The document describes the development of a laboratory scale conical spouted bed reactor for biomass gasification. Initial experiments involve cold flow studies to establish stable spouting conditions. Future work includes hot flow studies and thermodynamic modeling to evaluate favorable operating conditions for hydrogen-rich syngas production from fuels like glycerol and propane. Existing correlations for minimum spouting velocity were found to be inadequate, so a new correlation was developed that showed excellent agreement with experimental data. Preliminary equilibrium analysis of reforming systems indicates steam reforming produces less hydrogen than partial oxidation or auto-thermal reforming. Further experiments are needed to validate the modeling results.

1. 1
Development of a Laboratory
Scale Reactor for Biomass
Gasification
11th ME Graduate Student Conference
Louisiana State University, April 21, 2012
Mandeep Sharma
M.S. Candidate (Expected: December 2012)
Faculty Advisor: Dr. Ingmar Schoegl, ME, LSU

2. 2
Outline
• Objective
• Background Information
• Conical Spouted Bed (CSB) Reactor
• Two Phases
• Cold Flow Study
• Hot Flow Study
– Evaluation of favorable operating conditions
– Implementation to CSB reactor
• Experimental Setup
• Results and Discussion
• Acknowledgement

3. 3
Objective
 To develop a laboratory scale CSB reactor facility for the
purpose of producing H2 rich synthesis gas from various
biomass wastes* and other sustainable sources† via
thermo-chemical routes of gasification /reforming.
H2 rich synthesis gas
 mainly consists of H2 and CO, and traces of CO2, H2O and
sulfur compounds.
 Clean H2 rich syngas has applications in fuel cells, gas
turbines and engines for clean and efficient power generation.
Initial Stage biomass*: Glycerol, long Term biomass*: others and Validation Tests with
Propane †

4. 4
Glycerol
• Among the various types of biomass wastes, glycerol (C3H8O3),
a byproduct of biodiesel production, has been considered an
excellent candidate for H2 production.
• Only in the US, biodiesel production has increased dramatically
from 500,000 gallons in 1999 to 70 million gallons in 2005 [1].
• For every 9 kg of biodiesel produced, about 1 kg of a crude
glycerol by-product is formed.
• Glycerol is a potential feedstock, for hydrogen rich syngas
production because one mole of glycerol can produce up to four
moles of hydrogen.
[1]. National Biodiesel Board, 2006.

5. 5
CSB Reactor
Development of a CSB reactor divides into two phases:
• Cold Flow Studies
• Focus on Hydrodynamic Behavior for the purpose of
establishing stable spouting limits
• Hot Flow Studies (work in progress)
a. Focus on evaluation of favorable operating condition for H2
rich syn gas generation by conducting thermochemical
analysis and simple plug-flow reactor experiments.
b. Results from part A guides the development of the CSB
reactor.

6. 6
Brief Introduction
Conical Spouted Bed (CSB) Reactor
• Mathur and Gishler initially introduced spouted beds in 1954
as an alternative method for drying moist wheat grains.
• Recent applications include pyrolysis of solid wastes, e.g.
rice husk, sawdust, plastic wastes, scrap tires, etc.
• Potential for syngas gas generation from liquid biomass
wastes such as glycerol. (Almost no data is available)
Advantages of CSB reactor
• Perfect mixing
• Very efficient heat transfer because of cyclic movement
• Very short residence time
• Suitable for sticky, moist, irregular shaped bed material

7. 7
Conical Spouting Bed
Contacting of solids with fluid by injecting a steady axial jet of
fluidizing medium (air/N2/steam).
Schematic of CSB actual reactor model Spouting behavior of CSB cold flow model

8. 8
I. Cold Flow Studies
• Cold flow studies were conducted to establish stable
spouting range. Stable spouting occurs over a specific range
of gas velocity called min. spouting velocity (ums)o.
Different Spouting Regimes

9. 9
CSB Cold Flow Setup
Experiments were carried out at atmospheric
conditions using Alumina powder (ρ=3960 Kg/m3)
as bed material and air as spouting gas.
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
Experiment
Summary of operating parameters tested
*
*
* Indicates the best set of testing parameters which shows uniform cyclic
behavior of CSB.

