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Clean air, strong impact.
The urgency of the climate crisis is reshaping how industries must act today. Greenhouse gas emissions, air pollution, and increasingly strict regulations demand innovative, sustainable solutions – not tomorrow, but now.
Nitrous oxide (N2O) is a powerful greenhouse gas – nearly 300 times more potent than CO2. Major industrial sources include processes such as nitric acid production, and removing these N2O emissions has a huge impact. With the patented EnviNOx® technology, thyssenkrupp Uhde provides tailored solutions to significantly cut N2O and NOx emissions close to zero. As NOx (nitrogen oxides) cause smog and respiratory diseases, this ensures compliance with the strictest environmental regulations while supporting climate goals.
With over a century of experience in chemical plant engineering and construction, we deliver a proven, reliable, and durable emission reduction technology. Due to its modular design philosophy, EnviNOx® integrates seamlessly into diverse industrial processes and is already in use at over 60 chemical plants worldwide. Recognized as an EU nominated Best Available Technology (BAT), EnviNOx® pays off ecologically as well as economically.
Your benefits: easy installation, cost efficiency, and rapid ROI
Seamless integration: EnviNOx® can be easily implemented in existing plants with minimal investment and low operating costs.
Tailored solutions: A modular design enables customized configurations to match your operational and business requirements.
Reliable performance: Durable, long-life catalysts and a hazard-free process minimize risks while lowering long-term costs.
Quick return on investment: Significant emission reductions and potential carbon credit revenues accelerate payback time.
60+ EnviNOx® systems already installed – cutting CO2 equivalents and NOx emissions in real time, every second.
From first idea to complete solution: everything from a single source
With experience from over 3,000 chemical plants and projects delivered worldwide, thyssenkrupp Uhde is your full-service partner for high-performance, future-ready solutions. From initial concept to long-term operation, we deliver everything you need – engineering, technology, integration, and support.
Our EnviNOx® system is based on a set of process modules that can be tailored and scaled to your exact needs, cutting N2O and NOx emissions down to near zero. With more than 60 systems successfully installed across various industries, EnviNOx® stands for proven technology, robust quality, and smooth implementation.
We don’t just provide a product – we provide a complete solution.
Highest N2O & NOx abatement rate (up to 100%) even at low/moderate temperatures
Non-toxic, long-life catalyst
Sounds interesting? We look forward to listening to your story, your challenge or your vision. We will be happy to answer your questions or talk about realization possibilities!
Our exclusive offering and portfolio include supplementary services such as financing, consulting, and support. We provide additional vast expert know-how and support at a single point, ensuring comprehensive assistance.
The EnviNOx® catalysts are at the core of the EnviNOx® process, enabling the effective abatement of nitrous oxide (N2O) and nitrogen oxides (NOx) by converting them into environmentally harmless components – nitrogen (N2), oxygen (O2), and water (H2O).
The unique catalysts used in the EnviNOx® process were developed by Uhde in cooperation with selected catalyst manufacturers specifically for the EnviNOx® process and have been continuously optimized over the years. In particular, distinct zeolite catalysts loaded with iron are used, which are highly active, thermally stable, and non-toxic, providing both high efficiency and operational safety. A specially trimmed oxidation activity prevents the unwanted slippage of NH3 when it is used as a reducing agent. Uhde-certified EnviNOx® catalysts evidently achieve expected lifetimes of 10 years and more in industrial practice.
For pressurized gases, such as the tail gas from HNO3 plants, EnviNOx® catalysts are typically used in pellet form, usually installed in radial basket reactors based on a proprietary Uhde design. For unpressurised exhaust gases, such as those found in caprolactam plants or in the combustion of NH3, EnviNOx® catalysts are utilized as monolithic honeycomb bodies encased in adapted metal modules to further minimize pressure losses.
All catalysts are quality-tested in thyssenkrupp Uhde’s central laboratory before delivery to ensure they are fully on spec and fit to the intended application.
The preferred pellet type catalyst DeN2O®-TK2 is exclusively produced by BASF for thyssenkrupp Uhde and features exceptional performance across a wide temperature range from 200 to 600 °C.
