Heat exchanger and Pressure Vessel design_Singapore

The simplest category of heat exchangers, STHXs are made up of one tube or multiple in parallel (known as a tube bundle of tubings encased inside a cylindrical chamber (the shell). These devices are designed in such a way that at least one is a flow of the first fluid through the small tube while the second fluid flows outside and over the inner surface of this tube as well as between the tubes in the enclosed chamber. Other design characteristics offered for this kind of heat exchanger are finned tubes, single or two phase transfer, counter current, co current or cross current flow patterns, single, two or multiple pass. The categories of shell and tube heat exchangers include helical coil heat exchangers and double pipe heat exchangers while some uses include preheating, oil cooling, and steam production. Shell and tube heat exchanger applications The following is a description of more uses of the shell and tube heat exchanger; A detailed view of a heat exchanger tube bundle. Heat exchanger tube bundle with a view at the microscale.

A class of shell and tube heat exchangers, double pipe heat exchangers are the simplest heat exchangers both in terms of design and layout and a utilize two or more concentric pipes or tubes, one being a larger outer tube and the other one or more inner tubes. This is in accordance with the design of all shell and tube heat exchangers in which one fluid circulates through the smaller tube(s), and the other fluid moves on the outside of the smaller tube(s) within the larger tube.
The design features that Double pipe heat exchangers share from the previous two types- recuperative and indirect contact are that the two fluids remain separated and flow through their own channel for the entire heat exchange process. Nevertheless, the double pipe heat exchangers are not very rigid when it comes to flow arrangements as they can be designed for cocurrent as well as countercurrent and can be used either in series, parallel or in series parallel arrangement in a system

It is also called as Plate type heat exchangers where several corrugated thin plates are grouped in a heap. Each pair of plates forms a passage where one of the fluids can pass while the pairs are bound and overlapped and connected, by bolting, brazing or welding in a way that they also form a second passage for the other fluid to pass through.
The standard plate is also available with modifications in the design such as in the plate fin or the pillow plate heat exchangers. The plate fin type of exchangers have raised or lowered fins or spacers on the plates and can have more than two arrangements of flow and more than two fluids passing through the exchanger. Pillow plate exchangers normally use pressure upon the plates in order to enhance the heat that needs to be transferred across the surface of the plates. Other types include; Plate and frame heat exchangers, Plate shell heat exchangers, and spiral plate heat exchangers.

Boilers, condensers and evaporators are heat exchangers which operate in two-phase heat transfer process. In single phase heat exchangers, one or both fluids may undergo phase changes while in the two-phase heat exchangers, heat transfer involve phase change such as conversion of the fluid from liquid to gas or vice versa.
Condensers are heat exchanging equipment’s that condense the hot gas or vapor by cooling it so as to convert it to liquid form. On the one hand, in evaporators, and boilers, the heat exchange transforming the fluids in the liquid phase to gas and vapour phase.

Heat exchangers are used in many different application types of the diverse branches of industries. Therefore it is possible to note that there are several types off heat exchangers available depending on the demand and the peculiarity of the certain program. Apart from the types of heat exchangers that have been described above, other other types of heat exchangers include air cooled heat exchangers, fan cooled heat exchangers and adiabatic wheel heat exchangers.