scholarly journals The Residence Time Distribution of the Gas Phase in the Riser of a Circulating Fluidized Bed

2007 ◽  
Vol 79 (9) ◽  
pp. 1299-1300
Author(s):  
M. Van de Velden ◽  
J. Baeyens ◽  
J. Degrève
Keyword(s):  
Gas Phase ◽  
Fluidized Bed ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Circulating Fluidized Bed

Hydrodynamics of Double-Dipleg Circulating Fluidized Beds for Waste Incineration

2003 ◽  
Author(s):  
Xiaoyin Yun ◽  
Weigang Lin ◽  
Shaohua Wu
Keyword(s):  
Fluidized Bed ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Circulating Fluidized Bed ◽  
Waste Incineration ◽  
Pressure Profile ◽  
Gas Velocity ◽  
New Type ◽  
Superficial Gas Velocity

In order to solve the problems of high temperature chlorine induced corrosion and the emission of dioxins, a new type of double-dipleg circulating fluidized bed incinerator is under development at the Institute of Process Engineering, Chinese Academy of Sciences. Understanding the hydrodynamics of such new type of CFB incinerator are of crucial importance for successful design and operation of the system. Experiments have been carried out in a lab-scale double-dipleg circulating fluidized bed to study the hydrodynamics of such system. The investigation is focused on the pressure profile in the loop and residence time distribution of particles with different sizes and densities in the secondary dipleg. The results show that the pressure profile in such system is similar to that in the conventional CFB. The residence time distribution (RTD) function of particles in the second dipleg varies with particle recirculating rate, superficial gas velocity and the characteristics of the particles, such as density and size. The mean residence time of particles decreases sharply with an increase of the particle re-circulating rate and slightly decreases as the superficial gas velocity increases. It appears that the density of particle has a stronger influence on the residence time than the particle size. The lighter particles have a shorter residence time. The residence time distribution function of the particles is described by a tank-in-series model. The implication of the results to the design and operation of the double-dipleg circulating fluidized bed incinerator are discussed.

A method for measuring the residence time distribution of particles in a fluidized bed based on digital image analysis

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jiamin Li ◽  
Xiaoping Chen ◽  
Jiliang Ma ◽  
Cai Liang
Keyword(s):  
Image Analysis ◽  
Fluidized Bed ◽  
Residence Time ◽  
Digital Image ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Digital Image Analysis ◽  
Color Space ◽  
The Difference ◽  
Accuracy And Repeatability

AbstractTraditional methods for measuring the residence time distribution (RTD) of particles in a fluidized bed are complex and time-consuming. To this regard, the present work proposes a new measurement method with remarkable efficiency based on digital image analysis. The dyed tracers are recognized in the images of the samples due to the difference of colors from bed materials. The HSV and the well-known RGB color space were employed to distinguish the tracers. By enhancing the Saturation and the Value in HSV and adjusting the gray range of images, the recognition error is effectively reduced. Then the pixels representing the tracers are distinguished, based on which the concentration of the tracers and RTD are measured. The efficiency, accuracy and repeatability of the method were validated by RTD measurements experiments. The method is also fit for distinguishing the target particles from multi-component systems consisting of particles of different colors.

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