Numerical simulation of reactive transfers in spouted beds at high temperature: Application to coal gasification

Mendes, A.; Dollet, Alain; Ablitzer, Carine; Perrais, Christophe; Flamant, Gilles

doi:10.1016/j.jaap.2008.02.001

Cited by 21 publications

(7 citation statements)

References 40 publications

(50 reference statements)

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“…Spouted beds have been used in drying suspensions, solutions, and pasty materials [2][3][4][5][6][7]. Chemical reaction applications, such as catalytic polymerization [8], coal gasification [9,10], and waste pyrolysis [11][12][13], have also been under development. Since the 1990s, there has been considerable interest in the hydrodynamic regimes of conical spouted beds [14].…”

Section: Introductionmentioning

confidence: 99%

Bed-to-surface heat transfer in conical spouted beds of biomass–sand mixtures

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Bed-to-surface heat transfer in conical spouted beds of biomass–sand mixtures

et al. 2015

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“…It should be noted that high gasification selectivity toward CO2 fosters a high H2 production The kinetics of the Boudouard reaction may be improved in steam gasification of coal if its ash composition is high (Villacampa et al, 2011) or when gasification is performed at a temperature greater than 700 o C (Matsumoto et al, 2009). Mendes et al (2008) found that if char particles are used instead of coal particles, the minimum temperature needed to obtain the high kinetics characteristic of the Boudouard reaction decreases to 600 o C. Table 2 shows that the addition of the K2CO3 catalyst had an adverse effect on the H2/CO mole ratio in syngas, and syngas from catalytic gasification exhibited a lower H2/CO ratio than that from non-catalytic gasification. This finding is the same as that for lignite steam gasification conducted by Handayani et al (2013).…”

Section: Resultsmentioning

confidence: 99%

Catalytic Effect of K2CO3 in Steam Gasification of Lignite Char on Mole Ratio of H2/CO in Syngas

Tristantini¹,

Supramono²,

Suwignjo³

2015

IJTech

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To fulfill the requirement for synthetic fuel (synfuel) production in theFischer-Tropsch process, in which syngas fed to the process has a H2/CO mole ratio approaching 2, gasification of lignite coal is needed. In this research, char particles were prepared by pyrolysis of lignite coal at controlled heating rates to obtain the highest possible surface area for gasification. In the gasification process, char with a surface area of 172.5 m 2 /g was used, along with the catalyst K2CO3 in a fixed bed reactor. In this research, there were variations in the steam/char mass ratio Results of this research showed that the highest H2/CO mole ratio of 2.07 corresponding to the mole ratio of gas yield/carbon of 1.13 was achieved at the gasification temperature of 675 o C using the catalyst K2CO3; the steam/char mass ratio was 2.0. However, at the same gasification conditions-but without a catalyst-the H2/CO mole ratio and corresponding mole ratio of gas yield/carbon were 3.02 and 0.42, respectively. A finding of this research was that the addition of the catalyst K2CO3 to gasification of lignite char adversely reduced the mole ratio of H2/CO compared to gasification without catalysis. It is suspected that the high composition of mineral ash in coal ash reacted with the K2CO3 catalyst, thus causing the Boudouard reaction to compete considerably with the water-gas reaction. The increases in gasification temperature and the steam/carbon ratio lowered the mole ratio of H2/CO in syngas.

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“…The backflow rate of gas from the annulus dense‐phase zone to the jet zone depends on the radial gas velocity and the superficial area of the jet zone . The gas exchange rate ( U ex ) between the jet zone and the annulus dense‐phase zone is used as an index to evaluate the amount of the backflow of gas from the annulus dense‐phase zone to the jet zone.…”

Section: Equivalent Reactor Model Setupmentioning

confidence: 99%

“…Before gasification, the coal is pyrolyzed to coal char, ash, and volatiles including H 2 O, CO, CH 4 , and H 2 . Therefore, based on the elements and energy balance through these processes, with the addition of energy, the coal sample can be substituted by C(s), ash, H 2 O, CO, CH 4 , and H 2 . The total substitution of coal should satisfy the elements and energy balance in the process of the coal pyrolysis unit.…”

Section: Equivalent Reactor Model Setupmentioning

confidence: 99%

Influence of ash agglomerating fluidized bed reactor scale‐up on coal gasification characteristics

et al. 2014

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To study the influence of fluidized-bed reactor scale-up on coal gasification characteristics, a model of the ash agglomerating fluidized-bed reactor has been developed using an equivalent reactor network method. With the reactor network model, the scale-up effects of a gasifier were studied in terms of the characteristics of the chemical reactions in the jet zone, the annulus dense-phase zone and the freeboard zone. Results showed that the changes occurred in the inequality proportion of the volume of the jet zone during the reactor scale-up. Taking into consideration the utilization of a portion of the backflow gas, the expansion of the jet zone volume and the coal particle residence time, the temperature of the jet zone was increased from 1592 to 1662 K. Also, both the annulus dense-phase zone temperature and the freeboard zone temperature decreased, causing subsequent decrease in the carbon conversion efficiency.

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Numerical simulation of reactive transfers in spouted beds at high temperature: Application to coal gasification

Cited by 21 publications

References 40 publications

Bed-to-surface heat transfer in conical spouted beds of biomass–sand mixtures

Bed-to-surface heat transfer in conical spouted beds of biomass–sand mixtures

Catalytic Effect of K2CO3 in Steam Gasification of Lignite Char on Mole Ratio of H2/CO in Syngas

Influence of ash agglomerating fluidized bed reactor scale‐up on coal gasification characteristics

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