Would you like to permanently reduce your NOx emissions with a one-time investment and no increase in operational cost?
You should continue reading!

01 Introduction

What is Pyroredox and how does it work?

Pyroredox is a gasifying reactor that is installed between the kiln inlet chamber and the calciner. Our product optimizes the pyro process by separating reactions which are normally happening collectively in the calciner. By doing that Pyroredox supports the formation of desired chemical compounds at particular points in the pyro process to influence subsequent reactions. As a result, our gasifying reactor creates the ideal environment to significantly and permanently abate NOX emissions.
That is pretty great! Do you know what is even greater? Pyroredox has absolutely no negative impact on your clinker production capacity, fuel consumption and power demand! Well, we said you should continue reading, right? Below you’ll find even more great things to learn about Pyroredox!
02 Benefits

We’ve got a ton of arguments why the upgrade of Pyroredox is a no-brainer!

  • One-time investment solution that doesn’t increase operational costs
  • Pyroredox (as standalone solution) achieves emission levels below 200 mg/Nm³
  • In combination with an SNCR system <150 mg/Nm³ NOX is easily achievable
  • NOX reduction potential (of Pyroredox combined with a SNCR system) is in line with SCR system, but at a much better price
  • Absolutely no negative effect on production capacity, power demand and fuel consumption
  • Works with typical calciner fuels and even low volatile (flyable) alternative fuels
  • Can be retrofitted in almost any existing plant
  • No reagent cost (resp. reduced cost when Pyroredox is combined with an SCNR system)
  • Erection takes just 16-30 weeks and can be conducted while plant remains in operation
  • Commissioning and final process implementation takes between two and four weeks and can be done during a regular maintenance shutdown
03 In-Depth Functionality

What happens in my pyro process with Pyroredox?

01 | It all starts with a substoichiometric combustion

At the beginning of the Pyroredox loop we force a substoichiometric combustion by adding high amounts of fuel early in the process. The fuel reacts with the kiln exhaust gases which leads – thanks to the abundance of carbon (C) from the fuel – to the formation of a lot of carbon monoxide (CO). This is the so called Boudouard reaction and one of two essential steps for permanent NOX abatement with Pyroredox.


02 | Good things take (extra) time.

Thanks to the extended retention time that Pyroredox adds to your pyro process, the carbon monoxide can now develop its full denox potential while reacting with the existing NOX compounds in the kiln exhaust gases. That leads to the formation of naturally occuring, harmless nitrogen (N2) and the permanent reduction of NOX emissions in your production process!


03 | The typical reaction, but with the right prelude.

After the kiln exhaust gases have been reduced, the remaining lean gas is fed into the calciner where tertiary air and the raw meal is added. At this point the classic oxidation of the lean gases and the high-oxygen tertiary air takes place. This exothermal reaction is the final step in the calciner and ensures the thorough meal calcination.


04 | It’s all about the process. The devil is in the details.

Thanks to our profound process knowledge, KHD specialists will ensure that Pyroredox has the perfect size to offer the highest NOX reduction potential for your specific plant and production. Moreover, our process experts will find the best fuel injection concept that ensures a controllable and repeatable chemical reaction of the kiln exhaust gases, fuel and raw meal.

04 Case Study

It’s time to talk numbers!

An exemplary Pyroredox case study in China

We conducted various Pyroredox installations in China. Let’s put Pyroredox’s performance into tangible results: In a 5.500 tpd plant with an existing SNCR system, Pyroredox permanently reduced NOX emissions by a stunning 66% and ammonia reagent consumption by an even higher 78%!
We’re pretty excited about this. And you should be too!

Performance before
Pyroredox operation

Performance with Pyroredox
(no optimized fuel scenario)

Performance with Pyroredox
(with optimized fuel scenario)**

NOx emissions:
150 mg/Nm³
NOx emissions:
50 mg/Nm³
NOx emissions:
35 mg/Nm³
Ammonia demand:
2100 l/h
Ammonia demand:
400 l/h
Ammonia demand:
450 l/h

**The numbers from the optimized fuel injection are based on a conservative scenario.
That means the performance that Pyroredox can ultimately achieve is even lower!

And we have to repeat ourselves here:
Pyroredox makes all that possible without negatively affecting production capacity, power consumption or fuel demand.

05 Contact

Contact Form

If you want to get more out of your plant, it’s time to discuss your personal use case with our Pyroredox experts. Get in touch!

Don’t want to wait until we call you back? Take the initiative and get in touch today!

Norbert Streit
Director Process Innovation

Phone: +49 221 6504 1367
Mobile: +49 152 09 111 561

E-Mail: norbert.streit@khd.com