how to reduce moment on cyrogenic lines

Please how can one reduce the high moment around the nozzles connected to cyrogenic line of temp -12 F,the line is 36inches

Moment = Force x Distance

The longer the pipe the higher is the force. You can also check how you can restraint this force (through your pipe of course) in pushing (or in your case pulling) the nozzle. You may need to make a trial and error. Be sure you know the criteria of qualifying a pump nozzle bearing in mind that all rotary equipment are normally qualify based on Operating condition not design condition.

EddiB

EddieB, Moment = Force x Distance indeed. The longer the pipe the higher is the moment, if force is constant. But the longer the pipe leg, the lesser is the bending moment, in case the load is an imposed displacement (strain) applied perpendicular to the piping leg.

The design parameters here are too vague that nobody can realistically provide useful advice.

General advice:
• Model the nozzle as piping instead of an anchor. Model the vessel, too. At -12F, it's likely growing and shrinking, as well.
• Reroute the piping to allow for flexibility. Add an expansion loops.
• Support the piping to prevent growth. Add limits as needed, but only if you can't add flexibility.