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Full-Text Articles in Engineering

Hydrodynamics Of A Gas-Driven Gas-Liquid-Solid Spouted Bed, Jia Meng Aug 2018

Hydrodynamics Of A Gas-Driven Gas-Liquid-Solid Spouted Bed, Jia Meng

Electronic Thesis and Dissertation Repository

A novel cylindrical gas-driven gas-liquid-solid spouted bed was developed in this project, which has a high potential to be used for a biological wastewater treatment process. Solids motion, flow regimes, and regime transitions in this system were studied. With increasing gas velocity, four regimes were identified, including: fixed bed, semi spouted bed, full spouted bed and internal circulating fluidized bed. The respective gas velocities for the transitions between the four regimes were experimentally identified and termed as minimum spouting velocity, full spouting velocity and minimum circulating velocity. A new “basketing” method was adopted to measure the minimum spouting velocity while ...


Reactor Performances And Hydrodynamics Of Various Gas-Solids Fluidized Beds, Jiangshan Liu Aug 2016

Reactor Performances And Hydrodynamics Of Various Gas-Solids Fluidized Beds, Jiangshan Liu

Electronic Thesis and Dissertation Repository

The reactor performances and hydrodynamics were systematically studied in a multifunctional fluidized-bed system which included a bubbling fluidized bed (BFB), a turbulent fluidized bed (TFB) as well as a newly identified circulating turbulent fluidized bed (CTFB) using the same batch of activated FCC particles. Catalytic ozone decomposition was employed as the model reaction to experimentally investigate the reactor performances of BFB, TFB and CTFB. The complete mappings of ozone concentration were obtained in these fluidized beds, showing close relationship with the solids holdup distributions. In the BFBs and TFBs, the study of scale-up effect revealed that the static bed height ...


Investigations In Hydrodynamics And Mixing Pattern In The Bubble Column Equipped With Internals, Keller J H George Aug 2015

Investigations In Hydrodynamics And Mixing Pattern In The Bubble Column Equipped With Internals, Keller J H George

Electronic Thesis and Dissertation Repository

Bubble column reactors, with or without solid particles, have a number of applications in the chemical, petrochemical, biochemical and environmental industries. A number of these industrial applications require internals such as baffles, heat transfer surfaces and special distributors to meet demands. Proper selection and design of these internals can lead to the improved performance and efficiency of a bubble column reactor. Several experiments are carried out in a bubble column equipped with a concentric tube bundle (CT) and an internal combination consisting of a concentric tube bundle and concentric baffle (or static mixer) (CTB) respectively. Neutrally buoyant particles are used ...


Impact Of Local Bed Hydrodynamics On Jet-Bed Interaction, Maryam Mohagheghi Dar Ranji Nov 2014

Impact Of Local Bed Hydrodynamics On Jet-Bed Interaction, Maryam Mohagheghi Dar Ranji

Electronic Thesis and Dissertation Repository

In Fluid CokingTM or Fluid Catalytic Cracking liquid feedstocks are injected into a bed of fluidized particles. Uniform distribution of liquid feed on fluidized particles increases the yield of valuable products and improves operability in these processes. Contact between the injected liquid and the bed particles can be greatly affected by the liquid properties and local bed hydrodynamics.

The impact of parameters such as liquid properties, fluidization velocity, nozzle atomization gas flowrate, nozzle location and inclination were investigated on the distribution of liquid sprayed into a fluidized bed with a reliable and fast response capacitance meter. This method was ...


High Density Gas-Solids Circulating Fluidized Bed Riser And Downer Reactors, Chengxiu Wang Aug 2013

High Density Gas-Solids Circulating Fluidized Bed Riser And Downer Reactors, Chengxiu Wang

Electronic Thesis and Dissertation Repository

A systematic and comprehensive study of hydrodynamics and reactor performance was conducted in a 76 mm i.d., 10 m high riser and a 76 mm i.d., 5.8 m high downer reactor under high density/flux operating conditions using fluid catalytic cracking (FCC) catalyst particles. An optical fiber probe was used to obtain a complete mapping of local solids holdup and particle velocity. Catalytic ozone decomposition reaction was employed to study the characteristics of reactor performance in the CFB riser and downer. The superficial gas velocity (Ug) and the solids circulation rate (Gs) were 3-9 m ...


Development And Application Of An Experimental Model For The Fluid Coking Process, Carolina B. Morales Aug 2013

Development And Application Of An Experimental Model For The Fluid Coking Process, Carolina B. Morales

Electronic Thesis and Dissertation Repository

Liquid injection into a fluidized bed is used in industrial applications such as the Fluid CokingTM process for heavy oil thermal cracking. Poor initial liquid-solid contact results in the formation of agglomerates that limit heat and mass transfer processes, reduce the yield of valuable compounds and create operating problems. The present study develops a new experimental model to simulate the complex phenomena that occur when heavy oil is injected in a Fluid Coker through two-phase nozzles. The model is applied in a pilot scale fluidized bed using scaled-down industrial spray nozzles. The experimental results indicate that agglomerate formation slows ...


Hydrodynamics And Micro Flow Structure Of Gas-Solid Circulating Turbulent Fluidized Beds, Maozhan Qi Apr 2012

Hydrodynamics And Micro Flow Structure Of Gas-Solid Circulating Turbulent Fluidized Beds, Maozhan Qi

Electronic Thesis and Dissertation Repository

Circulating Turbulent Fluidized Beds (CTFB) refer to fluidized beds integrated into high density circulating systems to simultaneously achieve highly efficient gas-solid interactions existing in turbulent fluidized beds and low solids backmixing featured by circulating fluidized beds. Hydrodynamics and micro flow structure were experimentally studied in a CTFB (3.6 m high and 0.104 m id) using 76 µm FCC particle with air velocities of 0.5 ~ 5.0 m/s and solids circulation rates of 0 ~ 420 kg/m2s The distributions of solids holdup were acquired using optical fibre probes and pressure transducers at sampling frequencies of ...


Effects Of Internals Configurations On Heat Transfer And Hydrodynamics In Bubble Columns - With And Without Solid Particles, Anil Kumar Jhawar Dec 2011

Effects Of Internals Configurations On Heat Transfer And Hydrodynamics In Bubble Columns - With And Without Solid Particles, Anil Kumar Jhawar

Electronic Thesis and Dissertation Repository

Internals of different types are required in a number of industrial applications of bubble columns to achieve the desired mixing or to remove the heat of reaction to maintain desired temperature and isothermal conditions of operation. Some of these applications include Fischer-Tropsch synthesis, methanol synthesis, and production of dimethyl ether (DME). The presence of internals however can alter the column hydrodynamics and mixing patterns which could influence reactor performance. A fast response probe capable of capturing bubble dynamics, as well as detecting flow direction is used to study the effect of internals on local heat transfer and column hydrodynamics in ...