Facing the challenges to develop more efficient solar dryers, this work used the Computational fluid dynamics (CFD) to test different configurations of lateral air feeding in a fixed bed solar dryer. Through the simulations, it was found the best configuration of air inlet that provided a better fluid-particle contact. It was made a fixed bed solar dryer, which was tested using soybeans seeds and Moringa oleifera LAM leaves to evaluate the drying rate using two bed configurations: fully opened and partially opened inlets. The CFD results indicated that the air flow rate was more pronounced at the bed top, near the exhaust fan. This can explain the poor drying near the bottom for the experiments performed with all lateral inlets opened. According to the simulation results, the air velocity profile was more homogeneous when the air was fed only near the bottom. So, the use of a partially opened configuration led to a more homogenous solar drying, with a drying rate about 300% higher than the one using the fully opened inlets.
As práticas laboratoriais de separação de misturas sólido-gás fazem parte do currículo de diferentes cursos de engenharia. O objetivo deste trabalho foi a construção e avaliação de um kit didático de bancada para separação de partículas em câmara gravitacional, utilizado industrialmente na coleta de pós. O kit foi projetado e construído por alunos da disciplina de Laboratório de Operações Unitárias, que utilizou o Projeto Orientado como metodologia ativa de ensino. Desta forma, este trabalho é relevante pois além de incorporar métodos ativos na aquisição do conhecimento do aluno, também possibilita a aquisição de equipamentos de baixo custo para os laboratórios de ensino. A geometria da câmara de separação foi compacta e utilizou um cooler para promover alimentação do ar. Cerca de 234,5 g de areia foram alimentadas na entrada do equipamento. Após a coleta das partículas ao longo da câmara, as amostras foram peneiradas, calculando-se a eficiência individual de coleta. O diâmetro de corte das partículas retidas em cada compartimento foi calculado por correlações da literatura e simulações de fluidodinâmica computacional. Através das simulações, obteve-se o perfil de velocidade de ar dentro da câmara e a trajetória das partículas. Os resultados experimentais mostraram uma eficiência global de coleta próximo de 100%, em que cerca de 94% das partículas foram coletadas no primeiro compartimento. Os valores de diâmetro de corte preditos pelas correlações e as simulações computacionais foram similares e próximos aos observados experimentalmente. Assim, este trabalho desenvolveu um kit didático simples, de baixo custo e eficiente para a separação sólido-gás.
The brewing industries generate large amounts of barley residues (RM), which can be used as animal feed. However, the high moisture of RM can lead to losses due to mold or fermentation. In this context, solar drying can be an advantageous operation, as it will favor storage and transportation, while it keeps the waste nutritional quality. Thus, the aim of this work was to study the drying of RM using two equipments: a solar greenhouse and a fixed bed solar dryer. Initially, a study of the drying kinetics was performed at different temperatures, obtaining the Page model as the one that best represents the RM drying kinetics. In the solar drying tests, it was possible to determine the influence of factors such as solar radiation and wind speed on the temperatures obtained, as well as on the drying rate in both equipments. Computational fluid dynamics analysis of the fixed bed dryer showed the best way to feed air into the dryer, which favors drying. However, the solar greenhouse proved to be more efficient, promoting a more homogeneous drying of the material.
The drying process can be useful to change the particulate structure, improving the powder solubility. In this study, we investigated the drying of foliar fertilizer in a spouted bed using polyethylene pellets as inert particles to improve its solubility. A 23 factorial experimental design was used to evaluate how the powder yield and moisture were affected by the feeding time, intermittency time, and feed atomizer position. The spouting instability caused powder retention on the bed wall, which decreased the powder recovery efficiency by 2.3-26.6%. Although the powder recovery efficiency was low, the solubility time was reduced by 5.9 times, probably due to particle agglomeration, which increased the amorphous phase of the fertilizer. Design alterations, suggested by the CFD data, can increase spouted bed stability and facilitate centralized spouting. Based on this, the spouted bed drying technique was applied, and it effectively increased the solubility of commercial fertilizer, thus, incorporating more desirable characteristics for field applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.