Questions about steam generation and coal consumption in boilers?
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I would like to ask the experts: 1. Can a 35t circulating fluidized bed boiler actually generate steam in quantities greater than 35t? 2. Coal with a calorific value of over 3,600 kilocalories is used; what is the typical coal consumption?
1. It depends on your steam pressure. Low pressure means a larger volume. Generally, CFB boilers are designed to operate at 15% overload, but a specific analysis is required for practical applications. Look at the furnace type and fuel. 2. The lower calorific value of 3,600 kcal/kg is the minimum limit for category II bituminous coal. It still depends on the differences between the coal types used in design; if the volatiles content is low, or if washed medium coal (with very fine particle size), slime, or washed gangue is mixed in, the coal consumption will be higher.
Typical boilers come with a certain margin of capacity, meaning they can produce more steam than their rated output – up to 35 tons of steam or more, using coal with a calorific value of over 3600 kcal per unit. Such coal is mainly used in pulverized coal boilers; it is expensive, has low ash content, and helps reduce coal consumption. In contrast, ordinary industrial and steam boilers use lower-quality coal, and due to considerations related to energy savings, cost reduction, and coal prices, even when high-calorific-value coal is purchased, it is still mixed with other types of coal before use.