cpfd modeling of co modeling of co enhanced cpfd modeling of co

cpfd modeling of co modeling of co enhanced cpfd modeling of co

7th International Freiberg/Inner Mongolia
C f
Conference
on IGCC & XtL
X L Technologies,
T h l i
Coal Conversion and Syngas
CPFD MODELING OF CO
MODELING OF CO2 ENHANCED ENHANCED
COAL GASIFICATION IN CIRCULATING FLUIDIZED BED REACTOR
FLUIDIZED BED REACTOR
JoannaBigda, PhD
Józef Popowicz, MSc, TomaszChmielniak,PhD
7-11 June 2015, Huhhot, Inner Mongolia, China
Contents
• Introduction
• CPFD modeling of coal gasification
• Computational geometry and model setup
• Operating and boundary conditions
• CPFD governing equation and Chemical reactions
• Simulations results
• Instantaneous/Time
Instantaneous/Time-average
average Solids Volume Fraction
• Instantaneous Gas Species Mass Fraction
• Validation of results
• Conclusions
2
Introduction
• The work was carried out within the frame of strategic project "Development of
coal g
gasification technology
gy for high-efficiency
g
y production of fuels and energy"
gy
• Using of CO2 during pressurized gasification in circulating fluidized bed
 Attractive method of CO2 management removed during conversion of fossil fuels – chemical
recycling.
li
 Reduction of consumption of hard coal and technical oxygen for the same gas production.
 Increasing efficiency and decreasing emission from the process.
 Residence time of particles in the reaction zone promoting Boudouard reaction.
 „In
I situ”
it ” char.
h
 Filling a market gap for gasification rectors with a capacity of 50-150 MW.
 Increased reactor efficiency.
 Increase of conversion degree of coal as a result of pressure influence on the process kinetics.
Ballroom B – Session 8:
Gasification kinetics & experiments,
p
, 16:10-16:30
Ballroom B – Session 17:
Entire concepts
p II,, 13:20–13:40
Pilot scale studies on coal gasification in a circulating
fluidised bed reactor with CO2 addition as a gasifying agent
Concept of demonstration plant for methanol synthesis by
CO2 enhanced gasification of coal in fluidised bed reactor
(Aleksander Sobolewski, Institute for Chemical
P
Processing
i off C
Coall – Poland)
P l d)
(Tomasz Chmielniak, Institute for Chemical
P
Processing
i off C
Coall – Poland)
P l d)
3
The scope of IChPW research concerning The scope of ICh
research concerning on on solid fuels solid fuels high lid f l high temperature
hi h temperature
t
t
conversion
i
Testing of solid
fuels properties and
their kinetics in
laboratory scale
Gasification of solid fuels in CO2 in the
pressurized circulating fluidized bed
Parameters:
Pressure:
1,6 MPa
Coal stream:
100 kg/h
Gasification agents:
O2, CO2, steam
Non-pressurized gasification of solid
fuels (IPPS)
Parameters:
Pressure:
0,1 MPa
Coal stream:
200 kg/h
Gasification agents:
air, CO2, steam
Modelling of
gasification process
using CFD tools &
thermodynamic
calculation
4
Tests on pilot and
technical scale
installations
Computational Particle article F
Fluid Dynamic
(CPFD) simulation i
l ti
Computational geometry and model setup
• 102 432 mesh elements
• Coal density – 1200 kg/m3
• Char densityy – 650 kg/m
g 3
Particle Size Distribution
100
90
Cumulative weight, %
80
70
60
50
40
Test 1 coal
Test 1 char
30
Test 2 coal
20
Test 2 char
10
Test 3 char
Test 3 coal
0
0
5
0,2
0,4
0,6
0,8
Particle radius, mm
1
1,2
O
Operating conditions
ti
diti
Test No.
C l mass fl
Coal
flow rate
t
Unit
Test 1
Test 2
Test 3
kg/h
29 73
29.73
29 38
29.38
32 46
32.46
80.2
72.04
0.17
0.66
0.17
0.16
0.68
0.16
Gasifying agent mass flow
kg/h
61.93
rate
Gasifying agent composition (mass fractions):
‐
N2
0.17
‐
CO2
0.63
‐
O2
0.20
G if i agentt temp.
