Exhaust gas pollution exhaust sources in various large-scale industrial facilities such as petroleum refineries, natural gas processing plants, petrochemical plants and chemical production plants. However, these are often referred to as flue gases. Catalytic converters in cars intend to break down the pollution of exhaust gases using a catalyst. Scrubbers in ships intend to remove the sulfur dioxide (SO) of marine exhaust gases. The regulations on marine sulfur dioxide emissions are tightening, however only a small number of special areas worldwide have been designated for low sulfur diesel fuel use only. One of the advantages claimed for advanced steam technology engines is
Diesel exhaust U.S. 2010 emissions criteria, selective non-catalytic reduction (SNCR), and exhaust gas recirculation (EGR). Both are in the exhaust system of diesel engines, and are further designed to promote efficiency. Selective catalytic reduction (SCR) injects a reductant such as ammonia or urea — the latter aqueous, where it is known as diesel exhaust fluid, DEF) — into the exhaust of a diesel engine to convert nitrogen oxides (NO) into gaseous nitrogen and water. SNCR systems have been prototyped that reduce 90% of the NO in the exhaust system, with commercialized systems being somewhat lower. SCR systems do not necessarily need particulate