Papers by Keyword: Drying

Abstract: Spent coffee ground (SCG) consists of impact compositions and functional ingredients that could be applied to food products. Drying techniques and conditions had an impact on the qualities of SCG. The aim of this research was to investigate the chemical compositions of roasted coffee ground (CG) and SCG from Arabica (A) and Robusta (R) coffee, as well as the physical and functional properties of SCG before and after different drying using hot air tray dryer and freeze dryer. It was found that SCG had moisture and carbohydrate content of 64.79–65.87% wb and 16.55–18.57%. Arabica spent coffee ground (ASCG) had more lipid and less protein, caffeine and phenolic content than that of Robusta spent coffee ground (RSCG). The dried SCG had moisture content lower than 5% for all drying conditions. Moreover, the dried SCG had Aw, solubility, and rehydration in a range of 0.25-0.55, 6.02-6.92%, and 140.67-180.37%, respectively. Freeze-dried SCG retained more functional ingredients than tray-dried SCG across all drying conditions.

Abstract: The main directions of the economic and social development of the Republic of Azerbaijan envisage technical re-equipment in the ferrous metallurgy industry based on the wide application of progressive scientific and technical achievements. Here, an important place is given to the creation of new resource-saving technological processes and highly efficient equipment. The most important task of increasing the efficiency of obtaining iron from ore materials is to reduce the consumption of metal and energy. It is important to significantly reduce waste and losses during iron ore production by improving the quality of iron ore logs. The task set in the work is related to the conditions of production and remelting of iron ore logs in an electric furnace. Instead of melting metal waste in metallurgical plants, the steels obtained from the melting of metal logs with 95-97% iron content obtained from iron ore by one end processing method are economically very efficient and important issue for the Republic. The implementation of these important national economic issues is possible by solving the processes of drying and burning of iron ore logs, complex optimization, taking into account the limiting factors of the process of choosing rational temperature regimes and the practical application of the obtained results in the industry. The article belongs to the section "Metallurgical Heat Engineering".

Abstract: Performance of solar dryers were tested. In the past, to study the efficiency of solar dryers. A dryer with one drying chamber was built and tested by changing the conditions. In each experiment, the solar irradiance value is different, which can cause the results to be inaccurate. Therefore, in this study, a number of drying chambers are designed according to the number of experimental conditions to be studied during the same period. To reduce factors that will cause discrepancies in the experimental results. The solar dryer with 4 drying chambers was constructed in 1 unit and tested the performance of passive solar dryer (PSD) and active solar dryer (ASD). Air flowrate of ASD varied at 0.03 m³/s (ASD0.03), 0.06 m³/s (ASD0.06) and 0.09 m³/s (ASD0.09). Pork was selected as testing material with initial moisture content of 265% dry basis. Drying rate, solar dryer efficiency and specific energy consumption are criteria to evaluate of solar dryer performance. Result from the experimental was found that the performance of PSD is lowest compared with ASDs. Furthermore, it was revealed that the drying rate of ASD0.06 is higher than that for PSD, ASD0.03 and ASD0.09 by 22% 10% and 8%, respectively. Results from the experimental reveal the ASDs performance are higher than that of PSD. Moreover, it was found that the drying rate of ASD0.06 is higher than that for PSD, ASD0.03 and ASD0.09 by 22% 10% and 8%, respectively. Whereas, specific energy consumption of ASD0.06 is lower than that PSD, ASD0.03 and ASD0.09 by 26%, 11% and 9%, respectively. Finally, it was also found that solar dryer efficiency of PSD, ASD0.03, ASD0.06 and ASD0.09 are 11.68%, 13.34%, 14.89% and 13.73%, respectively.

Abstract: Drying process are important in many areas in the agriculture and food sectors, including increasing shelf life, improving transportability by reducing product weight or adding value to products. However, the main problem in the drying process is the relatively high energy consumption. Therefore, the development of energy-saving dryers is necessary. Based on the above reasons, this research aims to study the performance enhancement of heat pump dryers using R32 refrigerant by using heat recovery and nanofluid. The heat that is exhausted from the refrigerant by a heat exchanger. In this work, a Nano titanium dioxide (Ti₂O₃) was selected. Pork was dried under the conditions of drying temperature of 45, 50 and 55 °C and water flow rate in the heat exchanger at the front of the drying chamber of 2, 3 and 4 L/min. Criteria for evaluating heat pump dryer performance include drying rate, specific moisture extraction rate, specific energy consumption, heat pump dryer performance coefficient compared to heat pump dryers without nanofluid. The results showed that increasing the drying temperature and water flow rate in heat exchanger increased the drying rate, power and specific moisture extraction rate in the heat pump dryer using nanofluid. Whereas, the specific energy consumption was lower than the case without nanofluid. Increasing the drying temperature and the water flow rate in the heat exchanger had relatively little effect on the coefficient of performance (COP) of the heat pump dryer. Moreover, the study found that the coefficient of performance of heat pump dryer with nanofluid was in the range of 4.33 - 4.42.

