Evaluation of coffee drying costs: pre-drying on concrete terrace and complementary drying in co-current and counter-current flow dryer

The study of drying costs is an important tool to be considered when deciding on an adequate drying system. One needs to consider the energy needed for air heating, electrical energy needed to run the fans, energy to transport the product, labor costs, maintenance costs, depreciation, interest rates and breakdown costs. The objective of this study was to determine the total drying cost per bag of dry coffee beans (Coffea arabica L.), by drying processed coffee in the form of pulped cherries, with pre-drying on a concrete yard followed by complementary drying in a developed prototype dryer with concurrent and countercurrent flows. The dryer was constructed of a metallic frame and plates, with a static capacity of 1.55 m3. An initial concurrent drying stage was separated from a second counter-current flow drying stage by a repose chamber. Two treatments were applied: a) Treatment 01: 12 hours of intermittent drying with intermittent rotation and 12 hours of rest, with air temperature of 45 °C and rotation of the beans every 90 minutes for drying (for a period of 10 minutes each); b) Treatment 2: 12 hours of intermittent drying with continuous rotation and 12 hours of rest, with air temperature of 70 °C. Coffee quality was determined via a sensorial analysis (cup-test). It was concluded that: The fixed cost of the multiple flow dryer was the principal component in the total cost of drying, principally since it was treated as a prototype; Increase in the drying capacity of the system with application of treatment 02 (with continuous rotation), in relation to treatment 01 (with intermittent rotation), drastically reduced total drying costs; The results obtained from treatment 01 demonstrate its economic infeasibility, due to the elevated drying costs encountered for the proposed system under the conditions in which this study was performed.The study of drying costs is an important tool to be considered when deciding on an adequate drying system. One needs to consider the energy needed for air heating, electrical energy needed to run the fans, energy to transport the product, labor costs, maintenance costs, depreciation, interest rates and breakdown costs. The objective of this study was to determine the total drying cost per bag of dry coffee beans (Coffea arabica L.), by drying processed coffee in the form of pulped cherries, with pre-drying on a concrete yard followed by complementary drying in a developed prototype dryer with concurrent and countercurrent flows. The dryer was constructed of a metallic frame and plates, with a static capacity of 1.55 m3. An initial concurrent drying stage was separated from a second counter-current flow drying stage by a repose chamber. Two treatments were applied: a) Treatment 01: 12 hours of intermittent drying with intermittent rotation and 12 hours of rest, with air temperature of 45 °C and rotation of the beans every 90 minutes for drying (for a period of 10 minutes each); b) Treatment 2: 12 hours of intermittent drying with continuous rotation and 12 hours of rest, with air temperature of 70 °C. Coffee quality was determined via a sensorial analysis (cup-test). It was concluded that: The fixed cost of the multiple flow dryer was the principal component in the total cost of drying, principally since it was treated as a prototype; Increase in the drying capacity of the system with application of treatment 02 (with continuous rotation), in relation to treatment 01 (with intermittent rotation), drastically reduced total drying costs; The results obtained from treatment 01 demonstrate its economic infeasibility, due to the elevated drying costs encountered for the proposed system under the conditions in which this study was performed

Evaluation and characterization of a heating system for broilers called convective radiant tube

