What is AZO NOX?
“AZO NOX” means ammonia-based or urea-based chemicals widely used in industry to reduce emissions of harmful oxides of nitrogen (NOx) gases from industry and combustion plants.

Stricter environmental requirements encourage decisive action to prevent the formation of smog and acid rain, which are harmful to nature and human health. AZO NOX chemical product group helps to reduce the release of harmful nitrogen oxides into the atmosphere during the combustion process. These Gaschema products, produced using special technologies, are widely used in the energy industry, cogeneration plants, industrial boilers, waste processing plants, cement kilns, and the shipping sector.
The main ways to reduce NOx emissions are SCR (selective catalytic reduction) and SNCR (selective non-catalytic reduction). Ammonia or urea solutions are injected into these systems to help reduce nitrogen oxide emissions by up to 95%.
When implementing pollution-reducing technologies, it is equally important to choose a reliable and high-quality reagent. “Gaschema” offers you to purchase pollution-reducing products made on the basis of urea or ammonia, such as “AZO NOX AV1”, “AZO NOX AV2”, “AZO NOX AUS20” or “AZO NOX AUS40”. However, we can also offer you individually tailored products, i.e. i.e. we can produce a pollution-reducing product of the concentration required depending on the specifics, capacity or technological requirements of your company.

Products and transport containers
AZO NOX AV1
Aqueous solution of ammonia up to 25% concentration. A solution based on lower concentrations of ammonia water is easier to transport and store. For these reasons, it is more often transported abroad.
The transport of the product must comply with the safety requirements of ADR / RID
- ADR / RID class 8;
- UN identification number 2672;
- Packing class III;
- Classification code C5.
Transport in bulk according to Annex II of MARPOL 73/78 and the IBC Code.
- The bulk product is transported in accordance with Annex II MARPOL73 / 78 and the IBC Code. The Code does not apply to packaged goods.
Packing | Quantity | In the box | In the tray |
„AV1“ IBC container |
1000 l | – | – |
„AV1“ tank truck |
24 000 l | – | – |
AZO NOX AV2
Ammonia water with a concentration of more than 25%. Ammonia is a flammable product, so higher concentrations of ammonia in aqueous solution require special storage conditions.
The transport of the product must comply with the safety requirements of ADR / RID
- ADR / RID class 8;
- UN identification number 2672;
- Packing class III;
- Classification code C5.
Transport in bulk according to Annex II of MARPOL 73/78 and the IBC Code.
- The packaged product shall be transported in accordance with Annex II to MARPOL 73/78 and the IBC Code. The Code does not apply to packaged goods.
Packing | Quantity | In the box | In the tray |
„AV2“ IBC container |
1000 l | – | – |
„AV2“ tank truck |
24 000 l | – | – |
AZO NOX AUS 20
20% urea solution used to reduce harmful oxides of nitrogen in industrial kilns and factories. Used in both SCR and SNCR systems.
AZO NOX AUS 40
40% urea solution commonly used in industrial kilns, factories and diesel marine engines.
Marine diesel engines are highly efficient using low-quality fuel oil. However, the main disadvantage of these engines is their high exhaust (NOx) emissions, which exceed the NOx emissions of motor vehicles or electric power plants. The International Maritime Organization (IMO), which oversees the MARPOLO Convention (see Annex 6), has been in force since 2005. 19 May 2000, is committed to reducing the number of vessels built since 2000. January 1 and engines with an output exceeding 130 kW.
Although the AUS 40 has a specific odor, it is widely used due to the following features:
- Not toxic;
- Safe to operate;
- Ammonia is not released at ambient temperature.
Principle of SCR operation
To reduce NOx emissions, marine engines use an SCR system with an efficiency of up to 99%.

1 – capacity of urea solution (“AUS 40%”);
2 – pump;
3 – flow rate;
4 – spraying of urea solution (“AUS 40%”);
5 – static mixing;
6 – compressed air;
7 – SCR catalyst;
8 – oxidation catalyst;
9 – damper;
10 – NO analyzer.
A 40% urea solution (‘AUS 40%’) is supplied from the tank (1) by a pump (2) to the injectors (4) through which the exhaust gas (NOx) is injected. Exhaust gas (NOx) enters the flow distribution elements (3) before the static gas mixing (5) to form a linear flow. The gas mixture enters a catalyst block consisting of SCR (7) and oxidation (8) catalysts. The main function of the SCR catalyst (7) is to convert harmful exhaust gases (NOx) into harmless elements N2 and H2O:
1) 4NO + 4NH3 −> 4N2 + 6H2O
2) 6NO2 + 8NH3 −> 7N2 + 12H2O
As can be seen from the above reactions, ammonia is needed to reduce emissions (NOx), i. y. A 40% urea solution (AUS 40) decomposes at high temperatures to ammonia (NH3), which reacts with harmful NOx gas.
The main function of the oxidation catalyst (8) is to produce the elements formed during the combustion process, i. y. to convert carbon monoxide (CO) and gaseous hydrocarbons (CH) into non-toxic gases, i.e. y. carbon dioxide (CO2) and water vapor (H2O).
(1) CO+1/2O2 −> CO2
(2) [Hydrocarbons] + O2 −> CO2 + H2O
In order to make the exhaust gases more non-toxic more efficiently, air is added to the system (6). The use of the SCR system on board ships significantly reduces and controls the following substances: NOx gas, carbon monoxide (CO) and hydrocarbons (CH).
http://www.imo.org/ (Information about Annex 6 IMO)
https://www.dieselnet.com (Information about oxidation catalysts)