Callidus Burners

Meet NOx Reduction Requirements with Callidus Burners

For more than two decades, our design group has worked with global customers to develop the technology and solutions to some of their greatest NOx reduction challenges.



Callidus CUBL Burner Brochure


Callidus Scepter Pilot Brochure

Jade burner

Callidus Jade Burner Brochure

Callidus process burners are designed to meet NOx reduction requirements in refinery or petrochemical fired heater applications. Optimize your burner for more efficient use with our Next-Gen Ultra-Low NOx CUBL burners, Ultra-Low NOx line, Low-NOx line, Premix or Conventional Callidus raw Gas (CRG) burners.

Our custom burners fit almost any process heater application, including refinery heaters, reformers, ethylene cracking, and coker units.

Our computational fluid dynamics (CFD) modeling enables you to test burners in your furnace before building. We also offer 7 test furnaces at our R&D center for physical testing.

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Talk to us if you need equipment including pilots , flame monitoring equipment, burner management systems, and packaged fuel skids.


Ultra-Blue (CUBL) Burners

The advanced Callidus Ultra-Blue (CUBL) series of burners are specifically designed for each customer’s individual application and ensure maximum operational performance with minimum environmental impact, providing real value to refining and petrochemical industries.

Callidus CUBL process burners offer significant NOx reduction, maximum duty, excellent flame stability and wide turndown range. They also feature simple operation with minimum maintenance and a reduced physical footprint. There’s a next generation process burner for nearly every refining and petrochemical fired heater application.

Callidus Staged Gas Low NOx Burner – Improved Staged Gas Technology

UOP Callidus Staged Gas Low (CSGL) NOx Burner is a staged gas burner that uses an improved refractory flame holder design for greater stability and lower NOx emissions

Our engineers designed the CSGL burner to improve low NOx performance in a low maintenance, cost competitive piece of equipment. The CSGL burner utilizes Next Generation CUBL technology, which combines the conventional bluff body eddy zone with stabilization channels, notches, ledges and stagnation zones.

Performance – The CSGL was designed to meet the operating performance of traditional staged gas technology and to improve upon the stability, flame and NOx performance.

Stability – Extremely stable flames equivalent to those of conventional burner. The CSGL can achieve 10 to 1 turndowns and can operate on natural gas to as low as 66% of stoichiometry.

Flame Length – The CSGL technology produces a flame length in-line with traditional staged gas technology. The typical flame length of the CSGL is 1.56 m/MW.

NOx Performance – The CSGL produces NOx figures approximately 50% lower than traditional staged gas technology.

Two Main Advantages Resulting from the CSGL Tile Design

1. No Metallic Components Exposed to Flame: The flame stabilization mechanism on the CSGL is built directly into the burner tile, which is rated for 3,000° F.

2. Improved Stability: Unlike traditional staged fuel technologies, the CSGL tile is designed to form a flame on the air stream periphery, where the primary and secondary gases are separated by the tile and combine above the tile to form a continuous flame. This improves the flame stability, high and low excess air tolerance, and turndown capability.

Low NOx Burners

Our Low NOx Burners incorporate a mechanism for reducing the peak flame temperature relative to premix and conventional burners. This reduction in peak flame temperature results in lower NOx emissions.

Peak flame temperature is most commonly reduced by separating combustion into multiple zones, referred to as “stages.” A gas-firing low NOx burner typically has Primary and Secondary combustion zones. A combination gas/oil firing burner incorporates Primary, Secondary and Tertiary flame zones.


Callidus Low NOx Burners Feature:

  • Low NOx emission levels
  • Longer flame length than Conventional or Premix burners
  • Uniform heat flux transfer to process tubes
  • Capability to burn a wide range of fuels
  • Multiple firing orientations (vertical up or down, horizontal)

Typical Low NOx Burner Applications:

  • Where low NOx emissions are required
  • Where uniform heat flux distribution is important
  • Heater retrofits for the purpose of NOx reduction

Callidus Low NOx Burner Models:

  • CSG (Callidus Staged Gas)
  • CSGC (Callidus Staged Gas Combination)
  • COB-SA (Callidus Oil Burner – Staged Air)

Specialty Burners

Among many process heater types and configurations,  a few are so unusual in design and required performance, that a highly specialized burner is needed. One of our areas of expertise at  Callidus Technologies  is the development of high-quality burners for unique furnaces.

Specialty Burner applications include:

  • Coker Furnaces
  • Cracking Furnaces
  • Reforming Furnaces
  • UOP Platforming Furnace

Premix Burners

In a Premix burner, the fuel and air needed for combustion are drawn together and mixed prior to discharge from the burner tip.


Callidus Premix Burner Features:

  • Short and compact flame
  • High stability
  • Automatic fuel and air ratio control
  • Small size
  • Multiple firing orientations (vertical up or down, horizontal)

Typical Premix Burner Applications:

  • Cracking and Reforming furnaces
  • Furnaces with low available draft at the burners
  • Where a short flame pattern is desirable


Callidus Premix Burner Models:

  • CARW (Callidus Aerodynamic Radiant Wall)  Rising fuel in the heater negatively impacts the ability if the stage to down-fire.
  • LE-CARW (Low Emission)  Fuel jet energy brings about aspiration of its own combustion air, mixing with fuel prior to combust

Callidus Technologies has multiple solutions for the removal of sulfur compounds, both regenerative and non-regenerative. Let us help you determine the right solution for your application. Please contact us for more information

Conventional Burners

In a Conventional burner, the fuel and air needed for combustion are mixed in the throat of the burner where ignition and oxidation reaction occurs. There is a single flame zone.

In contrast, Low NOx burners typically use multiple flame zones.

Callidus Conventional Burners Feature::

  • Short flame length
  • Mechanical simplicity
  • High stability
  • High turndown
  • Capability to burn a wide range of fuel gases and oils
  • Small burner size
  • Multiple firing orientations (vertical up or down, horizontal)

Typical Conventional Burner Applications:

  • Where a short flame pattern is desirable
  • Where stringent NOx emissions are not required

Callidus Conventional Burner Models:

  • CRG (Callidus Raw Gas).
  • CRGC (Callidus Raw Gas Combination)