[Weekly Topic] What phenomena occur when the steam demand of a boiler exceeds its critical load? (5.23--5.30)
Thread Content
This post was last edited by zgj2405 on 2011-5-23 12:57. What phenomena occur when the steam demand of a boiler exceeds its critical load? Why? A. Increase in the level of water in the furnace B. Increased upward flow velocity of steam C. More water from the furnace splashing into the steam D. Formation of a thick foam layer on the surface of the furnace water
When the steam demand of the boiler exceeds its critical load, that is, when the instantaneous steam demand of the heating network is greater than the steam output of the boiler, this leads to a drop in steam pressure, expansion of the boiler water, and an increase in water level. This represents an overloaded operation of the boiler, which results in an increased steam flow rate and more water droplets being carried away, thereby causing foam to form on the surface of the boiler water
When the steam demand of the boiler exceeds its critical load, that is, when the amount of steam required is greater than the amount of steam produced by the boiler, this leads to a decrease in steam pressure, an increase in specific volume, and an rise in water level. This represents an overloaded operation of the boiler, which results in an increased steam flow rate and more water droplets being carried away, causing foam to form on the surface of the boiler water
When the steam demand of a boiler exceeds its critical load, the following phenomena occur: A. The water level in the boiler rises; B. The upward flow velocity of the steam increases; C. More water from the boiler splashes into the steam. Under constant conditions of steam pressure, boiler drum size, and water salinity, each boiler has a critical load. When the load is below the critical load, the increase in the amount of water carried by the steam as the load increases is small. When the load exceeds the critical load, the amount of water carried by the steam increases sharply. At high loads, the load on the evaporation surface, that is, the average speed at which steam escapes from the evaporation surface, is also high; as a result, it is easier to carry more water droplets.
If the heat source remains constant, an increase in the amount of steam inevitably leads to a decrease in pressure, a reduction in the volumetric equivalent of the steam, and an increase in the water level in the steam drum. A drop in pressure leads to foaming, a foam layer forms on the surface of the boiler water, and the amount of boiler water carried in the steam increases. As pressure decreases, the driving force for boiler circulation diminishes, and the upward flow velocity of steam should decrease as well
When the steam demand of the boiler exceeds its critical load, that is, when the amount of steam required is greater than the amount of steam produced by the boiler, this leads to a decrease in steam pressure, an increase in specific volume, and an rise in water level. This represents an overloaded operation of the boiler; as a result, the steam flow velocity increases, more water droplets are carried away, foam appears on the surface of the boiler water, and the amount of water carried in the steam increases. As pressure decreases, the driving force for boiler circulation diminishes, and the upward flow velocity of steam should decrease as well