Modern Gasworks Practice

124 MODERN GASWORKS PRACTICE radiation. The question at issue, however, is as to whether the greatest heat economy would be entailed by cooling the gas immediately it leaves the producer, and thus checking the further oxidation of CO to CO2, or whether the Conservation of sensible heat due to the lagging, etc., is desirable even at the expense of an inferior quality of gas. Outside producers, with the exception of the semi-external types, are always fed with cold coke, this accounting for additional thermal losses, unless the sensible heat in the coke as it leaves the retort is utilized (as in some vertical retort systems). When the cold coke is cliarged into the producer it should be as free from moisture as possible, otherwise this will be driven off in the form of steam, which passes on to the settings. As before mentioned, in some forms of external producer the furnace gases are taken off at a point sliglitly below the average fuel-level, so that any steam formed will be split up by passage through the hot coke.