Abstract:
Operation of a diesel engine with low particulate emissions is achieved. A diesel engine is equipped with a platinum-catalyzed particulate trap. The engine is operated with a blend of diesel fuel and a fuel-soluble cerium composition to reduce the balance point of the trap with reduced cerium content. Preferably, the fuel will also contain a fuel-soluble organo-platinum group metal compound, or an effective platinum group metal compound can be added to the exhaust or combustion air.
Abstract:
The effectiveness is prolonged for catalytic oxidizers to reduce emissions of both HC and CO from two-stroke gasoline engines. A compound of a platinum group metal is added to the cylinder of the engine, to make it available as an active oxidation catalyst by combustion of the fuel. Preferably, the platinum group metal compound is added with the lubricating oil, but can be added to the fuel or through a separate injection.
Abstract:
The present invention relates to a process for reducing nitrogen oxides emissions from a diesel engine, which comprises preparing an emulsion of water in diesel fuel which contains a catalytically effective amount of catalyst composition and a lubricity additive, and supplying said emulsion to a diesel engine for combusting therein, whereby combustion of the emulsion leads to a reduction in the nitrogen oxides emissions from the diesel engine when compared with combustion of diesel fuel alone.
Abstract:
A low-emissions diesel fuel comprises fungible aviation kerosene grade 55, 50–300 ppm detergent, 25–500 ppm lubricity additive and a bimetallic, fuel soluble platinum and cerium fuel borne catalyst (e.g., 0.1–2.0 ppm platinum COD and 5–20 ppm cerium oleate). The fuel can be used as is or in the form of an emulsion. A method of reducing the emissions of pollutants from a diesel engine, comprising running the engine on a fuel as defined. Retarding engine timing can further reduce NOx and the use of a diesel particulate filter and/or diesel oxidation catalyst can provide further reductions in carbon monoxide, unburned hydrocarbons and particulates.
Abstract:
A safe, reliable SCR system for reducing NO.sub.x emissions from a lean-burn internal combustion engine utilizes urea in aqueous solution. Overheating and hydrolysis of the solution are prevented by maintaining the temperature of the urea solution sufficiently low that it is not permitted sufficient time at elevated temperature to hydrolyze the urea to such an extent that solids precipitate. In a preferred embodiment, an injector system similar to those used for fuel injection provides a constant feed to injectors and a return line. The feed and injection can be controlled to provide sufficient urea for NO.sub.x reduction and sufficient cooling capacity for the feed and injection system to avoid hydrolysis and deposits of hydrolysis products.
Abstract:
The effectiveness is prolonged for catalytic oxidizers to reduce emissions of both HC and CO from two-stroke gasoline engines. A compound of a platinum group metal is added to the cylinder of the engine, to make it available as an active oxidation catalyst by combustion of the fuel. Preferably, the platinum group metal compound is added with the lubricating oil, but can be added to the fuel or through a separate injection.
Abstract:
A process is presented for reducing the concentration of pollutants in an effluent from the combustion of a carbonaceous fuel. The process comprises injecting a first treatment agent into the effluent at a first temperature zone and injecting a second treatment agent into the effluent at a second temperature zone, wherein the first and second treatment agents are injected under conditions effective to reduce the effluent pollution index. At least one of the treatment agents comprises an ammonium salt of an organic acid having a carbon to nitrogen ratio of greater than 1:1.
Abstract:
A method improves the operation of a diesel engine through the use of a fuel additive, a diesel particulate trap and a NO.sub.x -reducing catalyst. The operation of the NO.sub.x -reducing catalyst is enhanced by the introduction of urea or like compound upstream of the catalyst at temperatures effective for non-catalytic NO.sub.x reduction and the generation of ammonia. The additive comprises fuel-soluble compositions of platinum group metal in effective amounts to lower the emissions of unburned hydrocarbons and carbon monoxide from the trap. The catalytic activity provided to the exhaust system by the fuel additive is selective and preferably reduces the oxidation of SO.sub.2 to SO.sub.3. The platinum group metal compositions are preferably added in amounts effective to provide concentrations of the metal in the fuel of less than 1 part per million (ppm). Lithium and/or sodium compositions can be used in amounts effective to reduce the trap regeneration temperature, e.g. concentrations to provide about 1 to 100 ppm lithium metal, and/or 1 to 30 ppm sodium metal.
Abstract:
Urea is pyrolyzed in a chamber designed to facilitate gasification of the urea by pyrolysis with conversion of urea to ammonia and isocyanic acid (HNCO) with water vapor and carbon dioxide. The product gases are introduced into exhaust gases from a lean-burn engine, preferably upstream of a turbocharger. The exhaust gases are then contacted with an SCR catalyst.
Abstract:
The removal of sulfur oxides (SO.sub.x) and nitrogen oxides (NO.sub.x) from combustion effluents is enhanced by the supplying of reactants in a particular distribution pattern in the gas flow. To achieve the particular distribution pattern and to avoid impingement of the reactant on the heat exchanger tubes of the combustor, an elongated injection lance comprising c cooling jacket and plural spaced injections ports is employed. The cooling jacket protects the reactant supply to the injection ports from the high temperatures of the combustion gases.