Valve flash explosion refers to specific conditions, the valve or its surrounding space within the instantaneous violent explosion phenomenon. This explosion is usually sudden, high intensity and destructive, posing a serious threat to personnel, equipment and production environment.

Causes

1. Accumulation of combustible gas

When there is a combustible gas leakage in the piping system where the valve is located, the combustible gas may accumulate in the confined space around the valve. If the leakage of combustible gas concentration reaches the explosive limit range, encountering an ignition source will trigger a flash explosion.

For example, in the pipeline system to transport natural gas, liquefied gas and other combustible gases, if the valve seal is not tight, gas leakage in the valve well, the operation room and other relatively closed space accumulation, may form an explosion-hazardous environment.

2. Electrostatic build-up and discharge

In the fluid (especially flammable liquids) through the valve process, due to the fluid and the valve wall, spool and other parts of the friction, may produce static electricity. If the static electricity can not be channeled away in a timely manner, accumulated to a certain extent, when the electrostatic discharge generated spark energy is large enough, it may ignite the surrounding combustible gases or flammable vapours, triggering flash explosions.

For example, in the petrochemical industry, the pipeline system to transport flammable and explosive liquids, valves are prone to static electricity, if there is no good grounding measures for static electricity, it may lead to flash explosions.

3. High temperature triggered by spontaneous combustion

In some special circumstances, the valve may be due to external sources of ignition, friction heat and other reasons leading to local temperature rise. If the valve near the existence of low spontaneous combustion point of substances, such as some combustible dust, grease, etc., may be in the role of high temperature spontaneous combustion, which in turn triggered a flash explosion.

For example, in some high-temperature process piping system, the valve if there is no good thermal insulation measures, may make the surrounding combustible material to reach the spontaneous combustion temperature, triggering flash explosions.

Second, the hazards

1. casualties

Valve flash explosion generated by the powerful shock waves and flying debris may cause serious injury to nearby operators, and even life-threatening. For example, the fragments generated by the explosion may hit the human body, resulting in cutting injuries, puncture wounds, etc.; shock waves may cause personnel to be thrown up, hit the surrounding objects, resulting in fractures, craniocerebral injuries, etc..

2. Equipment damage

Flash explosion will cause serious damage to the valve and the surrounding pipelines and equipment. Valves may be blown up, damaged, resulting in pipeline rupture, leakage, further triggering a larger accident. For example, the flash explosion may cause damage to the sealing structure of the valve, so that the pipeline fluid leakage, pollution of the environment, or even cause a fire or explosion.

3. Production interruption

Valve flash explosion often leads to the interruption of the production system, bringing huge economic losses to the enterprise. Repair of damaged equipment and pipelines require time and money, at the same time, production interruption may also affect the upstream and downstream production links, resulting in a chain reaction.

Preventive Measures

1. Prevent combustible gas leakage

Ensure that valves have good sealing performance, conduct regular inspections and maintenance, and replace damaged seals in a timely manner.

Carry out pressure test and leakage detection on piping system, and find and repair the leakage point in time.

2. Static electricity protection

In the piping system for transporting flammable and explosive fluids, install static grounding devices to ensure that static electricity can be conducted away in time.

Control the flow rate of the fluid to reduce the generation of static electricity.

3. Eliminate ignition sources

Strictly control the ignition sources around the valve, prohibit smoking, use of open flames or operations that may produce sparks in the flammable and explosive areas.

Explosion-proof design and installation of electrical equipment to prevent electrical sparks caused by flash explosions.

4. Good ventilation

Ensure that the space where the valve is located is well ventilated, remove the leakage of combustible gases in a timely manner to reduce the concentration of combustible gases.

In places where combustible gas may accumulate, install combustible gas detection and alarm devices to detect dangerous situations and take measures in time.

5.Training and Emergency Management

Conduct safety training for operators to improve their safety awareness and emergency handling ability.

Formulate a perfect emergency plan and conduct regular drills to ensure that emergency response can be carried out quickly and effectively in the event of a flash explosion accident.