1, the basic indicators of the quality of coal First, moisture (M) The moisture of coal is divided into two types. One is the internal moisture (Minh), which is the water contained when the plant turns into coal. The other is the external water (Mf), which is attached to the coal surface and crack during the mining, transportation and other processes. The moisture in the whole water is the external moisture of the coal and the intrinsic sum. In general, the greater the degree of metamorphism of coal, the lower the inherent moisture. The internal moisture of lignite and long-flame coal is generally higher, and the moisture in lean coal and anthracite is lower. The existence of water is extremely unfavorable for the utilization of coal. It not only wastes a lot of transportation resources, but when coal is used as a fuel, the water in the coal will become steam, which will consume heat during evaporation. In addition, the moisture of the clean coal will also produce certain coking. Impact. For every 2% increase in moisture, the calorific value is reduced by 100kcal/kg (kcal/kg); for every 1% increase in moisture in smelted clean coal, the coking time is extended by 5-10 min. Second, ash (A) The residue left after the coal is completely burned is called ash, and the ash is extra ash and internal ash. The external ash is a rock fragment from the top plate and the research, which is closely related to the rationality of the coal mining method. Most of the external ash can be removed by sorting. The intrinsic ash is the inorganic matter contained in the original plant of the coal, and the higher the internal ash, the worse the selectivity of the coal. Ash is a harmful substance. The ash in the thermal coal increases, the calorific value decreases, the slagging amount increases, and the coal is easy to slag; generally the ash is increased by 2%, and the calorific value is reduced by about 10 okcal / kg. The ash content in the refined coal is increased, the utilization factor of the blast furnace is reduced, the coke strength is decreased, and the amount of limestone is increased. For every 1% increase in ash, the coke strength is decreased by 2%, the production capacity of the blast furnace is decreased by 3%, and the amount of limestone is increased by 4%. Third, volatile matter (V) When the coal is heated under high temperature and air-insulated conditions, the products of the discharged gas and liquid state are referred to as volatiles. The main components of the volatile matter are methane, hydrogen, and other hydrocarbons. It is one of the important indicators for identifying the type and quality of coal. In general, as the degree of coal deterioration increases, coal volatiles decrease. Lignite and gas coal have higher volatile matter, and lean coal and anthracite have lower volatile matter. Fourth, fixed carbon quality (FC) Fixed carbon content refers to the removal of moisture, ash and volatile residues, which is an important indicator for determining coal use. The difference between the moisture, ash and volatiles of the coal is subtracted from 100, ie the fixed carbon content of the coal. Based on the basis of the calculated volatiles used, the fixed carbon content of different benchmarks such as dry basis and dry ashless basis can be calculated. Five, calorific value (Q) Calorific value refers to the heat generated when the unit mass of coal is completely burned, and is mainly divided into high calorific value and low calorific value. The high calorific value of coal minus the heat of vaporization of water is the low calorific value. The international unit of calorific value is megajoules per kilogram (MJ/kg), and the common unit is megagrams. The conversion relationship is: 1MJ / kg = 239. 14kcal / kg ? 1J = 0.239gcal ? 1cal = 4. l8J. Such as calorific value 550kcaL / g, 5500kcal / kg = 550 ÷ 239. 14 = 23MJ / kg. For the sake of comparison, when we measure the consumption of coal, we must convert the coal of different calorific value actually used into standard coal, standard coal. The calorific value is 29.27 MJ/kg (700 okcal / kg). The common calorific value for domestic trade is to receive the base low calorific value (Qnet, ar), which reflects the application effect of coal, but external factors have a greater impact, such as moisture, so Qnet, ar can not reflect the true quality of coal. The general calorific value of international trade is air drying base high calorific value (Qnet, ar), which can accurately reflect the true quality of coal, and is not affected by external factors such as moisture. In the case of the same moisture, ash, etc., the high heat generation of the air drying base is about 1.25 MJ/g (300 