(340a) Commercial Experience with Emx™ - Ten Years after

EMx technology is a regenerable ?lean NOx trap? technology for control of combustion-generated NOx emissions. In it simplest form a NOx trap oxidizes NOx to NO2, which is then captured on a sorbent. Regeneration involves a dilute hydrogen stream, which, in excess, reduces trapped nitrate and nitrite to molecular nitrogen. Originally marketed as an ultra-deep (sub 2 ppm) NOx control technology, over the past ten years EMx has become operationally simpler and less costly to implement, while performance has continued to improve with both new formulations and added operational experience. Introduction of a sulfur guard bed has extended the maintenance period by a factor of 4 ? 6, while a new system hardware design has improved system simplicity and reliability. All commercial installations to date have been stationary gas turbines burning both natural gas and petroleum distillates. However, EMx has also been demonstrated on reciprocating engines burning diesel and biodiesel with both 15 ppm and 150 ppm sulfur content and NOx concentrations over 800 ppm. Presently the technology has over 300,000 commercial operating hours on 5 ? 50 MW turbines with better than 99 percent availability, and routinely achieves NOx emission levels below 0.5 ppm (at 15 percent O2).