ClearSign has installed the ClearSign Core™ technology into three Once Through Steam Generators (OTSG) in central California.

A California based customer approached ClearSign interested in applying the technology to meet the area’s strict emissions regulations. The initial field application scaled the bench scale burner with a firing rate of 250,000 Btu/hr to a 62.5 MMBtu/hr production unit with an emissions target of sub 6 ppm NOx (corrected to 3% O2, volume, dry)(all further emissions numbers will be corrected values). During commissioning and final testing for all three units, ClearSign technology delivered emissions as low as 2.2 ppm NOx and generally in the 3-5 ppm NOx range (all corrected to 3% O2, volume, dry).  The technology is proven to be uniquely flexible and easily tuned after installation to dial-in desired NOx performance.

Installation One – 2015
The first OTSG installation represented ClearSign’s first field demonstration of what had previously been lab development with lab-based testing and results. Automated controls were installed allowing the operators to simply push a local button to start the unit and another button to shut the unit down. Following commissioning, the design was updated and turned over to the customer with stable operation and emissions results of <6 ppm NOx, <10 ppm CO, well below the local requirements. This was achieved without the use of external flue gas recirculation, catalyst or significant excess air.

Installation Two – 2016
Following the success of the first unit, a second identical unit was retrofitted into a nearby identical OTSG and yielded the same impressive emissions performance and improved performance efficiency.

Installation Three – 2018
A third unit was also retrofitted but added a co-firing of low-Btu waste gas containing H2S. Similar to the first unit, both of these units have been in near continuous operation and achieving sub 6 ppm NOx (corrected to 3% O2, volume, dry). In many operating cases, emissions testing revealed approximately 2.5 ppm NOx which eliminated the necessity of a SCR system as a NOx solution to meet the regulatory requirements. The third installation featured an advanced mechanical design of the ClearSign Core™ technology that eliminated the need for field welds and featured a bolt in solution. This advancement helped reduced field installation to two days.

ClearSign Core™ Solution Results
In order to quantify the effects of the new technology on the existing equipment, the customer measured the process data before and after the retrofit of the ClearSign technology. Based on their data and calculations, the addition of the ClearSign Core™ technology increased the overall heater efficiency by at least 3%. It also eliminated the need for External Flue Gas Recirculation reducing the electrical consumption of each unit. By increasing the heater efficiency and reducing the electric load then end user is able to realize reduced fuel gas and utility costs while simultaneously achieving class-leading emissions performance.