11. 11
Effect of System Parameters on (ums)o
Effect of different Ho, Do and dp on (ums)o

12. 12
Evaluation of all 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 CSBs which were significantly larger than the model investigated
in present study

13. 13
…Evaluation of Correlations (cont’d)
Correlations‟ predictions comparison with experimental results
for a particular set of operating parameters

14. 14
Poor performance of correlations:

15. 15
Proposed Correlation
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

16. 16
II. Hot Flow Studies (work in progress)
• Need to evaluate favorable operating conditions (optimum
reactants feed ratio, temperature range etc.) for H2 rich syngas
generation.
• For validation purposes, first experiments will be tested on
simple plug flow reactor which uses propane as a supplying
fuel, while additional tests will use glycerol as a renewable fuel
source.
• In both cases, the selection of operating conditions is guided
by results from thermodynamic analysis.
• The knowledge of favorable operating conditions (through
thermodynamic analysis and plug flow reactor experiments) is
required for the further development of CSB reactor facility.

17. 17
Schematic for Plug Flow Reactor Test Facility
C3H8 : N2 for dry reforming (DR) C3H8 : N2 : Air for partial oxidation reforming (POR)
C3H8 : N2 : Steam for steam reforming (SR) C3H8 : Air : Steam for Autothermal reforming (ATR)

18. 18
Thermodynamic Analysis (work in progress)
• As a theoretical study, reaction kinetics, reactor design and
operation are not considered here.
• Initial tests are performed at T = 1200 K and P = 1 atm in
order to find optimum reactants ratio.
• A code written in MATLAB environment has been developed
using the „Cantera’ software library (object oriented software tools for
problems involving chemical kinetics, thermodynamics and transport properties;
Goodwin, 2006).
• Cantera‟s chemical equilibrium solver* , which involves
nonstoichiometric approach (element potential method), is used.
• ‘GRI-Mech V. 3.0’, (53 species) database have been used to
evaluate the thermodynamic properties of the chemical species
considered in the model.
*Cantera uses a damped Newton method to solve a set of nonlinear algebraic equations(=no. of elements, not
species).

19. 19
Thermochemical conversion routes
Dry Reforming (DR):
fuel(CnHmOp) + carrier gas(N2/He) ⇒ H2 + CO2
Partial Oxidation (PO):
fuel(CnHmOp) + N2 + air ⇒ H2 + CO2 + N2 ; (Exothermic)
Steam Reforming (SR):
fuel(CnHmOp) + N2 + steam ⇒ H2 + CO2 + N2 ; (Endothermic)
Auto-thermal Reforming (ATR): ATR = PO + SR
fuel(CnHmOp) + air + steam ⇒ H2 + CO2 + N2 ; (Exothermic)
last three cases will be discussed next…

20. 20
Ternary system Plot Reading

21. 21
… some preliminary results
Study 1: C3H8:N2:Steam ternary reaction system (SR case)
Directions for reading ternary plots:
Plot(a):∆T (Tadiabatic - Treactor) Plot(b): H2 mole fraction

22. 22
Equillibrium analysis (more preliminary results)
Study 1: C3H8:N2:Steam ternary reaction system
Plot(c): CO mole fraction Plot(d): C mole fraction

23. 23
Equillibrium analysis (more plots)
Study 1: C3H8:N2:Steam ternary reaction system
Plot(e): H2O mole fraction Plot(f): N2 mole fraction

24. 24
… some preliminary results
Study 2: C3H8:Air:N2 ternary reaction system (PO case)
Plot(a): ∆T (Tadiabatic - Treactor) Plot(b): H2 mole fraction

25. 25
Equillibrium analysis (more plots)
Study 2: C3H8:Air:N2 ternary reaction system
Plot(c): CO mole fraction Plot(d): CO mole fraction

26. 26
Equillibrium analysis (more plots)
Study 2: C3H8:Air:N2 ternary reaction system
Plot(e): H2O mole fraction Plot(f): N2 mole fraction

