The effect of CaO on emissions of nitric oxide from a fluidised bed combustor

Allen, Deborah; Hayhurst, A.N.

doi:10.1016/j.fuel.2015.06.030

Cited by 14 publications

(5 citation statements)

References 41 publications

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“…The increase in the NO x emission should be caused by the increased conversion ratio of fuel-N to NO x when the bed temperature increased . Limestone resulting in higher NO x emission was due to the fact that CaO produced during limestone decomposition worked as an active catalyst for the conversion of fuel-N to NO x …”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the significant decrease above 750 °C was mainly due to the fact that CaO has better sulfur removal efficiency than that of CaCO 3 . The desulfuration reactions are as follows …”

Section: Resultsmentioning

confidence: 99%

“…45 Limestone resulting in higher NO x emission was due to the fact that CaO produced during limestone decomposition worked as an active catalyst for the conversion of fuel-N to NO x . 46 3.4. Emission of SO 2 .…”

Section: Energy and Fuelsmentioning

confidence: 99%

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Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Bie²,

Zhang

et al. 2017

Energy Fuels

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For predicting and relieving ash-related problems and harmful gas emissions during fluidized bed combustion, release of K and Cl and emissions of NO x and SO 2 during reed black liquor (BL) combustion in a fluidized bed were investigated in this study. The effects of bed material (calcium-based zeolite and limestone) and bed temperatures (700−900 °C) were also studied. The results showed that higher temperature favored the K release for both calcium-based zeolite and limestone, and calcium-based zeolite caused lower K release due to the formation of K 3 Al(SO 4 ) 3 , KAl(SO 4 ) 2 , and K 2 O-Al 2 O 3 -SiO 2 eutectic compounds. Cl was mainly released in the form of HCl above 700 °C. Moreover, high temperature facilitated Cl release for calcium-based zeolite, whereas it had a complicated effect on Cl release for limestone. Although higher temperature increased the NO x emission for both calcium-based zeolite and limestone, limestone resulted in higher NO x emission due to the conversion of fuel N to NO x under CaO catalysis. Temperature had a slight effect on SO 2 emission for calcium-based zeolite, whereas it decreased the SO 2 emission for limestone. Reed BL combustion generated lower SO 2 emissions with the help of Na 2 CO 3 and K 2 CO 3 , and limestone resulted in much lower SO 2 emission with the help of CaCO 3 and CaO.

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Section: Resultsmentioning

confidence: 99%

“…Moreover, the significant decrease above 750 °C was mainly due to the fact that CaO has better sulfur removal efficiency than that of CaCO 3 . The desulfuration reactions are as follows …”

Section: Resultsmentioning

confidence: 99%

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Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Bie²,

Zhang

et al. 2017

Energy Fuels

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“…Studies have shown that CaO is a highly active substance catalyzing C–NO reaction. CaO and C reactions will generate CaC 2 , which can reduce the emission of NO in a reducing atmosphere [ 16 ]. Carbide slag is the waste residue produced during the preparation of acetylene.…”

Section: Introductionmentioning

confidence: 99%

Desulfurization and Denitrification Performance of Modified Rice Husk Ash-Carbide Slag Absorbent

et al. 2020

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In the cement industry, SO2 and NOx are generally removed separately. There are many problems, such as large area, high investment cost, secondary pollution and so on. Desulfurization and denitrification technology have become a frontier research direction in the field of air pollution control. In this paper, rice husk ash and carbide slag were compounded and modified to prepare modified rice husk ash-carbide slag composite absorbent, and its desulfurization and denitrification performance and mechanism were studied. The results showed that the NO conversion and SO2 conversion of the modified rice husk ash-carbide slag composite absorbent increased by 44% and 2%, respectively, at 700 °C. Fibrous calcium silicate and calcium silicoaluminate hydrates were formed during the hydration process, which made the specific surface area of the absorbent larger and provided more reactive sites. The hydration process increases the content of oxygen-containing functional groups, decreases the hydroxyl/ether C–O functional groups, and increases the content of carboxyl–COO functional groups are conducive to the denitrification reaction.

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“…Different from PC combustion, the FB combustion is featured by low operating temperature and high concentration of solids, many unburned char remained in the dense bed zone. Besides, a large amount of limestone was usually fed into the CFB boiler for desulfurisation, and CaO was proved to be an effective catalyst for NO reduction [6]. Hence, both of the above two regimes have an important effect on NO reduction during fluidised bed combustion.

NO + CO \overset{catalytic surface}{\to} 0.5 N_{2} + normalC O_{2},

NO + normalC false\to 0.5 N_{2} + CO,

2 NO + normalC false\to N_{2} + normalC O_{2} .

During oxy‐fuel combustion, the atmosphere inside the boiler differs greatly from that of conventional combustion with air.…”

Section: Introductionmentioning

confidence: 99%

Effects of CO ₂ and CO on the reduction of NO over calcined limestone or char in oxy‐fuel fluidised bed combustion

Liao

Shao

Zhang

et al. 2019

IET Renewable Power Generation

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To reveal the effects of CO 2 and CO on the reduction of NO in oxy-fuel fluidised bed combustion, NO-CO reduction catalysed by calcined limestone and NO-char reduction were studied in a suspension-bed reactor under CO 2 or N 2 atmosphere with the CO concentration varied from 0.28 to 1.88%. Results showed that the calcined limestone is an effective catalyst for NO-CO reduction. The activation energy of NO-CO reduction over calcined limestone was 157-164 kJ/mol at low temperature (600-800°C) and decreased to 58.7-102.1 kJ/mol at high temperature (800-100°C). In CO 2 atmosphere, the NO conversion ratio was nearly zero during the NO-CO reduction process, and for NO-char reduction, the NO conversion ratio in CO 2 was lower than that in N 2. However, CO showed promotion effect on NO reduction. In NO-CO reduction process, as the CO concentration increased from 0.28% to 1.88%, the NO reduction ratio increased from 0.40 to 0.75. For NO-char reduction in N 2 , the NO conversion ratio was obviously higher when 1% CO was introduced, and the promotion effect of CO became weaker as the temperature increased. Moreover, the promoting effect of CO was inhibited in CO 2 atmosphere.

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The effect of CaO on emissions of nitric oxide from a fluidised bed combustor

Cited by 14 publications

References 41 publications

Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Desulfurization and Denitrification Performance of Modified Rice Husk Ash-Carbide Slag Absorbent

Effects of CO ₂ and CO on the reduction of NO over calcined limestone or char in oxy‐fuel fluidised bed combustion

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The effect of CaO on emissions of nitric oxide from a fluidised bed combustor

Cited by 14 publications

References 41 publications

Release of K and Cl and Emissions of NOx and SO2 during Reed Black Liquor Combustion in a Fluidized Bed

Release of K and Cl and Emissions of NOx and SO2 during Reed Black Liquor Combustion in a Fluidized Bed

Desulfurization and Denitrification Performance of Modified Rice Husk Ash-Carbide Slag Absorbent

Effects of CO 2 and CO on the reduction of NO over calcined limestone or char in oxy‐fuel fluidised bed combustion

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About

Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Release of K and Cl and Emissions of NO_x and SO₂ during Reed Black Liquor Combustion in a Fluidized Bed

Effects of CO ₂ and CO on the reduction of NO over calcined limestone or char in oxy‐fuel fluidised bed combustion