Pulverizer Design Coal
The design of the pulverizer system determines the turndown capability of the steam generator. The minimum stable load for an individual pulverizer firing coal is about 50% of the pulverizer rated capacity. Normal utility minimum load operating practice is to operate at least two pulverizers. Thus the minimum steam generator load when firing coal without supporting fuel is equal to the full capacity of one pulverizer. A minimum of two pulverizers in operation is preferred, since a loss of one of two pulverizers will not require tripping the steam generator because of loss of fuel and loss of flame.
The selection of the pulverizer size, therefore. Determines the steam generator turndown. A pulverizer system composed of a few large pulverizers results in poorer turndown (higher minimum load) than a system composed of a large number of smaller pulverizers. The capital cost, however, typically is less for a system with a few large pulverizers than for a system composed of a larger number of small pulverizers.
An additional consideration in the selection of pulverizer number and size is the number of pulverizers of the same model already in operation within the owner's system. The use of the same pulverizer model number at other units or stations within the system offers the potential for sharing spare parts. Particularly during unplanned pulverizer outages.
The total number of a particular pulverizer model sold and operating should also be considered. This aspect is especially important if the pulverizer selection is a new model with relatively few sold and operating. The improved performance and improved maintenance features of a new pulverizer model should be evaluated as part of the risk assessment of purchasing a new pulverizer model.
1 2
Pulverizer related articles
What is a pulverizer?
The features of the pulverizer
pulverizer mills basic design
The Types Of Pulverizer 2 3
The principle of pulverizer |
