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.
WhatsApp: +86 18838072829The 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 ...
WhatsApp: +86 18838072829Coal 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 ...
WhatsApp: +86 18838072829The processrelevant property of ash fusion can be studied for example by classic ash fusion tests ... CoalB has a lower AFT value than CoalA due to higher Fe 2 O 3 content in ash, while BMC is ...
WhatsApp: +86 18838072829Coal is an organic rock with dual pore structure, and its thermal fracture mode is significantly different from that of sandstone, granite and other sedimentary rocks under heat treatment [1], [35], [36]. In the process of heat treatment, the free water in coal evaporates, which reduces the propagation speed of Pwave and Swave.
WhatsApp: +86 18838072829Investigation 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 ...
WhatsApp: +86 18838072829Song et al. reported that the AFT decreases with increasing CaO up to the concentration of 30%, above which increasing the CaO leads to an increase in the AFT. The result was attributed to the subliquidus phase transformation from anorthite to the gehlenite phase, increasing CaO by over 30%. ... The pyrolysis process of coal/biomass generally ...
WhatsApp: +86 18838072829Abstract 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 ...
WhatsApp: +86 18838072829During 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.
WhatsApp: +86 18838072829The United Mine Workers of America (UMWA) formed in 1890 to fight for better pay and working conditions for the nation's coal miners. In Colorado the union was most active in the early twentieth century, with thousands of members joining strikes in the southern coalfields of Fremont, Huerfano, and Las Animas Counties. In the spring of 1913, the UMWA led a strike there that resulted in the ...
WhatsApp: +86 18838072829Coal 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.
WhatsApp: +86 18838072829Effect 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 ...
WhatsApp: +86 18838072829Mining is a process that is known to have a tremendous effect on both the land that the mine is contained within and the surrounding areas. Two of the most common mining processes are those of underground mining and strip mining. Underground mining is known to cause a variety of things to take place, during the mining process. As a mining ...
WhatsApp: +86 18838072829The 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.
WhatsApp: +86 18838072829Commun 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 ...
WhatsApp: +86 18838072829NH 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 ...
WhatsApp: +86 18838072829The 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 ...
WhatsApp: +86 18838072829The 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 ...
WhatsApp: +86 18838072829Ash 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 ...
WhatsApp: +86 18838072829appetites for investments in new coal plants, and some have announced intentions to fully divest from coal assets within a few years (Polkinghorne 2017). The declining costs of Liquefied Natural Gas (LNG) could affect Indonesia's domestic energy mix and thus domestic coal demand, as it could replace coalfired electricity generation.
WhatsApp: +86 18838072829Considering 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 ...
WhatsApp: +86 18838072829The 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 ...
WhatsApp: +86 18838072829The 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 ...
WhatsApp: +86 18838072829Request 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 ...
WhatsApp: +86 18838072829This 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 ...
WhatsApp: +86 18838072829Accordingly, this study presents computational intelligence (CI) based nonlinear models to predict the four AFTs using the oxide composition of the coal ash as the model input. The CI methods used ...
WhatsApp: +86 18838072829This study aims to address the issues with repeatability by presenting a fully mechanised pellet production process and automated AFT process using a novel image analysis technique. Furthermore, for the first time, a wide range of pelleting methods will be directly compared, and an optimal preparation methodology has been identified. 2.
WhatsApp: +86 18838072829Gasification 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 ...
WhatsApp: +86 18838072829