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Interaction between a Turbulent Flow and Reaction under Various Conditions in Oxygen Blown HYCOL Gasifiers.

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Dev. Chem. Eng. Mineral Pmcess., 11(5/6), pp. 557-577, 2003.
Interaction between a Turbulent Flow and
Reaction under Various Conditions in
Oxygen Blown HYCOL Gasifiers
Hao Liua9b,Caixia Chenb and Toshinori Kojimaa*
a
Department of Applied Chemistry, Seikei University, 3-3- I
Kichijojikita-machi, Musashino-shi, Tokyo 180-8633, Japan
bResearch Fellow of NED0 (New Energy and Industrial
Development Organization), Japan
With a three-dimensional comprehensive computer simulation model, the
effect of mixture fraction fluctuations on the overall gasijiication
characteristics due to a turbulent flow was studied for gasification in oxygen
blown HYCOL entrained-flow coal gasifiers. The method compared the results
with or without fluctuation of the gas-mixture fraction. The theoretically
predicted results were also compared with experimental data obtained from a
50 ton/day pilot-scale HYCOL gasifier. Zt was seen that the fluctuation in
mixture fraction of gases produced from devolatilization is just as important
as that of char-02 reaction, i.e. neither of them can be neglected. They have
an important influence not only on the temperature and gas composition
distributions, but also on the cold gas efficiency and product gas composition.
However, the fluctuations of gas-mixture fractions produced from char-C02
and char-steam reactions have only a limited effect. This conclusion is valid
f o r a wide range of conditions of pressure, particle size and O2 concentration
during entrained-flow coal gasification. Based on these results, the simulation
model can be simplified without significantly influencing the validity of the
predicted results. The predictions that include fluctuations of mixture
fractions show better agreement with the experimental data.
* Author f o r correspondence (kojima@ch.seikei.ac.jp).
557
H. Liu, C.Chen and T Kojima
Introduction
In recent years, entrained-flow coal gasification has been highlighted as a
promising clean and efficient coal utilization technology for the future.
Gasification in an entrained-flow gasifier is very complex, mainly due to
turbulent flow, elevated temperature, etc. Theoretical studies on entrainedflow gasification are becoming more important due to these problems and the
high cost of experimental work. Several mathematical models have been
developed for entrained-flow gasifiers (e.g. Wen et al., 1979; Govind et al.,
1984; Villiams, 1995; Smoot et al., 1985; Hill et al., 1993). Those models
have the common features of solving the mass, momentum and energy
conservation equations with similar submodels by almost identical
mathematical methods (e.g. Smoot, 1993). Some models have been applied to
bench-scale entrained-flow gasifiers (e.g. Smoot 1987), but the simulation
capability for gasification was quite limited because of their
oversimplification of the chemistry.
In this work, a comprehensive three-dimensional coal gasification model
with a multi-solid progress variables (MSPV) method has been developed by
us and extended to the simulation of oxygen-blown HYCOL gasifiers. The
validity of the model has been shown by comparing the predicted results and
the experimental data from our previous studies for an IGCC gasifer (see Chen
el al., 2000a; Chen et al., 1999; Chen et al., 2000b; Chen et al., 2001). Owing
to the complexity of gasification in an entrained-flow gasifier, it is very
important to make appropriate simplifications to a comprehensive threedimensional coal gasification model, without losing the validity of the
predicted result. In a HYCOL entrained-flow gasifier, oxygen instead of air
(as in an IGCC gasifier) is used as the oxidizer. Furthermore, in a HYCOL
entrained-flow gasifier, the flow field is highly turbulent and leads to
fluctuations of gas-mixture fractions. Accordingly, these fluctuations of
mixture fractions due to a turbulent flow may affect the overall gasification
characteristics of a gasifier, which can only be clarified through simulation. In
our previous work (Liu et al., 2002), we clarified the interaction between a
turbulent flow and reaction in an air-blown IGCC gasifier and identified that
fluctuations of gas-mixture fractions produced from char-C02 and char-steam
reactions could be neglected without significant influence on the predicted
results. However the conditions in a HYCOL gasifer can be very different
from an IGCC gasifer, e.g. in O2 concentration, temperature, reaction rates,
intensity of turbulence, etc. Conclusions for IGCC gasification are not
necessarily applicable to HYCOL gasification. Furthermore, in our previous
558
TurbulentFlow and Reaction in Oxygen Blown HYCOL Gasifiers
work investigations only covered limited conditions and the effects concerning
devolatilization and char-02 reactions were not separated. Due to the high O2
concentration, intensive turbulence, etc., in a HYCOL gasifier, then a finer
simulation grid is required than for an IGCC gasifier in order to reach a
converged solution. Accordingly, calculation for a HYCOL gasifier through a
three-dimensional model takes a longer time than an IGCC gasifier and it
would be advantageous if the calculation time could be shortened.
