Effect of CaO mineral change on coal ash melting characteristics

High-efficiency flux was developed to lower the ash fusion temperature of coal LQ and reduce the addition content in coal gasification process. The effect of high-efficiency flux on the coal ash melting temperature and mineral transformation were studied by ash fusion temperature detector and XRD (X-ray diffractometer) respectively in reducing atmosphere. Compared with limestone flux, the high-efficiency flux can decrease the coal ash melting temperature effectively with half addition content. The ash flow temperature (FT) of coal LQ can be lowered to less than 1350°C with the addition of 3% high-efficiency flux ,while limestone flux need to add more than 8% to reach to this temperature. With the high-efficiency flux added, cordierite, anorthite and Mg-Fe-Al oxide were formed at high temperature, which is the main reason to sharply decrease the ash fusion temperature.

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Effects of temperature and additives on ash transformation and melting of high-alkali-chlorine coal

Thermal Science ◽

10.2298/tsci200313271z ◽

2020 ◽

Vol 24 (6 Part A) ◽

pp. 3501-3510

Author(s):

Jingbin Zi ◽

Daoyang Ma ◽

Zia Rahman ◽

Xuebin Wang ◽

Hao Li ◽

...

Keyword(s):

Coal Ash ◽

Ash Deposition ◽

High Sodium ◽

Melting Characteristics ◽

Ash Melting ◽

Calcium Magnesium ◽

Effects Of Temperature ◽

High Alkali ◽

Main Component ◽

High Aluminum

The high contents of sodium and chlorine in Shaerhu coal aggravate severe slag-ging ash deposition and corrosion in boilers. Adding proper additives is an effec-tive way to reduce slagging ash deposition and corrosion. Based on the experi-mental study, this paper investigated the effect of combustion temperature, types of additives, and its amount on the ash transformation and melting of high sodium chloride Shaerhu coal. The ash melting characteristics, elemental compositions and mineral compositions of the ash produced under different conditions were characterized. Results showed that the contents of calcium, magnesium, and sul-phur in the coal ash varied slightly with the temperature increasing. Chlorine and sodium released rapidly from coal at 550-815?C and 550-700?C, respectively. At 1050?C, calcium silicate was observed as the main component of the ash. The addition of different additives had no significant effect on chlorine and sodium capture. The addition of silicon species lowered the ash fusion temperatures, while the aluminum had an opposite effect. To prevent the furnace from slagging, a high aluminum additive is proposed to be adopted.

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Influence of coal ash on potassium retention and ash melting characteristics during gasification of corn stalk coke

Bioresource Technology ◽

10.1016/j.biortech.2018.09.053 ◽

2018 ◽

Vol 270 ◽

pp. 416-421 ◽

Cited By ~ 15

Author(s):

Heng Zhang ◽

Junguo Li ◽

Xin Yang ◽

Shuai Guo ◽

Haijuan Zhan ◽

...

Keyword(s):

Coal Ash ◽

Corn Stalk ◽

Melting Characteristics ◽

Ash Melting ◽

Potassium Retention

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Markov Chain Simulation of Coal Ash Melting Point and Stochastic Optimization of Operation Temperature for Entrained Flow Coal Gasification

Energies ◽

10.3390/en12224245 ◽

2019 ◽

Vol 12 (22) ◽

pp. 4245

Author(s):

Zhang ◽

Guan ◽

Hou ◽

Zhang ◽

Li ◽

...

Keyword(s):

Markov Chain ◽

Melting Point ◽

Stochastic Programming ◽

Optimization Model ◽

Coal Gasification ◽

Coal Ash ◽

Entrained Flow ◽

Sample Data ◽

Ash Melting ◽

Mc Simulation

In the entrained flow coal gasification process, the gas production is critically affected by the operating temperature (OT) and coal ash melting point (AMP), and the AMP is one of key factors for the determinations of OT. Considering the fact that coal is a typical nonhomogeneous substance and the coal ash composition varies from batch to batch, this paper proposes the application of the Markov Chain (MC) method in simulation of the random AMP series and the stochastic optimization of OT based on MC simulation for entrained flow coal gasification. The purpose of this paper is to provide a more accurate optimal OT decision method for entrained flow coal gasification practice. In this paper, the AMP was regarded as a random variable, and the random process method, Markov Chain, was used to describe the random AMP series of feed coal. Firstly, the MC simulation model about AMP was founded according to an actual sample data, 200 sets of AMP data from an industrial gasification plant under three simulation schemes (the sample data were individually divided into 16, eight and four state groups,). The comparisons between the simulation results and the actual values show that the founded MC simulation model descries the AMP series very well. Then, a stochastic programming model based on MC simulation for OT optimization was developed. Finally, this stochastic programming optimization model was optimized by genetic algorithm (GA). Comparing with the conventional OT optimization method, the proposed stochastic OT optimization model integrated MC simulation can ascertain a more accurate OT for guiding the coal gasification practice.

