Fouling tendency of ash resulting from burning mixtures of biofuels. Part 2: Deposit chemistry

Theis, Mischa; Skrifvars, Bengt-Johan; Zevenhoven, Maria; Hupa, Mikko; Tran, Honghi

doi:10.1016/j.fuel.2006.03.015

Cited by 123 publications

(70 citation statements)

References 17 publications

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“…The latter trend, although based on two fuel mixes, is opposite to findings of Capablo et al [15] who showed that DBU was correlated to ash content and that all fuels with an ash content above 3.5 wt-% resulted in deposit rates above 100 g·m -2 h -1 . The DBU (550 o C) in this work are in the lower ranges compared to deposition data from other work on combustion of pulverised biomass in laboratory scale [15,6]. Skrifvars et al [10] reports that during (pf) combustion of wood, with ash content between 0.4-0.7 wt-%, in a 80 MW th boiler, the DBU were between 15-75 g·m -2 h -1 .…”

Section: Deposit Formationmentioning

confidence: 44%

“…As the demand for CO 2 neutral energy resources will continue to increase, other fuels (and/or additives) than coal need to be considered for cofiring with straw. Several investigators have shown positive effects on fouling by cofiring of straw and peat [6] and by using additives such as sand and bentonite [7]. Other findings indicate that slagging, when firing pure woody fuels, can be decreased by addition of limestone [8].…”

Section: Introductionmentioning

confidence: 99%

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Ash transformations in pulverised fuel co-combustion of straw and woody biomass

Nordgren

Hedman²,

Padban

et al. 2013

Fuel Processing Technology

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Ash transformation processes have been studied during co-firing of wheat straw and pine stem wood and softwood bark. Pilot-scale trials in a 150 kW pulverised-fuel-fired burner were performed. Thermodynamic equilibrium calculations were made to support the interpretation of the results. The results show that fast reactions involving gaseous ash compounds are favored at the expense of reactions where condensed components participate. Accordingly, the conditions promote gas phase reactions resulting in the formation of chlorides, sulfate and carbonates whereas reactions involving condensed reactants are suppressed. Both the slagging and fouling propensity of all co-firing mixes was reduced compared to that for pure straw. For the wood/straw mixes this was mainly due to a dilution of the ash forming elements of straw whereas for straw/bark, an additional effect from interaction between the fuel ash components was observed to primarily reduce slagging. In general it can be concluded that under powder combustion conditions equilibrium are approached selectively and that the ash matter are strongly fractionated. The general results in this paper are useful for straw-fired power stations looking for alternative co-firing fuels.

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Section: Deposit Formationmentioning

confidence: 44%

Section: Introductionmentioning

confidence: 99%

Ash transformations in pulverised fuel co-combustion of straw and woody biomass

Nordgren

Hedman²,

Padban

et al. 2013

Fuel Processing Technology

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“…A plausible hypothesis is that on-field shredding with the forage harvester produced a loss of biomass material such as leaves, which are known to contain higher nutrient amounts (Fournela et al, 2015;Prohnow et al, 2009). Theis et al (2006) conducted a comparison of the straw, peat, and bark ash deposition behaviours with different chemical compositions. They concluded that straw had higher fouling tendency than peat and bark, due to the large amounts of water-soluble compounds occurring in the straw.…”

Section: Resultsmentioning

confidence: 99%

Comparison of selected parameters of biomass and coal

Lalak¹,

Martyniak²,

Kasprzycka³

et al. 2016

International Agrophysics

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As a fuel, biomass differs in its properties from fossil fuels and acquisition thereof for energy purposes is limited; hence, the ongoing search for new bioenergetically useful plants. The article presents the results of physical and chemical analyses of seven species of perennial grasses: tall wheatgrass, tall wheatgrass ‘Bamar’, brome grass, tall fescue ecotype, reed canary grass, giant miscanthus, and sorghum. The research involved technical and elemental analysis as well as analysis of the ash composition performed in order to determine their potential use for combustion process. The measurement results were compared with those obtained for hard coal and agricultural biomass, which is widely used in the energy industry. The results suggest that perennial grasses can successfully be combusted with similar performance to coal if burned in appropriate combustion installations.

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“…Straw is known to cause alkali related problems, such as bed agglomeration as well as building up corrosive deposits on the boiler tubes, during combustion [22,23]. Most of these problems are caused by formation of volatile KCl and viscous potassium silicate melts.…”

Section: Strawmentioning

confidence: 99%