Helpline offers Process Heating's readers a chance to solve problems that crop up in their heat processing applications.

We have purchased a hot oil system designed for SUN21. Unfortunately, we don't have this chemical. On the other hand, we do have Therminol 66. Will Therminol 66 work? Also, where can I get thermal and transport properties of SUN21? - P.K.

Therminol 66 has a wider operating range and is 30 to 40 times more thermally stable than mineral oil heat transfer fluids. Therminol 66 will probably work fine in this system. You should consult the system designer to evaluate specific details. Contact Sun Chemical for physical properties of their fluids. - Ander Beain, Solutia Inc., (314) 674-1000.