Low Temperature Gasification of Coconut Shell with CO<sub>2</sub>and KOH: Effects of Temperature, Chemical Loading, and Introduced Carbonization Step on the Properties of Syngas and Porous Carbon Product

Punsuwan, Natthaya; Tangsathitkulchai, Chaiyot; Takarada, Takayuki

doi:10.1155/2015/481615

Cited by 16 publications

(10 citation statements)

References 32 publications

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“…Because the surface properties of the carbon precursors are associated with an oxidation-reduction reaction during the activation process [17,18], an increase in O, which is an electron donor, on the carbon surface will strongly affect the pore development of the carbon matrix. Kopyscinski et al [19] and Quyn et al [20] have both proposed that C-O-K bound during the alkali-metal (i.e., K 2 CO 3 ) impregnation is reduced to C-K at the surface of the carbon body, accompanied by the generation of CO. Lee et al [21] and Punsuwan et al [22], who qualitatively and quantitatively measured the gases emitted during the KOH activation of AC, also confirmed that CO is the main syngas (K 2 O + C → 2K + CO at 800-850 • C [17,18]). To more closely investigate these binding properties of the carbon precursors, we deconvoluted the K and O peaks in the XPS spectra (Table 2).…”

Section: Changes In Thermal Stability Of Chemical Agentsmentioning

confidence: 93%

Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

et al. 2021

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The chemical activation of a carbon precursor with KOH generally results in an activated carbon (AC) with a high specific surface area. However, this process generates a large volume of wastewater that includes dissolved alkali metals, existing mainly as K2CO3. Thus, wastewaters with a high concentration of dissolved K2CO3 can potentially be used in place of KOH as a chemical agent. In the present study, to reduce the thermal stability of K2CO3, which decomposes at temperatures greater than 891 °C, K2CO3 was chemically impregnated into carbon precursors prior to activation of the precursors. The thermochemical properties and activation efficiency of the carbon precursors treated with K2CO3 were compared with those of carbon precursors treated with KOH. Analysis by XPS indicated that C–O–K complexes formed on the surface of the carbon precursors; in addition, their peak intensities were approximately the same irrespective of the chemical agent used. However, the specific surface area of the K2CO3-impregnated AC was 2162 m2/g, which was ~70% of that of the KOH-impregnated AC (3047 m2/g) prepared using the same K/C molar ratio of 0.5. XRD results confirmed that both K2CO3 and KOH transformed into KHCO3 and K4H2(CO3)3·1.5H2O during the impregnation. The peak intensities of these compounds in the XRD pattern of the K2CO3-impregnated carbon precursors were two times greater than those in the pattern of the KOH-impregnated carbon precursors. These compounds eventually transformed into K2CO3, which hardly participated as a chemical agent at the temperature used in the present study (850 °C). Therefore, recrystallisation of K2CO3, even during the impregnation, appeared to adversely affect the degree of activation. Nevertheless, the specific surface area of the K2CO3-activated AC was still ~1.6 times greater than that of the untreated carbon precursor (1378 m2/g), suggesting that the use of wastewater as a chemical agent is feasible for resource recycling.

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Section: Changes In Thermal Stability Of Chemical Agentsmentioning

confidence: 93%

Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

et al. 2021

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“…It also helps in the determination of interrelationships among response variables, representing their combined effect in any response. This method enables a researcher to conduct an effective study of an experimental process [14][15][16]. The optimization of industrial processes requires some response parameters that indicate the performance of systems to be optimized.…”

Section: Introductionmentioning

confidence: 99%

Adsorptive Capacity of Coconut Fibre Carbon Activated by Potassium Hydroxide for Wastewater Treatment

