WorkSafe , Alberta has published a safety bulletin titled "Controlling explosion hazards in vessels, tanks and piping systems. The following is mentioned:
"Two workers were welding an overflow pipe on top of a tank truck that contained residual flammable materials. Welding sparks ignited the materials, the tank exploded and the workers were killed. The explosive atmosphere in the tank had not been tested prior to the workers beginning their work. The tank previously contained produced water.
A vessel was purged with natural gas to remove hydrogen sulphide. The vessel was opened and a worker was washing the inside of the vessel with a water wand. A pyrophoric iron reaction on the demister pad started to release sparks inside the vessel. An explosion occurred and the worker was fatally injured.
Iron sulphide is a pyrophoric material. This means that it can spontaneously ignite when exposed to air. It is created when iron oxide (rust) is converted into iron sulphide in an oxygen-free atmosphere where hydrogen sulphide gas is present or where the concentration of hydrogen sulphide (H2S) exceeds that of oxygen.
When iron sulphide is subsequently exposed to air, it is oxidized back to iron oxide and either sulfur or sulfur dioxide gas is formed. This chemical reaction between iron sulphide and oxygen generates a considerable amount of heat. In fact, so much heat is released that individual particles of iron sulphide become incandescent and glow. This heat can ignite nearby flammable mixtures.
Most refineries experience spontaneous ignition of iron sulphide either on the ground or inside equipment. Pyrophoric iron fires most commonly occur during shutdowns when equipment and piping are opened for inspection or maintenance. Iron sulphide fires can be avoided by preventing the sulphide from contacting air. This can be achieved by maintaining a continuous layer of liquid or inert gas between the material and the air. Inerting vessels with nitrogen gas is one such method.
A vessel containing hydrogen sulphide was purged with propane. The workers then opened the vessel for clean-out. When the manway was opened, an explosion occurred resulting in the four workers receiving burns to their faces and hands. The possible source of ignition that caused the explosion was static discharge or metal-to-metal contact"
Read the Workplace health and safety bulletin in this link
Contribute to the surviving victims of Bhopal by buying my book "Practical Process Safety Management"
"Two workers were welding an overflow pipe on top of a tank truck that contained residual flammable materials. Welding sparks ignited the materials, the tank exploded and the workers were killed. The explosive atmosphere in the tank had not been tested prior to the workers beginning their work. The tank previously contained produced water.
A vessel was purged with natural gas to remove hydrogen sulphide. The vessel was opened and a worker was washing the inside of the vessel with a water wand. A pyrophoric iron reaction on the demister pad started to release sparks inside the vessel. An explosion occurred and the worker was fatally injured.
Iron sulphide is a pyrophoric material. This means that it can spontaneously ignite when exposed to air. It is created when iron oxide (rust) is converted into iron sulphide in an oxygen-free atmosphere where hydrogen sulphide gas is present or where the concentration of hydrogen sulphide (H2S) exceeds that of oxygen.
When iron sulphide is subsequently exposed to air, it is oxidized back to iron oxide and either sulfur or sulfur dioxide gas is formed. This chemical reaction between iron sulphide and oxygen generates a considerable amount of heat. In fact, so much heat is released that individual particles of iron sulphide become incandescent and glow. This heat can ignite nearby flammable mixtures.
Most refineries experience spontaneous ignition of iron sulphide either on the ground or inside equipment. Pyrophoric iron fires most commonly occur during shutdowns when equipment and piping are opened for inspection or maintenance. Iron sulphide fires can be avoided by preventing the sulphide from contacting air. This can be achieved by maintaining a continuous layer of liquid or inert gas between the material and the air. Inerting vessels with nitrogen gas is one such method.
A vessel containing hydrogen sulphide was purged with propane. The workers then opened the vessel for clean-out. When the manway was opened, an explosion occurred resulting in the four workers receiving burns to their faces and hands. The possible source of ignition that caused the explosion was static discharge or metal-to-metal contact"
Read the Workplace health and safety bulletin in this link
Contribute to the surviving victims of Bhopal by buying my book "Practical Process Safety Management"
No comments:
Post a Comment