A cost-effective, efficient in-line calciner that reduces NO_X emissions

Whether you are planning to build a new plant or upgrade your current calciner, the FLSmidth Low NO_X Calciner provides the best value of any calciner on the market. Its unique design allows for optimum NO_X reduction, reduced wall build-ups and lower operational costs.

With a goal to optimise production costs, our Low NO_X Calciner has been enhanced for operational stability, availability and combustion efficiency.

NO_X regulations are continuously being tightened around the world. Meeting NO_X emissions limits is therefore a key demand for cement producers, not only because NO_X-related issues, such as smog pollution, have a direct impact on the local society, but also because your plant’s license to operate is directly linked to its NO_X emissions.

The Low NO_X Calciner helps you significantly reduce NO_X emissions from your cement plant operations.

Reliable operations

Build-up of raw meal on the calciner's walls is a common operational challenge in calciners. It requires cleaning and can even cause unexpected shut-downs. Our Low NO_X Calciner is designed to abate this issue. It features a unique way of introducing material into the reduction zone and the lower calciner, which protects the walls from build-ups, while also maintaining a hot core for excellent combustion and NO_X reduction.

Extensive research and field tests

The unique design of the Low NO_X Calciner is the result of extensive research. We have combined comprehensive field tests with Computational Fluid Dynamics (CFD) modelling to develop the most efficient calciner in the market.

This includes the ability to burn almost any type of fuel – coal and natural gas, petcoke, and most solid and liquid waste fuels.

Full lifecycle support

Throughout the lifecycle of your Low NOX Calciner, we can provide the support necessary to ensure it delivers on its promise. From planning and implementation to maintenance and supply of spare parts, you can rely on expert support from our global organisation, when and where you need it.

Our Low NOX Calciner will have a significant long-term impact on your plant operations. Working closely with you, our experienced engineers ensure the calciner delivers to your operational goals. 

How the reduction zone works

Fuel is injected into the kiln riser below the tertiary air inlet at the base of the calciner. The volume between the fuel inlet and tertiary air inlet has an oxygen-deficient atmosphere that promotes NO_X reduction. The reduction zone is designed for optimal operation temperatures and adequate gas retention time. The temperature in the reduction zone is controlled by a material split from the second-lowest stage. This material split is also used to prevent potential build-ups in the kiln riser and the reduction zone.

Main calciner vessel

Located above the reduction zone is the main calciner vessel, which is divided into two or more sections separated by a notch. The changes in cross-sectional areas create turbulence that ensures effective mixing of fuel, meal and gas, improving heat transfer and combustion. The calciner outlet loop duct ensures optimum gas retention time, effective mixing and complete fuel burnout.

You also have the option to split the second-lowest or third-lowest stage cyclone material to allow for diversion of a portion of the meal into the upper section of the calciner. This creates a “hot zone” in the lower section of the calciner that boosts the burning of difficult fuels and further NO_X reduction.

Multiple fuel inlets

Multiple fuel inlets ensure optimal distribution between the kiln gases and the fuel.

To achieve the best distribution between the kiln gases and the fuel, there are multiple coal inlets (four or six, depending on plant size). Better fuel distribution provides optimal mixing, which gives the highest average cross-sectional temperature without any build-up problems.

Our Low NOX Calciner has the flexibility to burn almost any type of fuel. This includes traditional fuels, including coal and natural gas, more difficult-to-burn fuels, such as petcoke, and most solid and liquid waste fuels. All of these fuel types are burned while achieving low NOX and CO emissions.

Reduction zone and meal inlets

For optimal NOX reduction and minimised wall build-ups, the reduction zone has a round design with two raw meal inlets.

The round design of the reduction zone with two raw meal inlets is the result of extensive modelling using Computational Fluid Dynamics (CFD). This has provided the optimum design to maintain a cool outer wall and hot inner gas core. Wall build-ups and maintenance cleaning costs are minimised, while the highest possible average temperature in the core can be attained for optimal NOX reduction.

Lower calciner

Based on field experience and CFD modelling, the unique design of the lower calciner optimises dispersion of the raw meal into the gas stream. An optional meal split also allows the bottom section of the calciner to operate as a hot zone, further improving combustion and lowering NOX emissions when burning difficult fuels such as petcoke or solid waste fuels.