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Energy transport and chemistry are modeled in an extension of the Eulerian–Lagrangian computational particle fluid dynamics (CPFD) methodology. The CPFD methodology is based on the MP-PIC method. In our extension of CPFD, an enthalpy equation describes energy transport for fluid, and provides for transfer of sensible and chemical energy between phases and within the fluid mixture. Homogenous and heterogeneous chemistry are described by reduced-chemistry. A three-dimensional example of a hot fluidized bed coal gasifier is presented to demostrate the model. Introduction
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Hongna Wang Nov. 20, 2012
Journal Report
About Coal and sludge
Eulerian–Lagrangian method for three-dimensional thermal reacting flow with
application to coal gasifiers Dale M.Snider , SamuelM.Clark
CPFD Software LLC, USA Chemical Engineering Science
66 (2011) 1285–1295
Energy transport and chemistry are modeled in an extension of the
Eulerian–Lagrangian computational particle fluid dynamics (CPFD)
methodology. The CPFD methodology is based on the MP-PIC method.
In our extension of CPFD, an enthalpy equation describes energy
transport for fluid, and provides for transfer of sensible and chemical
energy between phases and within the fluid mixture. Homogenous and
heterogeneous chemistry are described by reduced-chemistry.
A three-dimensional example of a hot fluidized bed coal gasifier is
presented to demostrate the model.
Introduction
The CPFD cell chemistry uses properties mapped from
discrete particles to the grid, and the cell particle properties
used in chemistry vary from cell to cell depending on the
particle distribution in the system.
Modelling
Reactor
Results and discussion
Results and discussion
Results and discussion
The bed surprisingly has a uniform temperature except at the
feed-sparger arms .
There were variations in gas species radially and axially in
the bed such as pockets of H2 . In this coal gasifier would not be
modeled well by a simple plug-flow reactor model.
The sparger design used in this study appears to be
responsible for much of the bed non-uniformity in gas–solids
distribution and chemical reactions. The sparger design would
be a candidate to improve performance.
Conclusion
Rheology and thixotropic properties of slurry fuel prepared using municipal wastewater sludge
and coal Jian-zhong Liu, Rui-kunWang
Zhejiang University ,ChinaChemical Engineering Science
76 (2012) 1–8
Municipal wastewater sludge MWS can be directly
combined with coal, water, and additives to produce coal–
sludge slurry (CSS). Compared with coal–water slurry, CSSs
behaved as more obvious pseudo- plastic fluids and the sludge
enhances the pseudoplasticity and thixotropy of the slurry.
Introduction
Rheological and thixotropic behaviors are the major
character- istics that influence the stability of the storage
procedure, fluidity of the transportation procedure (Meng et
al., 2000), and spray- ability (Basel et al., 2005) and
flammability of the spray and combustion procedures of
slurry fuel.
Our research group has carried out studies on the
slurryability, rheology, and stability of CSSs.
Introduction
1.Slurryability properties of CSS
After the addition of sludge, the viscosity of the slurry increased and the FVC
decreased which can be attributed to sludge particles are abundant in cellular tissues
and flocs.
Results and discussion
2.Rheological characteristics of CSSs—C↑ n↓
Rheological index n was close to 1 and was reduced slightly with increasing
concentration, indicating that the non-Newtonian pseudoplastic behavior of CWSs
was enhanced.
Results and discussion
2.Rheological characteristics of CSSs—α↑ n↓
These parameters showed that the rheological properties well fitted the Herschel–
Bulkley flow model.
Results and discussion
3. Thixotropic characteristics of CSS---α ↑ thixotropic loop area ↑
Results and discussion
4.Effect of sludge particle size
The sludge disposal volume and CSS concentration can be improved by
properly grinding the sludge to reduce its particle size.
Results and discussion
With increasing CSS concentration, t and K increased, and
the pseudoplastic behavior and thixotropyof the CSSs
strengthened.
The flow behaviors of the CSSs well fitted the Herschel–
Bulkley model
The costs of CSS transportation can be reduced by
appropriately reducing sludge particle size.
Conclusions