Pulp & Paper



Metals Processing

LWA & Minerals

Oil & Gas


CFD Modelling

Engineering Services

Combustion Equipment

Site Services



KFS is now part of Metso

Find Out More

Combustion Equipment


Rotary Kiln Burners

For use with Gas, Liquid and Solid fuels.


A simple and elegant design that uses well established and proven changes in fuel/air mixing intensity to provide flame control. The Metso KFS designs avoid the complex mechanical adjustment mechanisms which are essential in the standard burner one-size-fits-all approach and avoids potential for local operations or maintenance to adjust incorrectly.

The primary air is split between axial air, for flame length and heat flux control, and swirl air for flame anchoring. A highly efficient aerodynamic swirler provides excellent flame stability. Each OptiMix™ burner is supplied with an integral pilot, including the extremely reliable natural gas or propane model.

The simplicity of the OptiMix™ design ensures that consistent performance is available over the lifetime of the burner.

The OptiMix™ range is custom-designed for firing all fuel types, either individually or in combination.

OptiMix™ G

For a wide range of gaseous fuels. Dual gas discharge locations ensure fine control on gas firing applications and turndown of over 20:1 ensuring the burner can be used in cold starts for refractory curing.

OptiMix™ L

For conventional liquid fuels, such as #2 to #6 oils and including waste and re-refined oils. Using the proprietary CM atomiser offers at least 8:1 turndown using either steam or air atomisation. The PJ atomiser is specific for pressure jet applications. For alternative liquid fuels Metso KFS offer the WS Atomiser with air/steam-assist atomisation.

OptiMix™ S

For pulverised coal and petcoke. Already a world leader in the pulp and paper industry where Metso KFS have burners firing natural gas, petcoke, methanol, and turpentine simultaneously. OptiMix™ S can also be designed to accommodate all types of solid alternative fuels such as lignin.


Focused particularly in the lime and cement industries, this advanced burner technology provides a straightforward retrofit to upgrade the performance of direct-fired systems or straight-pipe burners.

Developed using CFD Modelling, the DFN (direct-fired nozzle) burner has been proven across many projects to provide outstanding improvements in areas such as production, fuel consumption, NOx emissions, and ash ring formation.

Each DFN burner is custom-designed for the kiln both in terms of process performance and mechanical installation. High levels of performance are provided by careful use of bluff-body and swirl techniques to enhance fuel/air mixing combined with far greater flexibility than traditional straight-pipe.

The DFN burner can be provided in a number of variants to suit specific customer requirements or applications:

  • DFN nozzle for simple retrofit for solid fuel firing, including alternative fuels such as lignin.
  • DFN with integrated warm-up burner for all types of gas and liquid fuels. Ignition systems can be provided using a gas pilot or high-energy igniter, and fully-automated ignition can be achieved through use of insertion and withdrawal mechanisms.
  • DFN with semi-direct firing for enhanced system flexibility and NOx reduction. Metso KFS can provide full process design and equipment specification for conversion to semi-direct firing with a number of system variants available to suit each customer application burners. 


The Metso KFS warm-up combustion system provides a safe and effective method to heat a rotary kiln from cold start through to main fuel firing. The Metso KFS system is ideal for existing rotary kiln operations based on straight pipe burner technology.  

A key to a safe kiln warm-up is the ability to provide a stable flame for an effective and controlled heat release profile. The Metso KFS HeatSafe Burner (HSB) design is based on the proven Metso KFS OptiMix™ integrated kiln burner design operating in over 100 rotary kilns.

The HSB can be gas or oil fired and incorporates a dependable source of ignition with a proprietary design fuel nozzle and high efficiency air swirler to provide easy light-off and a stable flame under variable kiln conditions.

The burner can be mounted using a mono-rail, trolley or rollers, with motorised insertion/retraction available for most options.

Supporting the burner’s dependable flame stability are the associated fuel and primary air systems. Supervision of start-up, shutdown and operation of the HSB burner is provided by a Burner Managements System (BMS), which is fully compliant with the latest applicable standards. 


Ancillary Equipment

As part of system design, Metso KFS offers a number of ancillary equipment items which enhance or complete the combustion system upgrade. Options are available for process and detailed design only, or full equipment supply:

Fuel Handling

Valve trains for all gaseous and liquid fuels, and solid fuel storage and feed systems, all in accordance with customer and local specifications, and meeting appropriate regional standards.

Metso KFS NCG lances

Custom-designed to handle single or multiple streams (SOG, HVLC, LVHC, etc) to minimise impact on main burner and kiln.

Primary Air Systems

Fans and associated equipment with FM/EN approved thermal mass flowmeters used to accurately and reliably monitor primary air flowrates essential in maintaining optimum combustion performance.

Flame Scanners

Use of state-of-the art FM/EN approved ultra-violet (UV) and infra-red (IR) systems sourced in North America or Europe.

Burner Management Systems

Provision of PLC-based systems for single and multi-fuel applications in compliance with North American, European or other specific standards.

Igniter Systems

Natural or propane gas pilots for continuous or intermittent use, high-energy ignitors with automatic retraction system operation while also resolving issues such as ring formation.

Selective Non-Catalytic Reduction (SNCR)

Design and supply of SNCR systems for installation on combustion systems to reduce NOx emissions, utilising our in-house CFD Modelling capability to optimise injection lance arrangements.

Find Out More


+44 (0)1494 450539


© Metso UK Ltd. All Rights Reserved
Company Number: GB 706152855

Website by tr10.com