Shell and Tube Condenser

Tube-in-tube condenser structure
The tube-type condenser is mainly composed of the outer shell, tube sheet (also known as a header), tube bundle, and top cover (also called a head). Parallel tube bundles are installed inside the circular shell, with the ends of the tubes fixed on the tube sheet. The method of fixing tubes on the tube sheet is generally by welding or expansion. The top cover equipped with inlet or outlet pipes is connected to both ends of the outer shell flange with screws, forming a fluid distribution chamber between the top cover and the tube sheet. It is widely used due to its simple and sturdy structure, ease of manufacturing, wide material range, large processing capacity, and strong adaptability.
During heat exchange, cooling water enters through the connection pipe at the top cover, flows within 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 called the shell side; the surface area of the tube bundle is the heat transfer area. In the condensation recovery process, whether it is the condensation of saturated vapor or the condensation with non-condensable gases, generally, condensation occurs in the shell side of the horizontal condenser due to its reasonable performance in terms of heat transfer, pressure drop, and cleaning.

Tube-in-tube condenser classifications
(1) Fixed tube sheet heat exchangers: Simple, compact design; high-pressure resistance; low cost; easy tube cleaning; quick blockage or replacement in case of tube damage.
(2) Floating Head Heat Exchangers: Easy to clean both inside and between the tubes, and do not produce thermal stress.
(3) U-tube Heat Exchanger: Consists of a single tube plate with the bundle made up of multiple U-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 tube sheet heat exchangers: 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 coefficient is several times higher than that of vertical tube internal or external film, and non-condensables do not accumulate in dead corners, making them easier to discharge.
(2) The cooling water flowing inside the pipes is convenient for cleaning scale. Water flow through 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 condenser, positioning the lower tubes at the cooling water inlet and allowing condensate to accumulate at the bottom for temperature reduction. In surface condensation systems, further cooling of the condensate is crucial; if the condensation system temperature is high, organic gases will volatilize significantly upon contact with air. Typically, the outlet temperature of the condensate should be 60°C or lower. Of course, an additional cooler can be added, but this would increase costs.