Calcium-promoted catalytic activity of potassium carbonate for steam gasification of coal char: Influences of calcium species

Jiang, Mingquan; Zhou, Rong; Hu, Jie; Wang, Fuchen; Wang, Jie

doi:10.1016/j.fuel.2012.04.007

Cited by 97 publications

(58 citation statements)

References 40 publications

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“…Potassium, sodium, and calcium catalysts are the most common catalysts for catalytic gasification of coal because of its low price and good catalytic effect. Yeboah et al [27] and Sheth et al [28] selected Na 2 CO 3 and K 2 CO 3 to study their performance on coal catalytic gasification while calcium compounds were chosen by Jiang et al [29]. In addition to alkaline and alkaline-earth metal compounds, oxides and salts of transition metals, like Fe, also have catalytic action, which was shown in the studies of Domazetis et al [30], Popa et al [31], and Zhang et al [32].…”

Section: Comparison Between Actual and Fitted Dtg Curves For Coal-slumentioning

confidence: 99%

Sludge Acts as a Catalyst for Coal during the Co-Combustion Process Investigated by Thermogravimetric Analysis

2017

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Sewage sludge in China has the characteristics of low organic content and low heating value compared with other developed countries. Self-sustaining combustion of Chinese sludge cannot be achieved when the moisture content is high. Co-combusting a small amount of sludge in the existing coal-fired boilers is a usual sludge disposal method in China. Thermogravimetric (TG) and differential scanning calorimetry (DSC) analysis of a bituminous coal, three different sewage sludges, and their blends have been carried out. Fitted curves by linear calculation and actual curves of blends were compared to study the interaction between sludge and coal in their co-combustion process. The results indicate that the interaction between the two fuels takes place during the devolatilization and combustion period. Sludge acts as a catalyst for coal during the co-combustion process because of the large amount of inorganic salts contained in the sludge. Co-combustion of coal and sludge is more efficient than single burning of the two fuels.

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Section: Comparison Between Actual and Fitted Dtg Curves For Coal-slumentioning

confidence: 99%

Sludge Acts as a Catalyst for Coal during the Co-Combustion Process Investigated by Thermogravimetric Analysis

2017

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“…Furthermore, the interaction between K 2 CO 3 and the minerals in ash might be prevented due to the low ash content in Adaro lignite. The addition of calcium species on the coal surface was also suggested to be favorable to the formation of oxygenated groups, which leads to a higher gasification reactivity [14,23]. Calcium additives might result in a higher reactivity not only to suppress the potassium deactivation through the interaction with minerals in coal ash, but also to achieve synergistic effects.…”

Section: Catalytic Activity With K 2 Co 3 and Ca(oh) 2 Catalystmentioning

confidence: 99%

“…In previous studies, K 2 CO 3 is generally regarded as a superior catalyst in terms of carbon conversion [8][9][10][11]. However, a better reactivity was observed when two metal salts were impregnated [12][13][14]. Hu et al investigated the synergistic catalysis of calcium species and K 2 CO 3 for char steam-gasification, and they reported that the calcium species/K 2 CO 3 catalyst had a better catalytic effect [15].…”

Section: Introductionmentioning

confidence: 99%

The study on the effect of the substitution of K2CO3 with Ca(OH)2 on kinetics on CO2–lignite coal gasification

2015

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Three kinds of lignite were mixed with K 2 CO 3 and Ca(OH) 2 and were gasified with CO 2 to investigate the effect that the addition of Ca(OH) 2 had on the gasification kinetics. K 2 CO 3 and Ca(OH) 2 were impregnated and dried, their mixing ratio was varied, and the gasification experiments were conducted over a temperature range from 850 to 950°C at atmospheric pressure. The modified volumetric reaction model was applied as the gas-solid reaction model to analyze the carbon conversion results and thus obtain the kinetic parameters. The results indicate that the catalytic activity based on carbon conversion followed the order of K 2 CO 3 5 wt% ? Ca(OH) 2 3 wt% [ K 2 CO 3 8 wt% [ K 2 CO 3 3 wt% ? Ca(OH) 2 5 wt% [ K 2 CO 3 1 wt% ? Ca(OH) 2 7 wt%. The reaction rate was also influenced by the type of lignite, with a higher reactivity observed for Adaro lignite. The highest reaction rate constant was of 44.25 min -1 with Adaro lignite and K 2 CO 3 5 wt% ? Ca(OH) 2 3 wt% at 950°C. The lowest activation energy of 44.49 kJ/min was calculated for Mongolia lignite with K 2 CO 3 8 wt%. The reaction rate was enhanced by partly substituting K 2 CO 3 with Ca(OH) 2 , but further substitution resulted in a decrease in the reaction rate compared to that of K 2 CO 3 alone.

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“…It also showed that the calcium amounts in the gasification residues of SF and YCW coals were 17.14 % and 24.00 %, respectively, which was consistent with the XRD results that the crystalline phase was calcite (CaCO 3 ). Jie [14] and Jiang [15] inferred that the catalysis of potassium carbonate could be enhanced for steam gasification of coal by using calcium hydroxide during char preparation. In this way the calcium hydroxide promoted the catalytic role of potassium in the steam gasification process.…”

Section: Samples and Residues Analysismentioning

confidence: 99%

Transformation and Reactivity of a Potassium Catalyst during Coal–Steam Catalytic Pyrolysis and Gasification

et al. 2014

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The transformation of potassium catalyst during coal pyrolysis and steam gasification has been studied in a fixed‐bed reactor. The gasification residues were obtained by leaching in the water and drying in an oven. The crystallite constituents and ash constituent of the gasification residue were identified by X‐ray diffraction (XRD) and X‐ray fluorescence (XRF). The results showed that potassium aluminum silicate crystallites were derived from the interaction of potassium with mineral matter. The amount of reduced potassium in the gasification residue was measured by adding steam at low‐temperature conditions. The transformation of potassium catalyst and amount of metallic potassium intermediate were determined during pyrolysis and gasification. The amount of K2CO3 pyrolysis residue decreased as the pyrolysis temperature increased, and the reaction activity increased as the amount of reduced‐state potassium increased.

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Calcium-promoted catalytic activity of potassium carbonate for steam gasification of coal char: Influences of calcium species

Cited by 97 publications

References 40 publications

Sludge Acts as a Catalyst for Coal during the Co-Combustion Process Investigated by Thermogravimetric Analysis

Sludge Acts as a Catalyst for Coal during the Co-Combustion Process Investigated by Thermogravimetric Analysis

The study on the effect of the substitution of K2CO3 with Ca(OH)2 on kinetics on CO2–lignite coal gasification

Transformation and Reactivity of a Potassium Catalyst during Coal–Steam Catalytic Pyrolysis and Gasification

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