Mathematical modeling of intermittent and convective drying of rice and coffee using the reaction engineering approach (REA)

Putranto, Aditya; Chen, Xiao; Xiao, Zongyuan; Webley, Paul A.

doi:10.1016/j.jfoodeng.2011.03.036

Cited by 40 publications

(38 citation statements)

References 53 publications

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Section: Introductionmentioning

confidence: 99%

“…Mathematical modeling of the intermittent and convective drying of rice and coffee has been carried out successfully by using REA. The physics of drying is explained through the activation energy relative which is obtained from experimental drying data accurately [16] .Taking into account the complex structure and heterogeneity of food and organic products, the REA approach couples conventional drying with mechanistic models to produce a global model which is essentially a complete model combining several stages of mass transfers. This global model is advantageous in explain the complex transport phenomena behind the drying processes [17,18] , without the necessity to determine the critical water content.…”

mentioning

confidence: 99%

“…ψ represents the relative humidity of interface product-air. In this study we also assume that the temperature of the sample-air interface can be considered to be the product temperature.The activation energy ΔE v of evaporation is correlated to ψ using an Arrhenius type equation [16] :where ΔE v is representing the related activation energy, as a factor of the level correction high energy reflecting the difficulty of extracting water from the product to the low water content (J kmol -1 ), R= 8314.46 J kmol -1 K -1 is the universal gas constant. Therefore,…”

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confidence: 99%

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Application of the reaction engineering approach (REA) for modeling of the convective drying of onion

Compaoré

Dissa

Rogaume³

et al. 2016

Drying Technology

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In this study, the drying of thin layers of the 'Violet de Galmi' onion (a variety mainly grown in West Africa) is presented in this article, along with the Reaction Engineering Approach (REA) modeling for a comprehensive understanding of the drying kinetics.The experiments were conducted on a lab-scale dryer to form thin layer of cylindrical onion slice. By performing this experiment, the standard activation energy is evaluated and modeled. The model is validated by simulating the drying rates under various drying conditions. The comparison of simulation and experimental data is found to be satisfactory. This approach allows the determination of the internal characteristics of the onion for the further studies such as design of solar dryer for onion. Downloaded by [University of Birmingham] at 00:09 24 June 2016 2 NOMENCLATURE A Surface of the product (m 2 ) a w Activity of water Bi Biot number C ps Specific heat of dry mass (J kg -1 K -1 ) C pw Specific heat of water (J kg -1 K -1 ) D AB Water air diffusivity (m 2 s -1 ) H Heat transfer coefficient (W m -2 K -1 ) h m Mass transfer coefficient (m s -1 ) L p Diameter (m) m s Dry mass (kg) P sat Saturation pressure (Pa) R Universal gas constant = 8314.46 J mol -1 K -1 R 2 Coefficient of determination RH b Relative humidity RMSE Root-Mean-Square error T s Temperature at surface (K) T p Temperature of product (K or °C) T b Bulk air temperature (°C) Sh Sherwood number SSE Sum of squared error X Water content (kg water /kg dry mass ) X eq Equilibrium water content (kg water /kg dry mass ) Downloaded by [University of Birmingham] at 00:09 24 June 2016 3 ΔE v Activation energy (J kmol -1 ) ΔE v,b Equilibrium activation energy (J kmol -1 ) ΔH v Latent heat of vaporization (J kg -1 ) ρ v,b Vapor density in bulk air (kg m -3 ) ρ v,s Vapor density at surface (kg m -3 ) ρ v,sat Vapor density at saturation (kg m -3 ) μ air Dynamic viscosity of air(kg m -1 s -1 ) Ψ Fractional coefficient of vapor pressure INTRODUCTIONDrying is a final key process during the manufacturing of products in the food industry, such as fabrication of milk powder, production of drying of cereals and preservation of fruits [1] . Principally, drying removes most of the water content of the product to less than 5%. In addition, it is also an energy-intensive process that commonly requires hot air to allow the product to dry by combining simultaneous transfer of heat and mass between the drying air and the product. Indeed, the drying of food products is a traditional way of preservation of these products. However, as food products are one of the most complex materials in their natural form, then the fundamental understanding of the drying of these food products has not been fully comprehended [2,3] . Many studies have been published on the modeling of drying, but the extent of the differences between formulations of different models is quite significant. Each model of the drying of food products is reasonably effective to correlate experimental data obtained, but limited only to the similar type of food p...

