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Field Test of Non-Selective Catalyst Reduction Systems for Rich-Burn Engine NOx Reduction
A field test has been initiated with Spectra Energy at their Thomaston, TX compressor station on two large Ingersoll-Rand KVG rich-burn engines in mainline compression service. The objective is to evaluate the field performance of integrated and non-integrated NSCR systems that operate in compliance with all applicable federal NESHAP (air toxics) regulations, as well as Texas state regulations. Specific targets include achieving a level of stable emissions performance that allows for 3 to 6 months of continuous operation while maintaining an acceptable compliance margin, confirming the ability to self-detect emissions performance variations without the need to conduct stack testing, and improving the overall operability and reliability of the engines.
Installation and commissioning occurred in mid-2010, and after some initial fuel valve and carburetor reconfigurations, the systems so far has met or exceeded the above objectives, with the 3 to 6 month performance target expected to be achieved. The two NSCR systems are provided by Advanced Engine Technologies Corp (AETC) and Hoerbiger Corporation. The Hoerbiger system is considered the “integrated system” because it employs a system controller that is adaptable to individual engines via a controller algorithm mapping capability. Key components of the system include a NOx sensor in the exhaust that provides a feedback look to the system controller and the lambda sensor, as well as an upstream lambda sensor (oxygen sensor) that derives from natural gas vehicle-based oxygen sensors, and it thus tailored for methane chemistry instead of gasoline chemistry. The AETC system employs the existing engine NSCR controller, but applies the separate NOx exhaust sensor and the advanced lambda sensor into that package. This may provide simpler, less expensive field installation (since the existing controller can be used). A data logging capability and on-board diagnostic package is provided for both systems, which is a key step for long-term stable performance.
Testing will continue until the end of 2010, with detailed performance results expected to be available by the end of Q1/2011. These results will provide key inputs into ongoing PRCI research on NSCR systems to continue to improve system performance, stability and reliability in advance of the 2013 NESHAP compliance deadline, and individual state requirements that in some cases are more stringent than federal regulations.