Low NOx burners are designed to reduce the production of nitrogen oxide by controlling fuel and air mixing or reducing the peak flame temperature relative to premix and conventional burners. These burners offer improved burning efficiency, leading to 3% saving on fuel costs.
 

To control fuel combustion which accounts for 30% of all nitrogen oxide emitted in the atmosphere, the Seoul Metropolitan Government held the business owners responsible for managing the emission at large-scale sites and introduced a cap on the total amount of emission. However, it was difficult to apply the same measures to small business owners.

Expanding Support to Install Low NOx Burners
Since 2008, Seoul city government provided support to small- and medium-sized enterprises that switched to low NOx burners. After the general measures against air pollution were adopted in 2009, SMG encouraged more businesses to switch to low NOx burners moving away from the previous focus on industrial boilers to include burners at public facilities and those installed in heating and cooling devices.
In 2010, conventional burners inside household boilers, chillers and heaters, multi-unit dwellings, and drying facilities (limited to indirect heating equipment) were also switched to low NOx burners. From 2012, SMG decided to give preferential support to business operators with greater capacity and older equipment and from 2013, the city government strengthen the criteria for low NOx burners from 50ppm of NOx emission to 40ppm.
 
Providing Subsidy to Small- and Medium-sized Businesses
If small- and medium-sized enterprises, non-profit organizations, foundations, commercial building owners or residents of multi-unit dwelling switch the conventional burners installed in their boilers, heating or cooling devices, and drying facilities to low NOx burners, the city government will provide a subsidy of KRW 4.2 million to 21 million to reduce their financial burden.
 
Follow-Up Measures to Manage the Installed Low NOx Burners
For 2 years after the installation of low NOx burners, SMG will conduct follow-up inspections to check if the burners are in operation and if there are any changes in the subsidy provided to the businesses. Depending on the follow-up plan, performance test will be carried out for some targeted sites. If the NOx emission of the site exceeds the set criteria, the business owner, burner manufacturer, and the regulatory body will conduct a joint investigation to identify the cause. If mechanical problems are detected in the process, necessary repair works will be provided. Moreover, a special agency will be commissioned to conduct a re-inspection of the site and if the site fails to meet the criteria, the burner at the site may be delisted from the accredited low NOx burner list.

Lowering the Atmospheric Concentration of Carbon Dioxide
If the burner installed in an LPG-fired steam boiler with a capacity of 1ton/h is replaced with a low NOx burner, the emission of nitrogen oxide was found to drop by 186kg a year. From 2008 to 2014, SMG replaced 2,827 conventional burners with low NOx burners, leading to 1,188 tons of reduction in nitrogen oxide emission and the decrease in carbon dioxide concentration from 0.038ppm from 2008 to 0.033ppm in 2013.
 
Contributing to Seoul’s One Less Nuclear Power Plant Initiative
Switching low NOx burners leads to greater thermal efficiency, thereby saving 25,906 TOE of energy each year and contributing to Seoul’s One Less Nuclear Power Plant initiative.
 
Reducing Greenhouse Gas Emissions
Switching the burners of conventional boilers with 1~10ton/h capacity to low NOx, LNG burners will lead to 281,791ton less emission of carbon dioxide, which translates into a significant reduction in greenhouse gas emission. This is particularly meaningful considering the implementation of the Emission Trading Scheme in the near future. Switching to low NOx burners can be classified as an emission-reduction project under the Clean Development Mechanism (CDM), creating a revenue of KRW 220 billion for 10 years. To calculate this figure, the CER price was estimated at KRW 25,000 per 1 ton of carbon dioxide. Given the projected price increase of CER, greater revenue can be expected from this project.