Ice formation downstream LCV

[SZL]

We have drain boot connected to the gas headers upstream the dehydration plant. The liquid from the drain boot is sent to the Blow down system while the vapor is recycled back to the gas headers.
The pressure on the gas headers is around 400 psig and the temperature is between 100 to 120 F. The pressure of the blow down is 2 psig. The liquid level in the drain boot is controlled by level transmitter which sends signal to the level control valve to open or closed.
We are experiencing a problem that the ice is formed on the pipe downstream the control valve and the level increased at the same time while the control valve opens fully. However, after a while the level decreases and the ice melts and the level control valve start to control.
The valve is two phase globe valve, Is it really hudration???

 

[hsbcn]

Hi SZL: this might help.

http://www.cheresources.com/invision/topic/6673-performing-a-hydrate-study/

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