In this work, the interaction between a turbulent flow and reaction, i.e. the
effects of fluctuations of mixture fractions on the temperature and gas
composition distributions, cold gas efficiency and product gas composition,
were examined for a wide range of conditions of oxygen-blown HYCOL
gasification. Based on these results, simplification on the model can be
achieved without significantly losing the validity of the predicted results. This
work not only helps to provide an understanding of the characteristics and
mechanism of entrained flow gasification, but it also helps to build a valid
theoretical model and simplify it appropriately. Our investigation is essentially
different from the work of Smoot and Smith (1985) in that we studied oxygenblown entrained-flow coal gasification, but they studied a lifted coal
combustion flame.
Model Description and Simulation Method
The numerical methods and the sub-models recommended for the entrainedflow coal combustion and gasification process (Smoot and Smith, 1985) were
used in the present model. The gas phase is assumed to be a steady-state,
reacting, continuum field that can be described by general conservation
equation as follows:
where, CDrefers to any quantity of mass, velocity components (u, v and w),
turbulent kinetic energy (k), turbulent kinetic energy dissipation rate (e), gas
enthalpy (h), mixture fractions cfi) and their variances (gi). S, is the source
term. S,,, is an additional source term representing the interaction between gas
and particle phases (Smoot et al., 1985). The corresponding expressions of #,
559
H.Liu, C.Chen and 1: Kojima
S,, S,
a n d p are listed in Table 1. The reactions and rate expressions are
listed in Table 2.
Table 1. The source term S, and Sopfor different
Variable
z
s,
(€J
U
V
W
.”)
( ”1 +a( ”(e]
a +a( ”)a( $)
”(
”(a
-E
a + a $2)
a +L(
q $2)
a +a
- E +d p
-E+
Q
(p &)
Q
p
2)+
a
p
p
+
p
azcaaQ8caz
Q
variables in equation (I).
S *P
-;dn,u,)
- ;c,v,,
-~dn,W,)-m,a.
0
0
h
-sdn,h,)
dt
With a Lagrangian method, the pulverized coal particles are tracked. The
particle-source-in-cell model (Crowe et al., 1977) is used to deal with the
interaction between gas and particle phases through various particle source
terms. The net difference in the particle properties between leaving and
entering any given cell provides the particle source term S, for the gas-flow
equations. Turbulence in the gas-phase is modeled by Favre-averaging of the
560
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasifiers
gradient diffusion processes with the two-equation k - E model (Launder ei
al., 1972) for closure. The standard constants of the k - & model (Launder et
al., 1974) were used in the simulation. The particle stochastic trajectory model
(Shuen et al., 1983) based on instantaneous gas velocities is used to simulate
the particle motion and turbulent dispersion. The values of the fluctuating
velocities are assumed to follow a Gaussian distribution and are determined in
a stochastic manner within a turbulent eddy.
Table 2 Reactions and the rate expressions.