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Application of the reaction engineering approach (REA) for modeling of the convective drying of onion

Compaoré

Dissa

Rogaume³

et al. 2016

Drying Technology

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“…In order to optimize the drying process, the application of higher gas temperature at the beginning of the process and lower temperature at the end of the drying process is recommended. Putranto et al [12] proposed reaction engineering (REA) approach to develop mathematical modelling of intermittent and convective drying of coffee. Results show that the REA models the drying kinetics of coffee with well agreement between predicted and experimental data.…”

Section: Drying Coffee Beansmentioning

confidence: 99%

A field survey on coffee beans drying methods of Indonesian small holder farmers

Siagian

Setyawan

Gultom

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Physical and sensory quality of Java Arabica green coffee beans W B Sunarharum, S S Yuwono, N B S W Pangestu et al. Abstract. Drying agricultural product is a post-harvest process that consumes significant energy. It can affect the quality of the product. This paper deals with literature review and field survey of drying methods of coffee beans of Indonesia farmers. The objective is to supply the necessary information on developing continuous solar drier. The results show that intermittent characteristic of sun drying results in a better quality of coffee beans in comparison with constant convective drying. In order to use energy efficiently, the drying process should be divided into several stages. In the first stage when the moist content is high, higher drying air temperature is more effective. After this step, where the moist content is low, lower drying air temperature is better. The field survey of drying coffee beans in Sumatera Utara province reveals that the used drying process is very traditional. It can be divided into two modes and depend on the coffee beans type. The Arabica coffee is firstly fermented and dried to moisture content of 80% using sun drying method, then followed by Green House model of drying up to moisture content about 12%. The latter typically spends 3 days of drying time. On the other hand, The Robusta coffee is dried by exposing to the sun directly without any treatment. After the coffee beans dried follow by peeled process. These findings can be considered to develop a continuous solar drying that suitable for coffee beans drying.

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“…In order to analyse moisture content gradients and simulate intermittent drying of rough rice, some mathematical models have been developed (Cihan and Cem Ece, 2001;Cihan et al, 2007;Igathinathane et al, 2008;Nishiyama et al, 2006;Putranto et al, 2011). Through investigating moisture distribution in a rice kernel during tempering drying, Dong et al (2009) showed that MC gradients were produced during drying periods, which remarkably decreased at the early stage of tempering processes and then decreased gradually.…”

Section: Introductionmentioning

confidence: 99%

Head rice yield response to low and high drying and tempering conditions

Sadeghi¹,

Nasrnia²,

Masoumi³

et al. 2013

International Agrophysics

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A b s t r a c t. The influence of drying and tempering conditions on head rice yield of long-and medium-grain rough rice varieties was investigated. The head rice yield values for the medium-grain variety at high drying conditions and 1.5 and 3% points moisture content removal were even significantly higher than the corresponding values for the long-grain variety at low drying conditions. 1.5% points moisture content removal yielded the least damage to the rough rice. Under low drying conditions, tempering had no meaningful effect on head rice yield for all drying durations. For both varieties, using high drying conditions with 6% points moisture content removal at first drying stage associated with 120 min tempering duration could be suggested as a rapid and energysaving operation to achieve high head rice yield values.K e y w o r d s:

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Mathematical modeling of intermittent and convective drying of rice and coffee using the reaction engineering approach (REA)

Cited by 40 publications

References 53 publications

Application of the reaction engineering approach (REA) for modeling of the convective drying of onion

Application of the reaction engineering approach (REA) for modeling of the convective drying of onion

A field survey on coffee beans drying methods of Indonesian small holder farmers

Head rice yield response to low and high drying and tempering conditions

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