In on-site operation and maintenance, insufficient heat transfer capacity and abnormally increased pressure drop of shell and tube heat exchangers are often encountered, mostly related to the failure to match actual working conditions during selection. The following key points are for selection reference.
It is necessary to confirm the name, flow rate, inlet and outlet temperatures, working pressure, and allowable pressure drop of the hot side and cold side media. If the medium is prone to scaling, the heat transfer area margin should be appropriately increased, and cleaning channels should be reserved.
Select fixed tube sheet, floating head, or U-tube structure according to temperature difference, thermal expansion, and maintenance frequency. The materials of the tube side and shell side are selected based on the corrosiveness of the medium, commonly carbon steel, stainless steel, or duplex steel.
Calculate the required area based on heat load and logarithmic mean temperature difference, and determine tube diameter, tube length, and number of tube passes in combination with flow velocity requirements. Too low a flow velocity is prone to scaling, while too high a flow velocity increases pressure drop.
Check the nozzle orientation, flange standards, and support type to ensure connection with on-site pipelines. For nitrate or alkali media, the voltage should be reduced when in solid state, and the rated voltage can only be connected after the medium is completely melted.
Note: The above information and technical parameters are sourced from Yangzhou Darui Electric Co., Ltd. for compilation and release.
