Deposit Formation of the Low-Pressure Economizer in a Coal-Fired Thermal Power Plant

Chen, Heng; Jiao, Jian; Pan, Peiyuan; Zhao, Qinxin; Wang, Yungang

doi:10.1021/acs.energyfuels.6b03507

Cited by 12 publications

(4 citation statements)

References 22 publications

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“…They will be in steady status and deposit on the tube surface when the gas temperature is below the decomposition temperature. The possible formation process of (NH 4 ) 3 H(SO 4 ) 2 is as follows: Or NH 4 HSO 4 is well-known as an important component of ash fouling in a coal-fired boiler. , It has been generally accepted that the formation temperature of NH 4 HSO 4 was in the range of 190–240 °C . In this work, no NH 4 HSO 4 was found in the ash deposits.…”

Section: Resultsmentioning

confidence: 68%

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Investigation into the Ash Deposits in a Coal-Fired Traveling Grate Boiler with Ammonia Present in the Flue Gas

et al. 2018

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A study was undertaken of the ash deposits on different positions in a 140 MW coal-fired traveling-grate boiler with ammonia present in the flue gas. Several ash samples were collected from the slag tubes and three-stage heat exchanger of this boiler. The ash samples were examined using the combination of X-ray fluorescence and X-ray diffraction analysis to obtain their chemistry and mineralogy. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis was conducted to determine the microstructure and compositions of the ash deposits. The results showed that the fouling of the slag tubes was mainly attributed to Fe2O3. At the three-stage heat exchanger, complicated sulfates played an important role in the deposition formation. The deposition mechanism of sulfates gradually changed with the gas temperature at different stages of the heat exchanger. NH4Al(SO4)2, Na3Fe(SO4)3, and KAl(SO4)2 were more prone to deposit on the surface of the heat exchanger than ammonium salts [e.g., (NH4)3H(SO4)2] at higher temperatures (>340 °C). (NH4)3H(SO4)2 was found in the ash deposits at the outlet of the second and third stages of the heat exchanger, where the flue gas temperature was below 240 °C.

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Section: Resultsmentioning

confidence: 68%

“…NH 4 HSO 4 is well-known as an important component of ash fouling in a coal-fired boiler. 15,16 It has been generally accepted that the formation temperature of NH 4 HSO 4 was in the range of 190−240 °C. 16 In this work, no NH 4 HSO 4 was found in the ash deposits.…”

Section: Energy and Fuelsmentioning

confidence: 99%

Investigation into the Ash Deposits in a Coal-Fired Traveling Grate Boiler with Ammonia Present in the Flue Gas

et al. 2018

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“…Recently, researchers are mainly focused on the formation mechanism of the ABS . Only a few studies investigated the characteristics of ABS fouling . Codan Development Limited Liability Company has developed the sodium bisulfite (SBS) injection technology to remove SO 3 .…”

Section: Introductionmentioning

confidence: 99%

The influence of Na₂SO₃/NaHSO₃ on the formation process of low‐temperature ash deposition with an in situ measurement technique

Zhang

Zhou

Cen

et al. 2019

Asia-Pacific J Chem Eng

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Understanding the reduction mechanism of additives on ammonium bisulfate (ABS) fouling formation can alleviate ABS fouling problems. This paper presents an investigation of the influence of Na 2 SO 3 /NaHSO 3 on the formation process of ABS fouling with an in situ measurement technique. According to the thickness curves, both Na 2 SO 3 and NaHSO 3 can control the growth of ABS fouling, but Na 2 SO 3 shows a better inhibitory effect on the growth of ABS fouling. Meanwhile, the mitigation effect of the additive on ABS fouling increases with the increasing injection quantity of the additive. The results of the heat flux show that the heat transfer performance of the fouling probe becomes better with the injection of additives, whereas the heat transfer performance becomes worse with the increasing injection quantity of additives. The thermal resistance of ABS fouling provides a reasonable agreement with the results of the heat flux. The SEM-EDX results show that the additives have an effect on the formation of ABS fouling by controlling the ABS concentration, which can increase the viscosity of the particle, promote the agglomeration of the fouling particle, and enhance the heat transfer of the ABS fouling, providing a rational explanation for the experimental results. KEYWORDSadditive, effective thermal conductivity, in situ measurement, low-temperature ash deposition

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“…21 At present, extensive research such as the growth characteristic, mineralogy, and chemical composition of the ABS-bearing low-temperature fouling has been investigated. Chen et al [22][23][24] experimentally investigated the fouling characteristics of a rotary air preheater, a flue gas cooler, and a low-pressure economizer by analyzing the fouling samples. They proposed the coupling formation model of low-temperature fouling and corrosion and clarified the mechanisms of corrosion and low-temperature fouling.…”

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Experimental investigation of the strength characteristics of low‐temperature fouling containing ammonium bisulfate in boilers

Tang

Zhang

Wang

et al. 2022

Asia-Pacific J Chem Eng

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Low-temperature fouling is a severe problem in the heat recovery devices of coal-fired boilers; it is mainly caused by the condensation of ammonium bisulfate (ABS, NH 4 HSO 4 ) and is usually challenging to remove with soot-blowing equipment. This study investigates the strength of low-temperature fouling containing ABS, which is an essential indicator in soot blowing. The ash sample containing ABS with three different mass ratios was heated in a drop tube furnace (DTF) at several selected temperature conditions for different times.The compressive strength of ash blocks after heating was measured, and the energy-dispersive X-ray spectrometry (EDX) and scanning electron microscope (SEM) were used to clarify the relationship between ABS content with fouling strength. The results show that the higher content of ABS means higher fouling strength. The fouling strength could decrease by heating the fouling under the flue gas temperature is 350 C or more, and a higher heating temperature could result in lower strength of the fouling. To reduce the strength and maximize the removal of fouling effectively, taking into account the economy, the recommended heating condition is to heat the fouling for 5-20 min at a minimum temperature of 350 C.

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Deposit Formation of the Low-Pressure Economizer in a Coal-Fired Thermal Power Plant

Cited by 12 publications

References 22 publications

Investigation into the Ash Deposits in a Coal-Fired Traveling Grate Boiler with Ammonia Present in the Flue Gas

Investigation into the Ash Deposits in a Coal-Fired Traveling Grate Boiler with Ammonia Present in the Flue Gas

The influence of Na₂SO₃/NaHSO₃ on the formation process of low‐temperature ash deposition with an in situ measurement technique

Experimental investigation of the strength characteristics of low‐temperature fouling containing ammonium bisulfate in boilers

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Deposit Formation of the Low-Pressure Economizer in a Coal-Fired Thermal Power Plant

Cited by 12 publications

References 22 publications

Investigation into the Ash Deposits in a Coal-Fired Traveling Grate Boiler with Ammonia Present in the Flue Gas

Investigation into the Ash Deposits in a Coal-Fired Traveling Grate Boiler with Ammonia Present in the Flue Gas

The influence of Na2SO3/NaHSO3 on the formation process of low‐temperature ash deposition with an in situ measurement technique

Experimental investigation of the strength characteristics of low‐temperature fouling containing ammonium bisulfate in boilers

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The influence of Na₂SO₃/NaHSO₃ on the formation process of low‐temperature ash deposition with an in situ measurement technique