Coal Quality Index and Symbol Significance
Coal is one of the main sources of energy in the world. As a result, coal quality has a large impact on energy production. The coal quality index (CQI) is an indispensable tool for evaluating and managing coal production and use. It provides quantitative information about the properties of coal, including moisture content, sulfur content, ash content, heating value, coking properties, porosity and so on.
The coal quality index system typically evaluates coal properties in terms of their “relative” qualities, or grades. Each grade is assigned a numerical value, with higher values being assigned to higher grades. The higher the grade, the more favorable its performance. Grades below 5 typically indicate poor-quality coal, while grades equal to or greater than 5 indicate good-quality coal.
In addition to the CQI grades, the CQI is also symbolized using a variety of symbols that refer to a specific property or characteristic of the coal. Each symbol has a specific meaning, and its appearance is generally conserved from one CQI grade to another.
The most widely used coal quality index symbol is the dual-headed v symbol. It is intended to show that a particular coal has high coking and thermal properties, and usually indicates a premium grade of coal. A single-headed v symbol, on the other hand, indicates that the coal has low coking and thermal properties, and usually indicates a low grade coal.
The percent symbol (%) is also widely used with coal quality index grades to represent the volatile matter content of the coal. The higher the volatile matter content, the higher the grade of coal, and the higher percentage is associated with the percent symbol.
The plus (+) symbol is used to designate coal with higher sulfur content, while the minus (-) symbol is used to designate coal with lower sulfur content. The degree symbol (°C) is used to indicate the moisture content of the coal. The higher the moisture content, the lower the grade of the coal, and the lower the number associated with the degree symbol.
The “LH” symbol is used to designate coal with coking properties, while the “LH” symbol is used to designate coal with non-coking properties. The “TH” symbol is used to indicate higher thermal properties, while the “TL” symbol is used to indicate lower thermal properties.
Finally, the “NS” symbol stands for non-saponified, meaning that the coal is not easily saponified. This type of coal is generally harder and of a higher quality than saponified coal.
In conclusion, coal quality index (CQI) is an indispensable tool for evaluating and managing coal production and use. It is symbolized by a variety of symbols that refer to a specific property or characteristic of the coal. While each symbol has a specific meaning, its general meanings remain the same across all CQI grades. By understanding the meaning of these symbols, you can easily interpret the information on coal quality index grades.