Gasifying
t
o
C
142
149
148
Gasification zone temp.
o
C
839
671
655
0.440
0.42
12.20
9.73
53 40
53.40
3.82
0.58
20.08
0.18
10.70
9.07
54 10
54.10
4.02
0.57
21.39
0.16
Gasification pressure
W
A
C
H
N
O
S
6
MPa
%
%
%
%
%
%
%
0.38
Ultimate analysis
11.7
9.74
54
3.9
0.57
19.93
0.17
CPFD governing equations
CPFD governing
CPFD Fluid phase continuity equatio
equation
n
Fluid phase momentum equatio
equation
n
Fluid phase energy equation
The individual gas species transport equation
The gas mass production rate
Interphase
Inter
phase momentum transfer
7
Liouville equatio
equation
n
The acceleration of a particle
The equation for solid movement
The lumpedlumped-heat equation for the particle
The conservative energy exchange from
the particle phase to the fluid phase
Devolatilization and and moisture release
and moisture
Heterogeneous
reactions
Products
Volatiles
Carbon
DEVOLATILIZATION
O
O
AND MOISTURE RELEASE
Ash
Moisture
H2
CO
TAR
CH4
8
CO2
Homogeneous
reactions
H2O
Products
P d t
Devolatilization and and moisture release
and moisture
Sciazko model
Mass flow rate
of released
volatiles
9
Chemical equations and and reaction rates
and reaction
10
Input parameters in the CPFD simulation
Input parameters in the CPFD simulation
Particle-to-wall
interaction
Particle normal stress
model
Solver setting
11
N
Normal
l retention
t ti coefficient,
ffi i t en
03
0.3
Tangential retention coefficient, et
0.99
P
Pressure
constant
t t off the
th solid-phase
lid h
stress
t
model,
d l Ps
1P
Pa
Dimensionless constant of the solid-phase stress model, γ
3
Di
Dimensionless
i l
constant
t t off the
th solid-phase
lid h
stress
t
model,
d l θ
10-88
Maximum momentum redirection from collision
40%
Time step
step, t
1x10
1
10-44 s
Time, t
250 s
Beginning time for average
150 s
Results
Test 1
12
Instantaneous//Time
Instantaneous
Time--average Particle Volume Fraction
Test 2
Test 3
Test 1
Test 2
Test 3
Results
Instantaneo s Mass Instantaneous
Mass Fraction
Mass Fraction
F action of of Gas Species
of Gas
Test 1
T=839 oC
p=0.378MPa
Gg=62kg/h
13
Test 2
T=671 oC
p=0.44MPa
Gg=80kg/h
Test 3
T=655 oC
p=0.42MPa
Gg=72kg/h
Test 1
T=839 oC
p=0.378MPa
Gg=62kg/h
Test 2
Test 3
T=671 oC
p=0.44MPa
Gg=80kg/h
T=655 oC
p=0.42MPa
Gg=72kg/h
Results
Gas Species Mass Mass F
Mass Fraction
Fraction
action
Test 1
T=839 oC
p=0.378MPa
Gg=62kg/h
14
Test 2
T=671 oC
p=0.44MPa
Gg=80kg/h
Test 3
Test 1
T=655 oC
p=0.42MPa
Gg=72kg/h
T=839 oC
p=0.378MPa
Gg=62kg/h
Test 2
Test 3
T=671 oC
p=0.44MPa
Gg=80kg/h
T=655 oC
p=0.42MPa
Gg=72kg/h
Validation of of results
of results
Test 1
70
Test1‐exp
Test1‐CPFD
60
50
50
mol frraction, %
60
40
30
20
10
Test2‐exp.
Test2‐CPFD
40
30
20
10
0
0
CH4
CO
CO2
H2
N2
TAR
CH4
CO
Test 3
70
Test3_exp
Test3‐CPFD
N2
TAR
60
mol ffraction %
mol ffraction, %
Test 2
70
50
40
30
20
10
0
CH4
15
CO
CO2
H2
CO2
H2
N2
TAR
Validation of of results
of results
mol fractio
on of components (C
CPFD), %
70
60
50
40
CO2
CO
30
20
10
N2
TAR
CH4
H2
Test1
Test2
Test3
0
0
16
10
20
30
40
50
60
mol fraction of components (experimental), %
l f ti
f
t (
i
t l) %
70
Conclusions
• Developed model coresponds to changes in process
parameters and give results with a similar degree of
agreement for all three tests.
• The gas composition at the gasifier outlet using CPFD
model is comparable with experimental data. The
relative error of mol fraction is lower than 20%.
• The highest temperature (Test1) gives the highest
production
d ti off crucial
i l gaseous products
d t (CO,
(CO H2).
)
• The three-dimensional models and simulations provide
a promising way to simulate the coal gasification in
fluidized beds.
17
Acknowledgements
Thank you for your attention
attention!!
The research was carried out within the project
"Development
p
of coal g
gasification technology
gy for highg
efficiency production of fuels and energy", Task No. 3 of the
Strategic Program for Research and Development:
"Advanced energy generation technologies" funded by the
Polish National Center for Research and Development.
18