Cost Effective NOx Emission Retrofit Control Technologies
This paper discusses emission control technologies applied to a two-stroke cycle natural gas-fueled engine. In this first phase, a one-cylinder Ajax DP-115 (13 ½ bore x 16 stroke) is used to assess a variety of low-emissions technologies. These technologies are targeted to the exploration and production oil and gas field engines to meet clean air requirements. The primary goal in this project is to determine a roadmap that can use NOx reduction technologies that have been successfully used on pipeline engines on exploration and production engines, such as the Ajax. The paper describes the battery of tests that demonstrate synergies between some technologies, as well as the impact and capabilities of new technologies, such as ion sensing. The end goal is a closed loop control, low cost NOx retrofit package. The battery of tests includes a range of fuel nozzles, pre-combustion chambers, in-cylinder sensors, the means to adjust the air-to fuel ratio, and electronic fuel injection. The first series of tests will vary the air/fuel ratio and ignition timing to determine the optimal fueling rate, efficiency, and emissions from the baseline engine. Subsequent tests investigate the impact of pre-combustion chamber design, fuel nozzle design, ignition, and fuel injection, along with ion sensors and fiber optic pressure sensors to measure in-cylinder parameters in real time. The battery of tests with these technologies shows the capability of optimizing the engine and reducing NOx. By using the Ajax DP-115 as a surrogate for the smaller pipeline engines, these tests are completed in low-cost and efficient manner. The various technologies can be quickly swapped with different hardware and the cost to operate the engine is very expensive. This project is sponsored by the Department of Energy.