Case Study

SOLEX™ Combustion System

At a Glance

John Zink Hamworthy Combustion (JZHC) successfully delivered the SOLEX burner combustion system, achieving less than 5 ppm NOx emissions and nearly zero CO emissions across a broad range of operating conditions.

The SOLEX™ combustion system is JZHC’s next generation NOx technology industrial burner for process heaters in general refining service, designed with two combustion zones to achieve single digit NOx emissions without traditional post-combustion treatment methods, such as selective catalytic reduction (SCR).


GS Caltex, the fourth largest refinery and largest aromatics producer in the world, wanted to reduce overall emissions at their Yeosu, South Korea site. They requested JZHC review the application and offer a solution for reducing CO and NOx emissions, while also eliminating SCR expenditure, in No.3 HOU Vacuum Residue hydrocracker, 612F – 401, a twin cell horizontal box process fired heater with common convection section.


The operator required less than 9 ppm NOx and no CO emissions across a wide operating range, without requiring an SCR.


To achieve the desired reduction in emissions, JZHC provided 32 SOLEX burners and associated combustion controls as a system solution.

• Minimal changes reduced overall installation cost and time
• Reduced operational expenses (OPEX) on SCR by $150,000
• Reliable with significant variation in unit operation
• Achieved continuous single-digit NOx emissions below 5 ppm
• Included burner optimization through next-generation advanced process controls


The existing 612F – 401 heater, a vacuum residue hydrocracker, is a twin cell horizontal box heater with a common convection section. This fired heater operated with 32 conventional low NOx burners. To comply with the recently updated local emission regulation, the heater had been upgraded to fire fuel gas only with an SCR, but GS Caltex wanted to reduce emissions further, targeting a NOx guarantee of single-digit ppm.

  • Annual OPEX for the SCR was $150,000. This made a burner-only solution highly desirable from a total value perspective. The proposed JZHC burner-only solution met the NOx goal by reducing the emissions by a factor of four.
  • Site NOx emissions were regulated on a site-wide basis. Reducing NOx on this high-duty unit meant the end user could apply the reduction credit for further plant-wide operating flexibility.
  • Varying process conditions, such as heater process swings, preheated combustion air (design temp 276°C) and high propane, high hydrogen refinery fuel gas, created challenges that a traditional Ultra Low NOx burner would struggle to meet.
  • All installation work had to be performed during a scheduled turnaround, so the solution had to be implemented quickly with minimal risk on startup.
  • GS Caltex desired retrofitting the existing system with minimal rework of the existing firebox.


  • 32 SOLEX burners were designed and fabricated in the JZHC Tulsa, OK USA manufacturing facility. These were shipped to the site to bolt up to existing mounting as a plug-and-play solution.
  • Under normal operation conditions, SOLEX combustion systems achieve an industry leading low NOx performance of below 5 ppm.
  • Installing the SOLEX combustion system resulted in a significant fuel gas rate reduction.
  • The solution involved repurposing combustion air ducting, minimally modifying the gas piping, and reusing instrumentation to reduce the overall project cost and meet the turnaround schedule.
  • JZHC site service team assisted in commissioning and startup of the system to ensure quick and reliable integration.
  • The SOLEX combustion control system was implemented for fully automatic control of the burners. This automation allowed the burners to progress through normal process swings and operating conditions.

Revolutionize Your Industrial Combustion System

Revolutionize Your Industrial
Combustion System

Discover the transformative SOLEX™ Combustion System – an industry-leading solution that achieves outstanding emissions performance without the need for traditional post-combustion treatments. With NOx emissions below 5 ppm and almost zero CO emissions across a wide range of operations, including ethylene processes, this technology is a game-changer for process burners.