mandeep sharma 11th_gsc_lsu
TRANSCRIPT
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
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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
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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 †
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Glycerol
4
• 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.
CSB Reactor
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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.
Brief Introduction
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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
Conical Spouting Bed
Contacting of solids with fluid by injecting a steady axial jet of
fluidizing medium (air/N2/steam).
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Schematic of CSB actual reactor model Spouting behavior of CSB cold flow model
I. Cold Flow Studies
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• 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
CSB Cold Flow Setup
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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.
Experiments were carried out at atmospheric conditions using Alumina powder (ρ=3960 Kg/m3) as bed material and air as spouting gas.
Experiment
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Summary of operating parameters tested
*
* Indicates the best set of testing parameters which shows uniform cyclic
behavior of CSB.
*
Evaluation of all existing correlations for (ums)o
Source Correlation Eqn.
Markowski (1983)
(1)
Choi (1992) (2)
Gorshtein (1964)
(3)
Mukhlenov (1965)
(4)
Tsvik (1967) (5)
Olazar (1992) (6)
Olazar (1996) (7)
Bi (1997) (for Db/Do ≥1.66)
(8)
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They used CSBs which were significantly larger than the model investigated
in present study
…Evaluation of Correlations (cont’d)
Correlations‟ predictions comparison with experimental results
for a particular set of operating parameters
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Proposed Correlation
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Proposed correlation shows excellent agreement with experiments
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
- 17.15 %
+ 16.3 %
Pre
dict
ed (
u ms) o, m
/s
Experimental (ums
)o, m/s
Present Study, 60o cone angle
0.483 mm dp, 6.350 mm D
o
0.483 mm dp, 4.572 mm D
o
0.483 mm dp, 3.302 mm D
o
1.092 mm dp, 6.350 mm D
o
1.092 mm dp, 4.572 mm D
o
1.092 mm dp, 3.302 mm D
o
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.
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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)
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).
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Thermochemical conversion routes
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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…
… some preliminary results
Directions for reading ternary plots:
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Plot(a):∆T (Tadiabatic - Treactor) Plot(b): H2 mole fraction
Study 1: C3H8:N2:Steam ternary reaction system (SR case)
Equillibrium analysis (more preliminary results)
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Plot(d): C mole fraction
Study 1: C3H8:N2:Steam ternary reaction system
Plot(c): CO mole fraction
Equillibrium analysis (more plots)
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Plot(f): N2 mole fraction
Study 1: C3H8:N2:Steam ternary reaction system
Plot(e): H2O mole fraction
… some preliminary results
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Plot(b): H2 mole fraction
Study 2: C3H8:Air:N2 ternary reaction system (PO case)
Plot(a): ∆T (Tadiabatic - Treactor)
Equillibrium analysis (more plots)
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Plot(d): CO mole fraction
Study 2: C3H8:Air:N2 ternary reaction system
Plot(c): CO mole fraction
Equillibrium analysis (more plots)
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Plot(f): N2 mole fraction
Study 2: C3H8:Air:N2 ternary reaction system
Plot(e): H2O mole fraction
… some preliminary results
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Plot(b): H2 mole fraction
Study 3: C3H8:Air:Steam ternary reaction system (ATR case)
Plot(a): ∆T (Tadiabatic - Treactor)
Equillibrium analysis (more plots)
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Plot(d): C mole fraction
Study 3: C3H8:Air:Steam ternary reaction system
Plot(c): CO mole fraction
Equillibrium analysis (more plots)
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Plot(f): N2 mole fraction
Study 3: C3H8:Air:Steam ternary reaction system
Plot(e): H2O mole fraction
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.
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…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.
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Thank You!
Acknowledgements:
Dr. Ingmar Schoegl
Mathew Lousteau
Louisiana State University Council on Research Faculty Research
Grant Program
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I. Cold Flow Study(Evaluation of Correlations)
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best performing correlations align with the diagonal line
For one particular data set - e.g. 60°, 483 µm, 6.35 mm Do
Pressure Drop Measurements
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Effects of Ho and Do on stable pressure drops and maximum pressure drops
…Glycerol (Cont’d)
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Properties comparison of Crude Glycerol with other biomass wastes
[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.
Content Units Pine
sawdust[2]
Poplar
sawdust[2]
Bagasse[2] Almond
shells[2]
Grape
stalks[2]
Crude
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