Two phase flow pattern in a spiral wound heat exchanger

Your question requires an answer that is several orders of magnitude more complex than can be discussed on this forum. I strongly suggest you contact the manufacturer of that 'heat exchanger' and the licensor of the plant process and ask for technical assistance. You will have to pay for their services of course, as this is a very difficult question to answer. It requires extremely specialized knowledge, very sophisticated process modeling using physical and thermodynamic data not available to 'the public' and highly complex computational fluid dynamics analysis to even approach an understanding of what your real problem is.

It is unlikely, but possible,that 'slug flow' is causing the leaks. If there were significant slugging , enough to cause movement of the small diameter tubing in a repetitive back-and-forth motion, then abrasive wear or bending fatigue caused cracking might take place. Detailed inspection and analysis of the metal at the leak location will certainly be the first step to determine the mode of failure. Sometimes if process conditions have changed from those used in the design of these very special and extremely complex heat exchangers, fluid flow induced vibration might develop in areas not adequately braced for those new vibrations.

Some LNG plants with many years of successful operation have experienced new corrosion caused by mercury in the feedstock, usually carried from mercury balanced flow meters in producing wells and GOSP's . Often it takes years before this contamination arrives at the LNG plant, because the iron dust inside the pipeline traps it for a while. There is still much debate in the producing and technical support personnel about whether or not there is any mercury in the actual produced gas, or if the small quantities found are caused by contamination. 'Mercury trap guard beds' are low cost insurance against corrosive failure of these very costly spiral wound exchangers.

Good luck in your endeavor to resolve this problem. It is one of the most formidable technical challenges in the LNG field, and the economic consequences are enormous. Money spent for the highly specialized consulting necessary to address and resolve your problem is money very well invested and is very trivial in magnitude compared to the economic loss caused by exchanger failure.

Kamel,

We are able to design & manufacture of spiral wound heat exchangers, for repair pls send your enquiry officially to FRC@fidelityradocre.com.my (Fidleity Radcore Heat exchangers (M) Sdn Bhd) or contact me at my mobile: 6012 28888 09/ office: 603 5632 2800

regards,

Mike (FRC)