Industries benefiting from EnviNOx® – Proven N2O and NOx reduction for a cleaner future

Smart technology with maximum flexibility

The EnviNOx® process by thyssenkrupp Uhde is a proven and versatile solution for the effective reduction of nitrogen oxides (NOx) and nitrous oxide (N2O) in industrial exhaust gases.

Originally developed for nitric acid plants, this advanced catalytic process has since been successfully adapted for the off-gas cleaning of a wide range of chemical and energy-related applications – including caprolactam, adipic acid, niacin production. In addition, EnviNOx® is being further developed for future use in ammonia combustion and cracking processes, supporting the transition toward carbon-free energy.

Because nitrous oxide is approximately 270 times more potent than carbon dioxide and already accounts for approximately 8% of global warming, reducing these emissions is essential for climate protection. The United Nations Environment Programme (UNEP) warns that “without urgent action on rising N2O emissions, there is no viable pathway to limiting warming to 1.5 °C” (UNEP, 2024).

EnviNOx® addresses this challenge by offering a flexible, cost-effective, and industry-proven solution for abating N2O and NOx from industrial off-gases – supporting both compliance and long-term sustainability goals.

1. Nitric acid plants – Proven success for over two decades

The EnviNOx® process was first developed for nitric acid production – one of the largest sources of industrial N2O emissions worldwide.
With dozens of commercial references across the globe and more than 20 years of continuous operation, EnviNOx® has become the industry standard for nitrous oxide abatement in nitric acid tail gas treatment.

Key advantages

  • Compatible with all plant types: atmospheric-pressure, medium-pressure, dual pressure, and high-pressure.

  • Handles tail gas temperatures from 200 °C to 600 °C, as well as varying compositions and load conditions.

  • Achieves high conversion efficiency and reduced operating costs, especially when combined with secondary measures for N2O decomposition.

By integrating EnviNOx®, nitric acid producers can cut N2O emissions by more than 99 % – significantly reducing their greenhouse gas footprint and contributing to global climate protection efforts.

2. Caprolactam production – Reliable emission control for complex processes

Caprolactam, the precursor for nylon-6, presents unique challenges for emission reduction due to impurities in its production process.
The EnviNOx® system has proven highly effective in both Raschig (HSO) and HPO (hydroxylamine-phosphate-oxime) processes, offering tailored process and catalyst designs that handle contaminants such as sulfates and phosphates.

Benefits for caprolactam producers

  • Efficient tertiary abatement of both N2O and NOx across all process stages.

  • Customized catalyst configuration ensures stable performance, even with fluctuating gas compositions.

  • Proven commercial success with reference plants operating reliably for nearly 15 years.

This flexibility makes EnviNOx® the preferred solution for producers seeking reliable, low-maintenance compliance with tightening emission standards.

3. Ammonia combustion and cracking – Enabling low-emission hydrogen applications

As the global hydrogen economy evolves, ammonia is gaining importance as a carbon-free energy carrier.
When ammonia is used as a fuel – for heating purposes in industrial processes, as in ammonia cracking units or for NH3 fueled engines – significant NOx and N2O emissions can occur.

The EnviNOx® process uniquely addresses these emissions, enabling the virtually emission-free use of ammonia as energy vector.

Key Features

  • Treats exhaust gases containing large volumes of NOx, N2O, and unburned ammonia.

  • Designed to meet ultra-low emission standards for NH3-fired plants.

  • Integral component of the uhde® ammonia cracking process, supporting clean hydrogen generation.

By integrating EnviNOx®, operators in the energy and mobility sectors can achieve both regulatory compliance and tangible climate protection.

4. Energy and other chemical industries – Broad applicability and custom design

Beyond traditional chemical processes, EnviNOx® technology can be adapted to a wide variety of industrial and energy-generation environments.
Different process configurations and catalyst types allow for optimal performance in low-temperature and low-pressure exhaust gas conditions.

Applications and Advantages

  • Ideal for off-gas purification in specialty chemical plants such as niacin or other fine chemicals.

  • Compatible with CO or VOC oxidation systems for comprehensive exhaust gas cleaning systems.

  • Enables measurable reduction of greenhouse gases across diverse process streams.

The broad adaptability underlines the system’s strength as a modular emission-control platform capable of addressing complex environmental challenges across multiple sectors.

Smart technology for sustainable industry

What makes EnviNOx® truly unique is its ability to combine high efficiency, process flexibility, and long-term reliability within a single, integrated system.
Continuous development ensures that the technology remains future-proof, ready to support emerging industries that demand clean, efficient, and climate-neutral production.

By choosing thyssenkrupp Uhde, operators benefit from:

  • Decades of engineering and process expertise.

  • Proven industrial references worldwide.

  • Tailored solutions that integrate seamlessly into existing plants.

  • Maximum emission reduction with minimum operating costs.

Conclusion: Ready for the next step toward climate protection

From nitric acid to caprolactam, ammonia, and energy – EnviNOx® demonstrates how one technology can deliver meaningful climate protection across industries.
Its adaptability and proven performance make it a cornerstone solution for reducing N2O and NOx emissions on the path to a more sustainable future.

Contact us to learn how EnviNOx® can help decarbonize your plant operations and meet your emission targets.