COFFEE CHERRIES DRYING PROCESS AND THE INFLUENCE OF ENVIRONMENT RELATIVE HUMIDITY IN THE MATHEMATICAL MODELING, MOISTURE CONTENT, AND ENTHALPY OF VAPORIZATION

2014 ◽  
Vol 29 (2) ◽  
pp. 148 ◽  
Author(s):  
Paulo Carteri Coradi ◽  
Flávio Meira Borém ◽  
Carlos Henrique Reinato
2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.


2020 ◽  
Vol 122 (9) ◽  
pp. 2953-2963
Author(s):  
Sadoth Sandoval Torres ◽  
Daniel Lopez Cravioto ◽  
Juan Rodríguez Ramírez ◽  
Lilia L. Méndez Lagunas ◽  
Luis Gerardo Barriada Bernal ◽  
...  

PurposeMesquite pods offer a high nutritional content; A flour can be produced from them; nevertheless, the moisture content makes the milling process difficult. Then, before the milling operation a drying process must be implemented, but drying technology must be studied in order to characterise the process and identify the effect of drying temperature on the magnitude of drying rate.Design/methodology/approachProsopis Laevigata pods were collected in Oaxaca (Southern of Mexico) and they were dried. Three stages of maturity were identified and pods in the stage three of maturity were dried by forced convection. The internal structure of the pods was analyzed by scanning electron microscopy (SEM). The pods were dried in a tunnel dryer at 40, 50, 60 and 70° C, 10% relative humidity and air velocity of 2.6 m/s. From experimental data, a lumped analysis was conducted for drying.FindingsWe found that the internal microstructure of this material is a limiting factor for moisture migration. In order to reduce the moisture content in the pods, a minimum air temperature of 60° C must be applied. The characteristic drying curve shows a good agreement with the experimental drying kinetics. The nutritional composition (carbohydrates, sugar and protein) of pods reveals important applications for the food industry.Practical implicationsThe mesquite pods are important ethnic foods. In order to obtain flour, the drying of pods is mandatory. Drying must be applied in stage three of maturity which can be identified based on color changes and moisture content. The moisture content affects the performance of milling operation, then a minimum drying temperature of 60° C and low relative humidity must be applied. SEM images show the complex microstructure of the pods which hinders the moisture diffusion. The drying characteristic curve was deduced for the first time; it helps to understand the drying behavior of pods. The chemical composition of mesquite pods reveals interesting applications for the food industry. The methodology for drying is useful for researchers and producers.Originality/valueMezquite pods is an interesting ethnic food for people with celiac disease. This is the first time a research paper describes the drying process at detail. The SEM images, the convective drying operation and the characteristic curve are presented for the first time. The information will be useful for the industry and academia.


Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 261-267 ◽  
Author(s):  
C. Takahashi ◽  
Y. Ishimaru ◽  
I. Iida ◽  
Y. Furuta

Abstract To better understand mechano-sorptive creep, creep behaviors were compared in wood samples during the drying process, immediately after drying, and after a long conditioning under constant humidity and temperature. Creep was greater in the sample tested immediately after drying than in the sample conditioned for a long time under relative humidity equal to that after drying, despite the fact that these samples had almost the same moisture content (MC). While the wood that has been moisture-conditioned for a long time is in a stable state, the wood tested immediately after the drying is presumed to be in an unstable state. Moreover, creep of the sample tested during the drying process was greater than that of the sample tested immediately after the drying. It has also been found that the instability decreased with time, indicating that stabilization and destabilization occur simultaneously during the drying process. In recent studies, a decrease in the elastic modulus and an increase in the fluidity of wood immediately after a change in MC or temperature have been reported. These findings are attributed to the instability caused by changes in MC or temperature. Based on the results of the present study and recent studies, we consider the increase in the fluidity of wood as the MC changes to be attributable to instability.


2020 ◽  
Vol 4 (4) ◽  
pp. 362-371
Author(s):  
Antoni Hardi ◽  
Ichwana Ichwana ◽  
Rita Khathir

