This study developed and tested a laboratory-scale conical spouted bed (CSB) reactor model to investigate minimum spouting velocities. Existing correlations for predicting minimum spouting velocity were found to have shortcomings for small CSBs. Experimental results were used to develop a new empirical correlation that showed excellent agreement. Ongoing work includes further testing to develop a universally applicable correlation, installing a data acquisition system, and designing a CSB biomass gasifier for hydrogen generation.

1. 1
An Experimental Study of
Small-Sized Conical Spouted
Beds (CSBs)
11th ASME Early Career Technical Conference
Georgia Institute of Technology, November 4-5, 2011
Mandeep Sharma, Matthew Lousteau, Dr. Ingmar Schoegl
Department of Mechanical Engineering
Louisiana State University

2. 2
Background
Mathur and Gishler introduced Spouted Bed
Reactors at NRC Canada in 1954
• Alternative for drying moist wheat grains (peas,
lentils and flax)
• Combustion of solid and heavy liquid fuels
• Potential for gasification and pyrolysis of wastes:
 Biomass (rice husk, pine or hard wood saw dust
etc.)
 Plastics
 Tires

3. 3
Objective
 Major goal: develop a laboratory scale CSB
gasifier facility for generating H2 from biomass
 Reactor design depends on hydrodynamic
parameters
 Minimum Spouting Velocity
 Pressure drop across the bed
 Results from the Cold Flow CSB reactor model
provides foundation for hot flow CSB reactor

4. 4
Conical Spouting Bed
Contacting of solids with fluid by injecting a steady
axial jet of fluid
Spouting behavior
Schematic of CSB reactor model

5. 5
Unique Characteristics of CSBs
• Suitable for treatment of coarse, sticky, moist
and irregular shaped material
• Short residence time
• Better heat and mass transfer inside the reactor
• Economical

6. 6
Minimum Spouting Velocity (ums)o
- minimum superficial fluid velocity at which inert
particles bed remains in the spouted state
Two ways to find it
Experimental
Theoretical

7. 7
Experiment

8. 8
Cold Flow CSB model
• Fluidizing medium: Air
• Bed material: Aluminum oxide particles (dp = 483
µm and 1092 µm, ρ = 3960 Kg/m3)
• Column: ID of 63.5 mm
• Fluid inlet diameters: 6.35 mm, 4.572 mm and
3.302 mm
• The stagnated bed height: 10 mm to 50 mm- 60°
conical contactor

9. 9
CSB Cold Flow Setup
Air
Schematic of experimental set-up: (1) air manifold, (2) air filter (3), control valve, (4/5)
rotameters, (6) air inlet pipe, (7/8) pressure taps at bed inlet and outlet, (9) U-tube
manometer, (10) conical contactor, (11) bed material, and (12) cylindrical column.

10. 10
Different Spouting Regimes

11. 11
Effect of system parameters on (ums)o
Effect of different Ho, Do and dp on (ums)o

12. 12
Theoretical way

13. 13
Existing Correlations for (ums)o
Source Correlation Eqn.
Markowski
(1)
(1983)
Choi (1992) (2)
Gorshtein
(3)
(1964)
Mukhlenov
(4)
(1965)
Tsvik (1967) (5)
Olazar (1992) (6)
Olazar (1996) (7)
Bi (1997) (for
(8)
Db/Do ≥1.66)
They used significantly larger CSBs than the model
investigated in present study

14. 14
Summary of operating parameters used previously
and in the present study
Source Particle D0 Dc Di ϒ Ho (mm)
size (mm) (mm) (mm) (mm) (deg)
Markowski et 3.41 ~ 300 ~ 5.6 ~ 3.36 ~
5.6 ~ 300 37
al. (1983) 10.35 1100 300 690
Choi et al. 2.1 ~ 2.8 240 ~ 240 ~
21 ~ 35 38 60
(1992) 450 400
Olazar et al. 0.95 ~ 25 28 ~ 70 ~
30 ~ 60 360 60
(1992) 45 300
Bi H. T. et al. 1.16 12.7 ~ 65 ~ 30 ~ 80 ~
38.1
(1997) 25.4 95.8 60 335
Present Study 0.483, 3.3 ~ 63.5 ~ 3.3~
30, 60 10 ~ 65
(2011) 1.092 9.525 70 9.52
Evaluation of accuracy and applicability of
existing correlations for ums required small sized
CSBs

15. 15
Evaluation of Correlations …cont’d
Correlations’ predictions comparison with
experimental results for a particular set of operating
parameters

16. 16
Evaluation of Correlations …cont’d
For one particular data set - e.g. 60°, 483 µm, 6.35 mm Do
best performing correlations align with the
diagonal line

17. 17
Evaluation of Correlations …cont’d
Comparison of Gorshtein correlation for all data sets

18. 18
Evaluation of Correlations …cont’d
Comparison of Mukhlenov correlation for all data sets

19. 19
Evaluation of Correlations …cont’d
Comparison of Tsvik correlation for all data sets

20. 20
Evaluation of Correlations …cont’d
Comparison of Choi correlation for all data sets

21. 21
Poor performance of correlations:

22. 22
Proposed Correlation

23. 23
Proposed correlation shows excellent agreement with experiments
75 o
Present Study, 60 cone angle
70 + 16.3 %
0.483 mm dp, 6.350 mm Do
65 0.483 mm dp, 4.572 mm Do
60 0.483 mm dp, 3.302 mm Do
55 1.092 mm dp, 6.350 mm Do
Predicted (ums)o, m/s
50 1.092 mm dp, 4.572 mm Do - 17.15 %
45 1.092 mm dp, 3.302 mm Do
40
35
30
25
20
15
10
5
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
Experimental (ums)o, m/s

24. 24
Conclusions
• Available Correlations have shortcomings for
small-sized laboratory scale CSB studies
• Developed Simple empirical correlation for (ums)o
Showed excellent agreement with experimental
findings
• Results provide platform for design and fabrication
of hot flow facility

25. 25
Work in Progress…
• Additional tests required for the development of a
universally applicable correlation for ums
predictions for small-sized laboratory scale CSBs.
• Data acquisition system installation
• design and development of a laboratory scale
CSB biomass gasifier for H2 generation

26. 26
Questions?

27. 27
Thank You!
Acknowledgement: Louisiana State University Council on
Research Faculty Research Grant Program

28. 28
Backup Slides

29. 29
Pressure Drop Measurements
Effects of Ho and Do on stable pressure drops and
maximum pressure drops