Parameter
Devolatilization
dY - d(Y, + Y 2 )
_
= k, (Y,' - Y , )+ k,(Y,' - Y,)
dt
dt
k, = A, exp(-E, I RT,)
Value
k , = A, exp(-E, I RT,)
A1 (s-2
El (kJ mol")
A2 ( s - 9
E~ (H mol-')
Yl *
Y2*
Char-02,H 2 0 and C02 reactions
k, =A, expCE, I R T )
A , (kg Pa-'.' s-' m-')
C HzO
c - coz
c-0 2
E, (kJ mol-')
C - H20
c - co2
c-0 2
3.7~10'
7.4~
lo4
1.5 x1ol3
2.5~10'
0.565
0.565
0.0782
0.0732
0.052
1.15x lo5
1.125x 10'
0.61 x 10'
Coal devolatilization is modeled by a simple, two-step mechanism
(Ubhayakar et al., 1977). The particle surface reactions are characterized by
the 0.5 order, multiple, parallel reaction rate formulation of Smith (1982).An
extended version of the statistical coal-gas mixture fraction model with the
multiple solid progress variables (MSPV) method (Brewster et al., 1988) is
561
H.Liu, C.Chen and Z Kojima
used. Four components of coal off-gas, i.e. four coal-gas mixture fractions are
used to track the reaction products. These mixture fractions at a point are
defined as the mass ratio of coal off-gas to the total gas product and written as
(Brewster et al., 1988):
j 4
where mi (i = 1-4) represents the mass of gas originating from devolatilization
(i = l), ~ h a r - 0(i~ = 2), char-steam and char-C02 reactions (i = 3, 4)
respectively, mi, is the mass of inlet gas, andfi (i = 1-4) is the conserved
mixture fraction calculated by transport equations. The origin of char-steam
reaction is a result of the inherent moisture present in the coal. From the
general approach of the MSPV method, the other four mixture fractions are
defined by:
F,=
mi
I
(3)
j=I
From these definitions, each mixture fraction Fi (i = 1-4) varies
independently between zero and unity and, to a first approximation, is
assumed to be statistically independent of the other mixture fractions. Thus Fi
is related tofi by:
e.=
(4)
j=i+l
The average value of any dependent fluctuating gas property P(gas species,
temperature, density or viscosity) is a function of F1,F2,F3 and F4,and can be
calculated by convoluting the instantaneous value over the probability density
functions (PDF) of the independent mixture fractions:
562
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasijiers
Table 3. Property of the coal.
Proximate analysis (wt %)
Moisture Ash
VM
FC
5.3
12.1
46.7
35.8
I Ultimate analysis (dry, ash free, wt %)
IC
H
N
0
S
I 77.6 6.5 1.13 13.9 0.22
Table 4. Operating conditions (base conditions).
Parameters
Particle size distribution (pm)
(wt % for each size classification)
10%
10%
20%
20%
20%
20%
Mass mean diameter (pm)
Gas flow rate (kg s-I)
Lower coal burner
Higher coal burner
Particle loading (kg s")
Lower coal burner
Higher coal burner
Pressure (MPa)
Values
150
100
40
20
10
4
39.8
0.284
0.180
0.289
0.289
3 .O
The local variances of the mixture fractions are calculated from gi transport
equations similar to those of Launder and Spalding (1972). The PDFs are
assumed to have the form of a clipped-Gaussian distribution, adjusted to
account for turbulent intermittency (Smoot et al., 1985).
The governing partial differential equations for all the quantities were
reduced to their finite difference analogues by integrating over the
computational cells. The conservation equations are Favre-averaged and
solved by the SIMPLER method (Patankar 1980). A line-by-line iteration
technique was used to solve the finite difference equations. Solution of the
particle-phase conservation equations is coupled with the gas-phase. An
563
H. Liu, C.Chen and T.Kojima
overall convergence of the two phases is achieved using an iteration
procedure.
Simulation is based on a 50 todday oxygen-blown entrained-flow HYCOL
gasifier (Ueda et al., 1994; Nogita et al., 1986). The coal property is based on
Taiheiyo bituminite (see Table 3). The operating conditions used in the
simulations are listed in Table 4 (base conditions). To obtain a relatively
general conclusion, simulations were also conducted under other conditions, in
addition to the base conditions of Table 4 (while keeping other parameters the
same as the base conditions). The chemical reaction-rate constants from the
literature (Smoot et aZ., 1987) for a similar coal were used in the present
calculation.
To obtain a steady convergence in the calculations, the model tracked
15360 particle trajectories. A ‘ 4 3 x 4 3 ~ 6 8 ’ grid mesh was adopted. A
converged solution is defined when the global energy balances are within
0.3% deviation of the total combustion energy, and the normalized residual
(mean residuaymean inlet velocity) for each velocity component is less than
0.3%.
Results and Discussions
(0 Effect on the Temperature and Gas Composition Distributions
The effects of fluctuations of mixture fractions on the temperature and gas
composition distributions, due to a turbulent flow, were investigated for
gasification in a HYCOL gasifier as shown in Figures 1 and 2. The calculated
results are compared when the fluctuations of mixture fractions are included
with those results when the fluctuations of mixture fractions are not included.
