Ken Birchett looks at the critical requirements of pulverisation
Throughout the energy industry, vertical roller mills (VRMs) are classified as the predominant equipment used for coal pulverisation. The crucial prerequisites of pulverisation are grinding, heating, classification and transport on the pulverised coal with the pulveriser.
The grinding factors coupled with good alignment and compression are important to coal pulverisation within the reduce mill overall body (grinding zone) although the classification of your pulverised coal, discharge and recirculation, is critical in the upper mill human body (classification zone).
The correct metering, distribution and command of air circulation throughout the mill, known as most important air, is significant all over the pulveriser and is particularly the bridge involving the decrease grinding zone and the upper classification zone.
The coal pulveriser could be the vital element of the gasoline supply system and is particularly a serious affect of combustion performance within the burner zone together with the performance and efficiency on the furnace by itself. As a result the coal pulveriser is truly the 'heart' of your combustion process for a coal-fired electrical power station.
Coal pulveriser style and design
Generally speaking, coal pulverisers are intended to achieve the maximum rated potential grinding a design coal by using a grindability of fifty five HGI and 8-12 for each cent dampness and obtaining a discharge fineness of 70 for every cent passing a two hundred mesh screen (74 micron) and 99.five for each cent passing a 50 mesh screen. Variation from the coal hardness and/or humidity written content will effect, up or down, the discharge capability or maybe the discharge fineness.
To achieve these structure concerns it is vital that the grinding factors are in very good condition and they maintain a steady profile. The lack of the grinding profile success in the lack of grinding performance, this means the pulveriser have to perform more durable to achieve an equal end result.
In the end some extent might be arrived at where possibly a loss of potential or simply a loss of fineness will result less than uniform conditions. For a longer period lasting, far more consistent grinding features are critical to pulveriser procedure yielding more time functioning campaigns, lessened maintenance and also a reduce total invested cost.