Inhibition of lignite ash slagging and fouling upon the use of a silica-based additive in an industrial pulverised coal-fired boiler: Part 3 – Partitioning of trace elements

Low, Fiona; Girolamo, Anthony William De; Wu, Xiaojiang; Dai, Baiqian; Zhang, Lian

doi:10.1016/j.fuel.2014.09.015

Cited by 17 publications

(12 citation statements)

References 23 publications

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“…The condensation and deposition of Na 2 SO 4 and Ca 2 SO 4 play an important role on ash depositing on convection heating surfaces. Dai et al − researched the properties of ash deposits during the combustion of Zhundong coal mixed with silica additive in a 30 MW pulverized-fuel boiler. The results indicate that adding silica (>4 wt %) is essential in promoting the agglomeration of ash.…”

Section: Introductionmentioning

confidence: 99%

Transformation Characteristics of Sodium of Zhundong Coal Combustion/Gasification in Circulating Fluidized Bed

Song

et al. 2016

Energy Fuels

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In this study, the transformation characteristics of sodium in Zhundong coal were investigated, following its combustion (oxidizing atmosphere) and gasification (reducing atmosphere) in a circulating fluidized bed (CFB) experimental system of 0.25 t/d high alkali coal thermochemical conversion. The equilibrium distribution of Na is predicted under the oxidizing and reducing atmospheres by the thermodynamic equilibrium calculation. Na in bottom ash and fly ash evidently decreases as the temperature increases in both the combustion and gasification processes. More Na is retained in the ash during the gasification process. Na exists as sodium aluminosilicate in both combustion bottom ash and gasification bottom ash, and mainly as sodium sulfate (Na2SO4) in combustion fly ash and sodium chloride (NaCl) in gasification fly ash. Na undergoes different transformation processes through combustion and gasification. Gaseous metallic sodium, Na2O and NaCl are released from the coal and condense directly on the cold tube surface during gasification. When SO2 is present, Na reacts with it, forming a large amount of gaseous sodium sulfates during combustion.

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Section: Introductionmentioning

confidence: 99%

Transformation Characteristics of Sodium of Zhundong Coal Combustion/Gasification in Circulating Fluidized Bed

Song

et al. 2016

Energy Fuels

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“…Consequently, as a nonvolatile or semivolatile element, Cr is expected to be mostly retained in the high-temperature section. Furthermore, the RE factor of BA is expected to be higher than that of the cooling section ash, which has been reported by Low et al In these tests (S1 and S2), the BA collected from the high-temperature section possessed much lower enrichment factors than the HA sampled in the cooling section. This result implies that Cr in the feedstock is highly volatile.…”

Section: Resultsmentioning

confidence: 56%

“…Along the flow direction, the mean particle size is expected to have decreased because smaller particles were entrained from the upstream area to the downstream area. Cr is commonly considered a nonvolatile or semivolatile element. , According to classic vaporization–nucleation/condensation pathways, , trace elements were vaporized at high-temperature sections and nucleated or condensed on fine-particle surfaces at cooling sections. Consequently, as a nonvolatile or semivolatile element, Cr is expected to be mostly retained in the high-temperature section.…”

Section: Resultsmentioning

confidence: 99%

Co-Combustion of Tannery Sludge in a Bench-Scale Fluidized-Bed Combustor: Gaseous Emissions and Cr Distribution and Speciation

et al. 2017

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In this study, 11 coal mono-combustion tests and four co-combustion tests of coal and tannery sludge were conducted on a 35 kW fluidized-bed combustor. The combustion behavior and emission characteristics of the fuels were investigated on a bubbling fluidized bed (BFB) and a circulating fluidized bed (CFB). The effects of an excess air ratio, primary air rate, secondary air ratio, and fuel type on flue gas emissions were studied. The results showed that the fluidization status and temperature distribution had direct influences on CO emission. Sufficient fluidization and high temperature effectively reduced CO emission. NO x emission was relatively sensitive to the excess air ratio and increased with increasing excess air ratio. By comparing BFB and CFB, we found that CFBs have an advantage in optimizing combustion and controlling emissions by enhancing mixing and increasing freeboard temperatures. The Cr speciation and distribution among different ash types were extensively investigated in four co-combustion tests. The results showed that the distribution modes of Cr in BFBs and CFBs were different and determined by separate fluid dynamics modes of sludge ash particles in the combustor. The extent of Cr oxidation in ash in CFB tests was higher than that in BFB tests, particularly for bottom ash and heat exchanger ash, due to longer residence times in high-temperature regions.

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“…During coal combustion, SiO 2 [20][21][22] and CaO [22][23][24][25] are often added in coal as additives to reduce the harmful components release. Vassilev et al [4] stated the volatile Br can be adsorbed on the glass phase, and the Ca, Mg silicate generated in the process of combustion can fixed the Br from authigenic mineral in coal.…”

Section: Effects Of Additives On the Bromine Releasementioning

confidence: 99%

Study on bromine release from bituminous coal during combustion

Peng

2015

Fuel

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Inhibition of lignite ash slagging and fouling upon the use of a silica-based additive in an industrial pulverised coal-fired boiler: Part 3 – Partitioning of trace elements

Cited by 17 publications

References 23 publications

Transformation Characteristics of Sodium of Zhundong Coal Combustion/Gasification in Circulating Fluidized Bed

Transformation Characteristics of Sodium of Zhundong Coal Combustion/Gasification in Circulating Fluidized Bed

Co-Combustion of Tannery Sludge in a Bench-Scale Fluidized-Bed Combustor: Gaseous Emissions and Cr Distribution and Speciation

Study on bromine release from bituminous coal during combustion

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