BAGASSE AS FUEL 459 



Actual Results obtained in the Combustion of Bagasse. Following on 

 the computation given in the preceding section, some results of boiler trials 

 are given in tabular form below.* Of these Nos. 1-3 were made by Kerr, 8 

 and 4, 5, 10, n were made by the writer ; the rest are taken from " Steam," 

 published by the Babcock & Wilcox Co. In tests I and 2 flat grates with 

 Dutch ovens were used ; in 3 a flat grate with extended Dutch oven, the 

 volume of the combustion space being 3-83, 2*58, 6-00 cu. ft. per rated 

 B.H.P. respectively. The tests numbered 4, 5, 10, II, were made with 

 Dutch ovens with step grates. 



These tests seem to cover a wide range of conditions as regards grate 

 area, heating surface, and fuel burnt ; but there does not appear to be any 

 instance that can be picked out pointing to superiority in any one particular. 

 Roughly they may be interpreted as indicating that a well-designed steam 

 producing plant should actually afford 2-5 Ibs. steam per Ib. of bagasse 

 burnt, when the latter does not contain over 45 per cent, water ; and if 

 these trials count for anything this quantity should form a basis of design. 



The tests Nos. 4 and 5, which afforded results much higher than any of 

 the others, were made with two boilers set tandem, the second having been 

 added with the original installation of furnace and grate left unchanged. 

 Accordingly, a relatively small quantity of bagasse was burnt per sq. ft. 

 of heating surface. 



The term efficiency is used in two senses. In the line marked A, it refers 



. Heat in steam produced . , .. . , _ . , 



to the ratio =.-= : 2 TT~ - '> ln the line marked B, it refers to the 

 Heat in fuel burnt 



Heat in steam produced Heat in steam due to associated water in fuel, 

 ratio - == : 7 r-Tj - 



Heat in iuel burnt. 



This last ratio is unusual, but is a rational method of comparison. 



DATA OF VARIOUS BOILER TRIALS. 



123 4 567 89 10 ii 



Water per cent. 



bagasse .. 55.3 46.5 45.8 47.4 47.4 52.4 52.9 51-8 5 1 -? 45-9 45-Q 



Lbs. dry bagasse 



per sq. ft. heating 



surface per hour 0.44 0.81 1.94 0.39 0.37 0.79 0.70 0.76 0.84 0.77 0.85 

 Lbs. dry bagasse 



per sq. ft. grate 



area per hour .. 44.3 47.0 101.0 41.3 41.0 71.9 63.9 147.1 163.4 2 9- 8 33- 

 Heating surface 



Grate surface I ' 1 58 ' T 52tl Io8 ' 8 Io8 ' 8 QI ' 8 QI>8 IQ3 ' 4 IQ3 ' 4 s8 ' 6 38<6 



Flue gas F . . 624 529 597 429 434 536 541 522 547 520 631 

 Excess air per cent. 124 98 90 36 34 56 70 84 68 52 40 

 Lbs. steam from 



and at 21 2 F per 



Ib. dry bagasse 3.88 4.78 4.33 5.45 5.28 4.26 4.67 4.30 4.15 4.20 4.28 

 "Efficiency "A 45.0 55.5 50.3 63.3 61.3 49.4 54.2 49.9 48.2 49.4 49-7 

 "Efficiency" B 64.0 69.0 63.3 77.3 75.1 66.7 71.4 66.5 64.5 62.5 62.4 



The Connection between Quantity of Fuel burnt and Heating Surface. 



The combustion of a fuel gives rise to a quantity of hot gases at a certain 



* The data as published have been rearranged by the writer and certain of the items entered have been calcu- 

 lated from the records as given in the publication whence they are taken. 



