"Setting and Selection of Safety Valve" (HG/T 20570.2-95)

1. Pressure vessels with the maximum operating pressure at the top greater than or equal to 0.1MPa; (pressure relief of pressurized vessels)

2. Distillation towers, evaporation towers and stripping towers with the maximum operating pressure at the top greater than 0.03MPa (except those where the steam at the top of the stripping tower is passed into another distillation tower); (pressure relief from negative pressure vessels)

3. The outlets of each section of the reciprocating compressor or the outlets of positive displacement pumps such as electric reciprocating pumps, gear pumps, screw pumps (except for those that have safety valves in the equipment itself) (pressure relief from booster equipment)

7. Steam generators and other steam-producing equipment or their outlet pipes;

9 Steam outlet pipe of the condensing turbine;

8. Low boiling point liquid (liquefied gas, etc.) containers or their outlet pipes;

5. Equipment where flammable gas or liquid expands when heated and may exceed the design pressure; (material pressure relief)

3. Equipment and pipeline systems where the accumulation of non-condensable gas generates overpressure; (gas phase pressure relief)

5. The cut-off valves at both ends are closed, and the liquefied hydrocarbons, Class A B, and B A liquid pipeline systems are thermally expanded or vaporized due to the influence of ambient temperature, sunlight radiation or heat tracing;

10. Low boiling point liquid enters a container containing high temperature liquid.

4. When the equipment connected to the outlet of the blower, centrifugal compressor, centrifugal pump or steam reciprocating pump cannot withstand its maximum pressure, the outlet of the blower, centrifugal compressor, centrifugal pump or steam reciprocating pump; (high pressure connected to low pressure, high pressure Side pressure relief)

2. When there is no safety valve at the source of the pressure material of the container;

3 Containers and pipelines whose design pressure is less than the pressure at the pressure source;

10 In some cases, due to leakage of the pump outlet check valve, resulting in overpressure, a safety valve is installed on the pump inlet pipe;

2. The cooling water or reflux is interrupted, or the reboiler inputs too much heat, causing overpressure in the gas phase pipeline at the top of the distillation tower; (abnormal pressure increase and decrease in temperature)

6. Cooling or stirring failure, catalytic impurities entering, reaction inhibitor interruption, causing the exothermic reaction to run out of control in the reactor or the piping system upstream of the shut-off valve at its outlet;

9. Pipeline rupture or leakage may cause overpressure on the low-pressure side of the heat exchanger or its outlet pipe;

1 Independent pressure system (separated from other systems with shut-off valve). The system refers to full gas phase, full liquid phase or gas phase communication;

7 Overpressure parts caused by process accidents, automatic control accidents, power accidents, fire accidents and public engineering accidents;

6. Equipment with a maximum top operating pressure of 0.03~0.1MPa should be set according to process requirements. (Replenish)

4. In the outlet pipe of the thermal oil furnace, the upstream pipe of the shut-off valve or regulating valve;

6. If there is a shut-off valve or control valve on the outlet pipeline of the heating furnace, a safety valve should be installed upstream of the valve;