Static Strength Reliability Analysis of the FLNG Compact and High Efficient Heat Exchanger

Abstract

Abstract Because of the harsh marine environment and limited offshore natural gas liquefaction work space, the compact and high efficient heat exchanger is the best choice for FLNG (floating liquefied natural gas) heat exchanger. To optimize the heat exchanger’s structural parameters and improve the performance, the factors mostly affecting the strength of the heat exchanger need to be determined, and static strength analysis and reliability analysis should be required. The strength of the heat exchanger core is analyzed by using the Static Structural, and the stress intensity distribution is obtained. According to the operation conditions, the temperature boundary condition has been set and the mechanical stress and thermal stress are considered to evaluate the strength. By choosing the thickness between the cold channels, cold channel pressure, hot channel pressure and elastic modulus as input random variables, the reliability analysis of heat exchanger has been done by using the Six Sigma Analysis of ANSYS Workbench, and next the cumulative distribution function curves of the membrane stress intensity, membrane plus bending stress intensity, response surface and the sensitivity are obtained. The reliability analysis results have shown that the cold channel pressure loading is found to be the greatest factor to the structural strength. The reliability of the heat exchange is more than 99.9% without considering thermal stress.