Blown condensate seal

Figure 8.2 shows a common type of reboiler failure. The steam trap on the condensate drain line has stuck open. A steam trap is a device intended to open when its float is lifted by water. The steam trap remains open until all the water drains out of the trap. Then, when there is no more water to keep the trap open, it shuts. But, if the float sticks open, steam can blow through the steam trap. This is called a blown condensate seal. The average vapor velocity through the tubes... 

We can see, then, that either condensate backup, or blowing the condensate seal, will cause a steam reboiler to lose capacity. If you think either of these two problems could cause a loss in reboiler duty, try opening the bypass around the steam trap. If the reboiler duty goes up, the problem was condensate backup. If the reboiler duty goes down, then the problem might be a blown condensate seal. If it looks like a blown condensate seal problem, close the steam trap bypass. Then, partially close the valve downstream of the steam trap. If this increases the reboiler duty, a blown condensate seal failure is proved. 

Blown condensate seal. When this occurs, uncondensed vapor blows and channels right through the reboiler and out the condensate drain line. Heat transfer slumps and water hammer may follow. Experience shows that as much as half the reboiler duty is lost by a small amount of vapor blowing (239). Throttling the reboiler outlet reestablishes the seal. Installation of a condensate seal drum can cure this problem. Additional discussion is in Sec. 17.1.2. 

Blown condensate seal. This is the same problem as experienced with... 

To determine if this problem exists on a reboiler, establish a definite condensate seal by restricting the condensate effluent line. If the tower bottom s temperature increases, the reboiler has a blown condensate seal. This wastes steam and reboiler capacity. The correction is the same for condensate backup installation of a steam condensate seal drum. 

Blown condensate seal (reboiler problems), 273-275 Blue fire, 133 Boiler leaks, 112, 120 Bottlenecks (process), 482 Bottom txrol tem 5eralure, 283-284 Bottom-head removal (coking cycle), 59-60... 

Reactor vapor, 184, 186 Reboiler circulation, 272-273 Reboiler corrosion, 109 Reboiler leaks, 92 Reboiler problems (distillation lowers), 271-275, 280, 388 Irapoul pans, 271-272 plugged reboilers, 272-273 trapout pan repair, 273 steam-side problems, 273 blown condensate seal, 273-275 distillation, 388... 

Blown condensate seal Vapor or steam flowing through the condensate outlet nozzle of a condenser. 

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