Low-nitrogen retrofitting of gas boilers
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Gas boilers require low nitrogen emissions; how to carry out the modification?
In practice, it involves replacing a burner system, and the scope of work is generally not very large.
Replace the burner, the gas pipelines, and the control system as well
Enlarged furnace, replaced burner (pre-mixed)
For the low-nitrogen retrofit of gas boilers, low-nitrogen burners are generally installed, and in cases where higher performance is required, flue gas recirculation is employed.
The NOx generated during the combustion of gas in gas boilers is mainly of the thermal type. The key factors determining the amount of thermal NOx produced are the combustion temperature and the oxygen-rich air required for combustion. Therefore, the key technique for controlling NOx generation by burners is to optimize the mixing process of fuel and oxygen-rich air in order to reduce local high temperatures in the furnace. Current gas combustion technologies mainly include staged combustion, premixed combustion, flue gas recirculation, porous medium catalytic combustion, and flameless combustion.
Replace with a low-nitrogen burner; such burners utilize a combination of three techniques – fuel staging, flue gas recirculation, and air staging – to reduce nitrogen oxides