TY - JOUR
T1 - Mechanistic Model for Ash Deposit Formation in Biomass
Suspension Firing. Part 1: Model Verification by Use of Entrained
Flow Reactor Experiments
AU - Hansen, Stine Broholm
AU - Jensen, Peter Arendt
AU - Jappe Frandsen, Flemming
AU - Sander, Bo
AU - Glarborg, Peter
PY - 2017
Y1 - 2017
N2 - Two
models for deposit formation in suspension firing of biomass
have been developed. Both models describe deposit buildup by diffusion
and subsequent condensation of vapors, thermophoresis of aerosols,
convective diffusion of small particles, impaction of large particles,
and reaction. The models differ in the description of the sticking
probability of impacted particles: model #1 employs a reference viscosity
in the description of the sticking probability, while model #2 combines
impaction of viscoelastic particles on a solid surface with particle
capture by a viscous surface. Both models were used to describe the
deposit formation rates and deposit chemistry observed in a series
of entrained flow reactor (EFR) experiments using straw and wood as
fuels. It was found that model #1 was not able to describe the observed
influence of temperature on the deposit buildup rates, predicting
a much stronger influence of this parameter. Model #2 was able to
provide a reasonable description of the influence of temperature on
the deposit buildup rates observed in the EFR experiments. A parametric
study was conducted to examine the influence of some physical parameters,
including ash concentration, viscosity of ash and deposits, surface
tension, Young’s modulus, and porosity. On the basis of this
model evaluation, where a wide range of temperatures (700–1000
°C) and fuels (straw and wood) were applied, model #2 can be
regarded as a promising tool for the description of deposit formation
from biomass ashes.
AB - Two
models for deposit formation in suspension firing of biomass
have been developed. Both models describe deposit buildup by diffusion
and subsequent condensation of vapors, thermophoresis of aerosols,
convective diffusion of small particles, impaction of large particles,
and reaction. The models differ in the description of the sticking
probability of impacted particles: model #1 employs a reference viscosity
in the description of the sticking probability, while model #2 combines
impaction of viscoelastic particles on a solid surface with particle
capture by a viscous surface. Both models were used to describe the
deposit formation rates and deposit chemistry observed in a series
of entrained flow reactor (EFR) experiments using straw and wood as
fuels. It was found that model #1 was not able to describe the observed
influence of temperature on the deposit buildup rates, predicting
a much stronger influence of this parameter. Model #2 was able to
provide a reasonable description of the influence of temperature on
the deposit buildup rates observed in the EFR experiments. A parametric
study was conducted to examine the influence of some physical parameters,
including ash concentration, viscosity of ash and deposits, surface
tension, Young’s modulus, and porosity. On the basis of this
model evaluation, where a wide range of temperatures (700–1000
°C) and fuels (straw and wood) were applied, model #2 can be
regarded as a promising tool for the description of deposit formation
from biomass ashes.
U2 - 10.1021/acs.energyfuels.6b01659
DO - 10.1021/acs.energyfuels.6b01659
M3 - Journal article
VL - 31
SP - 2771
EP - 2789
JO - Energy & Fuels
JF - Energy & Fuels
SN - 0887-0624
IS - 3
ER -