Devido ao sistema termorregulador das aves não estar completamente desenvolvido, principalmente, nos 15 primeiros dias de vida, torna-se necessário fornecer um sistema de aquecimento complementar que propicie condições adequadas ao conforto térmico das aves de modo a evitar que as mesmas tenham menor conversão alimentar devido ao estresse térmico. Inserido nesse contexto, objetivou-se caracterizar quanto à distribuição de temperatura e aquecimento do ar o sistema de aquecimento denominado Tubo Radiante Convectivo (TRC). Um galpão com 96 m 2 de área foi preparado de modo a propiciar condições semelhantes à de um aviário e o equipamento foi alocado nesse ambiente. Para as temperaturas externas de 7 oC, 16 oC, 22 oC e 28 oC, verificou-se que o aquecedor não propiciou aquecimento adequado quando a temperatura externa estava a 7 oC, ou seja, para a pior situação, não sendo recomendado para aquecimento nas duas primeiras semanas de vida das aves. Para a temperatura de 16o C, o aquecedor propiciou aquecimento do ar adequado conforme demanda das aves. Para as temperaturas de 22 oC e 28 oC, o aquecimento do ar interno ao galpão foi excessivo tanto ao nível das aves quanto do ar ambiente, não sendo possível um bom ajuste da temperatura. Recomenda-se para trabalhos futuros, a caracterização do desempenho zootécnico das aves submetidas a esse sistema de aquecimento, uma vez que sua distribuição de temperatura bem como o potencial de aquecimento do ar já é conhecida.The thermoregulatory system of the broilers not being fully developed, especially in the first 15 days of life, therefore it is necessary to provide a complementary heating system that provides adequate conditions to the thermal comfort of the broilers in order to avoid that they have lower conversion feed. In context, was the objective of the present study it was to characterize a temperature distribution and heating of the air the heating system called Radiant Convective Tube (TRC). A shed with 96 m2 of area was prepared in order to provide conditions similar to that of an aviary and the equipment was allocated in that environment. For external temperatures of 7oC, 16oC, 22oC and 28oC, it was verified that the heater did not provide adequate heating when the external temperature was at 7oC, that is, the worst situation, and it is not recommended for heating in the two weeks of broilers life. For the temperature of 16o C, the heater provided adequate air heating according to the demand of the broilers. For temperatures of 22 ° C and 28 ° C, indoor air heating to the shed was excessive both at the level of broilers and ambient air and a good temperature adjustment was not possible. It is recommended for future work the characterization of the zootechnical performance of the broilers submitted to this heating system, since its temperature distribution as well as the air heating potential is already known.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Use of an automatic biomass gasifier on the quality of drying ripe coffee cherries

Para a manutenção da qualidade do café dentro dos padrões de comercialização, a etapa de pós-colheita precisa ser muito bem conduzida, principalmente, as relacionadas à limpeza, secagem e armazenamento, para que a qualidade não seja perdida durante o armazenamento. Destas etapas, a secagem é de fundamental importância e se mal conduzida pode comprometer a qualidade do produto. Ainda são poucos os estudos sobre a tecnologia da gaseificação, sobretudo na sua aplicação para secagem de grãos. Dessa forma, esta pesquisa visa contribuir para a aplicação do ar aquecido, proveniente de um gaseificador automatizado de biomassa (carvão de eucalipto), na secagem de café. A secagem do café cereja neste trabalho foi realizada em dois silos secadores acoplados a um gaseificador automatizado de biomassa, do qual provém o ar aquecido utilizado durante o processo. Três tratamentos foram determinados para a condução do trabalho, sendo eles: o tratamento 1 consistiu em 8 horas de secagem por dia com revolvimento da massa de grãos em intervalos de 2h e o tratamento 2 consistiu da secagem de café em terreiros suspenso e o tratamento 3 consistiu da secagem em terreiro de concreto. Para avaliar a influência da secagem do café através do sistema foram analisados os seguintes parâmetros: classificação de bebida, condutividade elétrica, lixiviação de potássio, massa de mil grãos. O café secado no sistema foi classificado quanto à bebida como apenas mole, obtendo nota média de 79 pontos. Com base nos resultados foram obtidos os seguintes valores médios: 146,86 Scm-1g-1 para condutividade elétrica; 34,04 ppm.g-1 para lixiviação de potássio; 160,90 g para o massa de mil grãos. De acordo com os resultados obtidos, o sistema de secagem apresentou-se como uma alternativa aos pequenos produtores de café, pois não houve perda de qualidade na sua bebida e por ser um sistema versátil, uma vez que além do café é possível secar outros grãos. Além disso, a automação do sistema propiciou um controle preciso da temperatura do ar de secagem durante todo o processo, o que é de fundamental importância para uma boa secagem do café.In order to maintain coffee quality within the commercialization standards, the post- harvest stages must be very well conducted, especially those related to cleaning, drying and storing, so that quality is not lost during storage.Among these stages, drying is the most important and if poorly conducted could put the quality of the product at risk. Drying requires clean warm air in order not to contaminate the product. Few studies have been performed on gasification, especially application of this process to drying grains. Therefore, the objective of the present study was to apply heated air generated by an automated biomass gasifier (eucalyptus charcoal) in coffee drying. Drying of the ripe coffee cherry in this study was performed in two drying silos attached to an automated biomass gasifier which generates the heated air used in the process. Two treatments were determined to conduct the study: treatment 1 consisted of 8 hours of drying per day, with revolving the grain mass every 2 hours; and treatment 2 consisted of drying the coffee on a suspended terrace and treatment 3 consisted of drying the coffee on concrete. In order to evaluate the influence of coffee drying in the system proposed, the following parameters were analyzed: beverage classification, electrical conductivity, potassium lixiviation and one thousand grain weight. Coffee dried in the proposed system was classified as a soft beverage, obtaining an average grade of 79 points. Based on the results, the following average values were obtained: 146.86 Scm- 1 -1 g for the electrical conductivity; 34.04 ppm.g-1for potassium lixiviation; 160.90 g as the one thousand grain weight. Drying performed using the proposed method showed to be viable since the dry coffee obtained presented good qualitative results regarding the specific mass, electrical conductivity, potassium lixiviation, color and other parameters which indicated that there was no risk of final quality loss in the beverage.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Considerações sobre a poluição do ar em grandes metrópoles

