In global industrialization, efforts have been made to increase the rate of heat transfer in heat exchanger, minimizing the size of heat exchanger to reduce cost as well as increasing the effectiveness. Helical coil h...In global industrialization, efforts have been made to increase the rate of heat transfer in heat exchanger, minimizing the size of heat exchanger to reduce cost as well as increasing the effectiveness. Helical coil heat exchanger (HCHE) has been proven to be effective in improving heat transfer due to its large surface area. In this study, HCHE was designed to provide hot air needed for fluidized bed drying processes. The HCHE design model was fabricated and evaluated to study the efficiency of the hot air output for a laboratory fluidized bed dryer. The mathematical model for estimation of the final (output) temperature of air, Taf, passing through the HCHE was developed and validated experimentally. The drying of bitter kola particulates was carried out with a drying temperature of 50C 3C and a bed height-to-bed diameter ratio (H/D) of 1.5. The time taken to dry bitter kola particulates to 0.4% moisture content was 1 hour 45 minutes. Hence, HCHE is recommended for use in the production of hot for laboratory-scale fluidized bed dryers.展开更多
Mango is a widely cultivated and consumed fruit in Brazil and one of the most important alternatives to take advantage of the production excess is dehydration. Therefore, this work aims at establishing better operatio...Mango is a widely cultivated and consumed fruit in Brazil and one of the most important alternatives to take advantage of the production excess is dehydration. Therefore, this work aims at establishing better operational conditions for ＂spray-drying＂ processes, in order to obtain the powder of mango pulp by means of a rotational central compounded planning, and also at carrying out the physicochemical characterization of both the integral mango pulp and the powder obtained from the operational conditions mentioned above. Both integral mango pulp and powder were analyzed as for the following physicochemical characteristics： humidity, pH, titratable acidity, soluble solids （~Brix）, vitamin C and color--through parameters L＊, a＊, b＊ and h0, Chrome （C＊） and color difference （AEL＊a＊b＊）. The experimental planning used presented significant differences at 5% of probability, showing that the model was adjusted to the data in accordance to F test, thus being possible to determine the best process conditions. In addition, the average results of the physicochemical parameters pointed out that the pulp used was in accordance with the patterns established by the quality and identity patterns for mango pulp. Moreover, it showed that the powder obtained had good physicochemical quality.展开更多
文摘In global industrialization, efforts have been made to increase the rate of heat transfer in heat exchanger, minimizing the size of heat exchanger to reduce cost as well as increasing the effectiveness. Helical coil heat exchanger (HCHE) has been proven to be effective in improving heat transfer due to its large surface area. In this study, HCHE was designed to provide hot air needed for fluidized bed drying processes. The HCHE design model was fabricated and evaluated to study the efficiency of the hot air output for a laboratory fluidized bed dryer. The mathematical model for estimation of the final (output) temperature of air, Taf, passing through the HCHE was developed and validated experimentally. The drying of bitter kola particulates was carried out with a drying temperature of 50C 3C and a bed height-to-bed diameter ratio (H/D) of 1.5. The time taken to dry bitter kola particulates to 0.4% moisture content was 1 hour 45 minutes. Hence, HCHE is recommended for use in the production of hot for laboratory-scale fluidized bed dryers.
文摘Mango is a widely cultivated and consumed fruit in Brazil and one of the most important alternatives to take advantage of the production excess is dehydration. Therefore, this work aims at establishing better operational conditions for ＂spray-drying＂ processes, in order to obtain the powder of mango pulp by means of a rotational central compounded planning, and also at carrying out the physicochemical characterization of both the integral mango pulp and the powder obtained from the operational conditions mentioned above. Both integral mango pulp and powder were analyzed as for the following physicochemical characteristics： humidity, pH, titratable acidity, soluble solids （~Brix）, vitamin C and color--through parameters L＊, a＊, b＊ and h0, Chrome （C＊） and color difference （AEL＊a＊b＊）. The experimental planning used presented significant differences at 5% of probability, showing that the model was adjusted to the data in accordance to F test, thus being possible to determine the best process conditions. In addition, the average results of the physicochemical parameters pointed out that the pulp used was in accordance with the patterns established by the quality and identity patterns for mango pulp. Moreover, it showed that the powder obtained had good physicochemical quality.
