Effect of MgO on AFTs of Coal Samples. MgO is a basic oxide in coal ash. 20 Generally, MgO could decrease AFT and improve flowability of ash samples. As shown in Figure Figure1 1, the AFTs of coal samples increase with increasing MgO content when its content in the original coal ash is above 10%.When the MgO content is 30%, the FT is 1550 °C. It demonstrates that MgO exhibits a negative ...
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Considering that the process of AFT regulation is usually needed in an industrial gasifier when the AFT of coal is higher than 1500 °C and to verify whether the correlation was not only available for raw coal but also for AFT regulation (coal blending, flux), the lowAFT ZL, flux (CaO and Fe 2 O 3) with a certain mass ratio were added to the ...
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Commun Serv Geol Portugal 1984; 299317.] for gasification purposes is the ash fusion temperature (AFT). The AFT of a coal source indicates the extent to which ash agglomeration and ash ...
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Formation of Coal (Process) Coal is composed of carbon, hydrogen, oxygen, nitrogen, sulphur, moisture, and incombustible mineral matter (, ash). Fluorinated gases are not formed by coal combustion. Coals are formed from the accumulation of vegetable debris in specialized environments. Obtaining coal from the mines is a difficult job.
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In Group 1, the content of Fe 2 O 3 and CaO are consistent as well as the sum of SiO 2 and Al 2 O 3. The S/A changes in the range of which covers the range of typical Chinese coal ashes. In Group 2, the total content of SiO 2 and Al 2 O 3 decreased to 70% and the content of CaO increased to 23%, correspondingly.
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Sintering related temperatures. Sintering is an important process at the transition of ash to slag, which is predominantly initiated by the neck growth between ash particles and is shown in Fig. 12. Sintering of coal ash is a result of phases transformation in solid and liquid states.
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There exists a number of studies, demonstrating that the chemical and mineral composition of the coal ash governs its melting characteristics and fusion temperatures (Gray 1987; Kucukbayrak et al. 1993; Vorres 1979; Vassilev et al. 1995; Winegartner and Rhodes 1975).Since the composition of the ash influences the AFT magnitudes and, thereby, performance of a coalbased process, it is essential ...
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Gasification of coal is a process whereby coal is converted to a syngas, which is predominately a mixture of carbon monoxide and hydrogen. ... The ash fusion temperature (AFT) is a common analysis performed on a coal sample as part of its routine characterisation, and can be a useful indicator of the general suitability of a specific coal for ...
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Fig. 1 shows the neutralizing capacity of coals and coalashes. All twelve lignites (Samples 112, Table 1) required l 1 M H 2 SO 4 per kg coal, to establish a stable pH at liquid to solid ratio 10:1. The only asphaltite, Sample 13, used l/kg, mainly due to the high 'ash' percentage. We use a selected range of particle sizes, μm.
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AFT of coals and coal blends is one of the parameters currently widely used in coal marketing and utilisation to assess coal quality, coal ash fusibility and melting characteristics, and to predict the melting behaviour of the coal ash in power generation reactors. ... Fuel Process Technol, 56 (1/2) (1998), pp. 3343. View PDF View article View ...
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Although the standard AFT analysis is currently used as prediction tool for AFT of coal, literature studies [1] have shown that this may not represent the actual flow temperature of certain minerals and mineral phases. For example iron (Fe) as Fe 2+ can react with other ash forming constituents leading to the formation of liquid phases at temperatures as low as 700 °C.
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During the process, the initial deformation temperature (IDT), hemispherical temperature (HT), and final fusion temperature (FT) were recorded according to the specific shapes of the ash cylinder. The ash fusion temperature (AFT) of the individual coal samples was determined and reported in table 2.
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The acid dissolves rocks—a process called chemical weathering—and releases calcium, magnesium, potassium, or sodium ions. ... Coal and other fossil fuels are a convenient source of energy, but when they are burned, the stored carbon is released into the atmosphere. This alters the balance of the carbon cycle, and is changing Earth's climate.
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Coal ash fusion temperature (AFT) is one important parameter for coalfired boiler design and evaluation in a power plant. The relationship between coal AFT and the chemical composition of coal ash is rather complex in nature and makes the modeling of AFT difficult. In this work, a leastsquares support vector machine (LSSVM) model, which was based on a dynamically optimized search technique ...
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Abstract To produce coal with a high ash fusion temperature (AFT) as the raw material for gasification, the addition of fluxes is often adopted. In this paper, the ash chemistry of coals from the HuainanHuaibei mining area (Zhuji and Taoyuan) was analysed to investigate the mechanisms of the composition modulation and, subsequently, the ash melting behaviour of coals with highash melting ...
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1. Introduction. To protect the environment and meet stringent NO x emission limits, selective noncatalytic reduction (SNCR) is widely applied in coalfired power plants owing to its simplicity and low operation costs (Ma et al., 2016).In the deNO x process of SNCR, the reducing agents—mainly ammonia or urea—are injected into hot flue gas streams to selectively reduce NO into N 2 (Daood ...
