Session: CT-03-01 Leak Tightness and Fugitive Emissions

Paper Number: 106374

106374 - Oxidation Properties of Graphitic Packings Used in Low Emission Valves 

Flexible Graphite is used in a variety of seals because of its good thermal resistance, chemical stability and high conformability. It is widely used throughout the industry, and it is present in most low emission packing solutions associated to some content of PTFE.  However, graphite will show appreciable oxidation when exposed to air at elevated temperatures and PTFE is subject to degradation thus leading to mass loss and consequently reducing sealing performance.

With the growing need to evaluate Fugitive Emission at higher temperatures, API 622 [1] has introduced in March of 2022 a High Temperature Testing Procedure to access seal performance at 400°C and modified its Packing Ring Weight loss Test procedure to include a 24h hold at 593°C to measure seal mass loss.

The scope of this paper is to evaluate the effect of temperature on low emissions packings composed of graphite and PTFE.  The influence of test method in the oxidation rate of inhibited graphite from different sources, using thermogravimetric analysis and a muffle oven are investigated at temperatures ranging from 400°C to 700°C.  A comparison is presented among different forms of graphite – tape, yarn and packing. Additional comparative weight loss data are reported among packings with PTFE, without PTFE, tested exposed to air and confined in a test rig simulating a stuffing box.

Presenting Author: Carlos D. Girão Teadit

Presenting Author Biography: Carlos D. Girão is a Professional Mechanical Engineer with a Master of Science from the State University of Rio de Janeiro, Brazil. Senior executive with leadership roles in the Americas and India, he has been in the Fluid Sealing Industry for the past fifteen years. Mr. Girão has published several papers, patents and championed studies for standard setting organizations and conferences. He currently holds the position of Technical Director for the Teadit Group.

Authors:

Carlos D. Girão Teadit
Mark Ruffin Teadit North America
João H. Pontes Teadit