According to the GB/T 151 "Heat Exchangers" standard, the heat transfer capacity and pressure drop characteristics of shell-and-tube heat exchangers are calculated based on medium operating parameters. During the model selection and verification stage, technical engineers can confirm item by item against the following parameter checklist.
It is necessary to record the chemical names, mass flow rate or volumetric flow rate, inlet and outlet temperatures, working pressure, and allowable pressure drop of the hot side and cold side media. When the flow fluctuation range exceeds ±15%, it should be specified separately. For media containing particles or prone to fouling, reference values for the fouling coefficient should be supplemented.
The GCH-120 heat exchanger has a nominal heat transfer area of 120 m², a tube-side design pressure of 2.5 MPa, a shell-side design pressure of 1.6 MPa, and a design temperature of 200°C. The heat exchange tube specification is Φ25×2.5 mm, the tube length is 6000 mm, and the tubes are arranged in a equilateral triangle pattern. During actual model selection, the required area should be back-calculated based on the system heat load and a 10%~20% safety margin to avoid insufficient area or excessive surplus.
The tube-side flow velocity is recommended to be controlled at 1.0~2.5 m/s, and the shell-side flow velocity at 0.3~1.0 m/s. Too low a flow velocity tends to aggravate fouling, while too high a flow velocity increases pressure drop. The allowable pressure drop should be determined in conjunction with the pump or fan head, and should not be selected based on experience alone.
It is necessary to confirm the maintenance space, tube bundle withdrawal direction, and cleaning method. If the medium is prone to fouling, chemical cleaning interfaces should be reserved or a removable channel head structure should be adopted. The above parameters are for reference in model selection and verification, and actual use should be combined with the system heat load and safety margin.
