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Development of a Laboratory Scale Reactor for Biomass Gasification 11 th 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 1

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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

1

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

2

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 †

3

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

5

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

6

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).

7

Schematic of CSB actual reactor model Spouting behavior of CSB cold flow model

I. Cold Flow Studies

8

• 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

9

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

10

Summary of operating parameters tested

*

* Indicates the best set of testing parameters which shows uniform cyclic

behavior of CSB.

*

Effect of System Parameters on (ums)o

11

Effect of different Ho, Do and dp on (ums)o

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)

12

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

13

Poor performance of correlations:

14

Proposed Correlation

15

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.

16

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)

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…

Ternary system Plot Reading

20

… some preliminary results

Directions for reading ternary plots:

21

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)

22

Plot(d): C mole fraction

Study 1: C3H8:N2:Steam ternary reaction system

Plot(c): CO mole fraction

Equillibrium analysis (more plots)

23

Plot(f): N2 mole fraction

Study 1: C3H8:N2:Steam ternary reaction system

Plot(e): H2O mole fraction

… some preliminary results

24

Plot(b): H2 mole fraction

Study 2: C3H8:Air:N2 ternary reaction system (PO case)

Plot(a): ∆T (Tadiabatic - Treactor)

Equillibrium analysis (more plots)

25

Plot(d): CO mole fraction

Study 2: C3H8:Air:N2 ternary reaction system

Plot(c): CO mole fraction

Equillibrium analysis (more plots)

26

Plot(f): N2 mole fraction

Study 2: C3H8:Air:N2 ternary reaction system

Plot(e): H2O mole fraction

… some preliminary results

27

Plot(b): H2 mole fraction

Study 3: C3H8:Air:Steam ternary reaction system (ATR case)

Plot(a): ∆T (Tadiabatic - Treactor)

Equillibrium analysis (more plots)

28

Plot(d): C mole fraction

Study 3: C3H8:Air:Steam ternary reaction system

Plot(c): CO mole fraction

Equillibrium analysis (more plots)

29

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

32

Back Up Slides

33

34

Evolution of Spouting regimes

I. Cold Flow Study(Evaluation of Correlations)

35

best performing correlations align with the diagonal line

For one particular data set - e.g. 60°, 483 µm, 6.35 mm Do

Evaluation of Correlations …cont’d

36

Comparison of Gorshtein correlation for all data sets

Evaluation of Correlations …cont’d

37

Comparison of Mukhlenov correlation for all data sets

38

Evaluation of Correlations …cont’d

Comparison of Tsvik correlation for all data sets

Evaluation of Correlations …cont’d

39

Comparison of Choi correlation for all data sets

Pressure Drop Measurements

40

Effects of Ho and Do on stable pressure drops and maximum pressure drops

…Glycerol (Cont’d)

41

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

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.

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