PTFE, FEP and PFA tubes in heat exchanger applications

Heat exchangers are used in a wide range of applications in industries such as air conditioning, power plants, oil refineries and internal combustion engines. You may not know that you are familiar with heat exchangers. Take for example the radiator in your car. Heat exchangers keep your equipment cool and prevent overheating and malfunction. You may have seen someone open the hood of their car on the side of the road and smoke comes out as a result of a radiator failure.

There are various heat exchangers on the market with different applications. The shell and tube heat exchanger is one of the more widely used. It is commonly found in power plants, hydroelectric, refineries and chemical processing plants. The basic structure consists of a large tube (shell) with many small tubes inside wrapped around the middle. The liquid in the shell and in the small tubes are different. The two liquids transfer heat between each other through the tube walls.

Shell and tube heat exchangers have high requirements for the internal tube bundle. The tube needs to have good thermal conductivity and must also be long lasting at high temperatures and pressures.

1. PTFE tubes for heat exchanger applications

PTFE tubes have excellent corrosion resistance and remain inert to almost all chemicals. Temperature resistance up to 260℃. It is an excellent inner tube for heat exchanger components

Disadvantages.

(1) Bonding problem. PTFE tube and sealing plate are difficult to bond. Since PTFE is not sticky, it must be chemically treated and then bonded with an adhesive. But the adhesive is easy to loosen under high temperature conditions or other chemical liquid corrosion

(2) Welding problem. Must use special modified PTFE in order to PTFE tube welding, welding technology requirements are very high

(3) Wall thickness and thermal conductivity conflicts. The heat exchanger must withstand the pressure generated by the fluid flow. In the case of higher pressure, PTFE tube wall thickness must be thick enough to have a long service life. But the thicker wall thickness PTFE tube thermal conductivity is poor.

2. FEP tubes used in heat exchangers

FEP tube corrosion resistance is also very good. Smooth wall, high light transmission, easy to weld, instead of PTFE tube used in heat exchangers is an option.

Disadvantages: FEP tube chemical inertness is slightly lower than PTFE tube, temperature resistance up to 200 ℃, lower than PTFE 260 ℃

3. PFA tube used in heat exchangers

PFA tube combines the advantages of PTFE tube and FEP tube, which is an excellent choice for heat exchanger. It inherits the strong corrosion resistance of PTFE and high temperature resistance up to 260℃, and also inherits the high permeability, smoothness and easy welding characteristics of FEP. High purity PFA tubes can also be used in medical, food, semiconductor and other industries heat exchanger tubes.

Disadvantages: expensive, raw materials rely on imports