Common Causes of Overpressure in Pressure Vessels

I. Operational and Equipment Factors

1. Safety Device Failure: Pressure gauges and safety valves are not calibrated on schedule or are corroded and stuck, resulting in loss of pressure relief function.

2. Control System Failure: PLC program errors or pressure sensor drift cause continuous gas supply or false alarms.

3. Illegal Modification: Using scrapped containers for modification, with substandard materials and wall thickness, resulting in tensile strength of only 72% of the standard value.

II. Environmental and Media Factors

1. Sudden Temperature Changes: Intense sunlight can cause the pressure inside the tank to rise by 0.05 MPa per hour, as seen in the case of an oilfield accident in Xinjiang where the pressure suddenly increased from 0.8 MPa to 1.4 MPa.

2. Media Characteristics: Liquefied gas evaporates due to heat or uncontrolled chemical reactions (such as exothermic polymerization), leading to pressure increases.

III. Human and Management Deficiencies

1. Operational Errors: Failure to close valves, misjudging pressure gauge readings, or overfilling (such as overfilling of liquefied gas tanks).

2. Management oversights: Failure to conduct regular inspections; unlicensed operators; or deliberate disabling of the alarm system.

IV. Design and manufacturing defects

The container itself has problems such as insufficient material strength and unreasonable structure, making it prone to rupture under overpressure.