Drying of rye (Lolium miltiflorum l.) in fixed bed with parallel air flow.

This work aimed to study the drying of ryegrass seeds (Lolium multiflorum L.) in fixed bed dryer with parallel air flow

Effectof osmotic dehydration in sucrose solution in the drying kinetics of cashew apple (Anacardium occidentale L.).

The ínfluence of osmotíc dehydratíon ín sucrose solution (52% w/w) for 165 minutes in the dryíng kínetícs of cashew apple was studied. Drying tests were conducted usíng a fixed bed dryer at three dífferent temperatures (50, 60 and 70°C) and aír velocíty of 2.1 m/s. Results showed that an íncrease of the aír temperature favoured the decrease of the dryíng time of the product. The water effectíve diffusion coefficients were determined accordíng to Fick's second law applied to a thín slab and were found to be ín the order of 10-10 m2/s. The effectíve diffusion coefficient decreased for the osmosed cashew apple, índícatíng a less favoured díffusíonal processo However, the pretreated samples were characterízed by a flexíble structure, by a smaller shrinkage and by presentíng a more natural coloratíon. The activatíon energy,calculated usíng Arrhenius equation, was found to be 36.45 kJ/mol for fresh fruit and 26.63 kJ/mol for the osmosed sample

Moisture evolution, thermal properties and energy consumption of drying spent grain pellets from a blend of some cereals for small scale bio-energy utilization: Modelling and Experimental study

© 2022 Springer Nature Switzerland AG. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s13399-022-02846-xA fixed bed convective dryer was used to assess the influence of drying temperature and geometry deformation on moisture and thermo-physical property evolution of solid fraction pellets (spent grain) from wet milling of cereal blends for bio-energy generation for small homes. The aim is to study the physical mechanism of drying the pellets that includes temperature and moisture behaviour, transport phenomena, the response rate to varying process conditions, drying time, and energy utilization which can be applied in the development of a fixed bed dryer for drying the pellets at a lower scale. The modified Cranck's diffusion model was used to study moisture loss by introducing shrinkage. The verification of the model gave the mean absolute error (MAE) for moisture content with shrinkage as 0.0366 - 0.1500 while for without shrinkage was 0.0729 - 0.1500 for 60- 80 oC. The effective moisture diffusivity with integrating shrinkage is lower than non- shrinkage though these values varied with drying time. Fitting the moisture ratio with the exponential drying curve equations shows that logarithmic equations were the best model for drying at 60 and 70 oC while Henderson and Pabis's model was better at 80 oC isothermal drying. Thermophysical analysis showed that the average specific heat capacity ranges from 5423.387 to 5198.197J/kgK while the thermal conductivity ranged from 0.115281to 0.136882W/mK at 60-80 oC. The energy and specific energy consumption ranged from 0.41 to 0.494 kWh and 108.39 to 119.29MJ/kg. The shrinkage ratios, effective diffusivity and energy and specific energy consumption were empirically presented as a function of moisture, temperature and or air velocity variations with a high degree of association.Peer reviewe

Options for Solar Drying Systems: Perspective in Malaysia

Solar drying provides an alternative to the use of fossil fuel. Solar drying system is one of the most promising applications of crop drying. However, there are problems associated with the intermittent natural of solar radiation and the low intensities of solar radiation. The problems can be remedied by the use of heat storage, auxiliary energy source, control system, larger surface collector and hybrid system. However, this will result in a high capital investment. Economic indicators such as cost ofmaintenance, payback period, internal rate of return can be used to calculate the economic of it application.This paper presents the experience in Malaysia on crop drying. We also present the performance of four solar assisted drying systems for crop drying using different collector types, (a) V-groove solar collector with cabinet dryer, (b) double-pass solar collector with porous media in the lower channel and a flat bed drying chamber, (c) Solar dehumidification system and (d) Photovoltaic-thermal solar drying system

Comparative study between current practices on cassava drying by small-size enterprises in Africa

