Graphite is a good choice for high-temperature applications up to 600°F (315°C). It also has good chemical resistance, which makes it suitable for use in a wide range of chemicals and liquids. However, it is not as durable as Teflon and may wear out more quickly in high-pressure, high-speed applications.
PTFE, also known as Teflon, is extremely durable and can handle high-pressure and high-speed applications. It can also handle temperatures up to 500°F (260°C), although its chemical resistance is not as good as that of graphite. However, Teflon is a more expensive option than graphite.
So, the choice between graphite and Teflon compression packing will depend on the specific requirements of the system, including the operating temperature, pressure, and chemical compatibility.