Los Altos, CA USA

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2012 Jul – Aug CLN Uprates 501 to 6 MW with under 18 ppm NOx and Zero CO – GTW.pdf

Today, we are faced with a very real and important problem of complying with ever more stringent environmental controls and emissions regulations while maintaining the efficiency, economy and viability of combined heat and power plants.

Cheng Power Systems (CPS) has developed a low-emissions combustion system, the Cheng Low-NOx (CLN®) system, which reduces simultaneously NOx and CO emissions. The CLN® system uses only steam to control the NOx and CO emissions of combustion turbines, fired boilers and other equipment burning gaseous fuels. No catalysts, ammonia, urea or other reagents, equipment or subsystems are required. The CLN® system works with any gaseous fuel burning in a diffusion flame. In combustion turbines and boilers, low single-digit parts per million NOx and CO levels are achievable under normal operating conditions.

CLN® system installations can be completed typically for much less than the cost of Dry-Low-NOx or Dry-Low-Emissions (DLN or DLE) systems, Selective Catalytic or Selective Non-Catalytic Reduction (SCR or SNCR) systems, or Low-NOx burner systems.

CLN® is the most quickly installed and least costly way for the operators of existing plants to create valuable credits from voluntary emissions reductions or to meet tightening pollution control requirements that are being ratcheted downward to meet new emissions levels. In new plants, the CLN® system is less costly, is less expensive to operate and maintain, and has better economics than DLN/DLE or Low-NOx burners as a precursor NOx control technology for SCR/SNCR or other active NOx and CO removal systems. In some jurisdictions, including locations for which DLN/DLE combustors or Low-NOx burners alone are sufficient, the CLN® system can be the sole method of emissions control.

The CLN® technology will be able to reduce the cost of producing electricity from any gaseous-fueled combustion turbine by between 5% and 15% as compared to achieving the same level of emissions control using a combination of DLN/DLE combustors and an SCR with a CO catalyst. The lower 5% range will apply if the plant electrical output is allowed to increase to its maximum (an increase of as much as 20%) as a result of the injected steam and if supplemental firing is required to replace for process loads the steam that is used for injection. The upper 15% range will apply if the plant electrical output is maintained constant and the plant specific heat rate is reduced accordingly by the steam injection. In either case, the CLN®technology will provide a significant net economic benefit to the plant owner or operator, which will presumably flow through to the electricity or heat consumer. This singular fact makes the CLN® technology the only air emissions control technology that generates a profit by reducing air emissions rather than incurring a cost. Additionally, the CLNâ technology uses lower cost diffusion flame combustors rather than more expensive DLN/DLE combustors, which considerably reduces hot-parts maintenance costs. Also, the CLN®technology uses no ammonia or catalyst, which eliminates the costs, space and risks associated with ammonia transportation, storage and injection and with catalyst replacement and spent catalyst disposal.


  • More than Doubles Hot Parts Life

  • No Catalyst Replacement Cost

  • No Ammonia Slip Stream

  • Improves Heat Rate

  • Reduces Greenhouse Gas

  • Increases Power Output

  • The CLN® is an emissions control system for combustion turbines to reduce emissions while improving efficiency and power

  • CLN® is the only emission control product with payback to the customer for their investment

  • CLN® reduces NOx & saves fuel in gas turbines simultaneously

  • CLN® is a NOx reduction system that does not alter combustion systems in gas turbines

  • CLN® immediately improves gas fired turbine efficiency by 20-40% with power boost of up to 25%

  • CLN® is applicable to any gaseous fuel

CLN® Emission Control Technology Candidates

  • AQMD regulations requiring lower turbine NOx emissions, those looking to reduce emissions due to regulatory requirement.

  • DLE to CLN® conversion, those that want to convert from the OEM DLE to less costly low emissions system.

  • Water injection to CLN®, those looking to convert from water injected systems for increased efficiency and lower emission levels.

  • New installations requiring new source review emissions limits.

  • Plants seeking Higher Power Output, Fuel Savings & Reduced O&M.