MEGASS AS FUEL. 



The total evaporation from 16 Brix is then = -8333 ; in the evapora- 



9o 



tion to syrup '7091 of the weight of the juice was removed, so that at simple 

 effect in the pan -1242 is removed, or 24,840 Ibs. water per 100 tons of cane. 

 At the prevailing vacuum in the pans each pound of water will require about 

 1070 B.T.CJ., so that the consumption of heat is 26,578,000 B.T.TL, or 18-5 

 per cent, of the total available. 



The above calculations are, the writer thinks, as far as the data available 

 allow one to go. Experimental data are so absent that the consumption of 

 heat in the motors, in losses in steam piping, in losses in the cooling of juices 

 and syrups cannot be even approximated. It is of course in the heating and 

 evaporation that the consumption of heat is greatest. Putting on one side 

 cylinder condensation, but very little heat is used in the motors, and the great 

 part of the heat of the steam entering the cylinders of the engine is available 

 for evaporation. 



In the calculations above with quadruple evaporation the total expenditure 

 in heating and in evaporation of juices and syrups sums up to 63'2 per cent, of 

 the total available, leaving a very large margin for use in other stations, on 

 which definite values cannot be put. 



It may then be stated that under ordinary conditions a sugar factory can 

 be worked with a heavy maceration on the fuel provided by the megass, and 

 that it is only under exceptional conditions (low fibre in cane, inefficient 

 furnace and boiler settings, waste due to losses in steam piping, cleaning of 

 juices in eliminators) that extra fuel is required. 



Losses in Steam Pipes. The following table gives the hourly loss 

 in B.T.TJ. from naked wrought-iron pipes ; this table is adapted from one 

 given by Hausbrand and expressed in Centigrade metric units : 



Excess Loss in B.T U. Excess Loss in B.T.U. Excess Loss in B.T.U. 



Temperature, per sq. ft. per Temperature. per sq. ft. per Temperature. per sq. ft. per 



The effect of lagging is shown in the following data, due to the same 

 authority : 



A steam pipe at 275 F. and external air at 59 F. condensed per square 



foot per hour 



Ibs. steam. 

 Naked -615 



Lagged with silk waste 1 in. thick '091 



,, ,, cork shavings 2-2 in. thick . -095 



,, ,, kisselguhr -131 - -183 



i.e. the losses can be reduced about 80 per cent. 



417 



27 



