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TU Bergakademie Freiberg I Department of Energy Process Engineering and Chemical EngineeringGerman Center of Energy Ressources I Fuchsmühlenweg 9 I 09596 Freiberg, Germany I phone +49(0)3731/39 4498
fax +49(0)3731/39 4555 I mail [email protected] I web www.energierohstoffzentrum.de
Department of Energy Process Engineeringand Chemical Engineering
Pyrolysis behaviour of brown coal in a pressuriseddrop tube reactor
Denise Reichel, Stephan Siegl, Kevin Günther, Steffen Krzack, Bernd Meyer
5th International Freiberg Conference on IGCC & XtL Technologies ‐ IFC2012
21st – 24th May 2012 – Leipzig, Germany
Session 10‐1
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany
I. Background & motivation
II. Experimental setup & investigations
III. Results Residence time
Pressure Influence on product yields and composition
Kinetic parameters for gas yields
IV. Future Prospects
2
Outline
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 3
I. Background & motivation
Thermochemical conversion behaviour of coal
EXPERIMENTS on coal behaviour during thermochemical conversion are a necessarystep for better understanding and simulation of thermochemical processes as well as
for an efficient use of energy sources.
• Gasification
• Pyrolysis
• Hydrogenation
• Combustion
Thermochemical processes
• Gasification
• Pyrolysis
• Hydrogenation
For Germany:
Focus on processesfor non‐energeticuse of coal
Thermochemical conversionbehaviour
• Process simulation as tool forprediction of conversionbehaviour
• Consistent data necessary forimplementation and validationof process models
Knowledge necessary for
• Technology development
• Optimisation
• Dimensioning of
these processes
• Exceptional position of pyrolysis
• a complex processmultitude of parallel reactionspartly dependant on each other
• Various influencing parameters (feedstock, process)
• Less data available for pressure influence
Pyrolysis
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany
II. Experimental setup and investigations
Pressurised drop tube reactor
4
Coal feeding
Coalparticle
Partiallypyrolysedparticle
Coke particle
Electricalfurnace
Argon feeding
Argon feedingElectric traceheating
Pyrolysis gas + argon
Coke collectorwith electrictrace heating
Reactor tubePyrolysis gas
FeedsCoal / biomassParticle size: 40…500 µmMoisture: < 10 wt.%Feed rate: up to 10 g/min
EquipmentHeated lenght: 1,100 mmReactor ID: 20 mm3‐stage condensing system(‐20 °C ethylene glycol/H2O)Online micro GC
Process conditionsTemperature: ≤ 800 °CPressure: ≤ 30 bar (g)Gas atmosphere: ArgonVolume flow rate argon:≤ 130 l/h (STP)
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 5
II. Experimental setup and investigations
Experimental procedureFeedstock
Drying (105 °C)
Grinding / Sieving
Pre‐drying (70 °C)
Pyrolysis in drop tube
40…100 µm
Material balance, char properties, kinetics
charliquid product (+THF) gas
tar/oil
Distillation
THF + water
analysis
analysis
gas chromatography
analysis
20 experiments + repetitions
Temperature: 600, 700, 750, 800 °C
Pressure: 1, 5, 10, 20, 30 bar
Gas atmosphere: Argon
Argon flow rate: 60 l/h (STP)
