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1
Content available Three-phases bubble column to polyethylene terephthalate depolymerization for cement mortar composites improvement
Hameed A. M., Alzuhairi M., Ibrahim S. I.
Journal of Achievements in Materials and Manufacturing Engineering
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2022
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Vol. 112, nr 1
5--12
EN
Purpose: This paper aims to prepare depolymerized polyethylene terephthalate (DPET) powder from recycled plastic water bottles. Adding this DPET powder to the cement mortar was also studied. Design/methodology/approach: The adopted PET depolymerization process includes the usage of both ethylene glycol (EG) as solvent and nano-MgO as a catalyst. A bubble column reactor was designed for this process. Five different mortar groups were made; each has different DPET content of 0%, 1%, 3%, 6% and 9% as a sand replacement. The flexural strength testand the water absorption measurement are done after two curing periods: 7 and 28 days. Findings: The research finding demonstrated that the flexural strength of mortar was reduced by increasing the DPET powder percentage and the maximum dropping was 15% when 9% of DPET was added. The ability of the mortar to absorb the water was reduced by 14.5% when DPET powder was 9%. The mortar microstructure is featured with fewer cavities and porosity. Research limitations/implications: This work’s employed bubble column technique is limited only to the laboratory environment and needs to be scaled up within industrial mass production. For future research, it is suggested to decrease depolymerization time by using smaller pieces of plastic water bottle waste and trying other types of nanocatalyst. Practical implications: The modified mortar can be utilized in areas where moisture, rainfalls, and sanitation systems exist. Originality/value: The article claims that depolymerized waste PET improves chemical process efficiency by lowering reaction time and improving mass and heat transfer rates. Besides, this approach saves money. It is found out that the depolymerized plastic waste is much more functional due to its high cohesion capability than being used as small PET pieces.
2
Content available Energy consumption in terms of shear stress for two types of membrane bioreactors used for municipal wastewater treatment processes
Ratkovich N., Bentzen T., Rasmussen M.
Archives of Thermodynamics
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2012
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Vol. 33, no. 2
85-106
EN
Two types of submerged membrane bioreactors (MBR): hollow fiber (HF) and hollow sheet (HS), have been studied and compared in terms of energy consumption and average shear stress over the membrane wall. The analysis of energy consumption was made using the correlation to determine the blower power and the blower power demand per unit of permeate volume. Results showed that for the system geometries considered, in terms the of the blower power, the HF MBR requires less power compared to HS MBR. However, in terms of blower power per unit of permeate volume, the HS MBR requires less energy. The analysis of shear stress over the membrane surface was made using computational fluid dynamics (CFD) modelling. Experimental measurements for the HF MBR were compared with the CFD model and an error less that 8% was obtained. For the HS MBR, experimental measurements of velocity profiles were made and an error of 11% was found. This work uses an empirical relationship to determine the shear stress based on the ratio of aeration blower power to tank volume. This relationship is used in bubble column reactors and it is extrapolate to determine shear stress on MBR systems. This relationship proved to be overestimated by 28% compared to experimental measurements and CFD results. Therefore, a corrective factor is included in the relationship in order to account for the membrane placed inside the bioreactor.
3
Content available Multifractal properties of large bubble paths in a single bubble column
Mosdorf R., Wyszkowski T., Dąbrowski K.
Archives of Thermodynamics
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2011
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Vol. 32, no. 1
3-20
EN
In the paper the paths of bubbles emitted from the brass nozzle with inner diameter equal to 1.6 mm have been analyzed. The mean frequency of bubble departure was in the range from 2 to 65.1 Hz. Bubble paths have been recorded using a high speed camera. The image analysis technique has been used to obtain the bubble paths for different mean frequencies of bubble departures. The multifractal analysis (WTMM - wavelet transform modulus maxima methodology) has been used to investigate the properties of bubble paths. It has been shown that bubble paths are the multifractals and the influence of previously departing bubbles on bubble trajectory is significant for bubble departure frequency f[b] > 30 Hz.
4
Content available remote Application of image tomography for determination of gas flow parameters in aeration process
Chałubiec J., Rząsa M. R., Dobrowolski B.
Zeszyty Naukowe. Elektryka / Politechnika Łódzka
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2009
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z. 114
47-52
EN
This paper presents test methods and preliminary results concerning determination of gas volume fraction in the aeration column with use of image tomography. In the presented method, image of the flowing gas bubbles is registered in two perpendicular directions of observation. The image is registered by one camera and a suitable system of mirrors. The proposed method allows to reconstruct bubble shapes and determine their trajectories in the aeration column.
5
Content available Mathematical modelling of wet oxidation of excess sludge
Chacuk A., Imbierowicz M.
