Calciner Addons

Combustion Chamber

Looking to go large with your alternative fuels? Our Combustion Chamber bolts-on to your existing calciner and allows you to integrate significant amounts of coarse alternative fuels into your process, even those challenging materials that need a very high ignition temperature.

Meal from penultimate cyclone

Humboldt combustion burner

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Combustion air inlet

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Meal inlet

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Tertiary air connection

Swirl air inlet (tangential)

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Combustion chamber

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Product Features

Effectively handle large quantities of coarse alternative fuels without impeding calciner performance or increasing maintenance risks. Interested? Read on.

Product Features

High temperature, extra retention time

The Combustion Chamber uses tertiary air as swirl and hot combustion air. Additionally, the Combustion Chamber contains a dedicated burner. This way temperatures of 1200 °C can be achieved – high enough to ignite even the most difficult of alternative fuels. Meanwhile, the use of tertiary air inside the Combustion Chamber provides a high-oxygen atmosphere to aid combustion.

At the same time, particles are retained in the Combustion Chamber long enough to ensure the ignited fuel particles lose sufficient mass to entrain in the air flow. This makes sure the extra energy ends up where it is wanted: in the calciner.

Product Features

Handle bulky alternative fuels

The less pre-processing of alternative fuels is required, the more cost-effective their use. At the same time, the fewer maintenance interventions are needed, the more efficient and productive the process overall.

The Combustion Chamber balances both concerns. Equipped with our mechanically-fed Humboldt Combustion Burner, it can handle even very bulky alternative fuels, with little needed by way of pre-processing, while mitigating the risk of blockages.

Product Features

Extend refractory life

All that heat is going to be hard on any refractory. To help protect it, we have designed the Combustion Chamber in such a way that the raw meal forms a curtain in front of the refractory. This autogenous protective layer reduces wear, ensuring trouble-free maintenance and much longer refractory life.

The raw meal curtain is created using tertiary air introduced into the Combustion Chamber in a tangential swirl. Depending on the size of the chamber and the available space in the preheater, the swirl air can be introduced via a single or double inlet.

Key Benefits

Take advantage of lower fuel costs, greater flexibility in fuel selection, low maintenance requirements – and reduce your carbon footprint.

Key Benefits

Flexible fuel selection

When it comes to alternative fuels, it pays not to be too fussy: ideally, you are able to use whatever is available with as little pre-processing as possible. It keeps the costs down and the substitution rates up.

The Combustion Chamber brings that flexibility. The high temperatures, oxygen-rich atmosphere and ability to handle coarse particle sizes enable you to fire a wide range of materials, including more complex materials, such as those with low calorific values.

Expanding your range of fuel options also makes procurement easier and lower cost, while you future-proof yourself against variation in the available types of alternative fuels. That is important as more and more will be recycled, meaning the types and qualities of materials available as fuel is likely to change over time.

Key Benefits

Low maintenance

Maintenance means downtime. Which means lost production and potentially expensive repairs. We have already mentioned the raw meal curtain, which protects the refractory lining – so you spend less on refractory replacement and your maintenance crews spend less time on the hazardous job of removing and replacing it.

The large fuel intake reduces the risk of downtime due to blockages to a minimum – another maintenance win. There are also no moving parts inside the combustion zone, reducing the chances that anything will go unexpectedly wrong. All in all, maintenance on the Combustion Chamber is unlikely to be keeping you up at night.

Key Benefits

Ideal upgrade for Pyroclon® Lownox AF calciners

The Combustion Chamber is the perfect upgrade option for our Pyroclon® Lownox AF calciners, as it can be retrofitted without major changes to the existing preheater building

Key Benefits

Reduce your carbon footprint

Lowering carbon emissions with alternative fuels is becoming an increasingly important business – as well as environmental – priority. For example, reducing your carbon intensity insulates you against the risk of future regulatory tightening. It could also help open up access to capital from sustainability-minded financial institutions. And it demonstrates responsible practice to your local communities and stakeholders, supporting your social licence to operate.

Discover more about how KHD technologies are reducing the environmental impact of cement on our Clean Solutions page.

Performance Data

Is the Combustion Chamber for you? Check out the performance data below. Or contact us to talk to an expert.

Fuel Mass Flow & TSR

2800 mm 15-25 TPH* 50-60 %*
3400 mm
4200 mm
5000 mm
*Achievable mass flow (alternative fuel feed) and thermal substitution rate depends on the individual pyroprocess and the used fuel types.

Usable Fuel Particle Sizes

Waste oil / Animal meal / Sewage sludge
Biomass max. 40x40x10 mm (3D)
Plastics max. 40x40x10 mm (3D)
RDF / Fluff max. 100×100 mm (2D)
Tire Chips max. 70x70x25 mm (3D)
Whole Tires x

How it works

Coarse fuel enters the Combustion Chamber, where optimized combustion conditions ensure fuel particles lose sufficient mass to entrain in the main calciner airflow.

Exhaust Gas (high NOx level)

Lean Gas (high CO level)

Tertiary Air (high O2 level)

Gas after combustion and calcination (low NOx, CO and O2 levels)

  1. Pyrotop®
  2. Penultimate cyclone
  3. Bottom cyclone
  4. Fuel feed
  5. Tertiary air duct
  6. Rotary kiln
  7. Meal to kiln
  8. Meal to combustion chamber
  9. Combustion chamber
  10. Oxidizing zone


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