Process conditions
Feedstock: Brown coalfrom Central Germany
Particle size: 40…100 µm
Moisture content: predried at 105 °C
Feed rate: about 6.2 g/min
Feed parameter
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 6
II. Experimental setup and investigations
Feedstock characterisation
Ash content determination at: * … 450 °C; ** … 815 °C
Brown coal from Central Germany
X‐ray fluorescence analysisProximate and ultimate analysis
Proximate analysis in wt.‐%
Moisture (r) 44.1
Ash (d) 22.2* 17.6**
Volatile Matter (d) 52.8
Fixed Carbon (d) 25.0 29.6Sum (d) 100.0 100.0Ultimate analysis in wt.‐% (daf)Carbon 76.3 72.0
Hydrogen 6.5 6.1
Nitrogen 0.6 0.6
Combustible Sulphur 2.9 2.7
Oxygen 13.8 18.6Sum 100.0 100.0Heating value in kJ/kg (d)HHV 24,913
LHV 23,817
Original Ashsample 450 °C 815 °C
Carbon (from carbonates) n.d. 0.95 b.d.l.Oxygen ‐ 49.01 47.76Sodium 0.01 b.d.l. b.d.l.Magnesium 0.17 1.33 1.42Aluminum 1.65 13.17 13.77Silicon 2.45 15.65 16.71Sulphur 3.42 7.46 6.85Chlorine 0.01 0.03 b.d.l.Pottassium 0.05 0.42 0.62Calcium 1.67 10.63 11.40Titanium 0.06 0.41 0.43Ferrum 0.07 0.59 0.65Barium 0.03 0.16 0.18Traces 0.02 0.19 0.21Sum 9.60 100.00 100.00
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 7
III. Results
Particle and gas residence time
Coal properties
• particle size range: 40…100 µm
• volume mean diameter: 60 µm
• sphericity (WADELL): 0,8
• apparent density: 950 kg/m3
Gas properties
• kinematic viscosity and densitycalculated with Aspen Properties
• real gas behaviour according toREDLICH‐KWONG‐SOAVE
Particle velocity (mean value of)
• STOKES (Rep ≤ 0,25 )
• BERANEK, MARTIN, KUNII (Rep = f(Ar))
• HAIDER‐LEVENSPIEL (cd = f(Rep, Ψ))
Particle residence time
+
0
5
10
15
20
25
600 650 700 750 800
Particlereside
ncetim
e in s
Temperature in °C
1 bar 5 bar 10 bar 20 bar 30 bar
pressure
Temperature Pressure1 bar 5 bar 10 bar 20 bar 30 bar
600 °C 3.2 12.4 25.3 51.9 77.2700 °C 2.2 8.9 19.6 36.2 52.8750 °C 3.3 6.3 15.9 31.3 43.2800 °C 2.0 7.5 12.9 26.7 37.2
Gas residence time
Particle residence time
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 8
III. Results
Pressure influence on product yields
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
Char Liquid product Gas
0
4
8
12
16
20
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
Liquid product Reaction water Tar/oil
0
4
8
12
16
20
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
600 °C
800 °C
Pressure↑• Main effect on product yields up to about 10 bar• Decrease of char and liquid product yield• Increase of pyrolysis gas yield• Tar yield shows minimum at 5 barTemperature↑• slightly decreasing char and liquid product yield• strong rise in gas yields
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 9
III. Results
Pressure influence on yields of main gas components
0
50
100
150
200
250
0 5 10 15 20 25 30 35
Yield in l (STP
)/kgCo
al (d
)
Pressure in bar
H2 CH4 CO CO2
0
50
100
150
200
250
0 5 10 15 20 25 30 35
Yield in (STP)l/kgCo
al (d
)
Pressure in bar
H2 CH4 CO CO2
600 °C 800 °C
Pressure↑
• Increase in CH4 production indicates favouring of secondary crackingreactions of volatiles (more distinctive at higher temperatures).
