1. Final Design Validation Problem Background Testing TDI Root Cause
Air Products has experienced multiple failures on a crucial pump used in the creation of pre polymers. The pumps are transferring Toluene Diisocyanate (TDI). Air Products needs validation of the root problem and a cost effective solution to eliminate failures.
Final Design
Testing
Team verified freezing in lubrication ports
Enclosure consistently heated at 1°F/Min
Pump thaws top to bottom, front to back
Approximately 30 minutes operation before
lubrication resumes
Aluminum enclosure
Rigid polystyrene foam insulation
Neoprene rubber sealant
2 x 90 Watt heat sheets
Digital temperature controller to maintain enclosure at 80°F
TDI
Zero Exposure Chemical – Toxic at 5 Parts Per Billion
High Freezing Point ~ 58°F
Reacts with itself and separates at 104°F
Root Cause
As a result of many failures occurring during colder, winter months and the relatively high freezing point of TDI, internal solidification of the pump lubrication ports (marked with yellow arrows below) is the suspected failure cause.
Value to Sponsor
Team 5’s enclosure will decrease the number of pump changes required and increase overall process efficiency. In addition, by elongating the pump service life, the Paulsboro facility will see significant savings on pump rebuild costs and plant downtime.
Validation
Air Products sought verification of root cause and validation of our final concept
Acknowledgements
Team 5 would like to thank our advisor, Dr. Keefe, for his direction, Andrew Zeigler at Air Products for his support and Steve Beard for his assistance in the machine shop.
Magnets
Working Fluid
(TDI)
Impeller
Bearings
Team 5 built an acrylic replica of Air Products pump to perform this validation
Acrylic allows the team to see freezing patterns and locations
Acetic acid pumped through the model simulates TDI
Similar dimensions, flow rates, and pressures allowed for accurate testing of enclosure effectiveness
Project Goals
Confirm failure mechanism and root cause
Prove proposed enclosure will maintain specified temperature and prevent TDI from freezing in pump