The relationship between low-nitrogen burners and boilers
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RT: I’m not very familiar with boilers. I would like to ask fellow sailors: Low-nitrogen combustion is an important aspect of environmental protection for boilers these days. But is it necessary to install low-nitrogen burners in order to achieve low-nitrogen combustion, or can any boiler do this? If older boilers may require modifications, then can new boilers achieve low-nitrogen combustion without any additional burners, or do they still need such burners? I would appreciate your further guidance. :)
The amount of nitrogen oxides produced depends only on the temperature of the outer flame of the burner, and is unrelated to whether it is a new or an old boiler. Low nitrogen oxide burners are of two types: fuel staging type and flue gas recirculation type.
Low-nitrogen burners have different requirements regarding furnace size compared to ordinary ones.
Low-nitrogen combustion is an important aspect of environmental protection for boilers today. But is it necessary to install low-nitrogen burners in order to achieve low-nitrogen combustion, or can any boiler do this? If older boilers may require modifications, then can new boilers achieve low-nitrogen combustion naturally, or do they still need low-nitrogen burners? I would appreciate your further guidance. . . . . . To address nitrogen oxides in boilers, low-nitrogen burners are just one method. Whether it’s an existing or new boiler, to solve this problem, installation is necessary. Other methods can also be selected based on the actual conditions of the boiler. New boilers can handle nitrogen oxides, so there’s no need to install anything additional.
It is necessary to refer to the local environmental protection standards; if no such standards exist, then the national standard \"Emission Standards for Air Pollutants from Boilers\" should be followed. Under the new national standards, the allowable emission level for NOx is 150 mg/m³, and most gas boilers can meet this requirement. In the Beijing area, if new installations are required to meet an emission level of less than 80 mg/㎥ according to local regulations, low-nitrogen burners must be used. To achieve low-nitrogen emissions with such burners, specific requirements are placed on the size of the furnace chamber; therefore, ordinary boilers need to be redesigned.
For pulverized coal boilers, low-nitrogen burners have requirements regarding the furnace height, as separate combustion air needs to be arranged.
A low-nitrogen burner is not new equipment added to the boiler; rather, it replaces the existing equipment in the boiler (although there are also some new components). Its function is to reduce the amount of NOx generated during combustion, thereby lowering the initial emissions of NOx. Its advantage is that it can reduce the pressure required for flue gas denitration (SCR, SNCR), decrease the amount of denitration chemicals and catalysts needed, and lower operating costs ； The downside is that, for different boilers and fuels, the low-nitrogen performance of the design scheme has its limits, and these limits generally fail to meet the required emission levels. So this is why, in the denitration upgrades of conventional (coal powder) boilers, low-nitrogen burners are modified, but it can’t be the only reason for such upgrades. Most older boiler burner designs did not take low-nitrogen effects into account; therefore, under the new emission standards, the original burners need to be modified into ones with low-nitrogen capabilities. These days, low-nitrogen burners are generally used in the design of new boilers. Of course, due to differences in expertise, it’s hard to say exactly how effective these low-nitrogen burners are; if they can ensure a low nitrogen level, then there’s no need for any further modifications.
According to your explanation, it means that the new boiler already has low-nitrogen combustion capabilities, so there’s no need to emphasize low-nitrogen burners any further – and this is exactly what concerns me. Since our company needs to install a boiler now, and we are in an area where strict limits on boiler emissions apply – with a nitrogen dioxide emission standard of 100 – and given the requirements for total emission control, the actual standard may be even lower. Therefore, we are interested in low-nitrogen burners, which raises the question of what level of denitrification efficiency SCR systems should achieve. Thank you for your answer
Low-nitrogen combustion is only meaningful when compared with current environmental protection standards; low nitrogen is just a concept, so specific numerical values are needed. How low, 100? 80? 50? This has a lot to do with the burner itself; the initial design remains pretty much unchanged, and as for how to deal with nitrogen oxides, there are many methods available. The simplest and most effective, as well as the most economical, method is to replace the burner. Some manufacturers claim to be able to achieve certain things, but this is just a way to deceive customers; therefore, it’s still necessary to consider the manufacturer’s capabilities and track record.
The nitrogen oxide standard in the Beijing area is currently 80mg, and it will be 30mg next year. This requires special technology in the burner to achieve it. This includes surface combustion technology and internal flue gas recirculation technology, and foreign manufacturers can ensure that their burners meet these NOx emission standards.
Is there a regulation for 30 in Beijing next year?