NOx reduction with SNCR and SCR systems using urea as a reducing agent
Urea is an important raw material for the chemical industry. It is widely used in NOx control systems to reduce emissions of nitrogen oxides (NOx). Yara is a leading urea producer in the world and has supplied its customers with urea for many years, including for the reduction of NOx emissions:
- With SNCR systems, urea is often the reducing agent chosen for safety reasons. However, it is less effective than ammonia as urea needs to be converted into ammonia before the process of reducing NOx can take place.
- We provide either solid urea, typically for dilution on site or urea in solutions with various concentrations
Why choose urea as a reagent to control NOx emissions:
- You may wish to choose urea for safety reasons. It has less risk in the workplace and requires no special training, unlike ammonia
- Urea is not dangerous. It is stable, non-volatile, non-flammable and non-explosive
- Urea can be safely transported, stored and handled without the need for specific training.
However, there are disadvantages in using urea as a reducing agent in the control of NOx:
- Urea may lead to additional emissions of nitrogen oxides or of carbon monoxide which are both harmful gases
- Urea is less effective than ammonia for NOx reduction
- There is an increased likelihood of contamination and corrosion in equipment downstream from the point of injection
- Leaks of urea solution cause the formation of a white precipitate salt which makes your equipment seem aged
- When mixed with hard water, urea and flakes can clog your NOx control system
- Solid urea is to be delivered and maintained at a temperature sufficient to prevent it from crystallizing. The crystallization point depends on the level of urea concentration. For example, 40% urea solution of crystallizes at 0°C.
Yara brings an uninterrupted supply to you as we are Europe’s largest urea supplier. We have multiple production facilities – and therefore are less impacted by unforeseen plant shut-downs. Thus, Yara offers a unique supply security. Our factories across the globe ensure a continuous backup supply.
We have a multi-modal distribution system by road, rail and sea and operate several product terminals for intermediate storage. The transportation means for urea solution are:
- Truck (solid urea packaged in bags) / silo truck (bulk)
- Container (solid urea packaged in bag or bulk)
- Wagon (solid urea packaged in bag or bulk)
- Ship / barge (solid urea packaged in bag or bulk)
We work with reliable and experienced logistics operators bringing you optimized cost reduction
Our experts in NOx control can give you support and advice tailored to your needs to ensure that your SNCR system running with urea is cost effective and meets all the necessary requirements.
Contact our NOx control expert for more information on the reliable delivery of urea, or read more about how to avoid scaling when using urea in your SNCR equipment.
Solve scaling problems when using urea as a reagent in SNCR systems
Some SNCR systems that use urea require the addition of water to dilute the urea before injection. If urea is used with hard water, it may cause problems with flaking or clogging of the injection nozzles, which stops the operation. Yara has developed a NOxCare anti-scaling solution to eliminate problems occurring in the SNCR NOx control system.
Yara is one of the largest producers of urea in the world, offering security and unmatched supply reliability, from its global production plants. Our experts in NOx control can provide you with technical support and advice to ensure that your SNCR NOx control system running with urea is effective and meets all the requirements of your specifications. Yara supplies you the reagent of your choice from our network of factories across the world, providing a constant supply alternative.