Geochemical characteristics of major and trace elements in Sahinali Coals,Aydin, Turkey

In this study, geochemical behavior of elements is investigated in 25 coal samples collected at 10 locations of ?ahinli coaliferous units at southeast of Ayd?n, Turkey. In all the samples, X-ray powder diffraction and inductively coupled plasma mass spectrometry analyses were performed and element and mineral compositions were determined. Total organic carbon (TOC) values of coals are between 14.6 and 37.7 wt% with average of 28.5 wt%. Samples are composed of quartz, calcite, feldspar, dolomite, mica, gypsum, and salt minerals which are accompanied by illite-, kaolinite-, and smectite-type clay minerals. Comparison of average element contents of world coals and studied samples yields that K > Fe > As > U > Cs > Y > Er > Al > Th > Rb > Yb > W > Tb > Dy > Lu > Ce > Sm > La > Ho > Si > Nd > Gd > Tm > Eu > Nb > Pr > Pb > Sn > Ni > Cu > Ga > Ta > Sb > Zr > Cd > V > Zn > Co > Mo > P > Hf > Ba are found to be enriched, while Mn > Be > Ca > Sr > Bi > Mg are found to be depleted. Statistically elements are correlated with TOC.     

Correlation between ash fusion temperatures and chemical composition in Albanian coal ashes

This paper presents an analysis of the ash fusion temperatures (AFTs) for 17 Albanian coals. The contribution of oxides to AFTs is investigated by considering oxides from various perspectives: as discrete species, acids and bases, crystal components, fluxing agents, and cement constituents, and in accordance with the periodic table. Empirical correlations use simple and multiple linear equations and polynomial equations, referring to both weight and molar percentages. The shift from the deformation temperature to the flow temperature is accompanied by a shift of influence from basic oxides to acidic oxides. Many predictive correlative equations are obtained.     

Application of chemometrics to study the kinetics of coal pyrolysis: A novel approach

In present investigation, chemometric tools, principal component analysis (PCA) and Hierarchical clustering analysis (HCA) are used to get the linkage between the coal properties and kinetics of pyrolysis. Thermo gravimetric analysis (TGA) of 10 perhydrous Indian coals was done. Devolatilization of these coals showed five independent reactions. Kinetic parameters were calculated for individual reaction. Activation energy and weight loss of each reaction has been analyzed as a function of coal properties (moisture, volatile matter, ash, fixed carbon, carbon, hydrogen, nitrogen and sulfur). By applying chemometric, was extracted information about the linkage between activation energies of each reaction and coal properties. The mathematical treatment of data has provided conclusions on properties of coal and kinetic parameters.     

3号高炉喷煤初步实践

介绍３号高炉喷煤系统工艺流程，对设备所做的完善、改造，各煤种使用情况，喷煤对高炉的影响及操业方面采取的对策。     

Carbonization and demineralization of coals: A study by means of FT-IR spectroscopy

Coal basically consists of two parts—a crystalline, inorganic part, and an amorphous, organic part. Based on this, we intended to study the changes that occurred on the composition and on the chemical structure of coals after carbonization at 1000 or 900° C and demineralization treatments with hydrochloric and hydrofluoric acids. For this, four coals of different categories (or levels) were chosen: semianthracite (A-O) and high volatile bituminous coal (B-O), which are high level coals, and lignite (Li-O) and leonardite (Le-O), these being low level coals. The coals were first analysed in terms of their proximate and elemental compositions and then carbonized and demineralized. Also, the starting coals and the prepared samples were examined by infrared spectroscopy. In addition, a study of the optimization of the application of this technique for only A-O was carried out. For A-O and B-O, the spectra recorded intense absorption bands that are ascribable to vibration modes in mineral components as quartz and aluminosilicates, such as kaolinite. For Li-O and Le-O, the spectra displayed some other bands as well, also quite intense, which have been assigned to bond vibrations in functional groups and structures of their organic part. The carbonization of the coals resulted in significant changes in their inorganic part as the content of quartz increased and the content of aluminosilicates decreased. In addition, the thermal decomposition of mineral carbonates occurred. The carbonization greatly affects the organic part of the coals, especially in Li-O and Le-O, as most functional groups and structures are not thermally stable under heating conditions. With regard to demineralization, HF is a more effective agent than HCl, achieving products with higher organic content. The mass losses are higher in Li-O and Le-O than in A-O and B-O. So, the infrared spectroscopy allows the analysis of both inorganic and organic parts of the coals and of their carbonization and demineralization products. These processes facilitate subsequent analysis of the inorganic and organic parts of coals by infrared spectroscopy. In the application of this technique, both the coal: KBr ratio and the thickness for the disks should be controlled, owing to the influence on the infrared absorption.     