27. 27
… some preliminary results
Study 3: C3H8:Air:Steam ternary reaction system (ATR case)
Plot(a): ∆T (Tadiabatic - Treactor) Plot(b): H2 mole fraction

28. 28
Equillibrium analysis (more plots)
Study 3: C3H8:Air:Steam ternary reaction system
Plot(c): CO mole fraction Plot(d): C mole fraction

29. 29
Equillibrium analysis (more plots)
Study 3: C3H8:Air:Steam ternary reaction system
Plot(e): H2O mole fraction Plot(f): N2 mole fraction

30. 30
Conclusions
I. Cold Flow Studies
• Available correlations for calculating min. spouting velocity
have shortcomings for small-sized laboratory scale CSB
studies.
• Developed Simple empirical correlation for (ums)o showed
excellent agreement with experimental findings.
• Cold flow hydrodynamic study provides a foundation for
design of hot flow CSB reactor facility.
• Hot flow tests are also needed to carefully examine the
stable spouting at high temperatures.

31. 31
…Conclusions
II. Hot Flow Studies
• From thermo-chemical equilibrium analysis, the optimum
ratio of reactants in each reforming case can be decided
based on optimum H2 mole fraction in syngas generation.
• PO and ATR produces more H2 mole fraction as compared to
SR, but steam mitigates the effect of carbon formation.
• Further analysis is required to study the effect of
temperature, reactants ratio on mole fraction of syngas
species for propane and glycerol fuels. Experiment tests are
required to verify the theoretical results.
• Results from this study will lay the foundation for follow-up
research, where similar tests will be performed for a bench-
scale CSB reactor facility for syngas production.

32. 32
Thank You!
Acknowledgements:
Dr. Ingmar Schoegl
Mathew Lousteau
Louisiana State University Council on Research Faculty Research
Grant Program

33. 33
Back Up Slides

34. 34
Evolution of Spouting regimes

35. 35
I. Cold Flow Study
(Evaluation of Correlations)
For one particular data set - e.g. 60°, 483 µm, 6.35 mm Do
best performing correlations align with the
diagonal line

36. 36
Evaluation of Correlations …cont’d
Comparison of Gorshtein correlation for all data sets

37. 37
Evaluation of Correlations …cont’d
Comparison of Mukhlenov correlation for all data sets

38. 38
Evaluation of Correlations …cont’d
Comparison of Tsvik correlation for all data sets

39. 39
Evaluation of Correlations …cont’d
Comparison of Choi correlation for all data sets

40. 40
Pressure Drop Measurements
Effects of Ho and Do on stable pressure drops and
maximum pressure drops

41. 41
…Glycerol (Cont’d)
Properties comparison of Crude Glycerol with other biomass wastes
Content Units Pine Poplar Bagasse[2] Almond Grape Crude
sawdust[2] sawdust[2] shells[2] stalks[2] Glycerol[3]
Moisture % mass 9.4 10.0 7.1 11.50 8.0 16.1
Ash % mass 0.9 3.9 0.9 2.9 4.8 1.2
C % mass 45.2 43.1 46.0 40.9 41.3 58.20
H % mass 5.4 5.1 5.4 5.2 6.2 10.58
O % mass 39.0 37.7 40.3 38.60 39.6 29.82
N % mass 0.1 0.2 0.2 0.9 0.1 0.19
S % mass 0.0 0.0 0.1 0.0 0.0 0.01
LHV MJ/Kg 16.2 15.5 16.2 16.0 16.7 16.0
[2]. Baratieri M. et al., 2007, “Biomass as an energy source: Thermodynamic constraints on the performance of the conversion
process”, Bioresource Technology, vol. 99, pp. 7063 – 7073.
[3]. Scott Q. Turn et al., 2007, “Experimental Investigation of Hydrogen Production from Glycerin Reforming”, American
Chemical Society, published on web.

42. 42
Enthalpy Calculations
Total input enthalpy is = biomass enthalpy + gasifying agent enthalpy
The enthalpy variation or change along the conversion process
represents the energy that is to be released or has to be supplied.