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Although a lot of documents indicated that sewage sludge could obviously change the AFT of coal in the process of thermal utilization. The articles that adding industrial sludge to change the AFTs of high AFT (FT > 1380 °C) coal for EFB gasification were rare and the corresponding regulation mechanism was imperfect. In this paper, the ash ...
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Chemical properties of coal. Coal comes in four main types or ranks: lignite or brown coal, bituminous coal or black coal, anthracite and type of coal has a certain set of physical parameters which are mostly controlled by moisture, volatile content (in terms of aliphatic or aromatic hydrocarbons) and carbon content.. Moisture. Moisture is an important property of coal, as all ...
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the process of pulverized coal combustion has been investigated in this paper. KEYWORDS. biomass, CC S, CFD, ... Federation. 160 364 391. Australia 144 818 14 301. China 138 819 39.
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This paper outlines research on the processes taking place within the coal mineral matter at high temperatures and development of the relationship between ash fusion temperatures (AFT) and phase equilibria of the coal ash slags. A new thermodynamic database for the AlCaFeOSi system developed by the author was used in conjunction with the thermodynamic computer package F ∗ A ∗ C ...
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Coal gasification fine slag (FS), a kind of byproduct of coal chemical industry, was recovered for the preparation of functional adsorbents by acid leaching process, which was orthogonally optimized by HCl, HNO3, HF, HAc, and H2SO4. Methylene blue () was used to evaluate the performance of functional adsorbents. The results demonstrated that % of the leaching efficiency (RLE) and ...
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To achieve a stable slagtapping process in entrainedflow coal gasifiers, the acceptable viscosity of coal ash slag is within 525 Pa·s in the temperature range °C and the tapping ...
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Investigation of migration and emission characteristics of NH3/NH4+ in coalfired power plants after experienced ultralow emission retrofitting shows that particlebound NH4+ concentration is mainly influenced by the relatively strength of desulfurization slurry scouring and flue gas carrying effects, and increases times through ...
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Hi, it looks like you're using AdBlock : (. Coal is a hard black coloured substance which is mainly carbonWhat are the uses of Coal?Different uses of Coal areIt is used in villages to cook foodIt is used in Thermal power plants to produce electricityIt was used in steam engines of train. It produced steam which ran the steam enginesHow is coa.
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The adiabatic flame temperature (AFT) is defined as the temperature attained when all of the chemical reaction heat released heats combustion products. In practical coal combustion systems, excess oxygen is usually applied to achieve complete coal burnout. In this chapter we set O 2 concentration in the flue gas at % v/v. AFT in pure oxygen ...
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There are many types of specifications used to describe coal, these. include: Geological location, basin, seam, and rank. Physical heating value, size, moisture, ash, HGI, ash fusion temp. Chemical sulfur, ash chemistry, ultimate and trace elements. The key to the use of these specifications is to understand the.
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The differences between K and M coal are also found in AFT under reducing conditions and ash analysis. AFT under reducing conditions of M coal is very low with deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and fluid temperature (FT) of 1090, 1090, 1120, and 1140 °C, respectively.
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The combination of K2O and Na2O may enhance the flux efficiency. In this work, the effect of K2O/Na2O mass ratio on fusion behavior of coal ash with high silicon and alumina level was evaluated by ...
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Blending is a promising method to modify the ashfusion characteristics of coal to meet gasification requirements. To investigate the variation in ashfusion behavior for high ashfusiontemperature (AFT) coal through coal blending and its regulating mechanism, the ashchemistry characteristics of four coals (Nantun, Pengzhuang, Biaodian, and Xiangyuan) were analyzed.
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the formation of slaglayer protection during the process of lowAFT coal EFB gasification, and it might abate the generations of fouling and Analytical methods deposition on the tube surface in subsequent operation unit (, superheater) [44]. Thus, it might be anticipated that the additions of CS or The ...
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The cogasification of coal and biomass is of importance for coal clean conversion and biomass utilization on a large scale. To investigate the effecting behaviors of biomass on ash fusion characteristics of low ashfusiontemperature (AFT) coal, the ash chemical properties of three materials (Shenmu coal (SM), chestnut shell (CS), and rice husk (RH)), the variations in SM mixed AFT with ...
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The coal combustion testing process was carried out at the Powder Coal Combustion facilities at National Research and Innovation ... with low ash and sulfur content. EFB, FRD, and coal have an ash content of %, %, and %, respectively. AFT values for coal, EFB, and blends are pretty lower than FRD and satisfy the minimum limit ...
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Coal is a solid, black, readily combustible fossil fuel that contains a large amount of carbonbased material approximately 50% of its weight. The formation of coal takes a significant amount of time (on the order of a few million years), and the first coalbearing rock units appeared about 290360 million years ago, at a time known as the Carboniferous or "coalbearing" Period.
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Coal B belongs to anthracite with high degree of metamorphism, and the Al 2 O 3 content in ash plays a "skeleton" role in the melting process is the highest ( wt%); these two points may be the main factors of its AFT higher than coal D and coal S.
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