Modern Gasworks Practice

CONTROL OF HORIZONTAL RETORT SETTINGS 133 into the setting, will merely pass outwards into the retort house, where it will soon be carried away. If, however, the lid is replaced over the charging aperture, the combustible gas must necessarily find an outlet by travelling through the setting; thus the latter is filled with an explosive mixture. No harm may come of this for a time, but as the temperature of the setting rises the ignition point of the gas is reaclied, when explosion occurs. The magnitude and force of the explosion depend, of course, upon the volume of the combustible mixture which is circulating in the setting at the time. Practical experience with. the type of setting in question is really the most reliable guide as to when the state of affairs is safe for the producer lid to be put in place. Usually it is merely sufficient to be satisfied tliat the producer arch. is just visibly red-hot, although more careful individuals go so far as to say that the bottom retorts should be at a duil red heat. The latter practice, however, is conducive to extravagance in fuel. But wliichever method is adhered to, the chief object is to ensure that any carbon monoxide and oxygen which may be passing through the producer will be ignited on arriving at the producer arch, instead of finding their way into the setting. Charging with Wet Coke In addition to the charging-lid danger, other, but less hazardous, risks are run by filling up the producer with decidedly wet coke, or by charging in an excessive quantity of cold coke at a time. In faet, the use of wet fuel should always be avoided ; for, lying in a stagnant layer on the surface of the liotter fuel, it permits the passage through the bed of carbon monoxide and oxygen, whilst the actual flames are choked and subdued, and the temperature of the upper portions of the producer is reduced for the time being. The result is that the inflammable gas is not burned in the furnace, and, circulating througliout the setting, it is eventually ignited when the heat of the fuel picks up, and the flames have broken through. Precisely the same argument applies to the use of cold coke, which, if used, should only be introduced in com-paratively small quantities at a time. By far the best practice, however, is to use nothing but red-hot fuel from the nearest beuch which happens to be in füll work. TEMPORARY STOPS On the majority of the larger gasworks it is now quite the general practice to dis-contimie the make of gas for a ceitain period on Sundays ; for by so doing the retort-house hånds are assured of awell-earned weeklyrest; whilst in many und ertakings it is the custom to pay double rates between 6 a.m. and 6 p.m. on this day. Hence the temporary stop entails some fairly considerable saving in carbonizing expenditure. As a general rule, the staff of a gasworks is not called upon to attend on Sunday, tlius the operations of discontinuing carbonization. and restarting it are practical problems with which many gas engineers are more or less unfamiliar. On first thoughts, the procedure would not appear to demand any exceptional amoirnt of attention, and this is, perhaps, evidenced by the smooth. way and unconcerned manner in which the works foremen carry out the duty week atter week. The