NOx Reduction Applications: Gas Turbines
Selective Catalytic Reduction (SCR) is the standard technology applied worldwide on gas turbines where high percentage NOx reductions or extremely low NOx emission concentrations are required.

For retrofit on combined cycle systems utilizing a gas turbine followed by a heat recovery steam generator (HRSG), there is usually insufficient space either before or within the HRSG for conventional or high temperature SCR. The CRI Low Temperature SCR Catalyst Technology offers the ability to position the SCR system completely after the heat recovery section and to achieve high NOx reductions at typical stack gas temperatures, even as low as 300° F (150° C).

Even at the low SCR operating temperatures existing at these locations, over 90% NOx reduction at controlled NH3 slip of 5-10 ppm or less can be achieved.

For gas turbine combined cycle retrofit applications, a critical factor is often limited pressure drop availability. A significant advantage of the CRI SCR technology is that the lateral flow (LFR) catalyst reactor modules can be designed for very low pressure drop through the SCR catalyst, typically 2-3" H2O (5-7.5 mbar) but even as low as 1" H2O (2.5 mbar) if required.

An additional and typically significant cost advantage of locating the SCR at the outlet of the HRSG is that no modifications to the HRSG are necessary and much of the site work and installation for the SCR can be accomplished while the unit is still operating, minimizing downtime.

The CRI low temperature SCR technology has been proven over many years of operation on a range of gas turbine types and sizes to offer reliable high NOx reduction performance.