scholarly journals Comparison of Riser-Simplified, Riser-Only, and Full-Loop Simulations for a Circulating Fluidized Bed

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 306 ◽  
Author(s):  
Min Wang ◽  
Yingya Wu ◽  
Xiaogang Shi ◽  
Xingying Lan ◽  
Chengxiu Wang ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Fluid Model ◽  
Pilot Scale ◽  
Pressure Balance ◽  
Solids Holdup ◽  
Mass Flow Rates ◽  
Scope Of Application ◽  
Two Fluid Model ◽  
Reasonable Prediction

With the development of computing power, the simulation of circulating fluidized bed (CFB) has developed from riser-simplified simulation to riser-only simulation, then to full-loop simulation. This paper compared these three methods based on pilot-scale CFB experiment data to find the scope of application of each method. All these simulations, using the Eulerian–Eulerian two-fluid model with the kinetic theory of granular theory, were conducted to simulate a pilot-scale CFB. The hydrodynamics, such as pressure balance, solids holdup distribution, solids velocity distribution, and instantaneous mass flow rates in the riser or CFB system, were investigated in different simulations. By comparing the results from different methods, it was found that riser-simplified simulation is not sufficient to obtain accurate hydrodynamics, especially in higher solids circulating rates. The riser-only simulation is able to make a reasonable prediction of time-averaged behaviors of gas–solids in most parts of riser but the entrance region. Further, the full-loop simulation can not only predict precise results, but also obtain comprehensive details and instantaneous information in the CFB system.

scholarly journals Catalytic Cracking of Heavy Oil from Waste Plastic in Tapered Circulating Fluidized Bed Riser Reactor

2020 ◽  
Vol 141 ◽  
pp. 01012
Author(s):  
Parinya Khongprom ◽  
Thanapat Whansungnoen ◽  
Permsak Pienduangsri ◽  
Waritnan Wanchan ◽  
Sunun Limtrakul
Keyword(s):  
Fluidized Bed ◽  
Heavy Oil ◽  
Catalytic Cracking ◽  
Circulating Fluidized Bed ◽  
Fluid Model ◽  
Plastic Waste ◽  
Hydrodynamic Behavior ◽  
Continuous Increase ◽  
Waste Plastic ◽  
Two Fluid Model

Because of the continuous increase in the amount of plastic waste, catalytic cracking is an interesting method that could be used to convert heavy oil from thermal cracking of plastic waste into fuel. The objective of this study was to investigate the hydrodynamic behavior and the performance of catalytic cracking of heavy oil in a circulating fluidized bed reactor using computational fluid dynamics. The two– fluid model incorporated with the kinetic theory of granular flow was applied to predict the hydrodynamic behavior with a reactive flow. Three reactor geometries were studied, which included a conventional riser, tapered–out riser, and tapered–in riser. The four–lump kinetic model was used to describe the catalytic cracking of heavy oil from waste plastic. A core–annulus flow pattern was found in the three reactor geometries. The solid fraction distribution of the tapered reactor was found to be more uniform than that of the conventional riser. The tapered–in riser showed the highest heavy oil conversion with the lowest gasoline selectivity. However, the heavy oil conversion and gasoline selectivity of the conventional and tapered–out reactors were not significantly different.

Carbon dioxide purity and combustion characteristics of oxy firing compared to air firing in a pilot-scale circulating fluidized bed

Energy ◽  
2019 ◽  
Vol 166 ◽  
pp. 183-192 ◽  
Author(s):  
Ji-Hong Moon ◽  
Sung-Ho Jo ◽  
Sung Jin Park ◽  
Nguyen Hoang Khoi ◽  
Myung Won Seo ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Pilot Scale ◽  
Combustion Characteristics

Simulations of vertical jet penetration using a filtered two-fluid model in a gas–solid fluidized bed

Particuology ◽  
2017 ◽  
Vol 31 ◽  
pp. 95-104 ◽  
Author(s):  
Shuyan Wang ◽  
Baoli Shao ◽  
Xiangyu Li ◽  
Jian Zhao ◽  
Lili Liu ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Fluid Model ◽  
Jet Penetration ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Vertical Jet

Pilot-Scale Study on Improving SNCR Denitrification Efficiency by Using Gas Additives

2018 ◽  
Vol 17 (3) ◽  
Author(s):  
Zhou Weiqing ◽  
Liu Meng ◽  
Huang Baohua ◽  
Qiu Xiaozhi
Keyword(s):  
Low Temperature ◽  
Fluidized Bed ◽  
Reaction Temperature ◽  
Temperature Region ◽  
Circulating Fluidized Bed ◽  
Catalytic Reduction ◽  
Pilot Scale ◽  
Incomplete Oxidation ◽  
Optimal Value

Abstract The experiment of improving Selective Non-Catalytic Reduction (SNCR) denitrification efficiency with gas additives (CH4 and C3H8) was carried out in the 50 kW circulating fluidized bed (CFB) pilot-scale equipment. The results show that the denitrification efficiency can reach 20 % when the reaction temperature is 650 °C, and the optimum mole ratio of C3H8/NH3 is 0.5. The denitrification efficiency can exceed 50 % when the mole ratio of C3H8/NH3 is 0.4 and the reaction temperature is 720 °C. However, the CH4 additive does not promote denitrification at this temperature. When the reaction temperature is 760 °C, the optimum denitrification efficiency of CH4 is 60 %, and the required CH4/NH3 is 0.8. Once the amount of CH4 exceeds the optimal value, the denitrification efficiency is suppressed. In addition, the concentrations of N2O and CO in the gas increase significantly with an increase of gas additives. Due to the incomplete oxidation of C3H8, a large amount of C2H4 is produced in the low-temperature region (< 750 °C) of SNCR.

Solids Holdup of High Flux Circulating Fluidized Bed at Elevated Pressure

2012 ◽  
Vol 35 (5) ◽  
pp. 904-910 ◽  
Author(s):  
S. Yin ◽  
B. Jin ◽  
W. Zhong ◽  
Y. Lu ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Elevated Pressure ◽  
High Flux ◽  
Solids Holdup
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