Carbon diesel catalysts

The second method used to reduce exliaust emissions incorporates postcombustion devices in the form of soot and/or ceramic catalytic converters. Some catalysts currently employ zeolite-based hydrocarbon-trapping materials acting as molecular sieves that can adsorb hydrocarbons at low temperatures and release them at high temperatures, when the catalyst operates with higher efficiency. Advances have been made in soot reduction through adoption of soot filters that chemically convert CO and unburned hydrocarbons into harmless CO, and water vapor, while trapping carbon particles in their ceramic honeycomb walls. Both soot filters and diesel catalysts remove more than 80 percent of carbon particulates from the exliatist, and reduce by more than 90 percent emissions of CO and hydrocarbons. 

In spite of this, we believe that there is a real potential in ceria as an anode for conversion of hydrocarbon fuels, because ceria can tolerate carbon precipitation and is able to oxidise the carbon. In this context it should be remembered that one of the oldest applications of ceria has been as a carbon oxidation catalyst, and still today it is used as a catalyst in self cleaning ovens and for the oxidation of diesel soot in automobiles. ... 

Figure 1 5. Conversion of carbon monoxide, gaseous hydrocarbons and sulfur dioxide reached over a diesel catalyst with and without measures to suppress the formation of sulfates, as a function of the exhaust gas temperature (monolith catalyst with 62 cells cm dedicated diesel washcoat formulations with platinum at a loading of 1.76 g I" diesel engine test bench light-off test at a space velocity of 120000 N1 F h diesel engine bench aging procedure for 100 h at a catalyst inlet temperature of 773 K).

Table 27. Amount of sulfur, phosphorus and carbon on a diesel catalyst after aging on a diesel engine bench, as a function of the platinum loading, and of the composition of the fuel and the engine lubricating oil. (Reprinted with permission from ref [69], C 1992 Society of Automotive Engineers, Inc.)...

Table 28. Emission of carbon monoxide, gaseous hydrocarbons, nitrogen oxides and particulate matter from a passenger car equipped with an IDI/NA diesel engine, and conversion over a diesel catalyst in the fresh and the engine aged state, in the different phases of the US-FTP 75 vehicle test procedure and of the European MVEG-A vehicle test procedure. ...

The reactions that occur to auto-exhaust emissions when exposed to plasma include oxidation of HCs, carbon monoxide, and partially diesel PM also. Nitric oxide (NO) can be oxidized by plasma to N02. Plasma alone, due to its oxidizing character, is not a viable NO control method. However, combinations of plasma with catalysts, referred to as plasma-assisted catalysts or simply plasma catalysts , have been suggested for NO reduction. The plasma is believed to show potential to improve catalyst selectivity and removal efficiency. Current state-of-the-art plasma catalysts have efficiencies comparable to those of active DeNO systems, removing about 50% of NO at a fuel economy penalty of less than 5% [85],... 

Compliance with the EuroIII standards (2000) forced the fitting of Diesel oxidation catalysts (DOC) in the exhaust line [for the after-treatment of unburnt hydrocarbons (HC) and carbon monoxide (CO)]. Additionally, the exhaust gas recirculation (EGR) was adapted to reduce the engine-out emissions of nitrogen oxides (NOx). 

In its commercial plants Sasol has to date used only iron based catalysts. (The preparation and properties of these catalysts have been reviewed elsewhere (2).) Not only is iron by far the cheapest of the metals (see Table I) but iron catalysts also produce large amounts of low molecular weight olefins which are important in the Sasol process. (These olefins are oligomerized to either gasoline or diesel fuel and this allows the production of these two liquid fuels to match the market requirement.) A major drawback of iron is that at high temperatures carbon deposition occurs which results in catalyst disintegration. 

ChemPete, Inc., bioremediation is an effective and continuous cleanup method for transforming gasoline, diesel fuel, fuel oil, kerosene, and chlorinated solvents to nonhazardous organic matter, carbon dioxide, and water, according to the vendor. ChemPete uses bacteria, nutrients, and a catalyst developed by Alpha Environmental Biosystems, Inc. ChemPete was the first company to achieve closure of both gasoline and fuel oil sites in situ in accordance with Illinois rigorous closure guidelines (5 parts per billion benzene). RIMS was unable to contact the vendor, and the commercial availability is unknown. 

Oil (also referred to as petroleum) is a complex liquid mixture of organic substances, principally of hydrocarbons containing five to sixteen carbon atoms. Most crude oil, once removed from a well, is sent by pipeline to a refinery, where it is distilled to separate it into gasoline, heating oil, diesel oil, and asphalt. The use of catalysts during the refining process increases the yield of gasoline. In 2001, 25.7 billion barrels of oil were used worldwide, with estimated reserves of 1.05 trillion barrels. (One barrel contains 159 liters.)... 

In this process, carbon from biomass is converted to gases (CO, CO2) by high temperature (above 800 °C). The produced CO2 can react with hydrogen to directly produce methane, but also other different products, such as diesel, and other chemicals such as 1-alkenes in the presence of catalysts (Dry, 1999). This process has been used to produce Fischer-Tropsch diesel (FT diesel). 

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