Internal combustion catalytic converter

Along with being a smog enhancer, sulfur affects the performance of internal-combustion catalytic converters in the same way as it affects fuel cells. Sulfur can increase emissions by 20%. California uses low-sulfur fuel and the concentration is about 40 parts per million. In the rest of the country it is about 350 parts per million. A national low sulfur standard is estimated to add five cents per gallon to gasoline. 

Numerous other entries 111 this volume take the energy /pollution interface into consideration. These include Air Catalytic Converter (Internal Combustion Engine) Combustion (Fuels) Energy Fuel Hydrogen (Fuel) Natural Gas Nuclear Power Technology Oil Shale and Tar Sands. 

Many gas-fired compressors that pump natural gas through millions of miles of pipelines are also equipped with exhaust catalysts to clean emissions at moderate conditions. Even fast-food restaurants are being equipped with catalysts to eliminate odors from the cooking process. The most widely used treatment of exhaust pollutants is that of the catalytic converter present in the exhaust manifold that cleans emissions from the internal combustion engines of gasoline- and diesel-fiieled automobiles and trucks. As modem commercial passenger jets fly above 30,000 feet there is a need to destroy the few ppm ozone that enters the airplane with make-up air to ensure passenger and crew comfort and safety. Radiators on select... 

Environmental Protection Agency without any modifications or accessories.32 However, concerns over cancer from Diesel exhaust have made the issue quite complicated in recent years, but those concerns are only for long-term effects. In any event, Diesels have always produced far less than 1%/vol. carbon monoxide, which is still the CO standard for all internal combustion engines. Gasoline engines have only met the same standard after many years of intensive research and the addition of many engine modifications and complex accessories including catalytic converters. 

Although such measures as catalytic converters and activated carbon canisters, which are used to help reduce geisoline fumes, have been somewhat effective, photochemic d smog still presents a problem. Until mankind develops an acceptable substitute for the internal combustion engine or requires mass transit, photochemical smog will remain with us for years to come. 

In order to generate acceptable power levels, however, low-temperature PEM fuel cells need catalyzed electrodes. Thus far, the electrocatalysts used in PEM fuel cells have been exclusively Pt based. However, Pt is an industrial metal, mainly mined in South Africa (with about 75 % of the world production) and Russia (about 15 % of the world production). Today, 50 10 % of Pt production of the 200,000 kg/year is used as chemical catalyst in catalytic converters for internal combustion engine vehicles. A mere glance at Fig. 10.1 immediately emphasizes the link between the cost of Pt, that of cmde oU, and the health of the economy. In other words, one cannot hope for a strong economy and for Pt price to stay low at the same time. 

This air/fuel mixture ratio can be and is exploited in the control of internal combustion engines. For example, cars fitted with catalytic converters can operate with adjustable air/fuel ratio X, which allows the air/ fuel mixture to be optimized during the running of the engine, thus minimizing CO and hydrocarbon emissions. On the other hand, one should note that nitrogen oxides are not directly related to the air/fiiel mixture ratio, and thus cannot be controlled in this way. 

Internal combustion produces water vapor and exhaust gases, which can condense in internal areas such as the exhaust system of automobiles [5,9]. This condensate chemis-tiy includes sulfate, sulfite, nitrate, ammonium, carbonate, bicarbonate, and chloride ions. The acidity of the condensate is high due to the presence of nitric, hydrochloric, sulfuric, and sulfurous acids. Nitric acid is formed from atmospheric nitrogen, which is converted to oxides in the engine and then to the acid. Sulfuric and sulfurous acids are formed because fuels and lubricatory oils contain sulfur, which converts to sulfur dioxide and then reacts with water vapor to form these acids. In addition, catalytic converters are designed to convert SO2 to SO3 yielding acids. Chloride additives to fuels yield hydrochloric acid. 

---