水煤气型两段炉煤种适用性考察

比较阜新长焰煤、沈北马古褐煤和宁夏灵武不粘结煤分别在水煤气型两段炉上工业试验的结果，提出了水煤气型两段炉适用煤种的基本估计。     

Coal to Liquid (CTL): Commercialization Prospects in China

Production of fuels/chemicals from syngas (CO + H₂) is receiving increased attention with the background of the resource depletion and the unstable prices of petroleum oil. The fuels, especially diesel, obtained from the syngas conversion via Fischer‐Tropsch synthesis (FTS), are proved to be of very high quality that will contribute much to environmental protection and raising the energy efficiency in the transportation sector when modern diesel engines are massively applied in vehicles. FTS technologies developed in recent years have reached the stage for the feasibility of construction of large‐scale complexes. Under a long‐term consideration of developing the field of coal to liquids (CTL), major issues in successfully applying CTL technologies are those controlling the feasibility of all kinds of projects. Points identified are, in general: (1) efficiency advantage over conventional processes (e.g. thermal power generation process); (2) cost and economic benefit; (3) environment advantage. These questions have been better answered using CTL‐based poly‐generation schemes. Among all the different schemes, in principle, the co‐production of liquid fuels and electricity are naturally the main frame. The simple efficiency increase due to the better energy balance in the co‐production mode and the environment protection advantage due to the easy‐to‐apply technology in the pollutant removal and treatment from syngas in a liquid fuel process has projected a bright future even for applying the more capital intensive IGCC + F‐T scheme, which can raise the efficiency (to end products) from 43–46 % in either single schemes to about 52–60 %. This new process will guarantee a better solution to environment protection.     

Volumetric Effects in Coal Sorption Capacity Measurements

Many types of materials e.g., rubber, polymer, coal, change their volume and structure after absorption of gaseous and liquid substances. Various kinds of volume changes affect the accuracy of absorption measurements by gravimetric and manometric methods, the two major techniques currently employed. The errors associated with the volumetric effects, specifically, the case of carbon dioxide sorption on coal, were investigated. It was demonstrated that the resulting error in the buoyancy correction in the gravimetric method is equivalent to the corresponding error in the assumed void volume in the manometric method. It is suggested that the integration of the two methods, combined with the binary gas mixture technique of in‐situ volume measurement, will contribute to dramatically improve the accuracy of absorption measurements for plastic materials.     

Modeling of Volatiles Combustion and Alkali Deposition in a Fluidized Bed Coal Combustor

A simplified kinetic model, coupled with the bed hydrodynamics and a volatile evolution region within the bed, was formulated to predict the extent of gas‐phase combustion in a laboratory‐scale fluidized bed coal combustor (FBC). A close examination has also been made to highlight the relevance of the reducing/oxidizing environment (computed with the present theoretical model) in relation to FBC materials exposed to fireside corrosion at high temperature, under various operating conditions. The model results revealed that, for high‐volatile coals with particle diameters (d_c) of 1–3 mm and sand particle size (d_s) of 0.674 mm, over one third of the original coal volatiles may burn in the freeboard region at bed temperature (T_b) ≤ 850 °C and excess air (XSA) ≤ 10 %. These values, together with the computed equilibrium conversion of alkali chlorides to sulfates, may suggest that sodium and potassium salts present in the vapor phase are likely to accelerate hot corrosion of heat exchange tubes above the bed when an FBC operates at T_b ≤ 840 °C, XSA ≤ 20 %, d_c < 5 mm, d_s < 1 mm, H_s ≤ 0.2 m and U_o < 1 m/s. Conversely, at T_b > 890 °C and XSA > 30 %, high oxidation rates may be present for the in‐bed tubes. At these higher T_b values and XSA < 10 %, a sulfidation mechanism presumably influences the extent of corrosion on the metallic components within the bed.