Figure 3 shows the effect of fluctuations of mixture fractions on the
temperature distribution. In Cases (a), (a*), (b) and (c), no fluctuation of
mixture fraction, the fluctuation of mixture fraction F1, the fluctuations of
mixture fractions F1 and Fz, the fluctuations of mixture fractions F1 through
Fq, were included respectively. Thus, in Case (b), the fluctuations of mixture
fractions concerning devolatilization and char-O2 reactions were included. In
Case (c), in addition to devolatilization and char-02 reactions, the fluctuations
concerning gasification reactions were also considered. For all the calculations
in this paper, all conditions are the same as the base conditions listed in Table
4 unless otherwise specified. All of the figures illustrate the horizontal crosssectional distributions (one-quarter of a circle). A jagged edge is used to
approximate the curved boundary. From Figure 3 it can be seen that the results
564
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasifiers
n
U
(1) upper burner
(2) lower burner
(3) throat
Heat recoveq
section
t
Gasification
section
(1)-
-4-
(2) =
e r f
A
Slag quenching
section
Figure 1. fa) Schematic diagram of a HYCOL gas$er. (8) Schematic overhead view
of nozzle geomem.
of Cases (a), (a*) and (b) are significantly different, with Cases (b) and (c)
nearly the same. These results suggest that the effect of fluctuations of gasmixture fractions produced from devolatilization on temperature distribution is
just as important as the fluctuation concerning char-02 reaction, i.e. neither of
565
H. Liu, C. Chen and T.Kojima
Gasifier
Coal
OxyP
Nitrogen
Tank
n
Ash treatment
Figure 2. Schematicflow diagram of a HYCOL gasifier.
them can be neglected. However, no significant influence of the fluctuations
of gas-mixture fractions produced from char-CO2 and char-steam reactions on
the temperature distribution is observed.
Figure 4 shows the effect of fluctuations of gas-mixture fractions produced
from various reactions on CO concentration distribution. The fluctuations of
mixture fractions concerning devolatilization and char-02 reactions
significantly influence the distribution of CO concentration, but the effect of
the fluctuations of mixture fractions concerning gasification reactions (charCOz and char-steam reactions) is limited. This is most likely due to the high
reaction rates of devolatilization and char-02 reactions, and the low reaction
rates of gasification reactions (char-COz and char-steam reactions). Figure 5
shows the effect of the fluctuations of mixture fractions on H2 concentration
distributions. Similarly, the results of Cases (b) and (c) are nearly the same,
while Cases (a), (a*) and (b) are very different.
566
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasijiers
Figure 3. EIfect of fluctuations of mixture fractions on the distribution
of temperature (K). cross-sectional distribution (onequarter of the cross section),
under base conditions. (a) No fluctuation, (a *) Fluctuation with FI.(6) Fluctuation
with Fl and F2. (c) Fluctuation with F1, F2, F3 and F,.
Figure 4. EIfect of fluctuations of mixture fractions on the distribution of CO
concentration, cross-sectional distribution (one-quarter of the cross section), under
base conditions. (a) No fluctuation, (a *) Fluctuation with FI. (6) Fluctuation with
Fl and F2. (c) Fluctuation with FI. F2,F3 and F4,
567
ff. tiu, C Chen and Z Kojima
Figure 5. Efect of fluctuations of mixture fractions on the distribution of H2
concentration, cross-sectional distribution (one-quarter of the cross section), under
base conditions. (a) No fluctuation, (a 8, Fluctuation with Fl. (b) Fluctuation with
Fl and F2-(c) Fluctuation with FI, F2,Fj and F,.
Figure 6. Efect of fluctuations of mixture ffactions on the distribution of CO
concentration for fine particles, cross-sectional distribution (one-quarter of the
cross section), diameter: 4 pn. (a) No fluctuation, (b) Fluctuation with F, and F2,
(c) Fluctuation with FI, F2,Fj and F,.
568
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasifiers
(ii) Effect of Fluctuation under Various Conditions
To obtain a general conclusion concerning the interaction between a turbulent
flow and reaction for entrained-flow gasification, the investigation was
conducted over a wide range of conditions. Figures 6 and 7 show the
concentration distributions of CO and H2 for fine particles (diameter 4 pm).
