Natural Solar Drying and Charcoal Production by Pyrolysis of Empty Shells of Cocoa Pods Using a Carbonisation Stove Fitted with a Chimney

The world’s production of cocoa highly has grown since 1960.In West Africa,the production reached about 3,000,000 tons in 2012.More than 50%of the world’s production of cocoa comes nowadays from Côte d’Ivoire and Ghana and Côte d’Ivoire is the biggest producer.After harvesting,the empty shells,considered as non-useful wastes,are abandoned in the fields where they become a source of pollution.That yields millions of tons of biomass that can be converted into charcoal,instead of being sources of pollution.In the present work,the drying kinetics of the empty wet shells were studied.Then,charcoal production by pyrolysis of those empty shells of cocoa pods was performed,using a carbonisation stove fitted with a chimney.The study showed that the empty shells have a high moisture content.The different phases of the drying were observed.The study compared the drying rates and the diffusion coefficients of a small sample and a big sample.Two experiences of carbonisation of the empty shells were successfully carried out.For the first experiment,the pyrolysis temperatures were recorded and the charcoal mass efficiency calculated.For the second experiment,the temperatures were higher and the result was colored charcoals.The colorations disappeared after some hours.

The Application of a Mathematical Modelling of Drying Kinetics in the Natural Solar Drying of Banana

In this work, a new mathematical modelling of drying kinetics is described. At first, the modelling of the transfer speed （St） of water was performed. Then St was used as basis to state the drying rate model. The drying rate depends not only on drying time, but also on some modelling parameters which are themselves time-dependent. All the modelling parameters are calculated directly from the experimental drying data. Then the theoretical model of the moisture content was stated. Subsequently, the drying kinetics of natural solar drying of plantain banana was studied as illustration. The drying rate was investigated. The comparison with other models encountered in literatures proved that the current theoretical model was decidedly more accurate. Then the modelling of moisture content of banana was performed and the results were compared with the Henderson and Pabis model. The current theoretical modelling provided by far the best fit.

Sustainability assessment of solar drying systems:a comparative life-cycle analysis of phase-change material-based vs.cylindrical solar dryers

Solar drying systems are becoming a popular alternative to traditional energy-based drying systems for agricultural products due to their effectiveness and reduced fuel consumption.Although the efficiency of solar drying systems has been thoroughly investigated,their sustainability has not been studied enough.This study aims to fill that gap by conducting a life-cycle assessment of two new solar drying systems built in Udaipur,Rajasthan,India.The environmental implications of an innovative cylindrical solar-assisted drying system and a phase-change material-based solar drying system were evaluated using cradle-to-gate life-cycle analysis.The study uses the ReCiPe 2016 endpoints(H)technique to calculate various aspects such as midpoint,endpoint,single score,normalization result,and network diagram for phase-change material-based solar drying and cylindrical solar-assisted drying.Results show that phase-change material-based solar drying has an average of 40%more impact on the environment than cylindrical solar-assisted drying,with a high impact found in human non-carcinogenic toxicity,mainly due to the production of phase-change materials.However,cylindrical solar-assisted drying system crossover phase-change material based solar drying in terms of its impact on human carcinogenic toxicity and fossil resource scarcity.The contribution to global warming of phase-change material-based solar drying is 13.7%more than that of cylindrical solar-assisted drying.The endpoint characterization indicates that phase-change material-based solar drying exceeds in terms of human health(40%)and ecosystem(37.04%),whereas cylindrical solar-assisted drying surpasses phase-change material-based solar drying in terms of impacts on resources,at 14%.The early drying in phase-change material-based solar drying makes up for its higher impact than that in cylindrical solar-assisted drying,which takes 3 hours longer to dry.This study offers guidance and methods for making the best choice of solar-powered dryers.

Study on Drying Edible Soya-bean Oil Using Solar Energy

Soya-bean oil （bean dregs） was dried in a solar energy drying system. Characteristics of the process were measured and the corresponding curves were done. The practicability of this process has been discussed. The results showed that the solar drying system could completely meet technological requirements of drying soy-bean oil, and it was feasible in technology to use the solar drying system to dry the vegetable oil.