kcal / kg) higher than the heat generated by the base. Sixth, the maximum thickness of the gel layer (Y) After the bituminous coal is heated to a certain temperature, the maximum thickness of the gel layer formed is the maximum value of the difference between the F layer and the F layer measured by the probe in the measurement of the bituminous layer index of the bituminous coal. It is one of the important criteria for coal classification. The thermal coal colloid layer has a large thickness and is easy to coke; the smelting clean coal has clear requirements for the thickness of the colloidal layer. Seven, the bond index (G) Under the specified conditions, the ability of bituminous coal to bond special anthracite after heating is one of the important criteria for coal classification and an important indicator for smelting clean coal. The higher the dry knot index, the stronger the coking property. Eight, coal ash melting temperature (ash melting point) The coal ash fusion deformation temperature (DT), the softening temperature (ST), the flow temperature (FT), and the usual softening temperature (ST) which are obtained according to the heating temperature obtained under the predetermined conditions are expressed. The higher the ash fusibility temperature, the less ash is easily formed. Due to different boiler designs, the ash fusibility temperature requirements are different. The degree of coal ash fusion temperature is directly related to the performance of coal as a fuel and gasification raw material. The coal ash has a low melting temperature, and the coal ash is easy to slag, which increases the difficulty of slagging, especially the solid slag boiler and mobile In the gasifier of the bed, the coal ash fusion temperature is required to be high. 9. Hastelloy Index (HGI) The Hastelloy index is an important indicator of the grindability of coal. The grindability of coal refers to the difficulty of grinding a certain amount of coal into the powder at the same energy consumption. The wearable index is Zhao Da, and the coal is easy to be ground into powder. In power generation pulverized coal boilers and blast furnace coal injection, the wearable index is an important indicator of quality evaluation. +, Gilman mobility (ddpm) The fluidity of coal is a measure of the viscosity of the colloid formed by coal during dry distillation and is one of the plasticity indices of coal. Fluidity is an effective means to study the rheology and thermal decomposition mechanics of coal. It can also characterize the plasticity of coal and can guide the prediction of coal blending and coke strength. Gilman's fluidity is a fluidity index expressed by the maximum rotational speed of a fixed moment in a colloid formed by coal heating, expressed as the angle of rotation per minute. XI, increase the expansion number of the pot (CSN) The expansion and expansion expansion number is the expansion index and plasticity index of the coal expansion program obtained by heating the coal in the disaster increase under the specified conditions. The magnitude of the expansion expansion number depends on the coal ash fusion and the colloid formation period. Gassing and impermeability of the colloid. 12. Coke characteristics (CRC) The shape of the remaining material after thermal decomposition of coal. According to different shapes, it is divided into 8 serial numbers, and its serial number is the coke slag feature code. 1 - powder. All are powders, no particles that stick to each other. 2 - Sticky. Flicking with a finger is a powder or a powder, in which a larger mass is lightly touched into a powder. 3── Weakly sticky. Press gently with your fingers to make it block. 4 ─ No fusion bonding. Use your fingers to break into small pieces, the upper surface of the coke is dull, and the lower surface is slightly silvery white. 5 ─ Do not swell and melt. Cinder blocks formed flat, not easy to distinguish the boundaries of the coal particles. Cinder upper surface of a clear silver metallic luster, more significantly the lower surface of the silver-white luster. 6──Micro-expansion fusion bonding. With the fingers can not be broken, the upper and lower surfaces of the coke slag have a silver-white metallic luster, but the surface of the coke slag has a small expansion bubble. 7──Expansion and fusion bonding. The upper and lower surfaces of the coke slag have a silver-white metallic luster and are obviously expanded, but the height does not exceed 15 mm. 8──Strong expansion and fusion bonding. The upper and lower surfaces of the coke have a silvery white metallic luster, and the coke slag height is greater than 15 mm. 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