We also studied the case when the reaction rate pre-exponential for the charC 0 2 and H20 reaction rates were increased by a factor of 10 (see Figures 8
and 9). Moreover, Figures 10 and 11 show the results at 1.5 MPa. Combining
our previous results for air-blown IGCC gasifiers (Liu et al., 2002) and the
results shown in Figures 3 through 11, it was identified that during entrainedflow gasification, over a wide range of conditions of particle size, pressure, O2
concentration, etc., then the fluctuation of gas-mixture fraction produced from
devolatilization is just as important as that of char-02 reaction. However, the
fluctuations concerning gasification reactions can be neglected.
We also investigated the case of low volatile matter (VM) content.
Calculation was performed at low volatile matter conditions, i.e. by changing
the VM content of the coal from 46.7% into 30% (wt% as received) while
keeping the other parameters the same as listed in Tables 3 and 4. The results
are shown in Figure 12. The conclusions derived for a high VM-content coal is
also applicable to the case of a coal with relatively low VM-content. However,
the influence of fluctuation of gas-mixture fraction produced from
devolatilization and char-O2 reaction is pronounced for a high VM-content
coal.
(iii) Effect on General Characteristics of a HYCOL Gasifier and
Comparison with Experimental Data
Figure 13 shows the effect of fluctuation of mixture fractions on the general
characteristics of a HYCOL gasifier and the comparison with experimental
data. Case (d) represents the experimental results measured on a 50 todday
pilot-scale oxygen-blown entrained-flow HYCOL gasifier. The cold gas
efficiency and concentrations of CO and H2 in product gas for Case (b) are
nearly the same as those for Case (c). However, the results for Case (a) are
different from Cases (b) or (c). These findings show that the fluctuations of
gas-mixture fractions produced from devolatilization and char-02 reactions
influence not only the distributions of temperature and gas composition, but
also the general characteristics of a gasifier, i.e. cold gas efficiency and
product gas composition, during gasification in an oxygen-blown HYCOL
gasifier.
569
H. Liu, C.Chen and Z Kojima
Figure 7. Efect of fluctuations of mixture fiactions on the distribution of H2
concentration for fine particles, cross-sectional distribution (onequarter of the
cross section), diameter: 4 p. (a) No fluctuation, (b) Fluctuation with FI and F2,
(c) Fluctuation with F,, F2,F3 and F,.
Figure 8. Eflect offluctuations of mixture fiactions on the distribution of CO
concentration when gasification rates were increased by a factor of 10, crosssectional distribution (onequarter of the cross section). (a) No fluctuation, @)
Fluctuation with Fl and F2, (c) Fluctuation with FI, F2, F3 and F4.
5 70
Wbulent Flow and Reaction in Oxygen Blown HYCOL Gasifiers
Figure 9. Efect of fluctuations of mixture fiactions on the distribution of Ht
concentration when gasijcation rates were increased by a factor of lo, crosssectional distribution (one-quarter of the cross section). (a) No fluctuation, (3)
Fluctuation with Fl and F2, (c) Fluctuation with F,,F2,F3 and F,,
Figure 10. Efect of fluctuations of mixture fiactions on the distribution of CO
concentration at 1S MPa, cross-sectional distribution (one-quarter of the cross
section). (a) No fluctuation, (b) Fluctuation with FI and Fa (c) Fluctuation with F,,
F2, Fj and F4.
5 71
H. Liu, C. Chen and I: Kojima
Figure 11. Eflect of fluctuations of mixture fractions on the distribution of H2
concentration at 1 .S MPa, cross-sectional distribution (one-quarter of the cross
section). (a) No fluctuation, @) Fluctuation with F, and F2,(c) Fluctuation with F,,
Fz,FJ and Fd.
The comparison between the predictions for various cases and the
experimental data (Case (d)) identified that the predicted CO and H2
concentrations in the product gas for Cases (b) and (c) agree better with the
experimental data than Case (a), i.e. including fluctuations of mixture
fractions gives a better prediction. This result is in agreement with OUT
previously simulated results for an IGCC gasifier as summarized in Table 5
(LIU et al., 2002).