Experimental Performance and Neural Network Modeling of a Large-scale Greenhouse Solar Dryer for Drying Natural Rubber Sheets

This paper presents experimental performance and artificial neural network modeling of a large-scale greenhouse solar dryer for drying of natural rubber sheets. The dryer consists of a parabolic roof structure covered with polycarbonate sheets on a concrete floor. The dryer is 9.0 m in width, 27.0 m in length and 3.5 m in height. Nine 15-W DC fans powered by three 50-W PV modules were used to ventilate the dryer. To investigate its performance, the dryer was used to dry six batches of natural rubber sheets. For each batch, 750 kg of rubber sheets were dried in the dryer. Results obtained from the experiments showed that drying temperatures varied from 32 ~C to 55 ~C and the use of the dryer led to a considerable reduction of drying time, as compared to the open air sun drying. In addition, the quality of the product from the dryer was high-quality dried products. A multilayer neural network model was developed to predict the performance of this dryer. The predictive power of the model was found to be high after it was adequately trained.

Moisture Content and Nutrient Composition of Alfalfa under Different Drying Methods

[Objective] The paper was to study the effects of different drying methods on moisture content and nutrient composition of alfalfa.[Method] Alfalfa collected from the same piece of land in early flowering period were dried through three different drying methods, solar drying,outdoor drying in the sun and outdoor drying in the shade, and the effects of different drying methods on contents of moisture, crude protein, crude ash and neutral detergent fiber（NDF） were measured. [Result] The moisture evaporation rate of different drying methods over the same period successively were solar drying 〉 outdoor drying in the sun 〉 outdoor drying in the shade. The crude protein content of alfalfa was the highest through solar drying（P〈0.05）, followed by outdoor drying in the shade, and the crude protein content through outdoor drying in the sun was the lowest. Under the condition of different moisture contents, the crude protein content of dried samples through outdoor drying in the sun decreased by 6.86%-22.43% compared to solar drying, and that through outdoor drying in the shade reduced by 4.92%-17.20%. Under the same moisture content, the crude ash content successively were outdoor drying in the shade 〉 outdoor drying in the sun 〉 solar drying; the crude ash content of alfalfa through solar drying was 3.72%-19.22% lower than outdoor drying in the sun, and 8.12%-29.93% lower than outdoor drying in the shade. The NDF content of alfalfa through outdoor drying in the sun was the highest, significantly higher than the other two drying methods（ P〈0.05）. The NDF content through solar drying was the lowest, 9.08%-27.25% lower than outdoor drying in the sun, and 4.84%-24.84% lower than outdoor drying in the shade. [Conclusion] The paper will provide some references for selection of appropriate alfalfa drying method.

Comparison of mixed-mode forced-convection solar dryer with and without stainless wire mesh in solar collector

A mixed-mode forced-convection solar dryer(MMFCSD)is a device that utilizes both direct and indirect solar energy.The solar col-lector,which stores thermal energy for indirect solar uses,is an essential component of the dryer.Unfortunately,the thermal effi-ciency of this device is generally low.In this study,a technique was employed to improve the heat transfer of the solar collector in a MMFCSD.The technique involved adjusting the air flow pattern into a swirling flow to disturb the thermal boundary layer on the absorber plate under forced convection by using stainless wire mesh.The experiment was conducted under actual conditions and bananas were used as the drying sample.The experimental results of the thermal efficiency of the solar collector(ƞ_(solar))and the drying efficiency(ƞ_(drying))are presented.The results indicated that the air outlet temperature andƞsolar of the solar collector with stainless wire mesh were higher than the case without stainless wire mesh,reaching a maximum temperature of 46.22°C and 37.97°C,and average ƞ_(solar) of 0.26±0.02 and 0.14±0.01,respectively.The MMFCSD with stainless wire mesh had a higher ƞ_(drying) than the case without stain-less wire mesh,with values of 0.048±0.004 and 0.039±0.003,respectively,resulting in an~23.07%increase.This was attributed to the air swirling flow through the stainless wire mesh and the heat accumulation in the drying chamber,which led to an increase in the drying chamber temperature from 54.03°C to 63.60°C,an increase in the effective moisture diffusivity from 7.28×10^(-7) to 1.19×10^(-6) m^(2)/s and a decrease in the drying time of 5 h 30 min.However,further research is needed to investigate the quality of the dried sam-ples and their economic value.