Abstrak. Sebagai produsen kopi Arabica, masyarakat Gayo terkendala pada suhu lokal di Aceh Tengah yang relatif dingin dan teknologi sederhana yang digunakan untuk proses pengeringan kopi. Suhu rata-rata harian adalah 23-29°C. Bahan yang digunakan pada penelitian ini yaitu biji kopi yang diolah dengan metode semi basah sebanyak 9kg. Parameter penelitian meliputi suhu pengeringan, kelembaban relatif, kadar air dan rendemen. Hasil penelitian menunjukkan bahwa suhu pengeringan menggunakan alat pengering Hohenheim jauh lebih tinggi sekitar 10-20°C dari suhu pengeringan secara penjemuran. Proses pengeringan kopi labu sampai bisa digiling membutuhkan waktu selama 12 jam yaitu 8 jam pada hari pertama dan 4 jam pada hari ke-2. Sedangkan proses pengeringan tahap 2 membutuhkan waktu selama 16 jam sampai menghasilkan kopi beras dengan kadar air 9,32%. Kualitas kopi beras yang dihasilkan sudah baik dengan kadar air  yang sudah memenuhi standar SNI, tidak berbau busuk, dan tidak terkontaminasi. Nilai rendemen kopi beras berbasis kopi labu adalah 35%.Study of Drying Semi Washed Gayo Coffee Use Dryer Type Hohenheim Abstrack. As an Arabica coffee producer, the Gayo community is constrained by the relatively cold local temperatures in Central Aceh and the simple technology used for the coffee drying process. The average daily temperature is 23-29 ° C. The material used in this study was coffee beans which were processed by the semi-wet method of 9kg. Research parameters include drying temperature, relative humidity, moisture content and yield. The results showed that the drying temperature using a Hohenheim dryer is much higher around 10-20 ° C than the drying temperature by drying. The process of drying pumpkin coffee until it can be ground needs 12 hours, which is 8 hours on the first day and 4 hours on the second day. While the process of drying stage 2 takes 16 hours to produce rice coffee with a moisture content of 9.32%. The quality of rice coffee produced is good with water content that meets SNI standards, does not smell bad, and is not contaminated. The yield of pumpkin coffee-based rice coffee is 35%.


2021 ◽  
Vol 64 (2) ◽  
pp. 475-484
Author(s):  
Seth Graham-Acquaah ◽  
Terry J. Siebenmorgen

HighlightsDrying conditions affect rice end-use functionality.Thermal exposure incurred by rough rice may differ depending on drying conditions.A framework is proposed for deriving an index that can show how much heat exposure rough rice incurs during drying.Abstract. Heated air is used to dry most rice in the U.S. Thus, commercial rice drying can be considered a thermal process that aims to remove moisture from rough rice until a desired moisture content is reached. Parallels can be drawn between rice drying and thermal sterilization that is targeted at reducing microbial load because moisture content reduction during drying follows similar decay rate kinetics as the reduction in microbial load during thermal sterilization. Given the different combinations of drying air conditions (air temperature and relative humidity), as well as drying and tempering durations, employed in various dryer designs for rice drying and the impact that these conditions have on rice end-use functionality, this study sought to derive a thermal treatment index (drying process values) that is similar to the F0 value concept used in thermal sterilization for quantifying and comparing the thermal exposure incurred by rice during drying under various scenarios. Using data collected from rough-rice drying experiments, a decimal desorption value (Dmv) that represents the duration required to cause a 90% reduction in moisture ratio during drying at a specified temperature was determined, from which a thermal desorption constant (Zmv) that represents the increase in temperature necessary to cause a 90% reduction in Dmv during drying was established. Subsequently, a thermal desorption value (Fmv) was derived to express the duration that a rice lot would have been heat treated at a reference temperature during drying to produce an equivalent effect on moisture content as that produced by the actual drying process. Keywords: End use, Moisture content, Peak viscosity, Postharvest, Relative humidity, Rice, Temperature.


2016 ◽  
Vol 6 (2) ◽  
pp. 51-56 ◽  
Author(s):  
Yuwana Yuwana ◽  
Bosman Sidebang ◽  
Evanila Silvia

This objective of this research was to design a dryer called “Teko Bersayap” model and then to test its performance in drying fish in order to solve problems arising from open air sun drying. The dryer consisted of drying chamber with trays inside, heat collectors equipped with air inlets at their lower ends, chimney with an exhaust fan inside and humid air outlet at its upper end, was constructed to dry fish, “Bleberan (Pepetak Leiognatus spp)” species. The results of the experiment indicated that the dryer produced the drying chamber temperature 8.83oC higher than the ambient temperature and the relative humidity 13.91% lower than the ambient relative humidity. The fish moisture content decreased exponentially with drying time and the dryer completed the fish drying process in 18.9 hours compared to 27.6 hours of drying time needed to complete the sun drying for the fish, suggesting that the dryer was ready for utilization


Author(s):  
Carolina M. Sánchez-Sáenz ◽  
Vânia R. G. Nascimento ◽  
João D. Biagi ◽  
Rafael A. de Oliveira

ABSTRACT Mathematical modeling enables dimensioning of dryers, optimization of drying conditions and the evaluation of process performance. The aim of this research was to describe the behavior of orange bagasse drying using Page's and Fick's second law models, and to assess activation energy (using Arrhenius equation), moisture content, water activity and bulk density of product at the end of the process. The drying experimental assays were performed in 2011 with convective air temperature between 36 and 64 ºC and infrared radiation application time in the range from 23 to 277 s in accordance with the experimental central composite rotatable design. Analysis of variance and F-test were applied to results. At the end of the drying process, moisture content was about 0.09 to 0.87 db and water activity was between 0.25 and 0.87. Bulk density did not vary under studied conditions. Empirical Page's model demonstrated better representation of experimental data than the Fick's model for spheres. Activation energy values were about 18.491; 14.975 and 11.421 kJ mol-1 for infrared application times of 60; 150 e 244 s, respectively.


