and CO<subscript>2</subscript> in the feed gas decrease the CH<subscript>4</subscript> selectivity and carbon yield, and enhance the CO<subscript>2</subscript> content. Extra CH<subscript>4</subscript> elevates the CH<subscript>4</subscript> content in the products, but leads to more carbon formation at high temperatures. O<subscript>2</subscript> significantly decreases the CH<subscript>4</subscript> selectivity and C<subscript>2</subscript>H<subscript>4</subscript> results in the generation of carbon. [ABSTRACT FROM AUTHOR]
- Subjects :
- CARBON monoxide
HYDROGENATION
WATER-gas
SYNTHETIC natural gas
THERMODYNAMICS
Subjects
Details
- Language :
- English
- ISSN :
- 20958293
- Volume :
- 5
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- International Journal of Coal Science & Technology
- Publication Type :
- Academic Journal
- Accession number :
- 133306141
- Full Text :
- https://doi.org/10.1007/s40789-017-0177-y