scholarly journals Slag and ash chemistry after high-calcium lignite combustion in a pulverized coal-fired power plant

2013 ◽  
Vol 9 (1) ◽  
pp. 77-82 ◽  
Keyword(s):  
Fly Ash ◽  
Power Plant ◽  
Inductively Coupled Plasma ◽  
Power Plants ◽  
Bottom Ash ◽  
Calorific Value ◽  
Emission Spectrometry ◽  
Northern Greece ◽  
Inorganic Matter ◽  
High Calcium

More than 73% of the electrical power requirements of Greece are generated in lignite-fired power plants. Greece is the thirteenth largest coal and the fifth largest lignite producer in the world. The lack of domestic high-rank coals makes necessary to use low quality lignite for power generation in Greece. These lignites are characterized by a high water and ash content and a low calorific value. The low quality of such lignites generates important technical and environmental problems during combustion. Slagging and fouling are common inside the power units and affect with particular severity the power plants performance. Slagging deposits take place in the high temperature radiant sections of the boiler, and are usually associated with some degree of melting of the ash. Fouling deposits are produced in the lower temperature convective sections of the boiler, and are generally related to condensation on the low temperature tube surfaces. Problems in boilers associated with ash deposits include modification of the heat transfer in different sections of the furnace, physical distortion of metal pieces due to the weight of the deposit, clogging of burners, and corrosion and erosion of metal walls. Feed lignite always carries more than 20% of inorganic matter, and its mineralogy and chemistry are originally related to geological factors. Five representative samples were collected from the inner surfaces of Unit 1 of the Agios Dimitrios Power Plant, Northern Greece, reflecting the main types of ash deposits occurring in the combustion facility. The chemistry of these high-calcium ash deposits has been investigated. Moreover, a fly ash and a bottom ash samples were taken and analyzed in order to investigate their possible impact on the environment after land-filling. All samples were digested by using 2.5 ml HNO3, 5ml HF and 2.5 ml HClO4 (1:2:1). Sixty element concentrations were determined in all samples by inductively coupled plasma–mass spectrometry (ICP–MS) and inductively coupled plasma – optical emission spectrometry (ICP-OES). Calcium is the most abundant element in all samples due to the dominance of calcium phases. The chemical composition of the bottom ash, fly ash, slag and fouling deposits, is mainly influenced by the chemical composition of the feed lignite and the co-excavated sterile materials, which are marly limestones containing, on average, 93% of calcite.

scholarly journals Effect of Additive Material on Controlling Chromium (Cr) Leaching from Coal Fly Ash

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 563
Author(s):  
Erda Rahmilaila Desfitri ◽  
Ulung Muhammad Sutopo ◽  
Yukio Hayakawa ◽  
Shinji Kambara
Keyword(s):  
Fly Ash ◽  
Inductively Coupled Plasma ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Calcium Content ◽  
High Calcium ◽  
Cr Concentration ◽  
Additive Materials ◽  
Sludge Ash

Coal fly ash contains a considerable number of toxic elements that can be leached into the environment, such as chromium (Cr), thereby quickly leading to severe contaminations. In this research, the leaching behaviors of Cr were analyzed from 14 kinds of coal fly ash samples collected from the electrostatic precipitators of coal-fired thermal power plants in Japan. The level of Cr concentration found in the samples varied from 0.00 to 82.93 μg/L. However, Cr toxicity depends on its valence state; Cr6+ is more toxic than Cr3+. Additive materials containing high calcium content were used to control the leaching concentration of Cr, such as Ca(OH)2, paper sludge ash, and blast furnace cement. This research used several instruments. An X-ray fluorescence was adopted to measure the major chemical composition of the fly ash samples and the additive materials. A thermogravimetric analyzer was used to examine the calcium compounds in the additive materials. Inductively coupled plasma was used to determine the Cr leaching concentrations from the fly ash samples. Findings showed that the three-additive mixture had a promising effect on controlling the Cr leaching concentrations. These results were also supported by FactSage 7.2 simulation.

