Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species

Feng, Dongdong; Zhao, Yibo; Zhang, Yu; Sun, Shaozeng; Gao, Jianmin

doi:10.3390/en11010205

Cited by 16 publications

(13 citation statements)

References 64 publications

(91 reference statements)

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“…Table 4 lists the contents of the major inorganic elements of the char samples. Compared with some works in the literature [14,19], CSC has a high content of K. After water-leaching treatment, the contents of the inorganic elements all decreased, and the mass fraction of K and Na dropped dramatically. The primary chemical form of K and Na in biomass char is water-soluble [14,34], so the water-leaching treatment caused a massive loss of K and Na.…”

Section: Preparation Of Char Samplesmentioning

confidence: 56%

“…Usually when the system has excess gasifying agent (steam), the partial pressure of H 2 (P H 2 ) can be neglected (K 3 P H 2 << K 2 P H 2 O ); thus, Equation ( 12) can be simplified to Equation (13) and further transformed to Equation (14), where k 1 and k 2 can be calculated by linearizing Equation (8). Then the value of A and Ea of the two main steps can be obtained.…”

Section: Kinetic Modelsmentioning

confidence: 99%

“…Results concerning the effects of the biomass char prepared conditions such as pyrolysis temperature [5][6][7][8], pressure [9,10], heating rate [11,12], atmosphere [13] and sample size [8] on biomass char gasification reactivity, which are summarized in Table 1. In addition, further research focused on the effects of alkali and alkali earth metals (AAEMs) on biomass char gasification behaviors [14][15][16][17][18][19][20][21] are shown in Table 2. Generally, K, Na and Ca have been found to remarkably increase the gasification rate of biomass char, of which the catalytic effect of K is the most prominent one.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Kinetic Studies on Steam Gasification of a Biomass Char

et al. 2021

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The maximum gasification rate of corn stalk char (CSC) appeared at high conversion range, and its quite different gasification behaviors from other carbonaceous materials are all derived from the catalytic effect of alkali and alkali earth metals (AAEMs), so it is necessary to study the effect of AAEMs and gasification kinetics of such biomass char. However, there are few systematic discussions about this effect and kinetic modeling. Thus, in this study, CSC samples were prepared in a fast pyrolysis fixed-bed reactor, and its gasification experiments were conducted on a pressurized magnetic suspension balance at various total pressures (0.1–0.7 MPa), steam concentrations (10–70 vol.%) and temperatures (725–900 °C). Moreover, a water-leached CSC (H2O-CSC) was also prepared to evaluate the impact of AAEMs on the gasification performance of CSC, and some well-known models were adopted to describe the gasification behaviors. On the basis of these results, the effect of primary AAEMs on the gasification behaviors of CSC and gasification kinetic modeling were obtained. Results showed total pressure had no obvious influence on the gasification rate of CSC, and the reaction order varied at 0.43–0.55 with respect to steam partial pressures. In addition, the modified random pore model (MRPM) and Langmuir–Hinshelwood (L-H) model were satisfactorily applied to predict the gasification behaviors of CSC. The catalytic effect of AAEMs on CSC gasification was weakened due to water-leaching treatment. A random pore model (RPM) could describe the gasification behavior of H2O-CSC well, followed by grain model (GM) and volumetric model (VM).

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Section: Preparation Of Char Samplesmentioning

confidence: 56%

Section: Kinetic Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental and Kinetic Studies on Steam Gasification of a Biomass Char

et al. 2021

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“…The reference reactions that are currently used to describe the process are shown in Table 2. The list is based mostly on the carbon chemistry and does not include the fate of heteroatoms and minerals contained in the feedstock which can largely affect conversion rates and gas quality [26,27]. At the typical process conditions, i.e., without catalyst and with a gas residence time of few seconds, the system does not reach the thermodynamic equilibrium.…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

Gasification of Agroresidues for Syngas Production

Cerone

Zimbardi

2018

Energies

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Biomass residues from agriculture and agroindustry are suitable sources for the production of energy because they don't compete with the food chain and they are produced cheaply. Their transformation into heat and power or energy vectors depends on morphology and composition. Shells of almonds and hazelnuts can be easily gasified in fixed beds because of their low fines content and high gas permeation. In this work we investigated the overall process performances and syngas composition, especially the H 2 /CO ratio, by changing the air and steam supply. The tests were carried out in a pilot updraft gasifier having a capacity of treating up to 20-30 kg/h of biomass. Experimental data were worked out by surface response analysis as function of the equivalence ratios (ER) in relation to the complete combustion and water reaction. By using only air at ER(O 2) 0.24 the ratio H 2 /CO in the syngas was 0.33 while adding steam at ER(H 2 O) 0.28 the ratio reached a value of 1.0. The energy conversion efficiency from solid to gas and oils reached maximum values of 76% and 28%, respectively. As anticipated by TGA, hazelnut shells produced less organic volatiles and gas efficiency was generally higher than for almond shells.

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“…The char gasification reactivity is strongly affected by the presence of inorganic elements in the raw biomass. Feng et al have examined the effect of chemical speciation (H 2 O/NH 4 Ac/HCl-soluble and insoluble) of alkali and alkaline earth metallic species on the steam gasification of sawdust biochar in a lab-scale, fixed-bed reactor, with the method of chemical fractionation analysis [14]. The results indicated that H 2 O/NH 4 Ac/HCl-soluble AAEMs have a significant effect on biochar gasification rates.…”

mentioning

confidence: 99%