Ethanol diesel engines

W. Bandel and L. M. Ventura, "Problems ia Adapting Ethanol Puels to the Requirements of Diesel Engines," 4th Int. Sjmp. on yllcoholFuels (Guamja, Brazil, Oct. 1980). 

There has been a recent revival in interest in the use of ethanol-diesel fuel blends (E-diesel) in heavy-duty vehicles as a means to reduce petroleum dependency, increase renewable fuels use, and reduce vehicle emissions [27]. E-diesel blends containing 10-15% ethanol could be prepared via the use of additives. However, several fuel properties that are essential to the proper operation of a diesel engine are affected by the addition of ethanol to diesel fuel - in particular, blend stability, viscosity and lubricity, energy content and cetane number (increasing concentrations of ethanol in diesel lower the cetane number proportionately) [28]. Materials compatibility and corrosiveness are also important factors that need to be considered. 

A.C. Hansen, P.W.L. Lyne, Q. Zhang, Ethanol-diesel blends a step towards a bio-based fuel for diesel engines, 2001 ASAE Annual International Meeting, Sacramento, CA, July 2001, Paper 01-6048 (http //www.ag-bioeng.uiuc.edu/ faculty/ach/ediesel/Publications/ infopub.pdf). 

Rapeseed methyl ester (RME) is another alternative biofuel that can be used in diesel engines. RME has the advantages that it is renewable compared to diesel, non-toxic and less flammable compared with many other fuels, like ethanol. RME has the same cetane number, viscosity and density as diesel, contains no aromatic compounds and is biologically degradable with minor contamination in soil. RME can be produced from vegetable oils, but is mostly produced from rapeseed oil by pressing of the seeds or by extraction. Up to 3 tons of rapeseed can be produced from one hectare. The fatty acids in rapeseed oil are mostly oleic acid, linoleic acid and linolenic acid. The oil is pressed from the plant and after some purification allowed to react with methanol in the presence of potassium hydroxide as a catalyst, to produce a methyl ester, see Figure 6.6. 

A microemulsion fuel suitable for use in diesel engines has been prepared from diesel fuel, ethanol, traces of water and cationic surfactants as emulsifiers, plus other additives [94]. Suitable cationic surfactants are alkyl polyamines and their alkoxylates. The fuels benefit from improved lubricity. 

A mixture of methyl or ethyl fatty acid esters that is produced from fats and oils (triglycerides) by transesterification with methanol or ethanol. This mixture can be burned in most diesel engines without modifications, (p. 1205)... 

Barker, L., Pucholski, T., and Tholen, K. (1981). Use of Ethanol in Diesel Engines, SIM No. 11026, Solar Energy Research Institute [NREL], Golden, Colorado. 

The oxide-semiconductor-based ethanol sensor is being used to screen intoxicated drivers. In the test condition on the road, the ambient concentrations of CO and N02 can be up to 100 and lOppm due to the emissions from gasoline and diesel engines, respectively.61 The results shown in Fig. 12.6 suggest that the present sensors may be applied for selective detection of ethanol. Acetone is a very rare component in an ordinary ambient atmosphere. However, the expiration of a diabetes patient can contain acetone.62 Acetone concentration in breath air can reach up to 300 ppm in the case of an aceto-acidotic coma related to diabetes mellitus.63,64 This might interfere the ethanol sensor. A high selectivity to ethanol is required for such applications. The SZ sensor at 300°C and the ZW sensor at 400°C can satisfy these requirements. On the contrary, to examine the health condition of a diabetes patient, selective detection of acetone without the interference with alcohol is desirable. In this case, the W sensor at 400°C will be of advantageous. 

The engineering target is to eventually create a catalyst that is both highly selective and highly active over the entire operating temperature range of the diesel engine. This paper concentrates on evaluation and characterization of base-metal oxide catalysts and precious metal catalysts for total oxidation of ethanol. 

The most important reactions that occur in catalytic aftertreatment of emissions from an ethanol-fuelled diesel engine are listed in Table 2. For a catalyst involved in this type of pollution control one of the most important qualifications is the selectivity towards complete oxidation of ethanol. This is indicated by the formation of acetaldehyde, which is the major by-product formed. Over some of the catalysts other by-products such as acetic acid, diethyl ether, methane and ethylene are also formed, but to a much lower extent. The low-temperature... 

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