Small-size enterprises drying cassava in Africa mostly use fixed-bed dryers or pneumatic dryers. The objective of this study was to determine which of those two dryers is the best choice for this operation. Energy performance, product quality and costs were measured and analysed using a comparative experiment design. Each dryer was considered as a treatment and experiments were performed in quintuplicate at a cassava processing small-size enterprise in Ghana. The energy performance of the pneumatic dryer was superior because of the better contact between the cassava grits and the drying air, resulting in greater heat and mass transfer. The cassava flour obtained from the fixed-bed dryer had a higher Whiteness Index, but the same level of lightness, and the staff responsible for managing product quality was not able to visually distinguish them. As a result of the pneumatic dryer’s better energy performance, its operating cost was lower. The capital cost of this dryer was higher, but to recover the additional investment only 194 days of operation were needed. Therefore, it was concluded that pneumatic dryers are a better choice of equipment for cassava drying by small-size enterprises in Africa

Effect of ultrasound on banana cv Pacovan drying kinetics.

The aim of this work was to study and to model the drying kinetics of fresh and ultrasonic pretreated banana cv Pacovan using the diffusional model (Fick?s second law) and an empirical two parameters model (Page model). The pretreatment was carried out in an ultrasonic bath at 30 °C. The drying process was carried out in a fixed bed dryer at two different temperatures (50 and 70 °C) and 3.0 m/s air velocity. Page empirical model provided the best simulation of the drying curves. The diffusional model was used to describe the moisture transfer and the effective diffusivities of water were determined and were in the order of 10 9 m 2 /s. These diffusivities increased with increasing temperature and with the application of ultrasound, while the process time reduced, which can represent an economy of energy, since air drying is cost intensive

Modeling the Drying Kinetics of Green Bell Pepper in a Heat Pump Assisted Fluidized Bed Dryer

In this research, green bell pepper was dried in a pilot plant fluidized bed dryer equipped with a heat pump humidifier using three temperatures of 40, 50 and 60C and two airflow velocities of 2 and 3m/s in constant air moisture. Three modeling methods including nonlinear regression technique, Fuzzy Logic and Artificial Neural Networks were applied to investigate drying kinetics for the sample. Among the mathematical models, Midilli model with R=0.9998 and root mean square error (RMSE)=0.00451 showed the best fit with experimental data. Feed-Forward-Back-Propagation network with Levenberg-Marquardt training algorithm, hyperbolic tangent sigmoid transfer function, training cycle of 1,000 epoch and 2-5-1 topology, deserving R=0.99828 and mean square error (MSE)=5.5E-05, was determined as the best neural model. Overall, Neural Networks method was much more precise than two other methods in prediction of drying kinetics and control of drying parameters for green bell pepper. Practical Applications: This article deals with different modeling approaches and their effectiveness and accuracy for predicting changes in the moisture ratio of green bell pepper enduring fluidized bed drying, which is one of the most concerning issues in food factories involved in drying fruits and vegetables. This research indicates that although efficiency of mathematical modeling, Fuzzy Logic controls and Artificial Neural Networks (ANNs) were all acceptable, the modern prediction methods of Fuzzy Logic and especially ANNs were more productive and precise. Besides, this report compares our findings with previous ones carried out with the view of predicting moisture quotients of other food crops during miscellaneous drying procedures. © 2016 Wiley Periodicals, Inc

Experimental investigation of drying of malt bagasse

[EN] The aim of this work was to investigate the convective drying process of malt bagasse and to evaluate the influence of this process on the application of this residue as adsorbent in methylene blue removel by adsorption process. The experimental system for drying was a fixed bed dryer with parallel airflow, with operating conditions: air temperature in the range of 40 to 90 oC and air veocity of 2 m/s. The adsorption experiments were perfomed with solution of methylene blue at 70 ppm concentration. The drying kinetics showed a constant drying rate period followed by a falling drying rate. The results obtained for the dye removal efficiency were 56% for in natura sample and in the range of 81.69% to 93.99% for dried samples.Zorzi, B.; Machry, K.; Krolow, P.; Moura, C.; Oliveira, E.; Rosa, G. (2018). Experimental investigation of drying of malt bagasse. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1029-1034. https://doi.org/10.4995/IDS2018.2018.7785OCS1029103

Influence of osmotic pretreatment on dried cashew apple acceptability.

Resumo P2.1.10