Can the boiler water wall tubes and downcomers be designed on the same horizontal line?
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Let’s discuss whether the boiler water wall tubes and downcomers can be designed on the same horizontal line, and why
No, haha – on the same horizontal plane, the circulation weakens
It should be possible. In natural circulation, the downcomer remains unheated; water with higher density in it descends naturally. The water wall is heated, causing the water there to have lower density and thus rise naturally, thereby creating natural circulation ； In forced-circulation boilers, operation relies on circulation pressure; the water is separated, so it is even less affected.
No, the riser pipes that face the downcomer pipes are better suited for receiving incoming water; the other pipes do not have this advantage, which results in poor local water circulation within the pipe array
Boilers with natural circulation are not feasible； Since the downcomer is not heated, gravity and density facilitate a natural circulation with the water wall tubes; as these tubes rise, they absorb heat from the furnace, then enter the drum at its upper part where steam and water are separated, while impurities and water of substandard quality are discharged through the drain. In forced circulation, provided there are no issues with the manufacturing of equipment such as the drum, it should be possible from a process perspective to design the boiler water wall tubes and downcomers on the same horizontal level.
I don’t understand the question posed by the original poster: are the water wall tubes and downcomer tubes designed to be on the same horizontal line?