Emission Abatement Conversions - Gas Turbines


As the international community transitions into a green economy driven by sustainable engineering practices, concern for environmental optimization is prompting governments throughout the world to require gas turbine users to reduce NOx emissions from their units.

Such environmental requirements vary from country to country and site to site, and the most cost-effective systems can vary according to factors such as the availability of resources and the wide diversity of governmental policies.

Gas Turbine Efficiency, Power Generation Solutions

Our team has extensive experience in the provision of complete emission abatement systems for gas turbine users including both "wet" and "dry" systems. We work with each customer to analyze their required NOx levels and the cost of each potential NOx reduction approach to identify the most cost-effective system for each individual case. In addition, we can also provide NOx emission calculations for each of the possible cases to assure the compliance of the system before its installation.

Once the optimum solution has been identified, our team can undertake the entire conversion including all required hardware and the software system modifications required on the existing control systems or the provision of new systems as necessary.

Modification Options

NOx compliance technology serves as a bridge to more than just environmental compliance for power plants, it is essential for power providers to know which technologies are available to them. The right technology leads to future profit, overall regulatory compliance and a boost in power production for the entire system.

Options to decrease NOx Emissions include combustion and post-combustion modifications.


Low-NOx Burners - These control fuel and air mixing to achieve staged combustion, which reduces both flame temperature and oxygen concentration during phases of combustion. This method reduces both lower thermal NOx and fuel NOx production.

Overfire Air - This method is used in conjunction with low-NOx burners to complete the combustion process at a lower temperature. As air is injected into the furnace above the normal combustion zone, the burners function at a lower-than-normal air-to-fuel ratio. This process reduces NOx formation.

Flue Gas Recirculation (FGR) - Part of the flue gas is recirculated to the furnace, and can also be used to alter conditions in the combustion zone by lowering the temperature and reducing the oxygen concentration. FGR is often used as a carrier to inject fuel into a reburn zone to increase penetration and mixing.


Selective Catalytic Reduction (SCR) - A catalyst vessel is installed downstream of the furnace. Ammonia (NH3) is injected into the flue gas before it flows over the fixed-bed catalyst. The catalyst prompts a reaction between NOx and NH3 to form nitrogen and water vapor. This method produces NOx reductions up to 90%.

Selective Noncatalytic Reduction (SNCR) - A reducing agent, such as NH3 or urea, is injected into the furnace above the combustion zone. It reacts with the NOx as in the case of the SCR. Critical factors in SNCR applications include sufficient time in the appropriate temperature range and equal distribution and mixing of the agent across the full furnace cross section.

Both SCR and SNCR can be used together as a hybrid or combined with low-NOx burners. Since the low-NOx burners with the over-fire air system can achieve between 60 to 70 percent decrease in emissions, power operators can sometimes avoid the SCR installation.

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Our team will work with your power plant to ensure the highest level of operational excellence with the lowest out of pocket cost for retrofitting or system upgrades. When it comes to regulatory compliance and emissions abatement, we know gas turbines and the challenges for the next era of power generation. Discover our comprehensive service offerings for power plant and station operations.

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Benefits of Emissions Abatement Conversions include the following:

  • Operational Flexibility
  • Power Increase
  • Emission Reduction
  • Availability and Reliability Increase
  • Efficiency Increase

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