Petroleum Refining

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. 1918 Excerpt: ...be raised to a maximum of 120. For example, to obtain the ratio 18 per cent. of steam (experiment 3), t must be below 94, about 85, and Tb, Te must be lowered to 179 and 113 respectively. "Per contra, if the pressure is diminished from 5 atmospheres (150 C.), steam must be used, but within the range of 30 per cent, of the distillate (experiment 4), giving t below 95. "Lastly, as regards the use of a vacuum in oil distillation if carried only to 70 (steam temperature), a vacuum is not unconditionally advantageous. If there has been already a decomposition, or quasicracking action, below 270, (1) the proportion of kerosene may have diminished, (2) that of the substances removable by washing with sulphuric acid may have increased (and therewith the need of chemical treatment), and (3) the quality of the oil may have deteriorated by increased carbonisation: all of which would be remedied by the use of a vacuum. It may, however, be laid down definitely that decomposition, indicated by a gentler rise of the curve of specific gravities, commences at 270. That is, a vacuum is not unconditionally necessary for the kerosene fraction, especially if the distillation is assisted by steam. If higher-boiling oils are to be carried over with the kerosene, the use of a vacuum is highly advisable." With reference to the amount of heat dissipated through the coils of an ordinary condenser, and this may be taken as applying also to preheaters, Mr George E. Davis 1 states: "That for ordinary con 1 A Handbook of Chemical Etujineering, 1902, vol. ii. pp. 260, 201. densers it is safer to take as a basis for designing 1000 B.T.U. per square foot per hour than to work upon the supposition that 250 B.T.U. will be dissipated per square foot per hour for each degree...