Dentre os problemas ambientais existentes em todas as cidades do mundo, principalmente nas grandes metrópoles, a poluição do ar ocupa um lugar de destaque e deve ser levada em consideração pela comunidade científica, população e órgãos públicos e privados. Emissões de veículos automotores, além daquelas originarias de indústrias, de centrais termelétricas e outras fontes, deixam o ar ambiente poluído e com potencial para causar problemas diversos, principalmente, à saúde humana. Neste estudo, problemas associados com a poluição do ar nas principais capitais brasileiras São Paulo, Rio de Janeiro e Belo Horizonte são apresentados.Among the environmental problems that exist in every city in the world, particularly in large cities, air pollution plays a very important role that should be taken into consideration by the scientific community, population and, public and private organizations. Emissions from vehicles, than those originating from industries, thermoelectric power plants and other sources, render the air polluted and with the potential to cause various problems, mainly to human health. In this study, problems associated with air pollution in major Brazilian capital São Paulo, Rio de Janeiro and Belo Horizonte are presented

Desenvolvimento de um software para o dimensionamento de sistemas de ventilação e resfriamento evaporativo em instalações avícolas climatizadas

Este trabalho foi conduzido com o objetivo de desenvolver um software para o dimensionamento completo de sistemas de resfriamento evaporativo, levando em consideração o balanço de energia dentro das instalações, o qual inclui o calor produzido pelas aves, radiação proveniente da cobertura e outros. Buscou-se, também, simular as condições de conforto dentro das instalações, assim como a temperatura, umidade relativa e demais variáveis psicrométricas do ar interno ao longo do comprimento das instalações. O programa foi desenvolvido na linguagem de programação Object Pascal, utilizando Delphi 6.0, para rodar em ambiente Windows. O programa apresentou-se simples e eficaz, resumindo, em poucas janelas, todos os dados necessários à análise do balanço de energia em um galpão avícola, equipado com sistema de resfriamento evaporativo, fornecendo informações suficientes ao dimensionamento desse sistema de resfriamento. Esse programa será extremamente útil para o correto dimensionamento de Sistemas de Resfriamento Evaporativo, pois, fornece para 10 pontos diferentes (de uma extremidade à outra do galpão) as principais características psicrométricas do ar interno, além do Índice de Temperatura e Umidade, contemplando os acréscimos de calor e massa das aves e de calor da construção. A desconsideração dessas variáveis tem levado a erros de projeto, os quais poderão ser evitados por meio dos subsídios, que o software venha oferecer. Além disso, por meio do programa, pode-se calcular o número de exaustores e definir a disposição, a área e o comprimento de placa porosa necessários, além da velocidade do ar na placa.This work aimed at developing software to entirely design an evaporative cooling system, taking into consideration the energy exchange in the building, which among other factors, includes the heat produced by the birds and radiation from the roofing. It also aimed to simulate the fluctuations of temperature, relative humidity, comfort conditions and other psychometric variables of indoor air along length of the installation. The program was developed with use of Paschal Object language, using Delphi 6.0, to work in Windows. The program was found to be efficient, in summarizing all necessary data, in few windows, for the analysis of energy exchange in an avian facility equipped with an evaporative cooling system, thus providing enough information to design a system for Brazilian facilities. Such a tool would be extremely useful for the correct design of evaporative cooling systems, as it also provides the main psychometric characteristics, air temperature and humidity index, contemplating heat addition, bird mass and heat at 10 different points of the installation. Ignoring these factors has led to design errors, which can be avoided by the use of this software. The program also calculates the number of exhaust fans and indicates their placement, the required area and length of pad material, and the air speed close to the pad