SNCR Process

For industrial operations that create flue gases, these gases can contain harmful nitrogen oxides (NOx) gases that become emitted into the environment. This NOx can be harmful to breathe and can contaminate water sources such as acid rain. Reducing the amount of NOx in the flue gas can be accomplished using the SNCR process.

What is the SNCR?

Selective non-catalytic reduction (SNCR) is a pollutant reduction process that creates a chemical reaction to change the harmful NOx gas into harmless nitrogen and water. This process is accomplished using a reductant such as urea, ammonia, or other chemicals. This reductant is sprayed using a spray nozzle system so it can completely mix with the NOx. To perform the chemical reaction, boilers are used to heat up the reductant to the desired temperature level.

SNCR Vs. SCR

Both selective non-catalytic reduction (SNCR) and selective catalyst reduction (SCR) are NOx pollution control processes that target nitrogen oxides and reduce them from exhaust gases. The main difference is that SNCR does not use a catalyst to create the chemical reaction required between the reductant and the NOx. SCR does use a catalyst bed to perform this reaction.

Applications for SNCR Process

SNCR is commonly used for industrial processes that create a high amount of NOx due to excess heat generated from processes. Refineries often employ SNCR for their boilers to obtain a NOx reduction in flue gases of up to 60%.

Paper and pulp mills deal with a large amount of NOx from wood waste, while electrical companies and co-generation companies deal with NOx pollution from coal used as fuel. Additional industries that use SNCR equipment include oil & gas, steel, cement, and chemical industries.

Key Components of SNCR Systems

SNCR systems come in varying setups and attached equipment. Most of these systems will have a reagent storage tank connected to a process & flow unit that will create the required reductants and direct them to the appropriate injector units.

There will also be boiler control interface that heats up the reductants to the appropriate level and spray nozzle systems that will spray the reductant into the flue gas stream. There will also be a control interface or management module that coordinates each of the connected systems.

Pros & Cons of SNCR

The main advantage is that the setup is simplified with an SNCR system as you don't require additional equipment to create the chemical reaction process. Since there is no catalyst, you can save money on repairs and replacement of this equipment. The SNCR system is also easy to install and can be retrofitted onto boilers.

Disadvantages to an SNCR system involve high water usage, boiler efficiency reduction, and requiring space for the storage tanks. Overcoming the high water usage can be accomplished by having a spray nozzle and lance system designed to conserve waste while still efficiently mixing the reductant with the NOx gases on the flue stream.

Explore Lechler's SNCR Solutions

Lechler offers SNCR, SNCR and DeNOx spray system solutions so companies can create advanced NOx control solutions for their operations. Our lance and spray nozzle products are designed to meet your process requirements and seamlessly integrate into your existing systems. Contact us today to learn more.