scholarly journals A Model for Predicting Arsenic Volatilization during Coal Combustion Based on the Ash Fusion Temperature and Coal Characteristic

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Bo Zhao ◽  
Geng Chen ◽  
Zijiang Xiong ◽  
Linbo Qin ◽  
Wangsheng Chen ◽  
...  
Keyword(s):  
Coal Combustion ◽  
Power Plants ◽  
Combustion Temperature ◽  
Published Data ◽  
Fusion Temperature ◽  
Equilibrium Calculation ◽  
Arsenic Distribution ◽  
Ash Fusion Temperature ◽  
Close Relationship ◽  
Coal Type

Arsenic emission from coal combustion power plants has attracted increasing attention due to its high toxicity. In this study, it was found that there was a close relationship between the ash fusion temperature (AFT) and arsenic distribution based on the thermodynamic equilibrium calculation. In addition to the AFT, coal characteristics and combustion temperature also considerably affected the distribution and morphology of arsenic during coal combustion. Thus, an arsenic volatilization model based on the AFT, coal type, and combustion temperature during coal combustion was developed. To test the accuracy of the model, blending coal combustion experiments were carried out. The experimental results and published data proved that the developed arsenic volatilization model can accurately predict arsenic emission during co-combustion, and the errors of the predicted value for bituminous and lignite were 2.3–9.8%, with the exception of JingLong (JL) coal when combusted at 1500 °C.

scholarly journals Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1267
Author(s):  
David Längauer ◽  
Vladimír Čablík ◽  
Slavomír Hredzák ◽  
Anton Zubrik ◽  
Marek Matik ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Product Analysis ◽  
Coal Combustion Products ◽  
X Ray ◽  
Wide Range ◽  
Silica Alumina

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

Application of vermiculite and limestone to desulphurization and to the removal of dust during briquette combustion

2003 ◽  
Vol 67 (6) ◽  
pp. 1243-1251 ◽  
Author(s):  
A. Lu ◽  
D. Zhao ◽  
J. Li ◽  
C. Wang ◽  
S. Qin
Keyword(s):  
Electron Microscopy ◽  
Coal Combustion ◽  
Combustion Temperature ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Retention Ratio ◽  
X Ray ◽  
Major Factors ◽  
Chemical Reactant ◽  
Scanning Electron

AbstractSmall domestic cooking furnaces are widely used in China. These cooking furnaces release SO2 gas and dust into the atmosphere and cause serious air pollution. Experiments were conducted to investigate the effects of vermiculite, limestone or CaCO3, and combustion temperature and time on desulphurization and dust removal during briquette combustion in small domestic cooking furnaces. Additives used in the coal are vermiculite, CaCO3 and bentonite. Vermiculite is used for its expansion property to improve the contact between CaCO3 and SO2 and to convey O2 into the interior of briquette; CaCO3 is used as a chemical reactant to react with SO2 to form CaSO4; and bentonite is used to develop briquette strength. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside the briquette, and thus brings enough oxygen for combustion and sulphation reaction. Effective combustion of the original carbon reduces amounts of dust in the fly ash. X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray analysis show that S exists in the ash only as anhydrite CaSO4, a product of SO2 reacting with CaCO3 and O2. The formation of CaSO4 effectively reduces or eliminates SO2 emission from coal combustion. The major factors controlling S retention are vermiculite, CaCO3 and combustion temperature. The S retention ratio increases with increasing vermiculite amount at 950°C. The S retention ratio also increases with increasing Ca/S molar ratio, and the best Ca/S ratio is 2-3 for most combustion. With 12 g of the original coal, 1 to 2 g of vermiculite, a molar Ca/S ratio of 2.55 by adding CaCO3, and some bentonite, a S retention ratio >65% can be readily achieved. The highest S retention ratio of 97.9% is achieved at 950°C with addition of 2 g of vermiculite, a Ca/S ratio of 2.55 and bentonite.

The Latest Research in Mongolia on the Utilization of Coal Combustion By-Products

2021 ◽  
Vol 323 ◽  
pp. 8-13
Author(s):  
Jadambaa Temuujin ◽  
Damdinsuren Munkhtuvshin ◽  
Claus H. Ruescher
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Power Stations ◽  
Thermal Power Stations ◽  
Coal Ashes ◽  
By Products