Abstract: This paper presents a case study of solar drying of hydroxide sludge in the region of Marrakesh, Morocco. The experiments of solar greenhouse drying processes of the hydroxide sludge were studied in summer and winter seasons. The representative samples were in three volumes. The greenhouse sludge dryer was designed and constructed as a horticultural plant. Results showed that the dry of the three samples was reached in only 13 hours in summer and 25 hours in winter. The time of solar greenhouse drying registered was significantly lower compared to several studies. The higher values of drying rate were obtained in early hours of experiments in summer. The maximum ranges obtained were 0.25 kg water/kgDS.h for the hot season and 0.020 kg water/kgDS.h for the cold season. The important influence of the temperature had a greater effect with wind speed on drying rate. The sludge water evaporation caused a large volume reduction with a shrinkage during the processes in both seasons.

Abstract: Sanitary ware, including toilets, washbasins, and bathtub, plays a crucial role in maintaining hygiene and sanitation in various settings. The drying process is a critical stage in the manufacturing of ceramic sanitary ware, as it influences product quality, production efficiency, and energy consumption. Then, the purpose of this work is to investigate the drying of sanitary ware at low temperature by experiments and empirical mathematical models. The idea is to accurately predict moisture loss of the ceramic parts under different operational conditions. Results of the drying kinetics have shown that higher temperatures and lower air relative humidity accelerate the drying process. Also, no cracks or fissures were observed as a result of drying sanitary ware at low temperatures and the two-term model provides the best fit for the dimensionless average moisture content as a function of the time. These findings contribute to a better understanding of the drying process and support the optimization of sanitary ware manufacturing.

Abstract: As miniaturization progresses, pattern collapse during the drying step of wet cleaning processes has become a critical issue in the semiconductor industry. In this study, we used reactive molecular dynamics simulations to analyze pattern collapse, with a focus on bondings and reactions. To simulate pattern deformation during the drying process of wet cleaning, we created a FinFET model as a HAR structure. The surface of this model was terminated with hydrogen atoms. The widths between the patterns were changed in order to create a Laplace pressure difference when water molecules were placed on the surface. The model was simulated by placing water molecules up to half the height of the pattern. As a result, the pattern was deformed. Furthermore, by removing water molecules and changing the Laplace pressure balance, it was found that the pattern contacted each other at the tip. The pattern remained in contact when water molecules were removed from the model. In the contact area, the covalent bonds, such as Si-Si and Si-O-Si, were not formed, but instead, hydrogen-to-hydrogen van der Waals bonds were formed between patterns. We calculated the total van der Waals forces between hydrogen atoms at the contact surfaces using the Hamaker equation and calculated the elastic force of the patterns using the beam deflection formula. Our calculations showed that the total van der Waals forces between hydrogen atoms at the contact surfaces were larger than the elastic force of the patterns, indicating that van der Waals forces could be a factor in maintaining the contact of the patterns.

Abstract: The most widely used materials in building construction are porous materials and the combined effect of rising dampness with soluble salts is one major problem. This phenomenon is caused by the migration of the salt ions dissolved in water into the porous network of the construction materials in the building walls, which causes fractures in the materials after several cycles of crystallization/dissolution. This work presents an extensive experimental campaign with different cycles of water absorption (capillarity absorption tests) and drying (drying tests). The samples of building material used are red brick, and the samples were, previously, submitted to capillarity absorption tests with two different saturated solutions (sodium sulphate and potassium chloride). The results showed that the two salts studied influence the porous materials and their capillary coefficient in clearly different ways and the samples immersed in sodium chloride present higher drying rates than those immersed in a saturated sodium sulphate solution.

Abstract: Technological solutions for brown coal processing, thermal influence on it at temperature change, thermo vacuum drying are analysed and qualitative and quantitative characteristics of semi – coking products are studied. The parameters of crushing and thermo vacuum drying of brown coal, heat treatment and cascade separation (electrostatic and magnetic) are substantiated. Studies on the manufacture of a pilot batch of carbon fuel with high quality characteristics are performed. Cascade treatment of heat-treated brown coal on electric and magnetic separators allowed to obtain a concentrate with ash content from 17.72 to 22.8%, volatile yield ≤ 35%, higher heat of combustion from 7256.1 to 7523.6 kcal/kg. It is determined that favourable modes of preliminary heat treatment of brown coal samples are in the temperature range of 200-400°С. The established characteristics of the obtained solid fuel correspond to the gas group of thermal coal. The obtained technological solutions for the processing of brown coal can be the basis for the manufacture of an industrial line, taking into account the thermo vacuum installation for further implementation in enterprises using carbon fuel.

Abstract: The objective of this research is to study the influence of temperature on drying and changes in carbohydrate composition during the drying. Chlorella pyrenoidosa was dried in oven at various temperatures and initial weight 2 g. The initial moisture content of Chlorella pyrenoidosa was 487.2% dry weight and the composition was hemicellulose (62.76), cellulose (2.39), and lignin (0.46% dry weight). Every 5 min, the moisture content was recorded. The critical moisture contents of Chlorella pyrenoidosa at 50, 60, and 70 °C are 7.2, 3.9, and 3.1% dry weight, respectively. Meanwhile, the equilibrium water contents are 0.53, 0.32, and 0.12% dry weight, respectively. The carbohydrate content in Chlorella pyrenoidosa cell as a result FTIR analysis indicates that the higher temperature of drying the carbohydrate content increases. Drying of Chlorella pyrenoidosa at temperatures of 50, 60, and 70 °C will decrease moisture content without disturb carbohydrate molecule, so the carbohydrate content increases. Therefore, drying of Chlorella pyrenoidosa before converting become bio-ethanol will give benefit to increase the carbohydrate content and initial rupturing of it’s cell.