Hydrogen emissions
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If hydrogen is released and diluted with air, what needs to be taken into consideration? If the hydrogen outlet is a vertical branch outlet that leads upward into the main air duct (horizontal), will an explosive noise occur?
If hydrogen is released into the atmosphere, a flame arrester should be installed on the outlet pipe, with venting at a high position； Control the pipeline flow rate so that it is not too fast; for specific requirements, refer to the \"Design Specifications for Oxygen Stations\". If the hydrogen outlet is a vertical branch duct that leads upward into the main duct (which is horizontal), no explosive noise will occur if the design is proper.
Hydrogen released should be diluted with nitrogen.
When releasing it, nitrogen is used for dilution, but the amount of nitrogen cannot always be guaranteed; therefore, some companies use steam to ensure safety.
The previous nitrogen generator was used for dilution with nitrogen gas.
Options available: 1. Dilution with nitrogen, which is more costly； ⒉Steam dilution is used, offering low costs and ease of operation ； ⒊Entering hydrorefining for development and utilization is economically reasonable ； ⒋Discharging it into the fuel gas network for resource recovery is more economical. ⒌It must not be diluted with air; don’t harm others or yourself. This post was last edited by Zhongyuanren on 2009-3-8 08:50]
Agreed. But there is a question: since air enters the main duct along a vertical direction, is it necessary to seal the air inlets? The hydrogen flow rate mentioned here is not very high, at 2 m3/h; therefore, it is more economical to dilute it with air, as there is little value in recovering it.
While controlling the gas flow rate, low-pressure steam should be introduced to prevent combustion
1. Dead zones must be prevented in the main air duct； 2. The flow velocity generally does not exceed 8 m/s ； 3. Anti-static measures must be in place ； 4. Prevent contact with open flames; install flame arresters on the main pipelines during evacuation, and take lightning protection measures in higher locations ； 4. Purge with nitrogen or steam before maintenance.
One approach is to install a flame arrester along with steam, or to connect a steam line directly to the hydrogen vent line. In my opinion, releasing the hydrogen mixed with steam can dilute its concentration at the time of venting; moreover, steam can extinguish fires. This method is both convenient and less costly than using nitrogen, so it can be widely adopted :)