About BASF Chemical Catalysts and Adsorbents
BASF is a leading global manufacturer of catalysts for the chemical industry, with solutions across the chemical value chain. The business comprises chemical catalysts, adsorbents and custom catalysts. Priority is given to developing new and improved products that enable the chemical industry transformation to net-zero emissions. To learn more, visit www.chemical-catalysts-and-adsorbents.basf.com.
The most extensively used and best proven application of the EnviNOx® process is for the reduction of N2O and NOx in the exhaust gas of nitric acid plants. The EnviNOx® process can be used in practically all types of nitric acid plants, from atmospheric pressure nitric plants through mono-medium and dual-pressure plants to mono-high pressure plants. The possible exhaust gas temperature ranges from approx. 200 °C to approx. 600 °C. In the case of N2O reduction at temperatures below ca. 300 °C, recuperative heating of the exhaust gas can be employed. In HNO3 plants, the EnviNOx® process can also be ideally combined with secondary measures for N2O decomposition. This not only enables a reduction in the plant size of the EnviNOx® unit and respective cost, but also ensures the highest abatement rates, especially in partial load operation of the plants. For applications in nitric acid plants alone, there are more than 60 commercial scale references worldwide.
Similar to nitric acid production, exhaust gases from plants for the production of caprolactam contain not only NOx nitrogen oxides, but typically also considerable amounts of N2O. This results in an average of approx. 5–13 kg/N2O per tonne of product, which in most cases are released into the atmosphere without further abatement measures. Since N2O is not only generated in the NH3 combustion step (as in HNO3 plants) but also in downstream process stages in the production of caprolactam, the elimination of N2O together with NOx emissions using the tertiary EnviNOx® technology represents a universal and most preferred solution. However, depending on the type of production process for caprolactam, specific impurities in the exhaust gases, such as sulphates or phosphates, must be taken into account. The Uhde EnviNOx® process is also pioneering in this area as it has already been successfully installed in caprolactam plants for the removal of N2O and NOx in different plant types operated according to a modified Raschig process as well as the HPO process.
Ammonia (NH3) represents a promising alternative and carbon-free fuel, whether for direct heating purposes or in internal combustion engines, to drive forward the decarbonization of energy generation. However, an ecological and technical challenge with NH3 combustion is the formation not only of considerable amounts of NOx, but also the formation of significant amounts of N2O which jeopardizes the desired ecological advantage of CO2 avoidance. In addition, the exhaust gases from NH3 combustion generally also contain notable amounts of unburned NH3, which must also not simply be released into the atmosphere. The Uhde EnviNOx® process offers a unique solution to effectively eliminate NOx and N2O as well as NH3 emissions. As the combustion of NH3 typically runs at non-pressurized conditions, the EnviNOx® catalysts are used in honeycomb form, which are integrated in modules in the flue gas duct, for example.
One example is the successful adaptation of the EnviNOx® process for use in exhaust gas purification in Uhde's proprietary process for NH3 cracking. Here, NH3 is not only used for the cracking of NH3, i.e. hydrogen production, but also as a C-free fuel for fueling the NH3 cracking reactor. With the use of the Uhde EnviNOx® process, both NOx and N2O emissions can be reduced almost completely without any NH3 slip occurring.
In principle, the EnviNOx® process can be used to reduce NOx and N2O emissions in a wide variety of exhaust gases from industrial production plants or plants for energy generation. The area of application is neither limited to pressurized gases, as present in nitric acid plants, nor does the exhaust gas temperature form a crucial restriction. So, if necessary, the exhaust gas can simply be heated, ideally using the enthalpy of reactions released by the N2O and/or NOx reduction. This means that the EnviNOx® rector is arranged in a heat exchanger circuit in which the outgoing purified exhaust gas flow transfers its thermal energy to the incoming raw gas flow.
For other applications it might also be useful to combine the EnviNOx® process with other exhaust gas purification stages, e.g. for CO or VOC oxidation. For example, the EnviNOx® process has been successfully installed in a plant for the production of niacin, in which not only N2O and NOx are reduced, but also large amounts of CO are oxidized at the same time.
