Environmental regulation of industrial and commercial boilers is getting tighter and more difficult to achieve without compromising operations. The implementation of environmental controls, either at the combustion source or post-combustion, has many undesirable limitations that impose considerable economic costs.
Operators of industrial boilers today must spend tens of thousands or even hundreds of thousands of dollars per boiler for NOx controls and then suffer an efficiency penalty, paying very high ongoing operating and maintenance expense along with decreased productivity to meet stringent US and European air quality regulations.
ClearSign estimates there are 34,000 large commercial and industrial firetube boilers installed in the US alone today, averaging 21 MMBtu/h each — some 60% of which are located in air quality 'non-attainment' regions. Many of these systems in non-attainment regions are required to emit no more than 9PPM of NOx with other regions requiring no more than 5PPM (with the rest of the country expected to follow). To reach 9ppm NOx today, these systems must be modified with a combination of Ultra-Low NOx burners (ULNBs), External Flue Gas Recirculation (EFGR) and systems to control and monitor their performance. To reach 5ppm, either the entire boiler burner system needs to be replaced, or a Selective Catalytic Reduction (SCR) system must be added.