The evolution of a solid-liquid model biological fluidised bed under a step change in fluid superficial velocity is described. During a transient step change, the fluidised bed divides into a top zone which remains at the initial porosity and a bottom zone which settles at the final porosity. The interface of discontinuity in porosity moves progressively upwards through the fluidised bed. The velocity at which the top of the fluidised bed expands or contracts and the upward velocity of the porosity transition interface depend only upon the initial and final states of the bed porosity and the fluid superficial velocity. This results in a linear evolution with time of the total bed height and the height of porosity transition interface. The proposed model is well suited to describe the transient response of low-density particles in a fluidised bed, such as encountered in biological systems, to a sudden change of liquid superficial velocity. The model was validated experimentally.
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http://dx.doi.org/10.1002/jctb.280480406 | DOI Listing |
Waste Manag
January 2025
Energy and Sustainability Department (EES), Federal University of Santa Catarina (UFSC), 88905-120, Araranguá, SC, Brazil. Electronic address:
Proper waste management and sustainable energy production are crucial for human development. For this purpose, this study evaluates the impact of blending percentage on energy recovery potential and environmental benefits of co-combustion of wastewater sludge and Brazilian low-rank coal. The sludge and coal were characterised in terms of their potential as fuel and co-combustion tests were carried out in a pilot-scale bubbling fluidised bed focused on the influence of the percentage of sludge mixture on the behaviour of co-combustion with coal in terms of flue gas composition and fluidised bed temperature stability.
View Article and Find Full Text PDFWaste Manag
July 2024
School of Environment, Tsinghua University, Beijing 100084, China. Electronic address:
The increasing application of municipal solid waste incineration (MSWI) emphasises the need for MSWI fly ash (FA) safe treatment. Based on the compositional complementarity of FA from grate furnaces (G-FA) and fluidised bed incinerators (F-FA), we proposed a co-reduction process to treat G-FA and F-FA together for producing vitrified slag and ferroalloys. The clean vitrified slag and Fe-Cr-Ni-Cu alloy were obtained with the mass ratios of 1:9 ∼ 6:4 (G-FA:F-FA) at 1300℃, which is about 300℃ lower than the conventional G-FA vitrification.
View Article and Find Full Text PDFHeliyon
April 2024
School of Pharmacy, University of Ghana, College of Health Sciences, Accra, Ghana.
Viability loss of probiotics often occur during processing, storage and gastrointestinal transit. In this study, the viability of freeze-dried LA-5® was assessed after controlled freeze drying and storage at 4 °C and 25 °C over six months using glycerol, skim milk and trehalose as protectants. The freeze-dried probiotic was filled into hard gelatin capsules and enteric coated with the co-polymer Eudragit L100-55 using a fluidised bed coater to determine if the freeze-dried probiotic will survive the enteric coating process and remain viable during gastric transit.
View Article and Find Full Text PDFJ Food Sci Technol
March 2024
Faculty of Food Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang,, Selangor Malaysia.
This work aims to produce a virgin coconut oil (VCO) creamer through two drying stages; spray drying followed by fluidised bed drying, and to examine its antioxidant properties and oxidative stability during different storage conditions. Evaluation of the physicochemical properties of spray dry VCO and oxidative stability of the VCO creamer were performed using peroxide value (PV), antioxidant activity (DPPH), and total phenolic content (TPC) at 25, 4, and 25 °C, respectively, for 8 weeks. Agglomeration process has improved the agglomerated VCO creamer's properties in terms of moisture content (4.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
February 2024
State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou, 310027, China.
This study investigates a circulating fluidised bed (CFB) incineration plant to examine the concentrations and fingerprints of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) at five locations downstream of the post-combustion zone. Sampling encompassed both flue gas and ash, spanning from the high-temperature superheater to the outlet of the baghouse filter, thus covering a wide range of flue gas temperatures. The analysis reveals a continuous increase in PCDD/F and PCB concentrations in the flue gas from the superheater to the inlet of the air pollution control system (APCS).
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