Chukwu¹,

Ononogbo²,

Nwakuba³

et al. 2022

IJASE

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Optimization of the yield and adsorptive effectiveness of activated carbon prepared with coconut fibre and potassium hydroxide (KOH) for the treatment of wastewater is presented. Different values of the operating parameters (activation temperature, X1 and impregnation ratio, X2) in the range of 350 to 550 o C and 1 to 3g/g for an activation time of 5 min were used to investigate the activated carbon yield. The study used wastewater laden with iodine to ascertain the prepared activated carbon's capacity to absorb its iodine content. The experimental results obtained showed the values of activated carbon yield (Y1) to be in the range of 3.99 to 17.45%; whereas the iodine adsorption capacity (Y2) ranged between 44.140 and 192.070 mg/g, respectively. It was observed that when the activation temperature was kept constant and the impregnation ratio was increased, the activated carbon yield increased gradually and then dropped. The same trend was observed when the impregnation ratio was kept constant, while the activation temperature was varied. An optimization study was carried out to determine the combined effect of X1 and X2 on the values of Y1 and Y2 which were to be maximized to determine the optimum conditions for activated carbon yield and its adsorptive capacity for wastewater treatment. The results of the best fit achieved for all 10 possible runs showed optimum values of activation temperature, impregnation ratio and adsorption capacity as 354.592 o C, 1.420g/g, and 4.830 mg/g, respectively. A suggestion for further studies is given.

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“…World Energy Agency (International Energy Agency-IEA) showed that at 2030 world energy demand increased by 45%, or an average increases of 1.6% per year and about 80% of the world's energy requirements are provided from fossil fuels that cause instability the price and supply of fossil fuels [1]. In addition, the burning of fossil fuels would produce CO2, SOx, NOx and other pollutants that are the main cause of acid rain and greenhouse gases that poses a threat to the global climate [2].…”

Section: Introductionmentioning

confidence: 99%

“…Biomass is a raw material generated from forests, agriculture and livestock industry that has the potential to reduce emissions on the environment and stabilize energy needs [3]. Biomass is an environmental friendly alternative energy because it contains no sulfur, carbonneutral, and a plentiful material [1]. These alternative fuels are obtained from resources other than petroleum.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Air Fuel Ratio and Temperature on Syngas Composition and Calorific Value Produced from Downdraft Gasifier of Rubber Wood-Coal Mixture

Tiara

Agustina

Faizal

2018

IJE

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Rubber wood (Ficus elastica) is one of the biomass waste that can be used as raw material for gasification process, and has a calorific value of 4069 cal/g. Gasification is a process to convert a solid fuels to syngas (CO, CH4, and H2) through a partially combustion process using limited air between 20% to 40% of air stoichiometry. Depending on the direction of airflow, the gasifier are classified as updraft, downdraft, and cross-flow. The downdraft type of gasifier produces a lower tar content than updraft type.The gasification of rubber wood and rubber wood-coal mixture were carried out in this research. The purpose of the research is to determine the effect of Air Fuel Ratio (AFR) and temperature on calorific value and composition of syngas using a downdraft gasifier.The variations of AFR were 0.64, 0.95, and 1.26. The temperature of gasification was varied between 600-1000ºC. The result showed that the percentage of CO, H2, and CH4 decreased with increasing of AFR and decrease in calorific value. The calorific value of syngas increased along with the temperature.The use of coal in the gasification process can maintain the stable combustion temperatures and increase the syngas produced. The best-operating conditions in this research occurred at AFR of 0.64, temperature of 800ºC and use of coal as a stabilizer.At this condition, the percentage of syngas of 35.95% of CO, 15.95% of H2, 9.38% of CH4, and caloric value of 9.42 MJ/m 3 was obtained. The highest gasification yield of 35.75% was also reached.

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Low Temperature Gasification of Coconut Shell with CO₂and KOH: Effects of Temperature, Chemical Loading, and Introduced Carbonization Step on the Properties of Syngas and Porous Carbon Product

Cited by 16 publications

References 32 publications

Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

Adsorptive Capacity of Coconut Fibre Carbon Activated by Potassium Hydroxide for Wastewater Treatment

The Effect of Air Fuel Ratio and Temperature on Syngas Composition and Calorific Value Produced from Downdraft Gasifier of Rubber Wood-Coal Mixture

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Low Temperature Gasification of Coconut Shell with CO2and KOH: Effects of Temperature, Chemical Loading, and Introduced Carbonization Step on the Properties of Syngas and Porous Carbon Product

Cited by 16 publications

References 32 publications

Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

Limitation of K2CO3 as a Chemical Agent for Upgrading Activated Carbon

Adsorptive Capacity of Coconut Fibre Carbon Activated by Potassium Hydroxide for Wastewater Treatment

The Effect of Air Fuel Ratio and Temperature on Syngas Composition and Calorific Value Produced from Downdraft Gasifier of Rubber Wood-Coal Mixture

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Low Temperature Gasification of Coconut Shell with CO₂and KOH: Effects of Temperature, Chemical Loading, and Introduced Carbonization Step on the Properties of Syngas and Porous Carbon Product