Conclusions
With a three-dimensional comprehensive computer simulation model, the
effects of mixture fraction fluctuations on the overall gasification
characteristics due to a turbulent flow were studied for gasification in an
oxygen-blown HYCOL entrained-flow coal gasifier. The method compared the
results with and without the fluctuation of gas-mixture fraction. The
theoretically predicted results were also compared with experimental data
obtained from a 50 todday pilot-scale HYCOL gasifier. It was shown that the
fluctuation of gas-mixture fraction produced from devolatilization is just as
important as that of ~ h a r - 0reaction,
~
i.e. neither of them can be neglected.
5 72
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasijiers
Figure 12. Eflect of fluctuations of mkture fiactions on the distribution of
temperature (K), cross-sectional distribution (one-quarter of the cross section),
under low volatile matter condition, i.e., 30% VMcontent (wt% as received). (a) No
fluctuation,(b) Fluctuation with FI and Fz, (c) Fluctuation with F], F2, F3 and F,.
They have important influences not only on the distributions of
temperature and gas composition, but also on cold gas efficiency and product
gas composition. However, the fluctuations of gas-mixture fractions produced
from char-CO2 and char-steam reactions have only a limited effect. This
conclusion is valid for a wide range of conditions of pressure, particle size and
O2 concentration during entrained-flow coal gasification. Based on these
results, the simulation model can be appropriately simplified without
significantly influencing the validity of the predicted results, and hence
reducing the calculation time. The predictions that include fluctuations of
mixture fractions show better agreement with the experimental data.
5 73
H. Liu, C. Chen and Z Kojima
Figure 13. Comparison between predictions and experimental results, under base
conditions. (a) No fluctuation, (b) Fluctuation with Fl and F2, (c) Fluctuation with
Fl, F2, F3 and F4 , (d) Experimental.
Table 5. A summary of previously simulated results for IGCC gasifier: a
comparison between predicted and measured heating values of product gas
(Liu et al., 2002).
Heating value of product gas (kcaVm3)
Case
No fluctuation
1014.1
Fluctuations with F1 and Fz
1046.7
Fluctuations with F,, Fz, F3 and F4 1056.6
Experimental measurement
1055.8
Acknowledgement
The authors would like to thank NEDOKCUJ for financial support of this
work under BRAIN-Cprogram.
Nomenclature
pre-exponential factors, s-’
pre-exponential factors, kg m-2s-’ Pa -03
acceleration due to gravity, m s-’
turbulent model constants
activation energies of devolatilization reactions, kJ mar'
apparent activation energy, k~ mol”
overall mixture fraction, the mass ratio of total coal off-gas to
the total gas product
mixture fractions defined in equations (2) and (3)
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gasijiers
variance of fi
thermal enthalpy, J kg-'
turbulent kinetic energy, m2 s-2
devolatilization rate constants, s-l
rate constant, kg m-'s-' Pa-'.'
mass of gas originating from gas solid reactions, kg
mass of inlet gas, kg
mass of particle, kg
static pressure, Pa
particle concentration, kg m-3
radiative heat flux, J m-'
generalized source term
source term arising from particles
time, s
particle temperature, K
gas velocity components, m s-'
particle velocity components, m s"
coordinate of three directions, m
volatile yield
volatile yield for low activation devolatilization reaction
maximum of Yl
volatile yield for high activation devolatilization reaction
maximum of Y,
average value of any gas property
dissipation rate of turbulent kinetic energy, m2se3
turbulent model constants
generalized variable
gas density, kg m-3
turbulent viscosity, kg m-' s-'
References
[ l ) Brewster, B.S., Baxter, L.L., Smoot, L.D., 1988. Treatment of coal devolatilization in
comprehensive combustion modeling. Energy & Fuels, 2, 362-370.
5 75
H.Liu, C.Chen and I: Kojima
[2] Chen, C.,Horio, M. and Kojima, T., 2000. Numerical simulation of entrained flow coal
gasifiers Part 1: Modeling of coal gasification in an entrained flow gasifier. Chem. Eng.
Sci., 55, 3861-3874.
[3] Chen, C., Miyoshi, T., Kamiya, H., Horio, M., Kojima, T. 1999.On the scaling-up of a two
stage air blown entrained flow coal gasifier. Can. J. Chern. Eng., 77, 745-750.
[4] Chen, C., Horio, M. and Kojima, T. 2000. Numerical simulation of entrained flow coal
gasifiers Part 2: Effects of operating conditions on gasifier performance. Chem. Eng. Sci.,
55,3875-3883.
