Adsorption of ethanol onto parent and surface treated activated carbon powders

El-Sharkawy, Ibrahim I.; Uddin, Kutub; Miyazaki, Takahiko; Saha, Bidyut Baran; Koyama, Shigeru; Miyawaki, Jin; Yoon, Seong Ho

doi:10.1016/j.ijheatmasstransfer.2014.02.046

Cited by 101 publications

(35 citation statements)

References 24 publications

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“…This indicates exceptional ethanol tolerance of investigated B-OMC-1 catalyst. Small reduction of ORR current (around 2 %) might be ascribed to ethanol adsorption on carbon surface [72,73]. As suggested previously [35,36], the presence of a large number of defects could enhance EtOH adsorption on the surface of the catalyst, but this effect is rather small.…”

Section: Orr At Doped Omcs In Alkaline Solutionmentioning

confidence: 63%

The Effects of a Low-Level Boron, Phosphorus, and Nitrogen Doping on the Oxygen Reduction Activity of Ordered Mesoporous Carbons

et al. 2015

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In order to elucidate the role of B, N, and P dopants in carbon materials on the kinetics of oxygen reduction reaction (ORR) and to provide a fair comparison of the effects of each dopant, a series of ordered mesoporous carbons (OMCs) with low concentration of heteroatoms (< 1 at%) has been prepared. Doped OMCs were characterized using X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), Raman spectroscopy, X-ray powder diffraction (XRD), and N-2 physisorption measurements. Comparative study of the ORR activity of these materials in alkaline solution was performed using rotating disk electrode voltammetry. The experiments evidenced that, compared to non-doped OMC, charge transfer kinetics was improved independently on the nature of the heteroatom. The decrease of the ORR overvoltage and the increase of the mass activity upon doping are similar for B and P and less prominent for N. On the other hand, OMCs doped with low levels of B and N were found to be selective for O-2 reduction to peroxide, while for P-doped OMCs, the apparent number of electrons consumed per O-2 molecule was up to 3.1. Experimental measurements were complemented by density functional theory (DFT) calculations

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Section: Orr At Doped Omcs In Alkaline Solutionmentioning

confidence: 63%

The Effects of a Low-Level Boron, Phosphorus, and Nitrogen Doping on the Oxygen Reduction Activity of Ordered Mesoporous Carbons

et al. 2015

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“…The adsorbent for water is silica gel (type A), while adsorbents for other refrigerants are activated carbons. The isotherm equations of these refrigerantadsorbent pairs were taken from literatures [6,2,3,1,5]. The calculation of the COP and SCE was based on an adsorption cooling cycle with refrigerant evaporation temperature of 10 • C, adsorption temperature of 30 C, condensation temperature of 30 • C and desorption temperature of 50 C to 100 C. It was assumed that the heat capacity ratio, M hex c hex /(M ac c ac ) equaled to 2, which is a reasonable value for a fin and tube type adsorption heat exchanger.…”

Section: Comparison Of the Theoretical Copmentioning

confidence: 99%

“…Ammonia and alcohols are major refrigerants studied in adsorption heat pump applications with activated carbons as the adsorbent [1,2,3]. The application of adsorption heat pump can be expanded to refrigeration with these refrigerants whereas water refrigerant cannot be used for cooling under freezing temperature.…”

Section: Introductionmentioning

confidence: 99%

Study toward high-performance thermally driven air-conditioning systems

Miyazaki¹,

Miyawaki²,

Ohba³

et al. 2017

AIP Conference Proceedings

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Abstract. The Adsorption heat pump is a technology for cooling and heating by using hot water as a driving heat source. It will largely contribute to energy savings when it is driven by solar thermal energy or waste heat. The system is available in the market worldwide, and there are many examples of application to heat recovery in factories and to solar cooling systems. In the present system, silica gel and zeolite are popular adsorbents in combination with water refrigerant. Our study focused on activated carbon-ethanol pair for adsorption cooling system because of the potential to compete with conventional systems in terms of coefficient of performance. In addition, activated-ethanol pair can generally produce larger cooling effect by an adsorption-desorption cycle compared with that of the conventional pairs in terms of cooling effect per unit adsorbent mass. After the potential of a commercially available activated carbon with highest level specific surface area was evaluated, we developed a new activated carbon that has the optimum pore characteristics for the purpose of solar or waste heat driven cooling systems. In this paper, comparison of refrigerants for adsorption heat pump application is presented, and a newly developed activated carbon for ethanol adsorption heat pump is introduced.

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“…The basket is inside an isothermal chamber and hanged up to a magnetic balance measuring the mass adsorbed with 1 µg accuracy not presented herein [12]. Dimensions of basket and adsorbent are provided in Table 1.…”

Section: A Geometrymentioning

confidence: 99%

“…The change of adsorption uptake with time were measured experimentally by gravimetric method and data were correlated with Fickian diffusion (FD) model given by (10) [12].…”

Section: Mathematical Modelmentioning

confidence: 99%

Non-isothermal adsorption rate model of activated carbon-ethanol pair for solar cooling applications estimated through CFD simulation

Jribi

Miyazaki

Koyama

et al. 2016

2016 7th International Renewable Energy Congress (IREC)

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Adsorption cooling systems (ACS) are feasible alternative to vapor compression cooling system as they employ natural and benign refrigerants and could be driven by solar energy or waste heat. Performance optimization of ACS could be carried out using CFD simulations with lower cost and faster time comparing to experimental testing. One of the crucial parameters to obtain reliable CFD simulation results is the diffusion time constant of adsorption rate equation estimated from experimental data. This study presents transient CFD simulations of ethanol adsorption onto activated carbon powder of type Maxsorb III carried out by Ansys-Fluent v14.5 software using 2D-axisymmetric geometry. The mathematical model consists of mass, momentum and energy conservation equations as well as adsorption isotherm and adsorption kinetic equations implemented via user defined functions (UDFs). The conditions used were same as those employed in gravimetric adsorption analyzer that is 30˚C, 2.25 kPa and 3.32 kPa for temperature, initial and inlet pressures, respectively. Through multiple CFD simulations, we estimated the appropriate diffusion time constant of non-isothermal linear driving force (LDF) equation which led to simulated adsorption uptakes agreeing fairly with those measured experimentally. The mathematical model employing non-isothermal LDF equation could be implemented to simulate the heat and mass transfer in large scale adsorption/desorption bed and to optimize the performance of activated carbon-ethanol based adsorption cooling system.

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Adsorption of ethanol onto parent and surface treated activated carbon powders

Cited by 101 publications

References 24 publications

The Effects of a Low-Level Boron, Phosphorus, and Nitrogen Doping on the Oxygen Reduction Activity of Ordered Mesoporous Carbons

The Effects of a Low-Level Boron, Phosphorus, and Nitrogen Doping on the Oxygen Reduction Activity of Ordered Mesoporous Carbons

Study toward high-performance thermally driven air-conditioning systems

Non-isothermal adsorption rate model of activated carbon-ethanol pair for solar cooling applications estimated through CFD simulation

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