Liquid fuels for internal combustion engines; a practical treatise for engineers & chemists

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ... and residua frequently yield over 10 per cent. of coke. The highest coke values are found in raw tars, horizontal retort tar averaging about 24 per cent, the larger part of which is free carbon. Inclined retort and coke oven tars yield low coke values (8-10 per cent.), while vertical retorts give values in the neighbourhood of 6 per cent. Even a low coke value makes an oil unsuitable for most vaporisers, and oils of high coke value are difficult to burn completely in semi-Diesel or Diesel engines on account of the tendency to produce coke on the walls of the combustion space (mainly on the top of piston and the exhaust valve head). Very efficient atomisation will overcome this difficulty. Water Content.--Many methods are available for the determination of the water content of liquid fuels.1 The more important of them may be classed as follows:--1. Estimation by direct settling. 2. Estimation by addition of a solvent and settling treatment. 3. Estimation by addition of a solvent and centrifugal treatment. 1 4. Estimation by direct distillation. 5. Estimation by addition of solvent and distilling. 6. Estimation by the liberation of acetylene on adding calcium carbide. 7. Estimation.by the liberation of hydrogen on adding sodium. The first two methods are the most rapid, but are only available when the oil will settle easily; many emulsions refuse to separate even when large quantities of suitable solvents are added. When the oil weighs less than water, heating the mixture facilitates settling, as oils possess a higher coefficient of expansion than water; therefore on heating, the difference in density between the two liquids becomes greater, and promotes separation. This method of estimation is best conducted in a graduated cylinder, when, by using 100 c.c. ...