The Iron and steel magazine . f unreduced oxides travels into a hotterzone where it is reduced by carbon and thereby cools this continues till the heat has receded sufficiently towardsthe hearth to give a longer zone for reduction through carbonmonoxide. The sketch Fig. 2 illustrates this: Curve a showsthe heat as it will likely be at the different levels in the furnacewith wet blast and curve b with dry blast. The curves a and bindicate the respective lengths of the zone where reductionprevails through carbon monoxide. In this zone the stockremains practically at the same temperatur
The Iron and steel magazine . f unreduced oxides travels into a hotterzone where it is reduced by carbon and thereby cools this continues till the heat has receded sufficiently towardsthe hearth to give a longer zone for reduction through carbonmonoxide. The sketch Fig. 2 illustrates this: Curve a showsthe heat as it will likely be at the different levels in the furnacewith wet blast and curve b with dry blast. The curves a and bindicate the respective lengths of the zone where reductionprevails through carbon monoxide. In this zone the stockremains practically at the same temperature, for a long timein every case, but it remains for a longer time if less iron isreduced by carbon. As the saving of coke by diminished gasification of cokethrough blast is 14^ per cent and by diminished gasificationthrough oxides is more than 14h per cent for 4 grains of moisture,we must expect at least a saving of 3 \ per cent for each grain ofmoisture removed from the blast per cubic foot. New Developments in Dry Blast 479. ** ooo ooo FIG. 2.—CURVES OF HEAT WITH WET AND DRY BLAST. 480 The Iron and Steel Magazine Now you see that the removal of the moisture must effecta large saving in fuel in the furnace, especially when we considerthat we otherwise have to burden the furnace for the highestamount of moisture likely to occur in the season, though it mayonly last a few hours at one time. But this saving is at theexpense of the calorific value of the blast-furnace gas. The heat energy brought into the furnace by the coke andblast cannot be destroyed and must appear, therefore, againin some form. At the wet-blast as well as at the dry-blastfurnace it appears again in the following forms: (1) Heat in the iron; (2) heat in the cinder; (3) heat radiatedfrom walls and given to the cooling water; (4) heat whichbecomes latent by chemical reactions; for instance, heat ab-sorbed by splitting of the ore into iron and oxygen, or heatabsorbed by splitting limestone into lime and carbon
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Keywords: ., bookcentury1800, bookdecade1890, bookidironsteel, booksubjectiron