Variability and Trends in Iowa Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
Scott Schlorholtz ◽  
Ken Bergeson ◽  
Turgut Demirel
Keyword(s):  
Fly Ash ◽  
Chemical Composition ◽  
Power Plant ◽  
Coefficient Of Variation ◽  
Power Plants ◽  
Chemical Properties ◽  
Physical Analysis ◽  
Fly Ashes ◽  
High Calcium ◽  
Physical And Chemical

ABSTRACTAn investigation has been made of the variability of physical and chemical properties of high-calcium (Class C) fly ashes from four Iowa power plants. The investigation summarizes results obtained from three years (1983 through 1985) of monitoring of the various power plants. All four of the power plants burn low-sulfur, sub-bituminous coal from Wyoming. Fly ash samples were obtained from the power plants in accordance to the procedures described in ASTM C 311. Laboratory testing methods were similar to those specified by ASTM C 311. During the three year period, 102 samples were subjected to chemical and physical analysis while an additional 349 samples were subjected to physical analysis only. In general, the four power plants produce fly ashes of similar mineralogy and chemical composition. The observed time variation of the chemical composition of fly ash from a single power plant was quite small. The sulfur content consistently showed the largest coefficient of variation of the 10 elements studied. Physical characteristics of the fly ashes (as measured by ASTM tests) were also fairly uniform over long periods of time, when considered on an individual power plant basis. Fineness, when measured by wet washing using a 325 mesh sieve, consistently exhibited the largest coefficient of variation of any of the physical properties studied.

Characterization of Coal Fly Ash, Bottom Ash and their Possibilities as Catalysts for Biodiesel Production

2021 ◽  
Vol 904 ◽  
pp. 413-418
Author(s):  
Wilasinee Kingkam ◽  
Sasikarn Nuchdang ◽  
Dussadee Rattanaphra
Keyword(s):  
Fly Ash ◽  
Palm Oil ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Biodiesel Production ◽  
Catalyst Loading ◽  
Free Lime ◽  
Operation Conditions ◽  
Class C

Coal fly ash (CFA) and bottom ash (BA) obtained from coal fired power plants in Thailand and local supplier were characterized using XRF, XRD and N2 adsorption-desorption techniques. Their possibilities for conversion of palm oil into biodiesel were investigated. Selected CFA was also modified with lanthanum (La) at different La loading and the influence of La loading on biodiesel conversion was evaluated. The resulted showed that the Class C CFA as contained large amount of CaO (free lime) could catalyze the transesterification to achieve the highest FAME content of 89% under the operation conditions; the reaction temperature of 200 °C, the reaction pressure of 39 bars, the catalyst loading of 5 wt% of oil, the molar of oil to methanol of 1:30 and the stirring speed of 600 rpm for 5 h. The addition of La on the Class C CFA had a negative effect on conversion of palm oil. The FAME content decreased gradually from 89 to 62% with increasing La loading from 0 to 1 wt%.

scholarly journals Study of the content of rare and rare earth elements in ash and slag waste of the Kemerovo state district power plant

2021 ◽  
Vol 315 ◽  
pp. 02004
Author(s):  
Tatiana Cherkasova ◽  
Anastasia Tikhomirova ◽  
Elizaveta Cherkasova ◽  
Andrey Golovachev
Keyword(s):  
Rare Earth ◽  
Power Plant ◽  
Rare Earth Elements ◽  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
High Tech ◽  
Inductively Coupled ◽  
Ash And Slag Waste ◽  
Slag Waste

In the context of restrictions due to the sanctions imposed, a key factor in the country's development is the development of new Russian high-tech materials and their production technologies. The study of ash and slag waste from the Kemerovo State District Power Plant was carried out in this work using the methods of inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). It has been established that matrix elements make up the predominant share of ash and slag waste. Rare and rare earth elements in terms of their content are classified as trace elements, however, some of them either have commercial values, or are close to it.

scholarly journals Leaching of Major and Minor Elements during the Transport and Storage of Coal Ash Obtained in Power Plant

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Rada Krgović ◽  
Jelena Trifković ◽  
Dušanka Milojković-Opsenica ◽  
Dragan Manojlović ◽  
Jelena Mutić
Keyword(s):  
Power Plant ◽  
Inductively Coupled Plasma ◽  
Ammonium Oxalate ◽  
Coal Ash ◽  
Atomic Emission ◽  
Life Forms ◽  
Emission Spectrometry ◽  
Plasma Atomic Emission Spectrometry ◽  
Negative Effects ◽  
Inductively Coupled

