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Drying
Published in Pau Loke Show, Chien Wei Ooi, Tau Chuan Ling, Bioprocess Engineering, 2019
Chung Hong Tan, Zahra Motavasel, Navin Raj Vijiaretnam, Pau Loke Show
Moisture in materials play a vital role in either maintaining or affecting the materials’ quality. Information about the moisture content is vital for safe storage and usage of materials, for instance, food products. Moisture content is described as the quantity of water present in the bulk material and is normally expressed as a percentage. Wet materials can be designated as binary mixtures of a dry solid material and water. The water concentration is expressed as the relative mass fraction of the liquid (XA), which is simplified by the equation below: () XA=mAmC
Landfill Bioreactor Studies
Published in Debra R. Reinhart, Timothy G. Townsend, Landfill Bioreactor Design and Operation, 2018
Debra R. Reinhart, Timothy G. Townsend
Moisture content, pH, temperature, availability of macro- and micro-nutrients and the presence of suitable microorganisms are the main parameters controlling the process of landfill stabilization and, therefore, are the parameters typically manipulated in the laboratory studies. Moisture content can be controlled by the addition of regulated quantities of water and/or leachate. The pH can be controlled by adding buffering compounds. Macro- and micro-nutrients are usually present in sufficient quantities in the waste and do not act as limiting factors in the stabilization process, hence nutrients usually are not added. Presence of suitable microorganisms responsible for stabilization can be ensured by adding anaerobically digested sludge in which acclimated anaerobic and facultative microorganisms are present. The impacts of these parameters have been investigated numerous times and will be discussed as appropriate in the review of each study.
Exergy Analysis of Food Drying Processes and Systems
Published in Mohammed M. Farid, Mathematical Modeling of Food Processing, 2010
Figure 36.8 depicts the variation of exergy efficiency with moisture content of the incoming products as the mass flow rate of evaporated water is varied. The exergy efficiency increases with increasing moisture content of the products. This variation is more pronounced as evaporation rate increases. In this case, the energy utilized for drying the product increases when moisture content of the products increases. For example, for given air inlet conditions, the energy utilized in the system is reduced, which in turn improves the exergy efficiency of the system. Furthermore, the drying-process exergy efficiency varies with the humidity ratio of the drying air entering the dryer for various mass flow rates of drying air. A linear relation is observed between exergy efficiency and humidity ratio. Interestingly, we note that exergy efficiency decreases only slightly with increasing humidity ratio of drying air.
Characteristics of straw particles of selected grain species purposed for the production of lignocellulose particleboards
Published in Particulate Science and Technology, 2021
Dorota Dukarska, Marta Pędzik, Wiktoria Rogozińska, Tomasz Rogoziński, Rafał Czarnecki
The grain species of straw strongly affects properties of lignocellulose particleboards, which results from different geometry of the particles. In comparison with rapeseed boards, panels made from rye and triticale straw are characterized by lower values of internal bond perpendicular to the surface determined both before and after the boil test. On the other hand though, they show higher values of modulus of rupture and modulus of elasticity as well as better dimensional stability when exposed to long-lasting action of water. Properties of the material are also affected by its moisture content. By increasing the moisture content of rapeseed particles, it is possible to improve modulus of rupture and modulus of elasticity. Yet, in the given pressing conditions, the water-resistance determined by V-100 test is deteriorated. The moisture content of straw does not, however, affect internal bond perpendicular to the board surface or thickness swelling after 24 h of soaking in water.
Energy and Exergy Analysis on Drying of Banana Using Indirect Type Natural Convection Solar Dryer
Published in Heat Transfer Engineering, 2020
Abhay Lingayat, V. P. Chandramohan, V. R. K. Raju
Drying is a most valuable process for preservation of agricultural products for a longer period of time. Drying process involves simultaneous heat and mass transfer within the product and also in between the product surface and its surrounding medium. For drying process, the moisture content in the product is a most important factor which affects the quality of the product as excessive moisture can result in product spoilage because of microbial growth, bacteria, molds, and chemical reaction. The drying process depends on many factors like air velocity, temperature, and humidity [1]. The energy, for drying, is supplied from various sources such as fossil fuel, natural gas, and solar. Drying is an effective technique used in industries dealing with agriculture and food, chemical/ceramics, paper, textile, building materials etc. Because of fossil fuel’s higher cost, uncertainty regarding future availability, and their effect on the environment, development of renewable energy sources had been taken into consideration. Solar energy is an alternative for these drying problems as it is free and clean energy [2].
Combined conventional thermal and microwave drying process for typical Chinese lignite
Published in Drying Technology, 2019
Jin Ge, Yong He, Yanqun Zhu, Zhihua Wang, Kang Zhang, Zhenyu Huang, Kefa Cen
The variance analysis was performed using SPSS 16.0 software. The results are presented in Table 6. The p value for all of the three variables was less than 0.05, which indicated that all of the three factors had significant impacts on energy consumption compared with the experimental error. Similar findings have been made in the studies from Akkoyunlu et al.[55] They used similar variance analysis method to determine the effects of factors on the moisture content of the dried coal. The results showed that the inlet air temperature was an effective parameter, while the inlet air relative humidity and inlet drying air velocity were less effective parameters. Mean square value reveals the effect of each factor on energy consumption.[52] It can be seen from Table 6 that the magnitude order of the effect was A (conversion moisture content) > C (microwave power) > B (hot air temperature). As previously mentioned, microwave drying is more efficient than conventional thermal drying. As the conversion moisture content decreased, the proportion of conventional thermal drying increased, which resulted in a longer drying time and greater energy consumption. Furthermore, the efficiency of microwave drying decreased because of the low moisture content. Therefore, the variation of conversion moisture has the most obvious impact on energy consumption.