A Furnace Wall Ash Monitoring System for Coal Fired Boilers

1981 ◽  
Vol 103 (3) ◽  
pp. 532-538 ◽  
Author(s):  
A. K. Chambers ◽  
J. R. Wynnyckyj ◽  
E. Rhodes
Keyword(s):  
Heat Flux ◽  
Monitoring System ◽  
Furnace Wall ◽  
Pulverized Coal ◽  
Ash Deposition ◽  
Reliable Measure ◽  
Successful Development ◽  
Utility Boilers ◽  
Ash Deposit

This paper describes the successful development of an ash-deposit monitoring system for use in large pulverized-coal fired boilers. Using commercially proven heat flux meters the system measures the severity of ash deposition by measuring the net decrease in heat flux through the boiler walls. Testing of a prototype in two Canadian Utility boilers burning Western coals has shown that the system gives a reliable measure of the cleanliness of furnace walls and of the effectiveness (or failure) of soot blowers to remove deposits. Indications are that the system will be valuable in improving efficiency of boiler operations and in minimizing slagging and fouling problems when firing difficult coals.

Fouling of Heat Exchanger Tubes in Pulverized-Coal-Fired Combustion Chambers

2008 ◽  
Author(s):  
Efim Korytni ◽  
Yuli Berman ◽  
Boris Davidson ◽  
Miron Perelman ◽  
Roman Saveliev ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Power Plants ◽  
Ash Deposition ◽  
Axially Symmetric ◽  
Combustion Chambers ◽  
Weakly Bound ◽  
Water Steam ◽  
Overall Heat Transfer Coefficient ◽  
Utility Boilers ◽  
Ash Deposit

Fouling is a major concern in coal-fired power plants caused by fly ash deposit on the heat exchanger tubes that decreases the overall heat transfer coefficient to water-steam mixture. Fouling has been characterized by weakly bound-loose form, which may be removed by various methods, such as soot-blowing, blast, and sand blowing. We have carried out experimental and modeling work on fouling to develop a methodology by which the thermal conductivity of the ash deposit would be determined in a way similar to the fouling process prevailing in real systems. For that we used tubes identical in material, diameter and temperature to those used in many utility boilers. In the experimental work we placed a tube in an axially symmetric 50 kW furnace, and tested fouling from three coals, bituminous and sub-bituminous. We also developed a dynamic model for the prediction of the ash deposition growth and its heat resistance. Comparison of the model prediction and experimental results yielded satisfactory fit. Consequently, thermal resistance of heat exchanger tuber with ash deposit of those coals was determined.

scholarly journals Investigation of Ash Deposition Dynamic Process in an Industrial Biomass CFB Boiler Burning High-Alkali and Low-Chlorine Fuel

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1092
Author(s):  
Hengli Zhang ◽  
Chunjiang Yu ◽  
Zhongyang Luo ◽  
Yu’an Li
Keyword(s):  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Deposition Process ◽  
Biomass Combustion ◽  
Ash Deposition ◽  
Biomass Ash ◽  
Cfb Boiler ◽  
Third Stage ◽  
Ash Deposit ◽  
High Alkali

The circulating fluidized bed (CFB) boiler is a mainstream technology of biomass combustion generation in China. The high flue gas flow rate and relatively low combustion temperature of CFB make the deposition process different from that of a grate furnace. The dynamic deposition process of biomass ash needs further research, especially in industrial CFB boilers. In this study, a temperature-controlled ash deposit probe was used to sample the deposits in a 12 MW CFB boiler. Through the analysis of multiple deposit samples with different deposition times, the changes in micromorphology and chemical composition of the deposits in each deposition stage can be observed more distinctively. The initial deposits mainly consist of particles smaller than 2 μm, caused by thermophoretic deposition. The second stage is the condensation of alkali metal. Different from the condensation of KCl reported by most previous literatures, KOH is found in deposits in place of KCl. Then, it reacts with SO2, O2 and H2O to form K2SO4. In the third stage, the higher outer layer temperature of deposits reduces the condensation rate of KOH significantly. Meanwhile, the rougher surface of deposits allowed more calcium salts in fly ash to deposit through inertial impact. Thus, the elemental composition of deposits surface shows an overall trend of K decreasing and Ca increasing.

On Ash Deposition Rates from Air and Oxy-Combustion of Pulverized Coal, Petroleum Coke, and Biomass

2019 ◽  
Vol 33 (7) ◽  
pp. 5849-5858 ◽  
Author(s):  
Yueming Wang ◽  
Xiaolong Li ◽  
Jost O. L. Wendt
Keyword(s):  
Petroleum Coke ◽  
Pulverized Coal ◽  
Ash Deposition ◽  
Deposition Rates

Control of ash deposition in pulverized coal fired boiler

2009 ◽  
Vol 32 (2) ◽  
pp. 2709-2716 ◽  
Author(s):  
Hiroshi Naganuma ◽  
Nobuya Ikeda ◽  
Takayuki Kawai ◽  
Tsuyoshi Takuwa ◽  
Tadashi Ito ◽  
...  
Keyword(s):  
Pulverized Coal ◽  
Ash Deposition

Control of Ash Deposition in Pulverized Coal Combustor

2010 ◽  
Vol 43 (10) ◽  
pp. 872-879 ◽  
Author(s):  
Ichiro Naruse ◽  
Ryo Yoshiie ◽  
Mikio Matsuura ◽  
Yasuaki Ueki ◽  
Hiroshi Naganuma ◽  
...  
Keyword(s):  
Pulverized Coal ◽  
Ash Deposition

Studies of sintering of coal ash relevant to pulverized coal utility boilers

Fuel ◽  
1984 ◽  
Vol 63 (12) ◽  
pp. 1664-1670 ◽  
Author(s):  
Richard E. Conn ◽  
Leonard G. Austin
Keyword(s):  
Coal Ash ◽  
Pulverized Coal ◽  
Utility Boilers
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