(114d) Pitfalls of Fluoropolymers in Mass Transfer of Hot Corrosives

Fluoropolymers are often used as alternatives to alloys, glass, or ceramics in corrosive service, e.g., when there are concerns about thermal shock, brittleness, abrasion, potential product contamination, or ability to fabricate with large diameters.

While fluoropolymers have good chemical resistance, mechanical toughness, and are melt-processable, these properties can result in some unexpected and unwelcome outcomes. This presentation gives examples and lessons learned from a variety of mishaps using fluoropolymers in mass-transfer services such as distillation, absorption, and stripping.

Examples of problems encountered include:

- Reduced mass transfer efficiency

- The implications of choosing liners vs coatings

- Trade-offs of fully vs partially fluorinated polymers

- Effect of high temperatures on the design & mechanical strength of solid plastic internals

- Sensitivity of allowable working temperatures to high acid concentrations

- Two-phase flow effects

- Permeation effects

- Instrumentation pitfalls

- Joint sealing & leakage

- Vacuum leaks

- Impact of base metal selection

The intention of this presentation is to make the audience aware of subtle potential issues when designing equipment using fluoropolymers in hot corrosive service.