Why is N2 used instead of air for transporting coal powder in dry coal powder gasification?
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:Handshake, as the title says, thanks!
The gasification reaction is actually a combustion reaction; the heat released during combustion can be largely controlled. However, when dry coal powder comes into contact with air, the two conditions necessary for combustion are present: the combustible material, namely coal powder, and the oxidizing agent, namely air (oxygen). If air is used for transportation, friction between the coal powder and the pipes can generate sparks that may exceed the ignition point of the coal powder, leading to combustion in mild cases and explosions in severe cases. I don’t think anyone would use air to transport coal powder! :handshake
I agree with the view from the second floor; coal powder in contact with oxygen, combined with friction, can easily lead to safety accidents.
Simply put, coal dust is a combustible powder; when mixed with air, it poses a risk of dust explosion
It will explode, comrade. Isn’t a dust explosion even more dangerous?
Preventing dust explosions – that’s really impressive!
Yes, inert gas must be used to prevent explosion accidents.
Coal powder cannot be transported by air because it can cause dust explosions, which falls under the scope of dust explosion prevention. This is what we commonly refer to as the explosion triangle. As the name implies, three conditions must be present for an explosion to occur. First: dust concentration; an explosion can occur only when the dust concentration reaches the minimum threshold required. Second: oxidizers, that is, oxygen; an appropriate oxygen concentration is the second condition necessary for an explosion. Third: a source of ignition; sources of ignition can be either open flames or non-open flames. Sparks are a source of ignition, and static electricity, being a form of non-flame ignition, is also a source of ignition.
If a hydrogen-containing gas such as syngas is used, will it explode? If hydrogen is used to transport the coal powder in a dry coal powder fluidized bed pressurized gasification furnace, will the reaction C+2H2=CH4 occur, thereby increasing the CH4 content to suit coal-based alternative natural gas?
The main reason is actually that the coal powder is too fine, meaning its specific surface area is very large, which accelerates the reaction rate! Dust explosions can easily occur in a confined space!