[5] Chen, C., Horio, M. and Kojima, T. 2001. Use of numerical modeling in the design and
scale-up of entrained flow coal gasifiers. Fuel, 80, 1513-1523.
[6] Crowe, C. T.,Sharma, M. P. and Stock, D. E. 1977.The Particle-Source-in-Cell method for
gas and droplet flow. J. Fluids Eng., 99,325-332.
[7] Launder, B. E. and Spalding, B. 1972. Mathematical Models of Turbulence, Academic
Press, New York.
[8] Launder, B. E. and Sharma B. I. 1974. Application of the energy-dissipation model of
turbulence to the calculation of flow near a spinning disc. Letters in Heat Mass Transfer, 1,
131-138.
[9] Liu, H.,Chen, C. and Kojima, T. 2002. Theoretical Simulation of Entrained Flow IGCC
Gasifiers: Effect of Mixture Fraction Fluctuation on Reaction owing to Turbulent-Flow.
Energy & Fuels, 16, 1280-1286.
[lo] Furue, T.,Hanayama, F., Ueda, A. and Koyama, S. 1995.Operation result of entrained flow
coal gasification in a pilot HYCOL plant. Karyoku Gensiryoku Hatuden, 46 (4), 35-41.
[ l l ] Govind, R. and Shah, J. 1984. Modeling and simulation of an entrained flow coal gasifier.
AIChE Journal, 30,79-91.
[12] Hill, S. C. and Smoot, L. D. 1993. A comprehensive three-dimensional model for
simulation of combustion system: PCGC-3. Energy & Fuels, 7, 874-883.
[13] Koyama, S. 1990. Key technologies of entrained-bed coal gasification system. Japanese J.
Multiphase Flow, 4 (2), 101-110.
[14] Mann, A. P. and J. Kent, H. 1994.A computational study of heterogeneous char reactions
in a full-scale furnace. Combustion and Flame, 99, 147-156.
[IS] Ni, Q.and Williams, A. 1995.A simulation study on the performance of an entrained-flow
coal gasifier. Fuel, 74, 102-110.
[I61 Nogita, S., Koyama, S. and Morihara, A. 1986. Development of HYCOL technology.
Sunshine J., (Japan) 7,( I ) 70-77.
[17] Patankar, S. V. 1980. Numerical Heat Transfer and Fluid Flow, Hemisphere Publishing
Corp., Washington.
576
Turbulent Flow and Reaction in Oxygen Blown HYCOL Gas$ers
[I81 Smith I. W. 1982. The combustion rate of coal chars: A review. In Proceedings of
Nineteenth International Symposium on Combustion, The Combustion Institute, Pittsburgh,
pp. 1045-1065.
I191 Smoot, L. D. and Brown, B. W. 1987. Controlling mechanism in gasification of pulverized
coal. Fuel, 66, 1249-1256.
[20] Smoot, L. D. and Smith, P. J. 1985. Coal Combustion and Gasification, The Plenum
Chemical Engineering Series, Plenum Press, New York, 1985).
[21] Smoot, L. D. 1993. Fundamentals of Coal Combustion for Clean and Eficient Use,
Elsevier, Amsterdam.
[22] Shuen, J. S.. Chcn, L. D. and Feath, G. M. 1983. Evaluation of a stochastic model of
particle dispersion in a turbulent round jet. AIChE J., 29, 167-170.
[23] Ubhayakar, S. K., Stickler. D.B., Von Rosenberg, C. Y. and Gannon, R. E. 1977. Sixteenth
International Symposium on Combustion, The Combustion Institute, Pittsburgh.
[24] Ueda, F., Yoshida, N., Hashimoto, R. and Nomura, K. 1994. Characteristics of oxygenblown entrained-bed coal gasifier investigated in SOtld pilot plant. Kagaku Koguku
Ronbunshu, 20 (6), 766-773.
[25] Ueda, F., Yoshida, N., Hashimoto, R., Endo, M., Nomura, K., Kida, E. and Koyama, S.
1994. Development of the HYCOL gasification. In Proceedings of 13* EPRI Conference
on Gasification in Power Plants.
[26] Wen, C.
Y. and Chaung, T. Z. 1979. Entrainment coal gasification madeling. Ind.
Eng.
Chem. Process Des. Dev., 18, 684-694.
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