Determination of heat exchanger type
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Current design: The design pressure for the shell side is 1.0 MPa, with an operating pressure of 0.3 MPa; the design temperature is 110 degrees, and the operating temperature is 12 degrees. The fluid used is chilled water. The design pressure for the tube side is 0.5 MPa, with an operating pressure of 0.3 MPa; the design temperature is 140 degrees, and the operating temperature is 71 degrees. The fluid in this section is highly hazardous. The heat exchange tubes are of type 19X2, with a total of 180 tubes. According to the regulations, it should be classified as Category II – is this correct? Please advise! Thank you
Check whether the pipe medium has reached its boiling point or is in gaseous state; if so, determine whether the PV product has reached 0.2 – if it has, it should be classified as category three
The tube side and shell side should be classified separately, and the requirements of the higher category shall be followed! I think category two is the correct one!
The tube medium is not clear, making it difficult to classify.
I think it should be determined based on the piping medium; as mentioned on the 2nd floor, first decide whether to classify it or not, and then decide whether it belongs to category two or category three.
Why is the design temperature set so high? Also, what is the medium inside the pipe? There are three important criteria for classifying containers: the medium, volume, and pressure
I think it should be classified as a type II pressure vessel. For this heat exchanger, the tube side should be considered; based on pressure, it should be classified as Category 1. However, since the medium is highly hazardous, its classification should be elevated by one category, so it is correct to classify it as Category 2.
“For multi-chamber containers, the pressure chamber with the highest pressure level is used as the category for that container, and management is carried out according to this category. Therefore, the container category should be determined based on the conditions in the piping system; with a design pressure of 0.5 MPa, it constitutes a low-pressure container. The medium used is highly hazardous. According to Article 6 of the Container Regulations, if the PV product is greater than or equal to 0.2 MPa·m3, it falls under category three pressure containers； If the PV product is less than 0.2 MPa·m3, it belongs to category II pressure vessels. Last edited by Yajiong on 2009-3-1 11:26.]
A brief discussion on the types of tubular heat exchangers: Tubular heat exchangers include coiled tube heat exchangers (immersed coiled tube heat exchangers, spray-type heat exchangers), shell and tube heat exchangers, and tube bundle heat exchangers. Tubular (shell-and-tube) heat exchangers are the most widely used type of heat exchanger in chemical manufacturing today. Main advantages: large heat transfer area per unit volume, excellent heat transfer performance, simple structure, high operational flexibility, ability to be manufactured from various materials, and strong versatility; tube-type (shell-and-tube) heat exchangers are particularly commonly used in high-temperature, high-pressure applications as well as in large-scale installations. When the temperature of the two fluids exceeds 50°C, thermal stress may cause equipment deformation, pipe bending, or even rupture; therefore, thermal compensation measures should be taken. Depending on the heat compensation method, the main types of shell and tube exchangers are as follows: Fixed-tube-sheet type (fixed-tube-sheet exchanger with heat compensation rings): The tube sheets at both ends of the exchanger and the shell are integrated, which makes it difficult to clean the shell side; therefore, it is required that the fluid in the shell side be clean and free from scaling, with a temperature difference between the two fluids of less than 70°C. U-tube heat exchanger: In a U-tube heat exchanger, each tube is bent into a U shape; the fluid inlets and outlets are located on opposite sides of the same end, and the end cap is divided into two chambers using a partition. Each tube can stretch and contract freely. Suitable for high-temperature and high-pressure environments where cleaning the inside of the pipes is difficult; therefore, it is required that the fluid inside the pipes remain clean and free from scaling.
First and foremost, it is necessary to meet the three essential requirements governed by the Compliance Regulations; failing to satisfy even one of these requirements means that the item cannot be classified, regardless of the type of medium involved； Only then can it be classified based on the classification criteria. I agree with the view from the second floor to a certain extent.
Check whether the pipe medium has reached its boiling point or is in gaseous state; if so, determine whether the PV product has reached 0.2 – if it has, it should be classified as category three； I strongly agree with this view.
Containers should be classified based on factors such as the medium, volume, and pressure, right?