We were asked to perform a design analysis of a high temperature pressure vessel used in the manufacturing of glass fibers.
The process involves impure molten glass at high temperature entering an inlet header, then flowing into a pressure vessel; from where it is discharged to an outlet header and fed to the glass fiber making process downstream at operating pressure. Attached to the inlet and outlet headers are two (2) pressure vessels connected via four (4) check valves. The check valves allow the vessels to alternate between a fill condition and a discharge condition. When the vessel is in the fill condition it is at atmospheric pressure or at a slight vacuum to help the glass flow. For the discharge condition the vessel is pressurized to 150 psi to feed the molten material to downstream processes. This cycle is repeated every 90 seconds, alternating between the two vessels to maintain a constant supply to the downstream processes.
The expected life for the (cast Haynes 188 alloy) pressure vessel is 2,200 hours at 1,900 ºF. Each vessel has an inlet nozzle, an outlet nozzle, and a vent nozzle. At these high temperatures creep rupture, creep ratcheting and creep fatigue damage are major concerns regarding the life of the vessel. ASME Code Procedures were used in the analysis.