Abstract
Tests were made with utmost care by well-trained and experienced observers, and the data presented are comparable in accuracy with carefully conducted tests burning coal. The boiler tested was a Babcock & Wilcox cross-drum, straight-tube type with interdeck superheater. The furnace was completely inclosed by Bailey-type water-cooled walls. The Babcock & Wilcox air heater was of tubular construction. Peabody combination oil and gas burners were used. The highest rate of output at which the boiler was tested was 450,751 lb. of steam per hour, which represented operation of the 3416-hp. boiler at 413.2 per cent of rating. Efficiency-capacity characteristics are straight lines between 100 per cent and 400 per cent rating. Efficiency with oil fuel is approximately 4 per cent higher than with gas due to higher “hydrogen losses” with gas fuel. Superheated-steam temperatures are considerably higher when burning gas than when burning oil fuel, due jointly to lower water-wall heat absorption and larger flue-gas volume while burning gas fuel. Maximum heat liberation was 27,300 B.t.u. per cu. ft. of furnace volume, although it is felt heat-liberation rates as high as 60,000 B.t.u. per cu. ft. might be satisfactorily maintained in this furnace.