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Experimental Investigation of Ash Deposit Behavior during Co-Combustion of Bituminous Coal with Wood Pellets and Empty Fruit Bunches

Energies ◽

10.3390/en12112087 ◽

2019 ◽

Vol 12 (11) ◽

pp. 2087 ◽

Cited By ~ 5

Author(s):

Tae-Yong Jeong ◽

Lkhagvadorj Sh ◽

Jong-Ho Kim ◽

Byoung-Hwa Lee ◽

Chung-Hwan Jeon

Keyword(s):

Melting Temperature ◽

Power Plants ◽

Bituminous Coal ◽

Coal Ash ◽

Milling Process ◽

Drop Tube ◽

Ash Deposition ◽

Wood Pellets ◽

Empty Fruit Bunches ◽

Ash Melting

In Korea, oil-palm empty fruit bunches (EFBs), which are byproducts of the crude palm-oil milling process, are among the most promising potential energy sources for power plants. However, the slagging and fouling characteristics of EFBs during combustion have not yet been fully studied. Accordingly, in this study, we investigated the fundamental ash behavior of EFBs in comparison to that of wood pellets (WPs) using a thermomechanical analyzer (TMA) and a drop-tube furnace (DTF). Ash melting and the deposition of ash particles were investigated with traditional prediction indices at several biomass blending ratios. The results demonstrated that, as the ratio of WPs to EFBs increases, the melting temperature decreases and the slagging propensity increases because of the increased biomass alkali content. Moreover, the penetration derived using the TMA shows a higher melting peak at which rapid melting occurs, and the melting temperature distribution is decreased with increased biomass blending. Conversely, the DTF results show different phenomena for ash deposition under the same blending conditions. Blend ratios approaching 10% WP and 15% EFB result in gradual decreases in ash deposition tendencies because of the lower ash contents of the co-combusted mass compared to that of the single coal ash. Further biomass addition increases ash deposition, which is attributable to ash agglomeration from the biomass. Thus, this study demonstrates that blending ratios of 10% WP and 15% EFB provide optimal conditions for co-combustion with the selected bituminous coal. In addition, it is shown that the slagging propensity of EFB is higher than that of WP owing to its ash content and simultaneous agglomeration.

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Experimental Study on MSW Incineration Fly Ash Melting Characteristics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.2949 ◽

2014 ◽

Vol 955-959 ◽

pp. 2949-2952

Author(s):

Jun Zhao ◽

Shu Zhong Wang ◽

Zhi Qiang Wu ◽

Lin Chen ◽

Hai Yu Meng

Keyword(s):

Experimental Study ◽

Iron Oxide ◽

Fly Ash ◽

Municipal Solid Waste ◽

Melting Temperature ◽

Calcium Oxide ◽

Reducing Atmosphere ◽

Msw Incineration ◽

Melting Characteristics ◽

Ash Melting

This paper studies the effects of calcium oxide and iron oxide in municipal solid waste (MSW) incineration fly ash on the melting temperature of fly ash by using different samples. In addition, this paper also studied the variation of fly ash melting temperature in oxidizing and reducing atmosphere by experiment.

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Influence of ammonium dihydrogen phosphate on potassium retention and ash melting characteristics during combustion of biomass

UQ eSpace ◽

10.14264/uql.2016.603 ◽

2016 ◽

Author(s):

Jianhui Qi ◽

Kuihua Han ◽

Hui Li ◽

QI Zuo ◽

Jie Gao ◽

...

Keyword(s):

Dihydrogen Phosphate ◽

Ammonium Dihydrogen Phosphate ◽

Melting Characteristics ◽

Ash Melting ◽

Potassium Retention

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The Effect of Calcium-Bearing Mineral on Ash Melting Behavior During Zhundong Coal Combustion

Volume 1: Boilers and Heat Recovery Steam Generator; Combustion Turbines; Energy Water Sustainability; Fuels, Combustion and Material Handling; Heat Exchangers, Condensers, Cooling Systems, and Balance-of-Plant ◽

10.1115/power-icope2017-3221 ◽

2017 ◽

Author(s):

Ma Haidong ◽

Wang Yungang ◽

Zhao Qinxin

Keyword(s):

Calcium Oxide ◽

Coal Combustion ◽

Coal Ash ◽

Melting Behavior ◽

Sintering Behavior ◽

Efficient Operation ◽

Transition Mechanism ◽

Ash Melting ◽

Zhundong Coal ◽

Ash Melting Behavior

Two typical pulverized Zhundong coal with different calcium oxide contents in ash were selected to use in this work. The liquid nitrogen was used to cool ash rapidly at different temperatures, in order to avoid changes in mineral condition. The ash melting behavior and mineral transition mechanism, especially calcium-bearing minerals was studied by ash melting point test platform, XRD, XRF, SEM and EDS. The results showed that the different states of calcium are the dominant reasons for different sintering behaviors of coal ash. The calcium-bearing minerals in ash, such as calcium oxide (CaO), calcium silicate (CaSiO3), gehlenite (2CaO·Al2O3·SiO2), and anorthite (CaO·Al2O3·2SiO2), etc., are the most important factors influencing the initial sintering behavior of coal ash in the temperature range from 1373K to 1473K under oxidizing atmosphere during coal combustion. That is the reason why ash starts to melt at relatively high temperature during ash melting behavior in laboratory, but has severe slagging and contamination characteristic at low temperature during coal combustion in boilers. The research achievments have important guiding significance for the design of partially or completely burning Zhundong coal boiler as well as its long-term safe and efficient operation. (CSPE)

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