The Cordova daily times., 1921-01-25
INCREASE HEAT EFFICIENCY
 OF COAL BY PULVERIzATION

NEW YORK, Jan. 25. - Necessity for conservation of coal resources and development of substitute fuels makes the increasing use of pulverized coal one of much economic importance, it is pointed out by the National Bank of Commerce in New York, in it's magazine. Commerce Monthly. Elk perimentation, the bank says, shows that by the use of pulverized coal, a saving of 20 per cent in heating eff. cieny, and from 20 to 30 per cent in consumption is possible.
 "The fundamental economic advant- age in burning pulverized coal lies in the complete stage to which combus- tion is carried in the furnace" says Commerce Monthly. "The contact surface between coal and air is greatly increased by splitting the coal into numerous particles of small size. The second advantage in the pulverization of solid fuel is the fact that it floats in the air, spreads and is carried off by even small air currents. This makes the intimate mixture of coal and air very easy. It simplifies the construction of burners and guaran- tees economical combustion The fin CT the coal powder the more nearly ideal conditions for complete cOmbus- tion are approached.
 Where proper apparatus and meth ods are in use, however, other more tangible economies are effected by the use of powdered fuel. The labor cost of firing is materially lowered and losses during short periods when steam pressure is not required are re- duced to a minimum. No air is al lowed to pass through the furnace when firing operations stop. SO that the radiant heat of the furnace is ab- sorbed by the boiler, avoiding the losses which occur with grates or stokers through the constant burning up of fuel and incomplete combustion of the gases generated from banked fires. The time necessary to get up steam is reduced by half when pull verized coal is substituted for the same fuel in lump form Recent ex- periments also show an economy in fuel consumption which is said to be as high as 30 per cent.
 Until very recently the impression has prevailed that only certain grades of bituminous coal were suitable for powdering. All the most recent de- velopments in the use of powdered coal as a fuel for steam generating plants have been made with anthra. cite culm, at one time definitely abandoned as fuel suitable for pow dering. High volatile soft coal gives best results, but mixtures of such a grade of coal with anthracite culm have proved entirely satisfactory and pulverization may be applied to any solid fuel, peat, Ignite or bituminous coals of any grade, as we'll as anthra- cite and coke.
 "Pulverized coal has obtained grow. ing recognition as the most satisfac- tory fuel for reverberatory furnaces by reason of the loss and nuisances arising from flue dust in blast furn- ace smelting, as well as the better fuel ratio and tonnage obtained with the new type of fuel. Although the practice dates back only to the last fifteen years it is now estimated that saving of 100000 tons of coal per 100000 tons of charge smelted is made annually in the United States. Pulverized coal in the mass is not explosive nor highly combustible.
 For time fuel oil seemed destined to replace coal in many industrial uses and it has done so to a consider able extent. But the great increase in the output of fuel oil in recent years has been through the discov-I cry of new sources of supply. Many of the early discovered fields have be- gun to exhibit decided decrease in production due to the exhaustion of the available supply, and the increase cost of fuel oil in the districts sup piled from these fields has in some cases made it necessary for indus trial consumers to turn again to coal
 "The economic importance, there fore, of conserving the present work