A model for the thermodynamic analysis in a batch type fluidized bed dryer

Özahi, Emrah; Demir, Hacımurat

doi:10.1016/j.energy.2013.07.001

Cited by 26 publications

(12 citation statements)

References 10 publications

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“…These unique advantages endow the exergy analysis with great potential application to analyze the energyintensive thermal operations, which are expected to lead to the misleading conclusions by using the conventional energy analysis. Literature survey showed that a remarkable amount of research works have been published regarding the exergy analysis as well as exergoeconomic analysis of drying processes and systems through the experimental and theoretical studies such as hot air drying [5][6][7][8][9][10], fluidised bed drying [11][12][13][14][15][16][17], spray drying [18][19][20][21][22][23][24], heat pump drying with various heating sources [25][26][27], solar drying and greenhouse drying [28][29][30][31][32], freeze drying [33,34], and vacuum drying [35]. The readers are referred to the review paper compiled by Aghbahslo et al [3] in which the application of exergy analysis for drying systems and processes was comprehensively discussed.…”

Section: Introductionmentioning

confidence: 99%

Exergetic simulation of a combined infrared-convective drying process

Aghbashlo

2015

Heat Mass Transfer

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Mass flow rate (kg/s) P Air pressure (kPa) Q Heat transfer rate (kJ/s) R Constant (kJ/kg K) t Drying time (s) T Temperature (K or °C) U Overall heat transfer coefficient (kW/m 2 K) v Air velocity (m/s) V Volume (m 3 ) X Mass fraction (-) Dimensionless numbers Le Lewis number Nu Nusselt number Pr Prandtl number Re Reynolds number Greeks ∆t Simulation time step (s) α Thermal diffusivity (m 2 /s) β Energy quality factor (-) ε Emissivity factor (-) λ Latent heat of water vaporization (kJ/kg) μ Dynamic viscosity of air (Pa s) ρ Density (kg/m 3 ) σ Stephan-Boltzman constant (W/m 2 K 4 ) υ Kinematic viscosity (m 2 /s) φ Hydraulic diameter (m) ψ Exergy efficiency (-) ω Humidity ratio of air (kg water/kg dry air) Subscripts 0 Dead state 1 Wet product 2 Inlet airAbstract Optimal design and performance of a combined infrared-convective drying system with respect to the energy issue is extremely put through the application of advanced engineering analyses. This article proposes a theoretical approach for exergy analysis of the combined infrared-convective drying process using a simple heat and mass transfer model. The applicability of the developed model to actual drying processes was proved using an illustrative example for a typical food. List of symbolsA Surface area (m 2 ) C Specific heat of product (kJ/kg K) D eff Effective moisture diffusivity of water (m 2 /s) E Energy rate (kJ/s) ex Specific exergy (kJ/kg) Ex Exergy rate (kJ/s) F Shape factor (-) h m Mass transfer coefficient (m/s) h T Heat transfer coefficient (W/m 2 K) IR Infrared radiation energy (kJ/s) J Junction k Thermal conductivity of air (kW/m K) D Diameter (m) m Mass (kg) M Moisture concentration (kg water/m 3 ) MC Moisture content (kg water/kg dry matter) * Mortaza Aghbashlo

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Section: Introductionmentioning

confidence: 99%

Exergetic simulation of a combined infrared-convective drying process

Aghbashlo

2015

Heat Mass Transfer

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“…Therefore, the elements or components of the material are heated individually and instantaneously . Both heat and mass transfer mechanisms are active during the evaporative drying process .…”

Section: Introductionmentioning

confidence: 99%

Conventional and microwave drying of hydrocarbon cutting sludge

Köse

Çelen

Çelik

2018

Env Prog and Sustain Energy

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The purpose of this article is to investigate the drying kinetics and determine the effectiveness of conventional and microwave drying processes for drying of hydrocarbon cutting sludge which is one of the most important waste occurring from petroleum and natural gas cutting activities. Drying experiments of hydrocarbon cutting sludge were performed at MW power levels of 120, 460, and 600 W using microwave dryer and at drying temperatures of 140°C and 180°C. The sample weights were selected as 50, 100, and 150 g. Energy consumption values were determined, according to the microwave power levels, drying temperature, drying times, moisture ratio, as 0.01–0.11 kW/h for microwave, and as 0.11–0.55 kW/h for conventional drying processes. The results showed that the microwave drying was the more effective drying process in terms of drying times and energy consumption. Furthermore, as a result of the statistical analysis, the most suitable model among five drying models was determined according to the χ2, es, and r criteria. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13104, 2019

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“…Yahya, Fudholi, and Sopian (2017) have conducted energy and exergy analyses of biomass using solar assisted fluidized bed dryer, reporting thermal efficiency in the range of 8.72-28.79% and exergy efficiency between 1.2% and 49.5% (Yahya et al, 2017). Özahi and Demir (2013) have modeled batch fluidized bed dryer for exergy analysis and exergy efficiency was obtained between 0.08 and 18.63% from model (Özahi & Demir, 2013). Karagüzel, Tek _ ln, and Topuz (2012) have studied the energy and exergy analyses of chickpea and bean using fluidized bed dryers and the reported exergy efficiency of bean drying is in the range of 56-65% and for chick peas drying it is in the range, 45-62% (Karagüzel et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Energetic and exergetic analyses of Barnyard millet drying using continuous multistage fluidized bed dryer

Devani

Yelamarthi

2019

J Food Process Engineering

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Most of the exergy studies reported were in batch fluidized bed drying process. The continuous dryer plays a pivotal role in industrial usage. In this study, exergy and energy analyses of multistage fluidized bed drying of Barnyard millet with stages connected externally were examined. The dryer was operated by changing wall temperature of stages (313–328 K), air inlet velocity (1.01–1.3 m/s), downcomer height (50–70 mm), and flow rate of solids (5–10 kg/h). Drying characteristics of Barnyard millet by changing process operating conditions of the dryer, were reported and the energy utilization ratio, exergy loss and exergy efficiency of dryer were also reported. The EUR of dryer at steady state has been found to be in the range of 0.25–0.46 and the maximum exergy efficiency of dryer was observed as 0.64 and lowest as 0.371 in the continuous drying process. Practical Applications Fluidized beds offer many distinct features and advantages for processing of particulate food materials. To decrease the drying time than that for single stage dryers, continuous multistage fluidized bed dryer was introduced. Reducing moisture content from feed materials in continuous dryers while discharging continuously, helps to process large quantity of solid materials with good quality of product. Several dryers with different modifications and designs have been suggested by many earlier investigators but continuous dryers play significant role in particulate industry. The multistage dryer is designed by connecting two or more fluidized beds internally or externally, where each bed is termed as a stage. Advantages of the multistage dryer are improvement in gas–solid axial mixing, which results in good quality of product. Due to stage‐wise contact of solids with gas, dried product with uniform moisture content can be obtained.

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A model for the thermodynamic analysis in a batch type fluidized bed dryer

Cited by 26 publications

References 10 publications

Exergetic simulation of a combined infrared-convective drying process

Exergetic simulation of a combined infrared-convective drying process

Conventional and microwave drying of hydrocarbon cutting sludge

Energetic and exergetic analyses of Barnyard millet drying using continuous multistage fluidized bed dryer

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