(111f) Safe Molecular Sieve Decommissioning & Unloading Process

Unloading the spent molecular sieve from the Primary Dryers in the Q-Chem Ethylene unit is a higher risk task that requires proper understanding of and handling during any shutdown period. Q-Chem has two Primary Dryers that each can hold a total of 95,000 KG of Molecular Sieve. The molecular sieve material is very reactive with moisture and can generate excess heat that can exhibit a significant safety threat to humans dealing with it directly. At the time of the February 2012 Turnaround, Q-Chem had not yet replaced these beds since commissioning (about 9 years operation).

This paper discusses Q-Chem’s approved experience in handling and unloading the spent molecular sieve safely from the dryer without impacting the equipment. The deactivation and unloading process will be explained thoroughly here with the time line and various process parameters controlled.