Heat Exchange Pressure Vessels

Only vessels simultaneously meeting the following three conditions can be classified as pressure vessels:

1. Operating pressure greater than or equal to 0.1 MPa (Note 1-2); 

2. Volume greater than or equal to 0.03 m³ and internal diameter (for non-circular cross-sections, refers to the geometric dimension of the inner boundary) greater than or equal to 150 mm (Note 1-3); 

3. Containing media that are gases, liquefied gases, or liquids with maximum operating temperature higher than or equal to their standard boiling points (Note 1-4). 

Note 1-2: Operating pressure refers to the maximum pressure (gage pressure) attainable at the top of the pressure vessel under normal operating conditions.

Note 1-3: Volume refers to the geometric capacity of the pressure vessel, calculated based on dimensions marked in design drawings (excluding manufacturing tolerances) and rounded to whole numbers. It generally excludes the volume of internal components connected inside the vessel.

Note 1-4: When the vessel contains liquid with maximum operating temperature below its standard boiling point, it still falls under this regulation's scope if the vapor space volume is greater than or equal to 0.03 m³.

Pressure Classification

Design pressure (p) of pressure vessels is categorized into four pressure levels:

(1) Low pressure (Code L): 0.1 MPa ≤ p < 1.6 MPa

(2) Medium pressure (Code M): 1.6 MPa ≤ p < 10.0 MPa

(3) High pressure (Code H): 10.0 MPa ≤ p < 100.0 MPa

(4) Ultra-high pressure (Code U): p ≥ 100.0 MPa

Category Classification

Pressure vessels are classified based on their functional principles in production processes into: reaction pressure vessels, heat exchange pressure vessels, separation pressure vessels, and storage pressure vessels. Detailed classifications are as follows:

(1) Reaction pressure vessels (Code R): Vessels primarily used for completing physical/chemical reactions of media, including reactors, reaction kettles, decomposition pots, vulcanizing tanks, decomposition columns, polymerization kettles, autoclaves, ultra-high pressure autoclaves, synthesis towers, shift converters, cooking digesters, spherical digesters, autoclaves, and gas generators.

(2) Heat exchange pressure vessels (Code E): Vessels primarily used for completing heat exchange of media, including shell-and-tube waste heat boilers, heat exchangers, coolers, condensers, heaters, sterilizers, dyers, drying cylinders, frying pans, preheating vessels, solvent preheaters, steamers, desolventizers, electrothermal steam generators, and gas generator water jackets.

(3) Separation pressure vessels (Code S): Vessels primarily used for fluid pressure balance buffering and gas purification separation, including separators, filters, oil collectors, buffers, scrubbers, absorption towers, copper scrubbers, drying towers, stripping towers, steam headers, and deaerators.

(4) Storage pressure vessels (Code C, spherical tanks Code B): Vessels primarily used for storing/containing gases, liquids, liquefied gases, etc., including various types of storage tanks.

When a pressure vessel simultaneously serves multiple functional principles, its category shall be determined by its primary function in the production process.