In power plant, coal ash obtained by combustion is mixed with river water and transported to the dump. Sequential extraction was used in order to assess pollution caused by leaching of elements during ash transport through the pipeline and in the storage (cassettes). A total of 80 samples of filter ash as well as the ash from active (currently filled) and passive (previously filled) cassettes were studied. Samples were extracted with distilled water, ammonium acetate, ammonium oxalate/oxalic acid, acidic solution of hydrogen-peroxide, and a hydrochloric acid. Concentrations of the several elements (Al, As, Cd, Co, Cu, Cr, Fe, Ba, Ca, Mg, Ni, Pb, and Zn) in all extracts were determined by inductively coupled plasma atomic emission spectrometry. Pattern recognition method was carried out in order to provide better understanding of the nature of distribution of elements according to their origins. Results indicate possible leaching of As, Ca, Cd, Cu, Zn, and Pb. Among these elements As, Cd, and Pb are toxicologically the most important but they were not present in the first two phases with the exception of As. The leaching could be destructive and cause negative effects on plants, water pollution, and damage to some life forms.

Western Fly Ash Research, Development and Data Center

1985 ◽  
Vol 65 ◽  
Author(s):  
G. J. McCarthy ◽  
O. E. Manz ◽  
R. J. Stevenson ◽  
D. J. Hassett ◽  
G. H. Groenewold
Keyword(s):  
Fly Ash ◽  
North Dakota ◽  
Knowledge Base ◽  
Great Plains ◽  
Data Center ◽  
Bottom Ash ◽  
Low Rank ◽  
Research Development ◽  
High Calcium ◽  
By Products

With financial support from utilities and ash brokers*, the Western Fly Ash Research, Development and Data Center was established under the aegis of the North Dakota Mining and Mineral Resources Research Institute in August of 1985. Research will be performed by the two North Dakota universities in Grand Forks and Fargo. The fundamental objective of the Center is to enhance the knowledge base of the properties (chemical, mineralogical and physical) and reactions of the coal by-products (principally fly ash, but including bottom ash and FGD waste) produced in the Midwestern and Great Plains regions of the US. Most of the study specimens will be high-calcium (ASTM Class C) ash derived from low-rank lignite and subbituminous coals mined in North Dakota, Montana and Wyoming, although ash from other regions and coals is also being studied. The enhanced knowledge base should lead to more widespread utilization of these by-products [1,2] or, where this is necessary, to their safe and cost-effective disposal [3].

scholarly journals Treatment of fly ash from power plants using thermal plasma

2017 ◽  
Vol 8 ◽  
pp. 1043-1048 ◽  
Author(s):  
Sulaiman Al-Mayman ◽  
Ibrahim AlShunaifi ◽  
Abdullah Albeladi ◽  
Imed Ghiloufi ◽  
Saud Binjuwair
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fly Ash ◽  
Thermal Plasma ◽  
Inductively Coupled Plasma ◽  
Power Plants ◽  
Plasma Reactor ◽  
Atomic Emission ◽  
Inductively Coupled ◽  
Scanning Electron

Fly ash from power plants is very toxic because it contains heavy metals. In this study fly ash was treated with a thermal plasma. Before their treatment, the fly ash was analyzed by many technics such as X-ray fluorescence, CHN elemental analysis, inductively coupled plasma atomic emission spectroscopy and scanning electron microscopy. With these technics, the composition, the chemical and physical proprieties of fly ash are determined. The results obtained by these analysis show that fly ash is mainly composed of carbon, and it contains also sulfur and metals such as V, Ca, Mg, Na, Fe, Ni, and Rh. The scanning electron microscopy analysis shows that fly ash particles are porous and have very irregular shapes with particle sizes of 20–50 μm. The treatment of fly ash was carried out in a plasma reactor and in two steps. In the first step, fly ash was treated in a pyrolysis/combustion plasma system to reduce the fraction of carbon. In the second step, the product obtained by the combustion of fly ash was vitrified in a plasma furnace. The leaching results show that the fly ash was detoxified by plasma vitrification and the produced slag is amorphous and glassy.

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