The effect of HCl on the formation of calcium silicates in sand beds in fluidized bed boilers

Partanen, Jatta; Backman, Peter; Hupa, Mikko

doi:10.1016/s0010-2180(02)00355-3

Cited by 16 publications

(11 citation statements)

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“…The ash-melting studies indicate that, when the ashes shrunk during melting, the DSC baseline was shifted upward. 28 The drift of the DSC curve is also caused by the movement of the sample holder from the center of the STA furnace during the setting and the removal of the sample and the reference crucibles during the STA measurements. 2 and 3 and Table 4 present the measurements from the STA tests using the model compounds and their mixtures.…”

Section: Resultsmentioning

confidence: 99%

“…One just has to be aware of the fact that effects will occur. The ash-melting studies indicate that, when the ashes shrunk during melting, the DSC baseline was shifted upward . The drift of the DSC curve is also caused by the movement of the sample holder from the center of the STA furnace during the setting and the removal of the sample and the reference crucibles during the STA measurements.…”

Section: Resultsmentioning

confidence: 99%

“…Thermal analysis is widely used in combustion research for the determination and understanding of various properties and the behavior of different fuels under a wide range of conditions and applications. − It has been reported that thermal analysis methods including thermogravimetric analysis/differential thermal analysis (TGA/DTA), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), thermomechanical analysis (TMA), and dynamic mechanical analysis (DMA) can be used to provide an estimation regarding the ash-melting characteristics of various coal and biomass samples. ,− In this work, a TGA/DSC instrument that is also called a simultaneous thermal analysis (STA) instrument is used to characterize the ash behavior of 12 annual biomasses. The study has been focused on obtaining information on both ash melting and the ash gas-phase release as a function of temperature, whereby the melting and gas-phase release behavior of the samples could be related to the chemical composition of the biomasses.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Thermal Analysis (STA) on Ash from High-Alkali Biomass

2004

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Improved knowledge of the melting and gas-phase release behavior of ash from biomass fuels is of premium importance, to reduce ash-related problems in straw-fired boilers. In this study, a simultaneous thermal analysis (STA) instrument was used to characterize the behavior of 12 significant different annual biomass ash samples, and several model compounds, such as SiO2, KCl, K2SO4, K2CO3, CaSO4, CaCO3, and some of their mixtures. The STA analyses provided information on mass loss and exothermic/endothermic reactions as a function of sample temperature. The mass loss curves of the biomass ashes during STA heating could, in most cases, be explained from the chemical composition of the ash. Below 800 °C, weight loss is caused by the release of CO2 from CaCO3. At temperatures of 850−1150 °C, KCl evaporates and K2CO3 reacts with SiO2 and CO2 is released. Above 1150 °C and up to 1450 °C, a weight loss from the ash samples may be caused by the release of K2O produced from the K2CO3 decomposition or from silicates or the release from sulfates. However, even at 1450 °C, a large fraction of the potassium derived from carbonates remains in the condensed phase in the form of silicates.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simultaneous Thermal Analysis (STA) on Ash from High-Alkali Biomass

2004

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“…The possible paths and release mechanisms of Cl during pyrolysis and combustion of biomass can be found in ref . HCl is formed when fuels containing organically bound chlorine or inorganic chloride salts are burned . Organically associated Cl can also be released in the gas phase as CH 3 Cl .…”

Section: Circulation Of Inorganic Volatiles Elementsmentioning

confidence: 99%

“…In the calciner, and along lower preheater stages, the HCl will be absorbed by free lime, according to reaction ; , however the absorption of HCl by limestone is strongly dependent on the humidity of the flue gas . The absorption of HCl by limestone has been extensively studied by Partanen. ,− …”

Section: Circulation Of Inorganic Volatiles Elementsmentioning

confidence: 99%

Review: Circulation of Inorganic Elements in Combustion of Alternative Fuels in Cement Plants

et al. 2015

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Cement production is an energy-intensive process, which traditionally has been dependent on fossil fuels. However, the use of alternative fuels, i.e., selected waste, biomass and by-products with recoverable calorific value, is constantly increasing. Combustion of these fuels is more challenging compared to fossil fuels, due to lack of experience and different chemical and physical properties. When complete oxidation of fuels in the calciner and main burner is not achieved, they burn in direct contact with the bed material of the rotary kiln, causing local reducing conditions and increasing the internal circulation of S, Cl, Na, and K. Compounds containing these elements, such as alkali salts, evaporate when exposed to high temperatures and subsequently condense in colder parts of the plant. The transformation of the volatile inorganic species at different locations in the cement plant is important, because a high internal circulation affects the process stability and operation through formation of build-ups and blockages, ring formation, and shell corrosion, resulting in reduced clinker production, higher heat consumption, and kiln or plant stops. The present review describes the internal cycles of inorganic elements that are established within the cement plant and their dependence on process parameters. Special focus is given to the sulfur cycle. This cycle is intensified by CaSO 4 decomposition, making it sensitive to local reducing conditions.

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Absorption of HCl by limestone in hot flue gases. Part I: the effects of temperature, gas atmosphere and absorbent quality

Partanen

Backman

et al. 2005

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The effect of HCl on the formation of calcium silicates in sand beds in fluidized bed boilers

Cited by 16 publications

References 1 publication

Simultaneous Thermal Analysis (STA) on Ash from High-Alkali Biomass

Simultaneous Thermal Analysis (STA) on Ash from High-Alkali Biomass

Review: Circulation of Inorganic Elements in Combustion of Alternative Fuels in Cement Plants

Absorption of HCl by limestone in hot flue gases. Part I: the effects of temperature, gas atmosphere and absorbent quality

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