Sorbent enhanced hydrogen production from steam gasification of coal integrated with CO2 capture

Sedghkerdar, Mohammad Hashem; Mostafavi, Ehsan; Mahinpey, Nader

doi:10.1016/j.ijhydene.2014.08.062

Cited by 31 publications

(19 citation statements)

References 14 publications

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“…In previous studies, the optimal carbonation temperature of Cadomin limestone over the temperature range of 600–750 °C and atmospheric pressure was found to be nearly 675 °C through thermogravimetric analysis. Optimal carbonation temperature was defined as the temperature at which the highest conversion of CaO occurs for the carbonation reaction.…”

Section: Resultsmentioning

confidence: 98%

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

et al. 2016

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Over the last few decades, research on the abatement of carbon dioxide (CO2) gas has gained momentum, due to its increasing atmospheric levels. This study investigated high‐temperature steam‐only gasification of woody biomass for the production of high‐purity hydrogen integrated with CO2 capture in a moving‐bed gasifier. Extensive process modelling and simulation were performed using the superior solid handling features of the Aspen Plus process simulator software. After validating the model with experimental data from a demonstration plant available in the open literature, a reversible carbonation‐calcination reaction of calcium oxide (CaO) with CO2 was added to the system. Sensitivity analyses were conducted to verify the predictive accuracy of the model. The effects of steam‐to‐carbon (S/C) ratio on the resulting gas composition were thoroughly studied to delineate the complex process of gasification. Beyond the mitigation of CO2 emissions, the introduction of a CaO‐based sorbent in the process simulation significantly enhanced hydrogen production by simultaneously promoting the forward water‐gas shift reaction and reducing tars through increased tar‐cracking reactions. The results show that hydrogen of a higher purity was produced with the inclusion of dry‐sorption CO2 capture in the gasification process. Moreover, the addition of the sorbent increased the higher heating values (HHV) by 3 times and improved the cold gas efficiency by 34 %.

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Section: Resultsmentioning

confidence: 98%

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

et al. 2016

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“…In another study on the steam gasification of coal, it was observed that, in the absence of a CaO sorbent, an increase in temperature caused an increase in the H 2 molar fraction. It can be concluded that an increase in temperature favoured the exothermic WGS reaction kinetically and the endothermic steam char gasification reaction both kinetically and thermodynamically …”

Section: Resultsmentioning

confidence: 99%

“…The calculation of the amount of catalyst based on the K + ions to the fixed carbon can be found elsewhere . The CaO/C ratio of 2 was selected based on the results of our previous study …”

Section: Methodsmentioning

confidence: 99%

“…[26] The CaO/C ratio of 2 was selected based on the results of our previous study. [21] The electric furnace increased the temperature of the reactor at a heating rate of 30 8C/min. Pure N 2 was fed into the reactor during the heating stage and used as an inert atmosphere for pyrolysis of the sample.…”

Section: Methodsmentioning

confidence: 99%

“…[4] The effects of temperature and the sorbent-to-carbon (CaO/C) ratio on the molar fraction of H 2 and coal conversion in the steam gasification of boundary dam (BD) coal at nearly atmospheric pressures was studied by our group. [21] It was asserted that the H 2 molar fractions and coal conversion increased with increased temperatures without a CaO sorbent. With the addition of a sorbent, the steam gasification showed an optimal gasification temperature of 675 8C.…”

Section: Introductionmentioning

confidence: 99%

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Potassium‐catalyzed steam gasification of ash‐free lignite coal with CO₂ capture

et al. 2017

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The purpose of this research was to study steam gasification of ash-free coal integrated with CO 2 capture in the presence of a K 2 O catalyst for enhancement of the key water-gas shift reaction and promotion of hydrogen production. To achieve this goal, gasification experiments on ash-free coal (AFC) were carried out at varying temperatures (600, 650, 675, 700, and 750 8C) with a sorbent-to-carbon (CaO/C) ratio of 2 and a catalyst (K 2 O) loading of 0.2 g/g (20 weight percent (wt%)) in a fixed-bed reactor equipped with a gas chromatography analyzer. The sorbent-to-carbon (CaO/C) ratio of 2 is based on dry and ash-free basis. The CaO/C ratio and K 2 O wt% were chosen to maximize hydrogen production based on our previously determined optimal values. The AFC was originally extracted from raw lignite coal using organic solvents, which allowed the sorptionenhanced gasification to be conducted with minimal ash-catalyst interactions. The effect of temperature on the yield and the initial reaction rate were investigated. The optimal reaction temperature of 675 8C was determined. Carbon balance and final carbon conversions were calculated based on the residue analysis. Activation energy was also calculated using intrinsic kinetics of the reaction. In this study, using AFC offered the potential advantage of operating the gasification process with catalyst recycle.

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Core‐shell structured CaO‐based pellets protected by mesoporous ceramics shells for high‐temperature CO₂ capture

et al. 2016

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In this study, a series of core-shell structured spheriform CO 2 sorbents were synthesized by using CaO-based pellets as cores and different mesoporous metal oxides (e.g. alumina, ceria, and yttrium-stabilized zirconia) as shells through a repeated wet impregnation coating process. Cyclic CO 2 capture performance of the obtained sorbents was investigated using a thermogravimetric analyzer. Among all the core/shell sorbents under study, the pellets coated with a layer of alumina exhibit the best performance in the retention of CO 2 uptake over 20 cycles with the lowest activity loss of only 30.4 %, attributed to the existence of the thermal stable porous alumina shell which prevents the sintering and the aggregation of the CaO grains. Moreover, the attrition study using an air-jet apparatus and a standard test method reveals that such sorbents exhibit enhanced attrition resistance due to the protection of the porous shell providing them with a great potential for application in fluidized bed conditions.

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Sorbent enhanced hydrogen production from steam gasification of coal integrated with CO2 capture

Cited by 31 publications

References 14 publications

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

Potassium‐catalyzed steam gasification of ash‐free lignite coal with CO₂ capture

Core‐shell structured CaO‐based pellets protected by mesoporous ceramics shells for high‐temperature CO₂ capture

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Sorbent enhanced hydrogen production from steam gasification of coal integrated with CO2 capture

Cited by 31 publications

References 14 publications

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO2 capture

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO2 capture

Potassium‐catalyzed steam gasification of ash‐free lignite coal with CO2 capture

Core‐shell structured CaO‐based pellets protected by mesoporous ceramics shells for high‐temperature CO2 capture

Contact Info

Product

Resources

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Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

Simulation of high‐temperature steam‐only gasification of woody biomass with dry‐sorption CO₂ capture

Potassium‐catalyzed steam gasification of ash‐free lignite coal with CO₂ capture

Core‐shell structured CaO‐based pellets protected by mesoporous ceramics shells for high‐temperature CO₂ capture