Polish Journal of Chemical Technology
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2007
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Vol. 9, nr 2
1-4
EN
A mathematical model enabling a quantitative description of wet oxidation of excess sludge in continuous bubble columns is proposed. The model consists of mass and heat transfer kinetic equations and material and heat balance equations of gas and liquid phases flowing through the absorber. The equations of material and heat balance refer to a parallel, co- current flow of gas and liquid phase and take into account a complex chemical reaction in the liquid phase core. The proposed model was used in a numerical simulation of wet oxidation in a bubble absorber for different process conditions: flow rate and composition of the gas and liquid phase, temperature and pressure, and different heights and diameters of the column.
6
Content available remote Mathematical modelling of wet oxidation of excess sludge in bubble columns
Chacuk A., Imbierowicz M.
Polish Journal of Chemical Technology
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2006
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Vol. 8, nr 2
1-4
EN
A mathematical model enabling a quantitative description of wet oxidation of excess sludge in continuous bubble columns is proposed. The model consists of mass and heat transfer kinetic equations as well as material and heat balance equations of gas and liquid phases flowing through the absorber. The equations of material and heat balance refer to parallel, the co- and counter-current flow of gas and liquid phase and take a complex chemical reaction in the liquid phase core into account. The proposed model was used in a numerical simulation of wet oxidation in a bubble absorber for different process conditions: the flow rate and the composition of the gas and liquid phase, the temperature and pressure, and different heights and diameters of the column.
7
Content available remote Intensification of nitric acid production
Chacuk A., Miller J.S., Wilk M.
Polish Journal of Chemical Technology
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2006
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Vol. 8, nr 3
1-4
EN
A mathematical model enabling a quantitative description of the oxidation of nitrous acid using the ozone-oxygen mixtures in the continuous bubble columns has been proposed. The model consists of mass transfer kinetic equations and material balance equations of gas and liquid phases flowing through the absorber. The material balance equations refer to the parallel, co-current flow of gas and liquid phase and take into account a complex chemical reaction in the liquid phase. The proposed model is used in a numerical simulation of oxidation in a bubble absorber for different process conditions: the flow rate and the composition of the gas and liquid phase, temperature and pressure, and different heights and diameters of the column.
8
Analiza hydrodynamiki przepływu gaz-ciecz w kolumnie pęcherzykowej
Zając D.
Zeszyty Naukowe. Mechanika / Politechnika Opolska
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2005
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z. 80
173-180
PL
W przedstawionej pracy podjęto próbę zastosowania metody cyfrowego przetwarzania obrazu w odniesieniu do przepływu mieszaniny gaz-ciecz w kolumnie pęcherzykowej. Zaprezentowano rezultaty prac badawczych prowadzonych przy użyciu metody analizy zmian poziomu szarości. Dzięki temu można było dokonać klasyfikacji poszczególnych struktur przepływu. Klasyfikacji dokonano zarówno na podstawie otrzymanych przebiegów zmian poziomów szarości, jak i po analizie stochastycznej tychże przebiegów. Za pomocą techniki PIV pokazano pola prędkości i tory ruchu pęcherzy dla wybranych przepływów. Obliczono również udział objętościowy metodą ekspandującego złoża.
EN
The aim of this work is an experimental hydrodynamic analysis of two-phase gas-liquid flow carried in simple bubble column. The continuous and dispersed phase was water and air, respectively. The flow was recorded by high speed camera. The gray level value of the obtained recordings from gas-liquid flow was the basic parameter for process investigation. Ali calculations were made by the use of Digital Image Processing method and Particle Image Velocimetry technique. The results are flow structures identification and gas phase velocity calculation.
9
Charakterystyka przepływu dwufazowego gaz-ciecz z wykorzystaniem metody cyfrowej obróbki obrazu
Zając D., Ulbrich R.
Inżynieria i Aparatura Chemiczna
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2004
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Nr 3s
187-189
EN
This paper presents an experimental study of identification and analysis of two phase gas-liquid flow using the digital image processing method. The process of two phase flow has been realized in a bubble column. The gray level value of the obtained recordings in gas-liquid flow was the basic parameter for process investigation.
10
Obliczenia symulacyjne hydrodynamiki kolumny barbotażowej
Rudniak L., Bielski P., Moniuk W., Pohorecki R.
Inżynieria Chemiczna i Procesowa
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2001
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T. 22, z. 3E
1237--1242
PL
W celu określenia wpływu własności fizykochemicznych cieczy na wielkość zatrzymania gazu wykonano obliczenia symulacyjne hydrodynamiki laboratoryjnej kolumny barbotażowej dla siedmiu cieczy organicznych w temperaturze pokojowej i pod ciśnieniem normalnym przy użyciu modelu ASMM zaimplementowanego w programie FLUENT. Wyniki obliczeń porównano z danymi doświadczalnymi.
EN
In order to establish the influence of liquid properties on gas holdup numerical simulation of laboratory bubble column hydrodynamics were carried out for seven organic liquids operated at atmospheric pressure and low temperature using ASMM model implemented in FLUENT software. Results from computer simulation were compared with experimental data.
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