Tube-in-tube condenser

Tubular Condenser Structure
The tube-type condenser is mainly composed of the outer shell, tube plate (also known as a header), tube bundle, and top cover (also known as a head). Parallel tube bundles are installed inside the circular shell, with the tube ends fixed on the tube plate. The method of fixing the tubes on the tube plate is usually by welding or胀管法. The top cover, equipped with import or export tubes, is connected to the outer shell flanges at both ends 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, broad material range, high processing capacity, and strong adaptability.
During heat exchange, cooling water enters through the connection pipes at the top cover, flows within the pipes, and this path is called the tube side; harmful vapors flow within the gaps 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 condensate recovery, whether it's the condensation of saturated vapor or the condensation with non-condensable gases, in general, the condensation on the shell side of the horizontal condenser is more reasonable, as it is more suitable in terms of heat transfer, pressure drop, and cleaning.

Tube-in-tube Condenser Types
(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 Exchanger: Easy to clean inside and between pipes, without generating thermal stress.
(3) U-tube Heat Exchanger: Featuring only one tube plate, the bundle consists of multiple U-shaped tubes, with both ends of the tubes fixed on the same 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-condensibles do not accumulate in dead corners, making them easier to discharge.
(2) Cooling water flowing through pipes is convenient for cleaning scale. Water flow within pipes ensures a higher velocity, which is beneficial for reducing scale formation and increasing 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 for temperature reduction. In surface condensing systems, it is crucial to further cool the condensate. If the condensing system temperature is high, there will be significant volatilization of organic gases upon contact with air. The general requirement for the outlet temperature of the condensate is 60°C or lower. Of course, an additional cooler can be added, but this would entail additional costs.