With a geological reserve of over 170 billion tons, coal is the most abundant energy source in Mongolia with six operating thermal power stations. Moreover, in Ulaanbaatar city over 210000 families live in the Ger district and use over 800000 tons of coal as a fuel. The three thermal power plants in Ulaanbaatar burn about 5 million tons of coal, resulting in more than 500000 tons of coal combustion by-products per year. Globally, the ashes produced by thermal power plants, boilers, and single ovens pose serious environmental problems. The utilization of various types of waste is one of the factors determining the sustainability of cities. Therefore, the processing of wastes for re-use or disposal is a critical topic in waste management and materials research. According to research, the Mongolian capital city's air and soil quality has reached a disastrous level. The main reasons for air pollution in Ulaanbaatar are reported as being coal-fired stoves of the Ger residential district, thermal power stations, small and medium-sized low-pressure furnaces, and motor vehicles. Previously, coal ashes have been used to prepare advanced materials such as glass-ceramics with the hardness of 6.35 GPa, geopolymer concrete with compressive strength of over 30 MPa and zeolite A with a Cr (III) removal capacity of 35.8 mg/g. Here we discuss our latest results on the utilization of fly ash for preparation of a cement stabilized base layer for paved roads, mechanically activated fly ash for use in concrete production, and coal ash from the Ger district for preparation of an adsorbent. An addition of 20% fly ash to 5-8% cement made from a mixture of road base gave a compressive strength of ~ 4MPa, which exceeds the standard. Using coal ashes from Ger district prepared a new type of adsorbent material capable of removing various organic pollutants from tannery water was developed. This ash also showed weak leaching characteristics in water and acidic environment, which opens up an excellent opportunity to utilize.

scholarly journals Quantifying primary and secondary humic-like substances in urban aerosol based on emission source characterization and a source-oriented air quality model

2018 ◽  
Author(s):  
Xinghua Li ◽  
Junzan Han ◽  
Philip K. Hopke ◽  
Jingnan Hu ◽  
Qi Shu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Coal Combustion ◽  
Power Plants ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Source Characterization ◽  
Air Quality Model ◽  
Coal Burning ◽  
Residential Coal

Abstract. Humic-like substances (HULIS) are a mixture of high molecular weight, water-soluble organic compounds that are widely distributed in atmospheric aerosol. Their sources are rarely studied quantitatively. Biomass burning is generally accepted as a major primary source of ambient humic-like substances (HULIS) with additional secondary material formed in the atmosphere. However, the present study provides direct evidence that residential coal burning is also a significant source of ambient HULIS, especially in the heating season in northern China based on source measurements, ambient sampling and analysis, and apportionment with source-oriented CMAQ modeling. Emissions tests show that residential coal combustion produces 5 to 24 % of the emitted organic carbon (OC) as HULIS carbon (HULISc). Estimation of primary emissions of HULIS in Beijing indicated that residential biofuel and coal burning contribute about 70 % and 25 % of annual primary HULIS, respectively. Vehicle exhaust, industry, and power plants contributions are negligible. Average concentration of ambient HULIS was 7.5 μg/m3 in atmospheric PM2.5 in urban Beijing and HULIS exhibited obvious seasonal variations with the highest concentrations in winter. HULISc account for 7.2 % of PM2.5 mass, 24.5 % of OC, and 59.5 % of water-soluble organic carbon, respectively. HULIS are found to correlate well with K+, Cl−, sulfate, and secondary organic aerosol suggesting its sources include biomass burning, coal combustion and secondary aerosol formation. Source apportionment based on CMAQ modeling shows residential biofuel and coal burning, secondary formation are important annual sources of ambient HULIS, contributing 57.5 %, 12.3 %, and 25.8 %, respectively.

scholarly journals CORROSION BEHAVIOUR OF ALUMINIUM 6061 NICKEL COATED CENOSPHERE COMPOSITE

2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Arvind R S ◽  
Prasanna Ram M ◽  
Prashanth T ◽  
Jaimon Dennis Quadros
Keyword(s):  
Coal Combustion ◽  
Metal Matrix ◽  
Power Plants ◽  
Corrosion Behaviour ◽  
Thermal Power ◽  
Stir Casting ◽  
Matrix Composites ◽  
Test Results ◽  
Immersion Corrosion ◽  
Aluminium Metal

Cenosphere fly ash is one of the most inexpensive and low-density material which is abundantly available as a solid waste by-product of coal combustion in thermal power plants. Aluminium metal matrix composites with Nickel coated cenospheres as the reinforcement is prepared by stir casting route. The composites are prepared with varying percentages of cenospheres in the percentage of 2-10% by weight of the composite. Immersion corrosion tests are conducted on the composites in three different medium and for three different time durations. It is evident from the test results as well as the microstructure images that the weight loss of samples with 8% Nickel coated cenospheres has shown least corrosion or the highest corrosion resistance when compared to the counterparts.

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