Heating furnace ignition
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Question I encountered while answering just now: Before igniting the heating furnace, after the combustible gas in the furnace chamber has been found to be within acceptable levels, steam purging is still required. Could you explain it?
The purpose of purging is to prevent the presence of combustible gases before ignition; if their concentration exceeds the explosive limit, hazards such as deflagration or explosion can occur.
Thank you for the reply! My question is: Since tests have already analyzed the level of flammable gases in the furnace and confirmed that it is below 0.5%, why is it still necessary to perform steam purging of the furnace?
It’s better to be prepared for the worst. From a safety perspective, the safer, the better.
It’s all for safety, to prevent the flammable gases generated during the testing process from reaching their explosive limit
It’s just double insurance; there’s no need to worry about it. Often, what seems like an extra step that serves no purpose is actually just a way of enhancing safety
Purging before starting up is a standard procedure to prevent flammable gas explosions when restarting the system after it has been shut down during operation, as a safety measure.
Steam purging is necessary to ensure safety, because sometimes, even though an analysis shows that everything is fine, there may still be residual areas where flammable gases or liquids have not evaporated; introducing steam helps to eliminate such risks.
When starting up the arching furnace here, we purge the furnace chamber with steam; once steam is seen coming out of the chimney for 10 minutes, it’s possible to start the furnace, as this prevents flash explosions caused by combustible gases in the furnace chamber.