Benjamin M. Statler College of Engineering and Mineral Resources 1
Coal and biomass bubbling fluidized bed gasifier - design and operation
Ali Sivri1
Cosmin Dumitrescu1
Amoolya Lalsare2
John Hu2
1 Center for Alternative Fuels Engines and Emissions (CAFEE)Department of Mechanical & Aerospace Engineering, West Virginia University
2 Department of Chemical Engineering, West Virginia University
NETL 2019 Workshop On Multiphase Flow Science
Benjamin M. Statler College of Engineering and Mineral Resources 2
• Motivation
• Objectives
• Experimental setup
• Material characteristics
• Results
• Conclusions
• Future work
Outline
Benjamin M. Statler College of Engineering and Mineral Resources 3
• Efficient use of conventional and alternative energy resources
• Bubbling fluidized bed gasifier (BFBG) can convert biomass and
coal into value-added chemicals and gaseous fuels for
transportation or electricity generation
• Understanding the parameters that affect the fluidization
hydrodynamics
• Collect experimental data representative of optimum conditions
and use it to develop numerical simulations
Motivation
Benjamin M. Statler College of Engineering and Mineral Resources 4
• Design and manufacture a BFBG that will help MFIX code
development
• Investigate parameters that affect fluidization hydrodynamics
• Investigate coal and biomass and coal gasification
o Efficiency
o Product composition
• Collect data for model development
Objectives
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Experimental setup - Cold flow visualization and measurements
Benjamin M. Statler College of Engineering and Mineral Resources 6
Expansion tanks
Heat exchanger
Screw feeder
Feeder control unit
Furnace
Screw feeder Reactor Furnace
Micro GC
Experimental setup – BFBG at high temperatures
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Particle geometry
- Particle size and sphericity distribution affects the efficiency and product gas composition
- Important for correct process simulation
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Material Average of
particle size
(µm)
Average of
Sphericity
Hardwood 432 0.564
Coal 361 0.847
Glass beads 279 0.933
Sand 368 0.863
Table 1. Material size and sphericity analysis
Material Characteristics
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Glass beads Sand
Close-up of bed material geometry
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Close-up of fuel material geometry
Biomass Coal
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0
0.5
1
1.5
2
2.5
0 0.05 0.1 0.15 0.2
ΔP
[K
Pa]
Uair [m/s]
Glass beads
100 g
200 g
300 g
0
0.5
1
1.5
2
2.5
0 0.05 0.1 0.15 0.2
ΔP
[K
Pa]
Uair [m/s]
Glass beads and coal
100 g
200 g
300 g
Results: Pressure drop across the bed - cold flow
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0
0.5
1
1.5
2
2.5
3
0 0.05 0.1 0.15 0.2
ΔP
[K
Pa]
Uair [m/s]
Glass beads and wood
100 g
200 g
300 g
0
0.5
1
1.5
2
2.5
3
0 0.05 0.1 0.15 0.2
ΔP
[K
Pa]
Uair [m/s]
Sand and wood
100 g
200 g
300 g
Results: Pressure drop across the bed - cold flow
Benjamin M. Statler College of Engineering and Mineral Resources 13
Movie 2. Sand and coal
0
0.5
1
1.5
2
2.5
3
0 0.05 0.1 0.15 0.2
ΔP
[K
Pa]
Uair [m/s]
Sand
100 g
200 g
300 g
0
0.5
1
1.5
2
2.5
3
3.5
0 0.05 0.1 0.15 0.2
ΔP
[K
Pa]
Uair [m/s]
Sand and coal
100 g
200 g
300 g
Results: Pressure drop across the bed - cold flow
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Results: Effect of temperature on ΔP across the distributor plate
0 1 2 3 4 5 6 7 8 9 10
0.06
0.12
0.18
0.24
0.30
0.36
0.42
0.48
0.54
0.60
Average reaction temperatures [oC]
26
138
323
539
716
805
ΔP
(1
-2)
[PS
I]
Qair [SLM]
Distributor plate (DP) pressure drop40 micron grade1/8 “ thickness
- Operating temperature affects the pressure drop across the distributor plate
- Temperature will affect bubbling characteristics
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0
0.4
0.8
1.2
1.6
2
0 0.04 0.08 0.12 0.16 0.2
ΔP
[K
Pa
]
Uair [m/s]
Sand 200 g
Ambient200400600800
oC
Results: Pressure drop across the bed – hot gasifier
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0
0.4
0.8
1.2
1.6
2
2.4
2.8
3.2
3.6
0 0.04 0.08 0.12 0.16 0.2
ΔP
[K
Pa
]
