Tube-in-tube condenser

Pipe-type condenser structure
The tube-type condenser is mainly composed of the outer shell, tube plate (also known as the header), tube bundle, and top cover (also known as the head). Parallel tube bundles are installed inside the circular shell, with the ends of the tubes fixed to the tube plate. The tubes are generally fixed to the tube plate using welding or expansion methods. The top covers equipped with inlet or outlet tubes are connected to the ends of the shell flanges with screws, forming a fluid distribution chamber between the top cover and the tube plate. It is widely used due to its simple and sturdy structure, ease of manufacturing, wide range of materials, high processing capacity, and strong adaptability.
During heat exchange, cooling water enters through the connection pipe at the top cover, flows inside the pipes, and this path is called the tube side; harmful vapor flows within the gap between the tube bundle and the shell, and this path is known as the shell side; the surface area of the tube bundle is the heat transfer area. In condensate recovery, whether it is the condensation of saturated vapor or the condensation containing non-condensable gases, generally speaking, condensation occurs in the shell side of the horizontal condenser because it is more reasonable in terms of heat transfer, pressure drop, and cleaning.

Tube-type Condenser Classification
(1) Fixed tube sheet heat exchangers: Simple and compact design, capable of withstanding high pressure, cost-effective, easy to clean the tube side, and easy to block or replace tubes when damaged.
(2) Floating head heat exchangers: Easy to clean inside and between pipes, without generating thermal stress.
(3) U-tube heat exchanger: Consists of a single tube plate with the tube bundle made up of multiple U-shaped tubes. Both ends of the tubes are fixed on the same tube plate, allowing for free expansion and contraction. No thermal stress is generated when there is a temperature difference between the shell and the U-tube heat exchanger.
(4) Sliding header heat exchanger: Simple structure, low cost, and can add baffles to the tube box as needed to enhance heat transfer.

Features of Tube-in-Tube Condensers
(1) Horizontal shell-side film heat transfer coefficients are several times higher than those of vertical tube internal or external films, and non-condensables do not accumulate in dead corners, making them easier to discharge.
(2) Cooling water flowing inside the pipes is conducive to cleaning scale. Water flow within the pipes ensures a higher velocity, which is beneficial for reducing the rate of scale formation and improving the heat transfer coefficient of the water film.
(3) Tube-in-tube condensers are used to position the lower tubes at the cooling water inlet, allowing condensate to accumulate at the bottom, thus reducing its temperature. In surface condensing systems, it is crucial to further cool the condensate. If the condensation system temperature is too high, upon contact with air, organic gases will volatilize excessively. Typically, the outlet temperature of the condensate should be 60℃ or lower. Of course, an additional cooler can be added, but this will increase costs.