MEGASS AS FUEL. 



from its analysis, and since it is now known that heat values thus obtained are 

 lower than those obtained by the use of the calorimeter, the calculations are to 

 a great extent invalidated. Further, the writer has come to the conclusion 

 that conditions in different districts are so widely variant that it is useless to 

 select typical instances, and that the subject can only be treated on broad 

 grounds, leaving it to those interested to adapt the general principles involved 

 to their own special cases. 



Effect of Fibre. Properly speaking, the fibre alone should be 

 considered as a fuel constituent of the cane, as the sugar is too valuable a 

 constituent to burn ; accordingly, the fuel produced by the cane will be in 

 direct proportion to the amount of fibre ; furthermore, where the canes are 

 crushed without the addition of water, not only is the amount of fuel increased 

 but the quantity of juice to be treated is proportionately lowered. For 

 example, let in one instance the canes contain 10 per cent, fibre, and in a 

 second 14 per cent, fibre; let the megass contain 45 per cent, fibre; then 

 in the first instance per 100 tons of cane 77-78 tons of juice and 22-22 tons of 

 megass result; in the second instance, 68*89 tons of juice and 31*11 tons 

 of megass. These differences are so large that one factory burning large 

 quantities of extra fuel may be really working more economically, in so far as 

 regards the production of steam, than one which has a surplus. 



Effect of the Solid Content of the Juice on Steam 

 required. Let canes containing the same amount of fibre yield in the one 

 case juice of 15 J3rix, and in a second case juice of 20Brix. Let the megass 

 in both instances contain the same amount of fibre ; then with a comparatively 

 small error the available fuel will be the same. The evaporation of juice of 



15 Brix to syrup at 55 Brix indicates the removal of -7272 parts 



of water per unit of juice ; if the evaporation is done at quadruple effect, the 

 equivalent evaporation at single effect is -1818. The evaporation of juice at 



Q e 1 r 



15 Brix to massecuite at 95 Brix indicates the removal of = '8421 



95 



parts of water per unit of juice ; the evaporation to syrup required the 

 removal of '7272 water per unit of juice, hence the evaporation at single 

 effect entails the removal of '1149 parts water per unit of juice; the total 

 evaporation, then, from juice to massecuite is equivalent to the removal at 

 single effect of -1818 + '1149 = -2967 parts water per unit of juice. 



Similar calculations for a juice at 20 Brix initially give the evaporation 

 to syrup at 55 Brix as equivalent to the removal of '1591 part water per unit 

 of juice, and the evaporation of the syrup to massecuite as equivalent to the 

 removal of '1532 part water per unit of juice, the total evaporation from 

 juice to massecuite being equivalent to the evaporation at single effect of 

 1591 4 -1532 = -3123 part of water per unit of juice. 



415 



