Drainage issue of torch molecule sealers
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For the torch sealers and drain valves, if they remain closed for an extended period of time, excessive water accumulation during torch ignition can lead to freezing. What are the issues if the drain valves are kept open?
There is a problem; this prevents ensuring that the upper part of the molecule seal as well as the torch tip remain at a slight positive pressure, which makes it easy for air to flow back in and cause an explosion
In my design, a vertical water seal tank is used, with the drain from the molecular seal being directly connected to the seal tank. The drain pipe should be insulated; the minimum diameter is dn80, while in the northern regions DN100 is generally used
Reply to 3# Storage and Transportation Engineer: Normally, the drain valve of the torch molecular seal in the plant is kept in the open position, and there is no water seal at the drain outlet. Water is drained intermittently only during the ignition of the torch; occasionally some gas is released, but nothing serious happens
For molecular seals installed at high locations, such as those on torch heads, the liquid discharge pipeline at the lower part should generally be connected to the ground. If the valve remains open, it will prevent the molecular seal from maintaining a slight positive pressure, allowing negative pressure to draw in air from the ground level. In the case of minor venting, a mixture within the molecular seal that reaches the explosive limit can form, which is very dangerous. Therefore, a water seal must be installed at the lower discharge outlet; as a minimum, the valve should be kept closed and checked regularly. The poster said that gas occasionally escaped during the lighting of the torch; it seems that the amount of gas being released was already quite high, and the positive pressure generated caused the gas to overflow from the drainage outlet, which confirms that it is indeed quite dangerous.
The drain outlet should be kept closed at all times, and condensate should be drained regularly. When doing so, two people must be present: one to operate the device and another to supervise. In fact, this kind of torch can be designed in such a way as to ensure safe operation.
The drain of the torch molecule sealer should be in an open position, and a water seal should be installed at the drain outlet.