116 EXPERIMENT STATION HKCOKl). 



r.. T. r. Tlieroforo, a varying ash ((mtcnl piddnccs a corrospoiidinf!: difforence 

 ill the lioat valiu'. Diirinj; tlu' coiiibiistinn di' ili(> li;mass(' tlu> avorafio flue gas 

 analysis yiokled S).01 per cent carl>()n dinxid, ;>.s:! iht coiit oxynen, and 0.17 per 

 cent carbon nionoxid, a total of I'.KOI per cent. Tins is 2 per cent le>'*s than the 

 theoretical t1j:nres, or tlie quantity which niijiht exist if caii)oii compounds and 

 oxyj^en were the only constituents of the f^as aualyztHl. The rate of combus- 

 tion (pounds of bagasse per square foot of yrate surface per hour) varied be- 

 tween 44 and 197, and the author assumes that under proper conditions the 

 rate should never be under 100. The air supply to the pound of bagasse \vas 

 ou the average 33.4 cu. ft., which witli a moisture content of 52 per cent in 

 the bagasse is equivalent to 16.03 cu. ft. i»er iiound as fired. The l)lower 

 supplinl on the average 24.7 per cent of the air. 



In regard to the relation of furnace tem])erature to air excess it was found 

 that with an average air excess of S5 per cent the average furnace temperature 

 was 1,475°, or with an average excess of 272 per cent 1,140°, showing that the 

 furnace temperature varies inversely with the air excess. "An air excess of 50 

 per cent or less is sufficient for bagasse." 



In studying the control of the air supply, the influence of the stack damper, 

 the ash-pit doors, and the speed of the blower were considered. With an 

 increasal air excess and wide-opened dampers there was much increase in 

 stack temperature, but the latter may also be due to an overload of bagasse 

 on the heating surface. According to the results in this series it is evident that 

 the stack temperature may be used to advantage in controlling the air. In 

 50 per cent of the furnaces tested the stack temperature was above 600° F, 

 Those of the Louisiana fui'nace temperatures, which could be measured by a 

 700° F. thermometer, averaged 540° F., whereas in only one of the Cuban 

 houses was the temperature above 600° F. The cause for the difference in 

 stack temperature was found in the different areas of heating surface. From 

 the results of the tests in the Louisiana houses it was seen that the high 

 stack temperature was always present when the furnace had an overload of 

 heating surface. 



In addition to the furnace tests an evaporative test was made with a 318 H. P. 

 boiler (rated) in order to establish the evaporation value of bagasse. The 

 weights of bagasse employed were obtained by difference, that is, by subtract- 

 ing w^elght of juice from total amount of cane employed. With an overload 

 of 24 per cent firing, based on the builder's rating, an equivalent evaporation 

 of 2j lbs. of water per pound of bagasse was found. The amount of moist 

 fuel fired (52.1 per cent of water) was G,017 lbs. per hour, and the temperature 

 of the furnace was on the average 1,200° F. 



Comparing these i-esnlts with those obtained in one of the test series, 

 which had a normal evaporation of about 3 lbs. per square foot of heating sur- 

 face, it is shown that the evaporation by the bagasse was 6.1 lbs. of water 

 per square foot, which is an excess. Calculating on a normal basis, " not more 

 than 1.5 lbs. of bagasse should be burned per square foot of heating surface 

 per hour." The boiler capacity per ton of cane for 24 hours is less in Louisiana 

 than in Cuban or Hawaiian houses. " Not less than 1.5 boiler H. P. should be 

 provided per ton of cane for 24 hours." 



Burning oil and bagasse together " may i-esult in higher furnace temperatures 

 than with either of them alone, also in better combustion if the furnace is of 

 proper design, but care must be taken to prevent overloading the heating 

 surface. 



"A good working furnace depends more upon the proportion of heating 

 surface to grate surface, rate of combustion and other matters of design, and 

 operation than upon the form or type. 



