What are they and what is their purpose?
A heat exchanger is a device used to transfer heat between two or more fluids.
There are different categories of tubular heat exchangers; one of the most common is the shell and tube exchanger.
A shell and tube exchanger consists of a number of tubes mounted inside a cylindrical shell.
Two fluids can exchange heat: one fluid flows over the outside of the tubes while the second fluid flows through the tubes. The fluids can be single or two phases and can flow in a parallel or a cross/counter flow arrangement.
The shell and tube exchanger consists of four major parts:
- Front end (header distributor), where the fluid enters the tube side of the exchanger
- Rear end, where the tube side fluid leaves the exchanger or where it is returned to the front header in exchangers with multiple tube side passes
- Tube bundle composed of tubes, tube sheets, baffles and tie rods to hold the bundle together
- Shell where the fluid enters the shell side of the exchanger; this contains the tube bundle.
Mechanical Design and Construction
Shell and tube heat exchangers shall be designed according to the most common international code, such as ASME VIII div.1 or Div. 2 or BS 5500, or EN13445 and Tubular Exchanger Manufactures Association (TEMA) Standard.
Shell and tube exchangers are normally made of carbon steel or stainless steel, depending on the type of application and fluids.
Heat exchangers can be supplied complete with inlet and outlet valves, drain and vent valves, pressure and temperature gauges, according to customer’s request.
Exchanger sizing is carried out by means of sizing program like Hysys or HTRI, to guarantee thermal efficiency and process performance.
In 44 years of life Forain has produced a lot of shell and tube heat exchangers which have been installed in almost all the countries of the world, in onshore and offshore plants.