The lowest temperature that a high-pressure ball valve can withstand
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Our plant is a coal-to-methanol plant that uses Texaco gasification. A high-pressure ball valve is installed in the lockhopper section of the gasifier to control the pressure relief of the lockhopper. This valve suffered from internal leakage; some analysts believe that this was caused by water accumulating inside the valve chamber, which prevented complete drainage and led to the valve freezing, thereby causing the ball to deform – it was the freezing that resulted in the deformation of the ball valve and the subsequent internal leakage. The temperature here is between -13 and -15 degrees. I would appreciate it if experts could help analyze whether this is correct.
I personally think that internal leakage is caused by damage to the sealing surface; such a low temperature should not result in much deformation of the ball valve, so it shouldn’t lead to this situation
I’m not sure how long it’s been in use; even a small gap between the valve body and the valve ball can cause internal leakage, and sometimes it’s a problem with the sealing ring.
The seat of the ball valve in this location needs to be hardened; otherwise, internal leakage is likely to occur. The deformation of the sphere mentioned by the original poster should be impossible. The valve seat must be damaged!
I wonder what the original poster’s final conclusion is? I’ve really never heard of low temperatures causing deformation of valve cores; it should have been taken into account during the design phase. I’m not very familiar with chemical processes, and methanol is also an organic solvent – could that possibly damage the sealing grease? Please correct me if I’m wrong!