Uair [m/s]
Sand 300 g
Ambient200400600800
oC
Results: Pressure drop across the bed – hot gasifier
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1st Run 2nd Run
10
20
30
40
50
60
44
.9
56
.3
35
.4
24
.9
17
.8
14
1.7
3 4.4
4
0.1
51
0.3
58
0 0
Coal steam gasification – Product composition
H2:CO = 3.2
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1 min 2 min 3 min 4 min 5 min
10
20
30
40
50
60
70
37
.8
66
.1
43
38
.2
64
19
.1
16
.8
14
14
.2
14
.6
20
.5
2.6
4
32
.7
34
.5
10
.6
18
.7
14
.3
8.7
2
10
9.9
6
3.8
9
0.0
66
1.6
1
3.0
3
0.8
12
0.0
56
0 0.0
25
0.0
50
4
0.0
30
3
Coal steam gasification – Product composition
H2:CO = 3.2
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2 gr 1.6 gr 1.5 gr 0.8 gr 1.5 gr
10
20
30
40
50
605
7.2
1
63
.15
49
.85
52
.89
51
.32
23
.00
19
.54
31
.99
29
.55
28
.95
9.4
4
8.4
0
8.1
5
4.6
8
6.7
7
9.1
7
7.8
3
8.9
4 11
.84
11
.58
1.2
9
1.0
8
1.0
7
1.0
4
1.3
9
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
• Reverse water gas shift reaction affects product composition
Biomass gasification – product composition
H2:CO = 0.5
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Conclusions
• Binary mixtures with lower voidage ratio and higher
bulk densities improve fluidization
• Operating temperature also effects the pressure drop
through the distributor plate
• Preliminary results of coal and coal gasification are promising
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Future work
• Improve the feeding system (continuous)
• Improve the product gas sampling (continuous)
• Improve measurement (multiple locations)
• Improve temperature control
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Acknowledgements
Benjamin M. Statler College of Engineering and Mineral Resources 23
Thank you
Benjamin M. Statler College of Engineering and Mineral Resources 24
BFBG experimental setup
Expansion tanks
Heat exchanger
Screw feeder
Feeder control unit
Furnace
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BFBG experimental setup
Bubbling fluidized bed reactor system.P: Pressure sensor, T: Temperaturesensor, 1: Nitrogen tank, 2:Compressed air tank, 3: Expansiontanks, 4: Bed reactor, 5: Furnace, 6:Feeding system gas flow line, 7:Feeding point, 8: Output gas line, 9:Gas sampling valve, 10: Bed reactorcooling gas line, 11: Bed reactorfluidization gas line.
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0
0.1
0.2
0.3
0.4
0.5
0.6
26 226 426 626 826
Pre
ssu
re D
rop
(1-2
) [P
SI]
Temperature [oC]
1 SLM
2 SLM
3 SLM
4 SLM
5 SLM
6 SLM
7 SLM
8 SLM
9 SLM
10 SLM
Benjamin M. Statler College of Engineering and Mineral Resources 27
0
0.1
0.2
0.3
0.4
0.5
0.6
0 1 2 3 4 5 6 7 8 9 10
Pre
ssu
re D
rop
(1-2
) [P
SI]
Q [SLM]
100
200
300
400
500
600
700
800
[oC]
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Table 2. Material elemental analysis
MaterialMoisture,
(%)Volatile, (%) Ash, (%) Nitrogen, (%) Carbon, (%) Hydrogen, (%) Oxygen, (%)
Biomass
(Hardwood) 7.16 75.65 0.32 0.9 45.25 4.65 49.2
Coal
(Pittsburgh #8) 1.3 34 10.6 1.6 85.6 5.8 7
Benjamin M. Statler College of Engineering and Mineral Resources 29
• Design, build and operate a laboratory-scale bubbling fluidized bed gasifier
(BFBG) using biomass (hardwood) and coal as feedstocks.
• Analyze the fluidization hydrodynamics of binary mixtures with biomass and
coal as feedstocks by using a laboratory-scale BFBG cold-flow rig (CFR).
• Analyze the effect of temperature on fluidization hydrodynamics at actual
experimental conditions up to 800 oC.
• Perform biomass and coal gasification operations in accordance with the data
obtained from cold flow experiments and analyze the product gas compositions.
• Provide high quality data for NETL Multiphase Flow Group for modeling.
Objectives
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0
0.2
0.4
0.6
0.8
1
1.2
0 0.04 0.08 0.12 0.16 0.2
ΔP
[K
Pa
]
Uair [m/s]
Sand 100 g
Ambient200400600800
oC
BFBG fluidization hydrodynamics analysis
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Material(Mixtures)
Bulk density (g/cc)
Voidage(%)
Glass beads + coal 1.61 35
Glass beads + hardwood 1.43 38
Sand + coal 1.56 41
Sand + hardwood 1.38 44
Table 2. Material bulk density and voidage analysis