• Slight increase of CO, CO2 and H2 yields mainly up to 10 bar
Temperature↑
• Strong increase in H2, CH4 and CO production, while effect on CO2 is less
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 10
III. Results
Pressure influence on yields of gaseous hydrocarbons
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35
Yield in l (STP
)/kgCo
al(d)
Pressure in bar
C2H6 C2H4 C3H8 C3H6 C4H10
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35
Yield in l (STP
)/kgCo
al(d)
Pressure in bar
C2H6 C2H4 C3H8 C3H6 C4H10
600 °C 800 °C
Pressure↑
• Increase in C2H6 yield (≤ 700 °C), decrease at p ≥ 5 bzw. 10 bar (T≥700 °C)• Reduction of saturated hydrocarbons (C2H4, C3H6) due to secondary cracking stronger effect at higher temperatures
• Increase of C3H8 yield up to about 15 bar, then slight reduction (600 °C)
• C3H8 dissappears at T>600 °C
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany
III. Results
Kinetic parameters for main gas components
Arrhenius plot fortotal gas formation
11
y = ‐4431.4x + 1.3242R² = 0.868
y = ‐5435.4x + 1.6335R² = 0.9913
y = ‐4810.8x + 0.4808R² = 0.9491
y = ‐4258.2x ‐ 0.4087R² = 0.999
y = ‐4563x ‐ 0.1754R² = 0.9998
‐5.5
‐5.0
‐4.5
‐4.0
‐3.5
‐3.0
‐2.59.0E‐04 1.0E‐03 1.1E‐03 1.2E‐03
ln k [k
mol
gas/(kmol
coal∙ s)] daf
1/T [1/K]
1 bar 5 bar 10 bar 20 bar 30 bar
Pressure 1 bar 5 bar 10 bar 20 bar 30 barGas total 37 45 40 35 38
H2 115 123 93 90 84
CH4 54 68 80 51 50
CO 44 52 34 49 62CO2 14 25 23 16 19
Pressure 1 bar 5 bar 10 bar 20 bar 30 barGas total 3.8 5.1 1.6 0.7 0.8
H2 5.1*103 8.7*103 143 72 33
CH4 5.8 17.8 60.4 1.6 1.2
CO 1.3 1.8 0.1 0.5 1.9CO2 0.05 0.1 0.05 0.01 0.02
Activation energy EA in kJ/mol Frequency factor k∞ in s‐1
∙ ∙
∙
Arrhenius equation
• For calculation of kineticparameters for total gas andgas components formation
DecreasingE A
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 12
IV. Future Prospects
New drop tube reactor – PYMEQ
Feeds
Coal, max. 500 g,
up to 10 g/min
40…1,000 µm
Moisture: < 10 wt.%
Equipment
Heated lenght: 2,500 mm
Reactor ID: 18 mm
2‐stage condensing system
(‐20 °C)
Online MS for gas analysis
2 sampling points (volatiles)
1 optical port
Process conditions
T ≤ 800 °C, p ≤ 100 bar (g)
Argon, H2, steam, CO2,
CH4 and mixtures
(rate: ≤ 400 l/h STP)
PYMEQ – PYrolysis MeasurementEQuipment
• Reasearch task 1: Structuredetermination of energy sources
• Pyrolysis as important process
• New reactor for investigationof pyrolysis behaviour of coals
• Parameter studies, determination of reactionmechanisms and kinetics
• Cooperation with chemists fordetailled tar and feed analytik
German Center for Energy Resources Freiberg – DER
• Better understanding aboutoccuring reactions and influencingparameters
• Correlation between feedproperties and conversion behaviour
Results
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 13
IEC – TU Bergakademie Freiberg
Contact:Denise Reichelphone + 49 (0)3731 / 39 4450mail [email protected]‐freiberg.de
Acknowledgement
Thanks to:
German Federal Ministry of Education and Research
RWE AG, Vattenfall Europe AG, MIBRAGmbH and Romonta
Thank you for your attention – Questions?
Stephan Sieglphone + 49 (0)3731 / 39 4815mail [email protected]‐freiberg.de
5th International Freiberg Conference on IGCC & XtL Technologies 21.-24. May 2012 in Leipzig, Germany 14
III. Results
Pressure influence on product yields
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
Char Liquid product Gas
0
4
8
12
16
20
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
Liquid product Reaction water Tar/oil
0
4
8
12
16
20
0 5 10 15 20 25 30 35
Prod
uct y
ields in wt.%
(d)
Pressure in bar
600 °C
800 °C