Our EnviNOx® system achieves very high rates of N2O and NOx removal, with N2O typically reduced by 98-99+% and NOx outlet concentrations below 1-10 ppmv, depending on the EnviNOx® variant. With a long catalyst lifetime of over 15 years, our technology allows for the reduction of emissions to virtually zero along with a sustainable and efficient operation.
EnviNOx® technology has been nominated twice as the best available technology (BAT) in the EU (2007) and USA (2012), underscoring its effectiveness and innovation.
Many EnviNOx® customers have been recognized as climate pioneers and heroes, highlighting the positive impact of our technology on their reputation. EnviNOx® dramatically reduces the carbon footprint, contributing significantly to emission reduction and climate protection through clever engineering know-how and expertise. This creates a win-win situation, offering both savings and environmental benefits. The reduction of N2O helps to achieve CO2 goals not only for the respective plant but for the entire production site, industry sector, and sometimes also for the entire country.
With our EnviNOx® system we offer moderate investment costs and a pricing model tailored to your specific requirements. We can optimize the product according to your needs, whether it's CAPEX, OPEX, or other technical or commercial requirements, with almost no limits. A fast return on investment is possible, depending on the individual design of the abatement system. This ensures that our customers can achieve their financial goals quickly and efficiently. Additional income can be generated by trading CO2 certificates.
Our catalysts are durable and non-toxic (chlorine-free), with each batch tested in our own laboratory according to high quality standards. This ensures the highest quality and safety.
thyssenkrupp Uhde selects construction materials for EnviNOx® equipment based on corrosion resistance and cost-effectiveness. We address special challenges posed by corrosive components in tail gas, such as sulfur compounds, through careful material selection and process configuration. EnviNOx® reactors can be supplied to all common design codes, including ASME and European PED. As thyssenkrupp Uhde we handle procurement and expediting, working exclusively with validated and vetted equipment suppliers.
Our offerings are 100% tailored to our customer's needs, following a modular design principle. We have developed a broad portfolio of different variants for the abatement of NOx and/or N2O. This high level of customization ensures that our solutions perfectly fit your specific requirements, showcasing our unique flexibility.
EnviNOx® can be installed at the end of the line with no influence on the production, offering scalability and no space issues. Our technology is easy to implement ("install & forget") and low-cost to operate, with no negative impact on the production process and avoiding long shutdown times. It is always possible to retrofit the system into existing installations.
The efficient mechanical design of EnviNOx® reactors and catalyst baskets makes initial catalyst installation and later catalyst changes, if ever needed, straightforward.
Our EnviNOx® system offers excellent total cost of ownership (TCO) due to the long lifetime of the catalyst and low maintenance cost. Our "no strings attached" approach means no costly maintenance after installation, no use of problematic substances, and no involvement of harmful/critical materials.
Our technology meets all current and future regulations, ensuring compliance with thresholds and long-term adherence to environmental standards. EnviNOx® is future proof, providing sustainable solutions that enhance the company's image and reputation.
We offer a one-stop-shop experience, from catalyst optimization to process control, all handled by thyssenkrupp Uhde. This includes lifetime technology support, ensuring ongoing assistance, and expertise. Our comprehensive approach ensures that everything is provided from one source, simplifying the process for our customers.
We provide supervised installation of our solutions, ensuring each implementation is seamless and efficient. Our solutions are very safe during operation, minimizing unwanted emissions, and ensuring failure-safe performance.
The EnviNOx® technology is reliable and proven, with low process risk and high process reliability. The system is fully automated.
Using specialized in-house design tools including CFD, we ensure optimal performance and efficient use of materials and catalysts, while minimizing pressure drops and impact on the rest of the plant. Our technology ensures efficient use of reducing agents, thanks to a special dosing and mixing system upstream of the EnviNOx® reactor. This ensures excellent distribution and mixing in the tail gas, eliminating the need for excessive amounts of reducing agents.
Our EnviNOx® systems are designed to prevent ammonium nitrate deposition and ammonia slip, addressing the potential explosion risk of ammonium nitrate and the often strict emission limits of ammonia through intrinsic design and advanced control and monitoring systems.
Proven global impact