Author(s):  
Marina Sergeevna Maklusova ◽  
Maria Konstantinovna Kosheleva ◽  
Olga Roaldovna Dornyak

The object of research is a fiber-forming polymer - polycaproamide. The process of drying of polycaproamide granules, after aqueous extraction of low-molecular compounds from them, is an important stage of producing of polyamide fiber nylon and largely determines the quality of the target product. To obtain a high-quality fiber, the drying of the granules should provide a sufficiently high degree of its dehydration. The average final moisture content of the material should be no more than 0.1%. With a low moisture content, the drying process slows down, so the calculation of the kinetics of dewatering of granules can not be carried out using a constant effective mass-transfer coefficient (moisture diffusion). In this paper we present a calculation technique for determining two local parameters of mass transfer: the water diffusion coefficient in polycaproamide (as a liquid) and the so-called criterion for phase transitions, which depend on the moisture content of the material and are determined by its sorption properties. The report presents the results of numerical calculations illustrating the development of two-dimensional fields of moisture content, temperature, pressure and vapor concentration in the vapor-gas phase for cylindrical granules in convective drying. To describe the processes of heat and mass transfer during the drying of granules, a nonstationary nonlinear 2D model is used that includes transport equations averaged over the microvolume of the material: the liquid phase transfer equation; heat equation; equation for vapor-gas phase pressure; equation for the concentration of the vapor component. The nonstationary nonlinear conjugate mathematical model is studied numerically. A feature of the presented model is the possibility of an analytical calculation of the local mass transfer coefficients of a liquid, taking into account the sorption properties of the material, the permeability coefficient and the local values ​​of humidity and temperature. Determination of the local coefficients of moisture transfer is carried out on the basis of the formulas obtained in the analysis of a more general mathematical model of heat and mass transfer carried out based on the mechanics of multiphase systems developed in the works of R.I. Nigmatulin, and S. Whitaker. The structure of the samples was investigated by three independent methods in order to obtain the most complete idea of ​​it and to compare the obtained characteristics. The isotherms of the sorption of polycaproamide were obtained experimentally on a vacuum sorption plant with Mac-Ben-Bakr weights. Comparison of the results of mathematical modeling of heat and mass transfer in the granule and data of the laboratory experiment on the kinetics of polycaproamide granule drying showed good agreement between the calculated and experimental data. The constructed mathematical model allows to form energy-efficient resource-saving regimes for drying granules of polycaproamide.Keywords: convective drying, mathematical modeling, polycaproamide.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2514
Author(s):  
Jacqueline F. B. Diniz ◽  
João M. P. Q. Delgado ◽  
Anderson F. Vilela ◽  
Ricardo S. Gomez ◽  
Arianne D. Viana ◽  
...  

Vegetable fibers have inspired studies in academia and industry, because of their good characteristics appropriated for many technological applications. Sisal fibers (Agave sisalana variety), when extracted from the leaf, are wet and must be dried to reduce moisture content, minimizing deterioration and degradation for long time. The control of the drying process plays an important role to guarantee maximum quality of the fibers related to mechanical strength and color. In this sense, this research aims to evaluate the drying of sisal fibers in an oven with mechanical air circulation. For this purpose, a transient and 3D mathematical model has been developed to predict moisture removal and heating of a fiber porous bed, and drying experiments were carried out at different drying conditions. The advanced model considers bed porosity, fiber and bed moisture, simultaneous heat and mass transfer, and heat transport due to conduction, convection and evaporation. Simulated drying and heating curves and the hygroscopic equilibrium moisture content of the sisal fibers are presented and compared with the experimental data, and good concordance was obtained. Results of moisture content and temperature distribution within the fiber porous bed are presented and discussed in details. It was observed that the moisture removal and temperature kinetics of the sisal fibers were affected by the temperature and relative humidity of the drying air, being more accentuated at higher temperature and lower relative humidity, and the drying process occurred in a falling rate period.


Sign in / Sign up

Export Citation Format

Share Document