In 2004, Northeast Texas Air Care (NETAC) commissioned a pilot project to demonstrate the effectiveness of available technology in reducing nitrogen oxide (NOx) emissions from compressor engines used in gas production operations. This pilot project has succeeded in retrofitting five gas compressor engines with controls that reduced NOx emissions from those engines by greater than 90 percent. The positive conclusion of this project has resulted from the cooperation of local stakeholders, the selection of a highly effective control technology and carefully planned and executed emissions testing procedures. This report documents the design, implementation and results of the compressor retrofit pilot project.
Significant emission reductions implemented over the past few years through NETAC programs have allowed the NETAC area to be designated by EPA as an ozon attainment area. However, the margin of safety between monitored levels and the standard is small. On December 20, 2002 local governments in Northeast Texas (Gregg, Harrison, Rusk, Smith, and Upshur counties) entered into an Early Action Compact (EAC) with the U.S. Environmental Protection Agency (EPA) and the Texas Commission on Environmental Quality (TCEQ). The purpose of the EAC is to develop and implement a Clean Air Action Plan (CAAP) that will reduce ground level ozone concentrations throughout the five county area to comply with the 8-hour ozone standard by December 31, 2007 and maintain the standard beyond that date. The pilot program to retrofit gas compressor engines has been implemented to support an emission reduction strategy discussed in the CAAP for Northeast Texas.
The 2002 Northeast Texas emissions inventory estimated that 53.9 thousand tons of NOx were emitted annually by sources in the five county area. Non-point gas compressor engines were estimated to contribute approximately 12 thousand tons per year; over 22 percent of the total (NETAC, 2005). Unlike other major NOx emissions sources, such as large industrial facilities and onroad motor vehicles, many compressor engines do not have emissions controls.