Hi Kk,

During periods when horizontal pipelines are partially filled with LNG during filling or draining operations, temperature differentials between top and bottom of the pipe up to 60°C may occur. This will then lead to “Cryogen-ic bending” with consequently extra stresses, support loads and angular deflections and rotations, particularly at the elbows of the pipeline. Stresses due to this cryogenic bending or bowing are to be classified as displacement stresses.

In the calculation, the temperature differential will be assumed to be linearly distributed from top to bottom. Temperature differentials for the various parts of the system shall be considered. However, the design shall al-low for a temperature differential of 60°C. Weight has a hold down effect on the cryogenic bending. In evaluating the cryogenic bending, the line shall be considered to be filled only half full with LNG

Supports uplift during cryogenic bending shall be limited to 50mmn and will be controlled with 100mm high guide thrusts.

Thermal Bowing Delta Temp +60.000 C

1. W+T1+P1 OPE Operating case at operating temperature + Design pressure - Operating case
2. W+P1 SUS Sustained case + Design pressure - Sustained Stress
3. T1 EXP Operating temperature including 60°C of Cryogenic delta T - Thermal Stress Check.

Important points.

For supporting use the cold shoes and hold down frames.
check the surge loads.

provided the limit stop at the loops.