| 论文简介 |
Ash fusion characteristics of biomass have significant effect on slagging. In this
work, the effects of ash fusion characteristics on slagging have been studied by
ash fusion experiments and CFD modelling. Based on the basic ash composition
of biomass, the mixture of silicon dioxide, calcium oxide, potassium oxide, and
aluminum oxide have been selected as simulated ashes for ash fusion characteristics
investigation. The results indicate that deformation temperature decreases
with increased potassium oxide. High content of calcium oxide and silicon dioxide
increase deformation temperature for the skeleton effect, respectively. The
reactions of potassium oxide, calcium oxide and silicon dioxide lead to low melting
products and decrease deformation temperature. Aluminum oxide increases
deformation temperature by forming Si-Al-K compounds while K content is
high and decreases deformation temperature while Ca or Si content is high due
to the Si-Al-Ca compounds. On basis of the experimental results, an ash particle
adhesion model has been developed using the corresponding characteristic
temperatures of adhesion. Combined with the deposition model of inertial impaction,
a CFD modelling study of ash deposition on heating surface has been
performed. For a kind of cotton straw ash with low melting temperature, the
modelling results indicate that adhesion of molten ash plays a major role during
slagging. The accretion rate of molten ash adhesion accounts for 85% of
the total accretion rate. For a kind of corn straw ash with high melting temperature,
the proportion is only 37%. Compared with the actual slagging during
biomass combustion, the modelling results can reflect a similar slagging situation
on the surface of tube |
(创新港)
