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 ...
The typical Realtor is a 60yearold white woman who attended college and owns a home, according to NAR statistics. Realtors on average worked 30 hours per week in 2022, according to the group ...
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.
The AFT can be increased to >1350 °C by adding AFT increasing minerals or species, for example Al 2 O 3 or kaolinite, to the coal blend before it is fed into the gasification process. By increasing the AFT, the direct effect will be that steam consumption can be decreased, which in turn will improve carbon utilization.
Ash fusion temperature (AFT) is an important index for coal gasification. A blend of fluxing agent with coal can decrease the AFT to meet the requirements of specific gasification process. Effect of alkaline oxide and silica alumina ratio on decreasing AFT is focused in this study. Simulation ash was used to investigate the effect of alkaline oxide on AFT. The experimental results showed that ...
Materials. Huainan (HN) coal from Huainan coalmining area in China was selected in this work to be representative of AFT coals. Table 1 gives the characterization of HN coal, in which the proximate, ultimate analysis of the tested coal was conducted according to the Chinese standards GB/T, GB/T, GB/T, GB/T, GB/T and GB/T .
Request PDF | Chemical fractionation tests on South African coal sources to obtain speciesspecific information on ash fusion temperatures (AFT) | Coals from the different sources used by Sasol ...
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 ...
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.
The coal formation process involves the burial of peat, which is made of partly decayed plant materials, deep underground. The heat and pressure of burial alters the texture and increases the carbon content of the peat, which transforms it into coal, a type of sedimentary rock. This process takes millions of years. Types, or "ranks," of coal are determined by carbon content. There are four ...
the ash composition and its relation with AFT indicates Sialoferric nature of these coals. The corre ... coal industry. The AFT partially reflects the extent of ash agglomeration during coal conversion,, combustion, gasification, liquefaction, ... the process, the initial deformation temperature (IDT),hemisphericaltemperature(HT ...
The sintering and slagging of coal ash in the combustion chamber is mainly influenced by the melting point or ash fusion temperature (AFT) and the chemical contents of coal (Shi et al. 2021). The ...
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 ...
The slagliquid transformation temperature or AFT is the highest at the point where Al 2 O 3 is a maximum, which is the point in the bottom left corner of Fig. AFT at that point is >1900 ° a twodimensional area where Al 2 O 3 is kept fixed at any point, the AFT in the levels between SiO 2 and TiO 2 are almost the same. The above result is in agreement with the results found on ...
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 ...
This chapter deals with coal gasification, which is a process that converts carbonaceous materials, such as coal, petroleum, petroleum coke, or biomass, into carbon monoxide and hydrogen. ... The AFT of a coal can be manipulated by adding fluxes, such as limestone, or by blending with low ash fusion coals, thus decreasing the melting properties ...
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.
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 ...
Coal is the main fuel for the manufacture of cement in India, given the high cost and inadequate availability of oil and gas. The consumption of coal in dry process system ranges from 2025per cent of clinker production. That means T of coal is consumed to produce one tonne of clinker. The cement industry consumes about ten million ...
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.
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 ...
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 ...
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.
Mining coal. Coal miners use large machines to remove coal from the earth. Many coal deposits, called coal beds or seams, are near the earth's surface, but others are deep mining methods allow coal miners to easily reach most of the nation's coal reserves and to produce about three times more coal in one hour than in 1978.
The ash fusion temperature (AFT) test gives average bulk melting temperatures. These are important parameters in the design of reactors for coal utilization, the initial deformation temperature (IDT) has important implications for the design of furnaces and the marketing thereof [1]. The melting temperatures are indicators of the slagging ...
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.
NH 3 as reducing agent in selective noncatalytic reduction (SNCR) is widely used for the deNO x of coalfired boiler flue gas, where fly ash significantly influences the conversion of residual NH 3 that does not participate in deNO, few studies have been conducted on the exact nature of this influence. The adsorption and reaction of NH 3, NO, and O 2 on the fly ash at 50850 °C ...
The AFT calculation in the ammonia cofiring cases shared the same calculation method as above, depicted in Fig. S1 (b). The results showed that the AFT of the furnace in the base case was 2214 K. The coal feed rate, NH 3 feed rate, air feed rate, AFT, and EAC of different NH 3 cofiring ratio conditions under different scenarios are listed in ...
The characteristics of raw materials used in the test, such as cement, CGP and coal gangue, are shown in Table this experiment, the coal gangue produced by Zhang Jiamao coal mine in Shenmu City, Shaanxi Province is selected, and the XRD7000L Xray diffractometer was used to obtain the mineral composition analysis of coal gangue, activated CGP and cement and the gradation of fine ...
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 ...
Gasification of coal is a process whereby coal is converted to a syngas, which is predominately a mixture of carbon monoxide and hydrogen. ... The AFT is a common analysis performed on a coal sample as part of its routine characterization and can be a useful indicator of the general suitability of a specific coal for entrainedflow gasification ...
The leaching kinetics is characterized by a quick release of rare earth elements within the first few minutes of the process. For the West Kentucky No. 13 coal source, ∼75% of the REEs were leached in the first 15 min from the specific gravity (SG) fraction that was calcined at 600 °C. Additionally, the leaching kinetics of the ...
The Shell coal gasification process (SCGP) can operate on a wide variety of feedstocks. It consists of three principal stages: 1. Gasification (partial oxidation), in which the feedstock is converted to syngas in the presence of oxygen and a moderating agent (steam) in a refractorylined gasification reactor. 2.
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 ...
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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