Radiotracer Technology in Mixing Processes for Industrial Applications

Othman, Nur Tantiyani Ali; Kamarudin, Siti Kartom

doi:10.1155/2014/768604

Cited by 14 publications

(18 citation statements)

References 44 publications

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“…In some cases this can be difficult to find directly from a plot of E versus t because of the fine scale around the endpoint. Brown et al [6][7][8] had proposed that mixing time is the time after the injection of tracer, when tracer concentration of normalized curve is within ± 5 % of the final equilibrium value. In order to obtain accurate value of mixing time from the measured curves, variance with respect to C(f) is plotted as a function of time and mixing time corresponding to 0.05 of variance is obtained.…”

Section: Data Analysis and Resultsmentioning

confidence: 99%

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Goswami

Biswal

Samantray

et al. 2014

J Radioanal Nucl Chem

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Mixing times and holdup of solids were measured in a gas-solid fluidized bed using radiotracer technique. Sand and air were used as solid and gas phase, respectively in the fluidized bed. Gold-198 labeled sand particles were used as radiotracer for mixing time measurement at different operating conditions and 137 Cs sealed source was used for holdup measurement at different axial and radial positions. The experiments were conducted at different operating conditions. The measured mixing times ranged from 1.4 to 21 s at different conditions. It was observed that at a particular bed height, the mixing time initially decreases with increasing gas velocity and tend to become constant at higher gas velocities. However, mixing time increases with increasing bed height. The holdup fraction of solid was found to be more towards the wall compared to the centre of the column. The study provided inputs to improve the existing design, design of a new system and scale-up of the process.

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Section: Data Analysis and Resultsmentioning

confidence: 99%

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Goswami

Biswal

Samantray

et al. 2014

J Radioanal Nucl Chem

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“…The theoretical mean hydraulic retention time (MHRT) of the systems were calculated using Eq. (1) [10,11,20,21].…”

Section: Calculation Of Theoretical and Experimental Mhrtmentioning

confidence: 99%

“…The RTD analysis technique has been extensively used to characterize system performance by identifying possible anomalies present in reactors [8][9][10][11][12]. This is achieved by injecting a minute amount of tracer into the inlet of the reactor and monitoring the outlet.…”

Section: Introductionmentioning

confidence: 99%

“…Although several chemical, optical and radioactive tracers have been employed to investigate RTD in wastewater treatment plants, properties like high detection sensitivity and high selectivity, which facilitate in-situ measurements and the online collection of data, make radiotracers a superior choice in terms of the RTD analysis of large-scale industrial systems. The advantages of using radiotracers in RTD studies of full-scale industrial processes have been discussed in detail by many researchers [10][11][12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Radiotracer investigation of a pulp and paper mill effluent treatment plant

et al. 2017

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The pulp and paper industry is highly dependent on water for most of its processes, producing a significant amount of wastewater that should be treated to comply with environmental standards before its discharge into surface-water reservoirs. The wastewater generated primarily consists of substantial amounts of organic, inorganic, toxic and pathogenic compounds in addition to nutrients, which are treated in an effluent treatment plant that often combines primary, secondary, tertiary and advanced treatments. However, the treatment methods vary from industry to industry according to the process utilized. The effective performance of effluent treatment plants is crucial from both environmental and economic points of view. Radiotracer techniques can be effectively used to optimize performance and detect anomalies like dead zones, bypassing, channelling, etc. in wastewater treatment plants. Experiments on the distribution of residence time were performed on the aeration tank and secondary clarifier of a full-scale pulp and paper mill to study the flow behaviour as well as locate system anomalies and hence evaluate the performance of the treatment plants using the radiotracer I-131. The convolution method was applied to model the system with an imperfect impulse radiotracer input. The aeration tank was working efficiently in the absence of any dead zones or bypassing. Various hydrodynamic models available in the literature were applied on the aeration tank and secondary clarifier to obtain the hydraulic representation of the systems.

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“…Hydrodynamics of such intricate systems and processes can be examined using the residence time distribution (RTD) technique [7][8][9]. RTD is a well-established method that has been applied form many decades to study the hydrodynamics of complicated industrial systems [10][11][12][13]. Several RTD studies performed on ASP shows that the AT acts as a complete mixing tank and excessive air supply is needed to ensure the aerobic condition, provided by air diffusion systems or surface aerators.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics and parametric study of an activated sludge process using residence time distribution technique

Sarkar

Sangal

Bhunia

2019

Environmental Engineering Research

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Hydrodynamic study of Activated Sludge Process (ASP) is important to optimize the reactor performance and detect anomalies in the system. Residence time distribution (RTD) study has been performed using LiCl as tracer on a pilot scale aeration tank (AT) and ASP, treating the pulp and paper mill effluent. The hydraulic performance and treatment efficiency of the AT and ASP at different operating parameters like residence time, recycle rate was investigated. Flow anomalies were identified and based on the experimental data empirical models was suggested to interpret the hydrodynamics of the reactors using compartment modelling technique. The analysis of the RTD curves and the compartment models indicated increase in back-mixing ratio as the mean hydraulic retention time (MHRT) of the tank was increased. Bypassing stream was observed at lower MHRT. The fraction of dead zone in the tank increased by approximate 20-25% with increase in recycle rate. The fraction of the stagnant zone was found well below 5% for all performed experiments, which was under experimental error. The substrate removal of 91% for Chemical oxygen demand and 96% for Biochemical oxygen demand were observed for the ASP working at a hydraulic mean residence time 39 h MRT with a 20% recycling of activated sludge.

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Radiotracer Technology in Mixing Processes for Industrial Applications

Cited by 14 publications

References 44 publications

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Measurement of mixing time and holdup of solids in gas–solid fluidized bed using radiotracer technique

Radiotracer investigation of a pulp and paper mill effluent treatment plant

Hydrodynamics and parametric study of an activated sludge process using residence time distribution technique

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