Pilot-scale investigation of the influence of coal-biomass cofiring on ash deposition. Robinson, A., L., Junker, H., & Baxter, L., L. Energy Fuels, 16:343-355, 2002.
abstract   bibtex   
Cofiring biomass with coal is a promising short-term option for reducing the net CO2 emissions from existing coal-fired power plants. This paper examines the effects of cofiring biomass and coal on ash deposition under conditions representative of those found in the superheater region of pulverized-coal boilers. Experiments were conducted with blends of eight different fuels-three types of bituminous coal, sub-bituminous coal, two types of straw, switchgrass, and wood. For each fuel, reference tests of unblended fuel establish a baseline against which to compare the results from the cofiring tests. The deposition rates for the cofire blends are between the measured deposition rates of the unblended fuels. Therefore, blending straw with coal reduces the high deposition rates observed while firing unblended straw, and cofiring coal with wood results in slightly lower deposition rates than those that occur while firing unblended coal. The primary interaction between the biomass and coal during cofiring is the reaction of the sulfur from the coal with the alkali species from the biomass. This sulfation reduces the stickiness of the deposit, which substantially reduces the deposition rate of the coal-straw blends in comparison to expectations based on the performance of the unblended fuels. Sulfation also reduces the chlorine content of the deposits, potentially reducing the corrosion potential of the deposits. A scaling parameter is proposed to estimate the deposit chlorine content on the basis of the properties of the cofire blend; the ratio of fuel-S to available alkali must be in excess of 5 times the S-to-alkali stoichiometric ratio to eliminate chlorine from the deposit. The results demonstrate that cofiring can mitigate some of the fouling difficulties associated with combustion of high-fouling biofuels. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94550 USA.
@article{
 title = {Pilot-scale investigation of the influence of coal-biomass cofiring on ash deposition},
 type = {article},
 year = {2002},
 pages = {343-355},
 volume = {16},
 id = {64582a65-e442-3e31-96e5-f19d8b3cd0fb},
 created = {2014-10-08T16:28:18.000Z},
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 profile_id = {363623ef-1990-38f1-b354-f5cdaa6548b2},
 group_id = {02267cec-5558-3876-9cfc-78d056bad5b9},
 last_modified = {2017-03-14T17:32:24.802Z},
 read = {false},
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 hidden = {false},
 citation_key = {Robinson:EF:2002a},
 source_type = {article},
 private_publication = {false},
 abstract = {Cofiring biomass with coal is a promising short-term
option for reducing the net CO2 emissions from existing coal-fired
power plants. This paper examines the effects of cofiring biomass
and coal on ash deposition under conditions representative of those
found in the superheater region of pulverized-coal boilers.
Experiments were conducted with blends of eight different
fuels-three types of bituminous coal, sub-bituminous coal, two
types of straw, switchgrass, and wood. For each fuel, reference
tests of unblended fuel establish a baseline against which to
compare the results from the cofiring tests. The deposition rates
for the cofire blends are between the measured deposition rates of
the unblended fuels. Therefore, blending straw with coal reduces
the high deposition rates observed while firing unblended straw,
and cofiring coal with wood results in slightly lower deposition
rates than those that occur while firing unblended coal. The
primary interaction between the biomass and coal during cofiring is
the reaction of the sulfur from the coal with the alkali species
from the biomass. This sulfation reduces the stickiness of the
deposit, which substantially reduces the deposition rate of the
coal-straw blends in comparison to expectations based on the
performance of the unblended fuels. Sulfation also reduces the
chlorine content of the deposits, potentially reducing the
corrosion potential of the deposits. A scaling parameter is
proposed to estimate the deposit chlorine content on the basis of
the properties of the cofire blend; the ratio of fuel-S to
available alkali must be in excess of 5 times the S-to-alkali
stoichiometric ratio to eliminate chlorine from the deposit. The
results demonstrate that cofiring can mitigate some of the fouling
difficulties associated with combustion of high-fouling biofuels.
C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94550 USA.},
 bibtype = {article},
 author = {Robinson, A L and Junker, H and Baxter, L L},
 journal = {Energy Fuels}
}

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